Light-emitting device, high-molecular material and electronic device

Abstract

A light-emitting device comprising a light-emitting element (150; 152) comprising: a high-molecular material (131; 141) comprising a first high-molecular chain and / or a second high-molecular chain; and a guest material (132; 142), where both the first high molecular weight chain and the second high molecular weight chain comprise: a first framework (131_1; 141_1) having a hole transport property; a second framework (131_2; 141_2) with an electron transport property; and a third scaffold (131_3; 141_3), wherein the first frame (131_1; 141_1) and the second frame (131_2; 141_2) are connected to each other via the third frame (131_3; 141_3), and wherein the first high molecular weight chain and the second high molecular weight chain are configured to form an excited complex.

Description

Technical area

[0001] An embodiment of the present invention relates to a light-emitting element or a display device, an electronic device and a lighting device each including the light-emitting element.

[0002] It should be noted that an embodiment of the present invention is not limited to the above technical field. The technical field of an embodiment of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. An embodiment of the present invention additionally relates to a process, a machine, a product, or a composition. Specifically, examples of the technical field of an embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a storage device, a driving method for any of them, and a manufacturing method for any of them. State of the art

[0003] In recent years, intensive research and development has been conducted on light-emitting elements that utilize electroluminescence (EL). The basic structure of such a light-emitting element consists of a layer containing a light-emitting substance (an EL layer) sandwiched between a pair of electrodes. By applying a voltage between the electrodes of this element, light emission from the light-emitting substance can be obtained.

[0004] Since the above light-emitting element is of a self-luminous type, a display device using this light-emitting element has the following advantages: high visibility, no need for backlighting, and low power consumption. Furthermore, such a light-emitting element is also advantageous in that the element can be manufactured thinly and lightweight, and has a high response speed.

[0005] In a light-emitting element whose EL layer contains an organic compound as a light-emitting substance and is provided between a pair of electrodes (e.g., an organic EL element), applying a voltage between the pair of electrodes causes the injection of electrons from a cathode and holes from an anode into the EL layer with a light-emitting property, thereby causing a current to flow. As a result of recombination of the injected electrons and holes, the light-emitting organic compound is excited to provide light emission.

[0006] As the organic compound contained in the light-emitting element, a low-molecular compound or a high-molecular compound can be used. Since the high-molecular compound is thermally stable and can easily form a thin film with excellent uniformity by a coating method or the like, a light-emitting element containing the high-molecular compound has been developed (for example, see Patent Document 1).

[0007] It should be noted that an excited state formed by an organic compound can be a singlet excited state (S*) or a triplet excited state (T*). Light emission from the singlet excited state is called fluorescence, and light emission from the triplet excited state is called phosphorescence. The generation ratio of S* to T* in the light-emitting element is 1:3. In other words, a light-emitting element containing a compound that emits phosphorescence (phosphorescent compound) has higher light-emitting efficiency than a light-emitting element containing a compound that emits fluorescence (fluorescent compound).Accordingly, light-emitting elements containing phosphorescent compounds that can convert the triplet excited state into light emission have been actively developed in recent years (see, for example, Patent Document 2).

[0008] The energy required to excite an organic compound depends on the energy difference between the LUMO level and the HOMO level of the organic compound, and the energy difference is approximately equal to the energy of the singlet excited state. In a light-emitting element containing a phosphorescent organic compound, the triplet excitation energy is converted into light emission energy. Therefore, when the energy difference between the singlet excited state and the triplet excited state of an organic compound is large, the energy required to excite the organic compound exceeds the light emission energy by the amount corresponding to the energy difference. The energy difference between the energy required to excite the organic compound and the light emission energy increases the drive voltage in the light-emitting element and affects the element properties.Therefore, a method for reducing the driving voltage has been sought (see Patent Document 3).

[0009] Among light-emitting elements containing phosphorescent compounds, a light-emitting element that specifically emits blue light has not been put into practical use so far because it is difficult to develop a stable compound with a high triplet excitation energy level. Therefore, a light-emitting element containing a more stable fluorescent compound has been developed, and a technique for increasing the light-emitting efficiency of a light-emitting element containing a fluorescent compound (a fluorescent element) has been researched.

[0010] One of the materials that can convert part of the energy of the triplet excited state into light emission is a thermally activated delayed fluorescent (TADF) emitter. In a thermally activated delayed fluorescent emitter, a singlet excited state is formed from a triplet excited state through reverse intersystem crossing, and the singlet excited state is converted into light emission.

[0011] To increase the light emission efficiency of a light-emitting element using a thermally activated delayed fluorescent emitter, not only efficient generation of a singlet excited state from a triplet excited state but also efficient emission from a singlet excited state, i.e., high fluorescence quantum yield, is important for a thermally activated delayed fluorescent emitter. However, it is difficult to create a light-emitting material that meets these two requirements.

[0012] Patent Document 4 discloses a method: In a light-emitting element containing a thermally activated delayed fluorescent emitter and a fluorescent compound, the singlet excitation energy of the thermally activated delayed fluorescent emitter is transferred to the fluorescent compound, and light emission is obtained from the fluorescent compound. [Reference][Patent Documents] [Patent Document 1] Japanese Patent Laid-Open No. JP H05 - 202 355 A [Patent Document 2] Japanese Patent Laid-Open No. JP 2010 - 182 699 A [Patent Document 3] Japanese Patent Laid-Open No. JP 2012 - 212 879 A [Patent Document 4] Japanese Patent Laid-Open No. JP 2014 - 45 179 A Disclosure of the invention

[0013] In a light-emitting element containing a light-emitting organic compound, an energy difference between the singlet excited state and the triplet excited state of a host material is preferably small in order to increase the light emission efficiency or reduce the driving voltage.

[0014] To increase the light emission efficiency of a light-emitting element containing a fluorescent compound, it is preferable to efficiently generate a singlet excited state from a triplet excited state. Furthermore, it is preferable to efficiently transfer energy from a singlet excited state of the host material to a singlet excited state of the fluorescent compound.

[0015] In view of the foregoing, an object of an embodiment of the present invention is to provide a light-emitting element containing a fluorescent compound or a phosphorescent compound and having high light-emitting efficiency. Another object of an embodiment of the present invention is to provide a light-emitting element with low power consumption. Another object of an embodiment of the present invention is to provide a novel light-emitting element. Another object of an embodiment of the present invention is to provide a novel light-emitting device. Another object of an embodiment of the present invention is to provide a novel display device.

[0016] It should be noted that the description of the above object does not preclude the existence of other objects. In one embodiment of the present invention, it is unnecessary to achieve all of the objects. Objects other than the above objects will become apparent from the explanation of the description and the like and can be derived therefrom.

[0017] One embodiment of the present invention is a light-emitting element containing a compound that efficiently forms an excited complex. Alternatively, one embodiment of the present invention is a light-emitting element in which a triplet exciton is converted into a singlet exciton, and light can be emitted from a compound containing the singlet exciton, or light can be emitted from a fluorescent compound due to energy transfer of the singlet exciton.

[0018] Therefore, one embodiment of the present invention is a light-emitting element containing a high molecular material and a guest material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The guest material has a function of emitting fluorescence. The first high molecular chain and the second high molecular chain each have a first framework, a second framework, and a third framework. The first framework and the second framework are bonded to each other via the third framework. The first framework has a function of transferring holes. The second framework has a function of transferring electrons. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0019] Another embodiment of the present invention is a light-emitting element containing a high molecular material and a guest material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The guest material has a function of converting triplet excitation energy into light emission. The first high molecular chain and the second high molecular chain each have a first skeleton, a second skeleton, and a third skeleton. The first skeleton and the second skeleton are bonded to each other via the third skeleton. The first skeleton has a function of transferring holes. The second skeleton has a function of transferring electrons. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0020] Another embodiment of the present invention is a light-emitting element containing a high molecular material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The first high molecular chain and the second high molecular chain each contain a first framework, a second framework, a third framework, and a fourth framework. The first framework and the second framework are bonded to each other via the third framework. The first framework has a function of transferring holes. The second framework has a function of transferring electrons. The fourth framework has a function of emitting fluorescence. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0021] Another embodiment of the present invention is a light-emitting element containing a high molecular material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The first high molecular chain and the second high molecular chain each include a first skeleton, a second skeleton, a third skeleton, and a fourth skeleton. The first skeleton and the second skeleton are bonded to each other via the third skeleton. The first skeleton has a function of transferring holes. The second skeleton has a function of transferring electrons. The fourth skeleton has a function of converting triplet excitation energy into light emission. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0022] Another embodiment of the present invention is a light-emitting element containing a high molecular material and a guest material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The guest material has a function of emitting fluorescence. The first high molecular chain and the second high molecular chain each contain a first skeleton, a second skeleton, and a third skeleton. The first skeleton and the second skeleton are bonded to each other via the third skeleton. The first skeleton contains a π-electron-rich heteroaromatic skeleton and / or an aromatic amine skeleton. The second skeleton contains a π-electron-deficient heteroaromatic skeleton. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0023] Another embodiment of the present invention is a light-emitting element containing a high molecular material and a guest material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The guest material has a function of converting triplet excitation energy into light emission. The first high molecular chain and the second high molecular chain each contain a first skeleton, a second skeleton, and a third skeleton. The first skeleton and the second skeleton are bonded to each other via the third skeleton. The first skeleton contains a π-electron-rich heteroaromatic skeleton and / or an aromatic amine skeleton. The second skeleton contains a π-electron-deficient heteroaromatic skeleton. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0024] Another embodiment of the present invention is a light-emitting element containing a high molecular material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The first high molecular chain and the second high molecular chain each contain a first skeleton, a second skeleton, a third skeleton, and a fourth skeleton. The first skeleton and the second skeleton are bonded to each other via the third skeleton. The first skeleton contains a π-electron-rich heteroaromatic skeleton and / or an aromatic amine skeleton. The second skeleton contains a π-electron-deficient heteroaromatic skeleton. The fourth skeleton has a function of emitting fluorescence. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0025] Another embodiment of the present invention is a light-emitting element containing a high molecular material. The high molecular material contains at least a first high molecular chain and a second high molecular chain. The first high molecular chain and the second high molecular chain each contain a first skeleton, a second skeleton, a third skeleton, and a fourth skeleton. The first skeleton and the second skeleton are bonded to each other via the third skeleton. The first skeleton contains a π-electron-rich heteroaromatic skeleton and / or an aromatic amine skeleton. The second skeleton contains a π-electron-deficient heteroaromatic skeleton. The fourth skeleton has a function of converting triplet excitation energy into light emission. The first high molecular chain and the second high molecular chain have a function of forming an excited complex.

[0026] In each of the above structures, the π-electron-rich heteroaromatic skeleton preferably contains a thiophene skeleton and / or a furan skeleton and / or a pyrrole skeleton. The π-electron-poor heteroaromatic skeleton preferably contains a pyridine skeleton and / or a diazine skeleton and / or a triazine skeleton. The third skeleton preferably contains a biphenyl skeleton and / or a fluorene skeleton.

[0027] In each of the above structures, the first high molecular weight chain and the second high molecular weight chain function to form the excited complex with the first scaffold in the first high molecular weight chain and the second scaffold in the second high molecular weight chain. Furthermore, the excited complex preferably functions to emit thermally activated delayed fluorescence at room temperature.

[0028] Another embodiment of the present invention is a display device comprising the light-emitting element having one of the above-described structures and a color filter and / or a transistor. Another embodiment of the present invention is an electronic device comprising the above-described display device and a housing and / or a touch sensor. Another embodiment of the present invention is a lighting device comprising the light-emitting element having one of the above-described structures and a housing and / or a touch sensor. The category of an embodiment of the present invention includes not only a light-emitting device comprising a light-emitting element but also an electronic device comprising a light-emitting device.Therefore, the light-emitting device in this specification refers to an image display device and a light source (e.g., a lighting device). The light-emitting device may be included in a module in which a connector such as a flexible printed circuit (FPC) or a tape carrier package (TCP) is connected to a light-emitting device, a module in which a printed circuit board is provided at the end of a TCP, or a module in which an integrated circuit (IC) is directly mounted on a light-emitting element by a chip-on-glass (COG) method.

[0029] An embodiment of the present invention can provide a light-emitting element containing a fluorescent compound or a phosphorescent compound and having high light-emitting efficiency. An embodiment of the present invention can provide a light-emitting element with low power consumption. An embodiment of the present invention can provide a novel light-emitting element. An embodiment of the present invention can provide a novel light-emitting device. An embodiment of the present invention can provide a novel display device.

[0030] It should be noted that the description of these effects does not preclude the existence of further effects. An embodiment of the present invention does not necessarily include all of the effects described above. Further effects will become apparent from and can be derived from the explanation of the specification, the drawings, the claims, and the like. Short description of the drawings

[0031] The accompanying drawings are as follows: Fig. 1A and Fig. 1B are schematic cross-sectional views of a light-emitting element of an embodiment of the present invention and Fig. Figure 1C shows the correlation of energy levels in a light-emitting layer; Fig. 2 is a schematic cross-sectional view of a light-emitting layer of an embodiment of the present invention; Fig. 3A and Fig. 3B are schematic cross-sectional views of a light-emitting element of an embodiment of the present invention and Fig. Figure 3C shows the correlation of energy levels in a light-emitting layer; Fig. 4 is a schematic cross-sectional view of a light-emitting layer of an embodiment of the present invention; Fig. 5A and Fig. 5B are each a schematic cross-sectional view of a light-emitting element of an embodiment of the present invention; Fig. 6A and Fig. 6B are each a schematic cross-sectional view of a light-emitting element of an embodiment of the present invention; Fig. 7A to Fig. 7C are schematic cross-sectional views illustrating a manufacturing method of a light-emitting element of an embodiment of the present invention; Fig. 8A and Fig. 8B are schematic cross-sectional views illustrating a manufacturing method of a light-emitting element of an embodiment of the present invention; Fig. 9A and Fig. 9B are a plan view and a schematic cross-sectional view illustrating a display device of an embodiment of the present invention; Fig. 10A and Fig. 10B are schematic cross-sectional views each illustrating a display device of an embodiment of the present invention; Fig. 11 is a schematic cross-sectional view illustrating a display device of an embodiment of the present invention; Fig. 12A and Fig. 12B are schematic cross-sectional views each illustrating a display device of an embodiment of the present invention; Fig. 13A and Fig. 13B are schematic cross-sectional views each illustrating a display device of an embodiment of the present invention; Fig. 14 is a schematic cross-sectional view illustrating a display device of an embodiment of the present invention; Fig. 15A and Fig. 15B are schematic cross-sectional views each illustrating a display device of an embodiment of the present invention; Fig. 16 is a schematic cross-sectional view illustrating a display device of an embodiment of the present invention; Fig. 17A and Fig. 17B are schematic cross-sectional views each illustrating a display device of an embodiment of the present invention; Fig. 18A to Fig. 18D are schematic cross-sectional views illustrating a method of forming an EL layer; Fig. 19 is a conceptual diagram illustrating a droplet ejector; Fig. 20A and Fig. 20B is a block diagram and a circuit diagram illustrating a display device of an embodiment of the present invention; Fig. 21A and Fig. 21B are circuit diagrams each illustrating a pixel circuit of a display device of an embodiment of the present invention; Fig. 22A and Fig. 22B are circuit diagrams each illustrating a pixel circuit of a display device of an embodiment of the present invention; Fig. 23A and Fig. 23B are perspective views of an example of a touch screen of an embodiment of the present invention; Fig. 24A to Fig. 24C are cross-sectional views of examples of a display device and a touch sensor of an embodiment of the present invention; Fig. 25A and Fig. 25B are cross-sectional views of examples of a touch screen of an embodiment of the present invention; Fig. 26A and Fig. 26B is a block diagram and timing diagram of a touch sensor of one embodiment of the present invention; Fig. 27 is a circuit diagram of a touch sensor of an embodiment of the present invention; Fig. 28 is a perspective view illustrating a display module of an embodiment of the present invention; Fig. 29A to Fig. 29G illustrate electronic devices of an embodiment of the present invention; Fig. 30A to Fig. 30D illustrate electronic devices of an embodiment of the present invention; Fig. 31A and Fig. 31B are perspective views illustrating a display device of an embodiment of the present invention; Fig. 32A to Fig. 32C are a perspective view and cross-sectional views illustrating light-emitting devices of an embodiment of the present invention; Fig. 33A to Fig. 33D are cross-sectional views each illustrating a light-emitting device of an embodiment of the present invention; Fig. 34A to Fig. 34C illustrate an electronic device and a lighting device of an embodiment of the present invention; and Fig. 35 illustrates lighting devices of an embodiment of the present invention. Best mode for carrying out the invention

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and its modes and details can be changed variously without departing from the purpose and scope of the present invention. Therefore, the present invention should not be construed as being limited to the contents of the following embodiments.

[0033] Note that the position, size, range, or the like of each structure illustrated in drawings and the like may not be precisely illustrated in some cases for the sake of simplicity. Therefore, the disclosed invention is not necessarily limited to the position, size, range, or the like disclosed in the drawings and the like.

[0034] Note that ordinal numbers such as "first," "second," and the like are used in this specification and the like for convenience, and do not indicate the order of steps or the arrangement order of layers. Therefore, for example, an appropriate description can be made even if "first" is replaced with "second" or "third." Furthermore, the ordinal numbers in this specification and the like are not necessarily the same as those specifying an embodiment of the present invention.

[0035] In the explanations of the modes of the present invention in this specification and the like based on the drawings, in some cases, the same components in different drawings are generally denoted by the same reference numerals.

[0036] In this specification and the like, the terms "film" and "layer" may be interchanged depending on the case or circumstances. For example, in some cases, the term "conductive layer" may be replaced with the term "conductive film." Furthermore, in some cases, the term "insulating film" may be replaced with the term "insulating layer."

[0037] In this specification and the like, a singlet excited state (S*) refers to a singlet state with excitation energy. An S1 level refers to the lowest level of singlet excitation energy, i.e., the lowest excitation energy level in a singlet excited state. A triplet excited state (T*) refers to a triplet state with excitation energy. A T1 level refers to the lowest level of triplet excitation energy, i.e., the lowest excitation energy level in a triplet excited state.

[0038] In this specification and the like, a fluorescent compound refers to a compound that emits light in the visible light range when relaxing from the singlet excitation state to the ground state. A phosphorescent compound refers to a compound that emits light in the visible light range at room temperature when relaxing from the triplet excitation state to the ground state. That is, a phosphorescent compound refers to a compound that can convert triplet excitation energy into visible light.

[0039] A thermally activated delayed fluorescent emission energy refers to an emission peak (including a shoulder) on the shortest wavelength side of a thermally activated delayed fluorescence. A phosphorescence emission energy or triplet excitation energy refers to an emission peak (including a shoulder) on the shortest wavelength side of the phosphorescence emission. Note that phosphorescence emission can be observed in a low-temperature environment (e.g., 10 K) by time-resolved photoluminescence.

[0040] It should be noted that in this specification and the like, “room temperature” means a temperature higher than or equal to 0°C and lower than or equal to 40°C.

[0041] In this specification and the like, a high molecular material and a high molecular compound are each a polymer having a molecular weight distribution and whose average molecular weight is 1 × 10 3 up to 1 × 10 8 A low molecular weight compound is a compound that has no molecular weight distribution and whose molecular weight is less than or equal to 1 × 10 4 is.

[0042] Furthermore, the high-molecular material and the high-molecular compound are a material or a compound in which one or more types of structural units are polymerized. That is, the structural unit refers to a unit, at least one of which is contained in the high-molecular material and the high-molecular compound.

[0043] In addition, the high molecular weight material and the high molecular weight compound may each be a block copolymer, a random copolymer, an alternating copolymer or a graft copolymer or another embodiment.

[0044] In the case where a terminal group of the high molecular material and the high molecular compound each has a polymerization-active group, the light-emitting properties and the luminance lifetime of the light-emitting element may be reduced. Therefore, the terminal group of the high molecular material and the high molecular compound is preferably a stable terminal group. As the stable terminal group, a group covalently bonded to a main chain is preferable, and a group bonded to an aryl group or a heterocyclic group via a carbon-carbon bond is particularly preferable.

[0045] In this specification and the like, a wavelength range of blue refers to a wavelength range greater than or equal to 400 nm and less than 490 nm, and blue light emission refers to light emission having at least one peak of the emission spectrum in the wavelength range. A wavelength range of green refers to a wavelength range greater than or equal to 490 nm and less than 580 nm, and green light emission refers to light emission having at least one peak of the emission spectrum in the wavelength range. A wavelength range of red refers to a wavelength range greater than or equal to 580 nm and less than or equal to 680 nm, and red light emission refers to light emission having at least one peak of the emission spectrum in the wavelength range. (Embodiment 1)

[0046] In this embodiment, a light-emitting element of an embodiment of the present invention will be described below with reference to Fig. 1A to Fig. 1C and Fig. 2 described. <Strukturbeispiel 1 des Licht emittierenden Elements>

[0047] First, a structure of the light-emitting element of an embodiment of the present invention will be described below with reference to Fig. 1A to Fig. 1C described.

[0048] Fig. 1A is a schematic cross-sectional view of a light-emitting element 150 of an embodiment of the present invention.

[0049] The light-emitting element 150 includes a pair of electrodes (an electrode 101 and an electrode 102) and an EL layer 100 between the pair of electrodes. The EL layer 100 includes at least one light-emitting layer 130.

[0050] The EL layer 100, which is Fig. 1A, comprises, in addition to the light-emitting layer 130, functional layers such as a hole injection layer 111 and an electron injection layer 114.

[0051] Although in this embodiment, a description is given assuming that the electrode 101 and the electrode 102 of the pair of electrodes serve as the anode and the cathode, respectively, the structure of the light-emitting element 150 is not limited to this. That is, the electrode 101 may be a cathode, the electrode 102 may be an anode, and the arrangement order of the layers between the electrodes may be reversed. In other words, the hole-injection layer 111, the light-emitting layer 130, and the electron-injection layer 114 may be arranged in this order from the anode side.

[0052] The structure of the EL layer 100 is not limited to the structure shown in Fig. 1A, and a structure including at least one layer selected from the hole-injection layer 111 and the electron-injection layer 114 may be employed. Alternatively, the EL layer 100 may include, for example, a functional layer capable of lowering a hole- or electron-injection barrier, improving a hole- or electron-transport property, inhibiting a hole- or electron-transport property, or suppressing a quenching effect by an electrode. Note that the functional layers may each be a single layer or a multilayer.

[0053] Fig. 1B is a schematic cross-sectional view showing an example of the light-emitting layer 130 in Fig. 1A. The light-emitting layer 130 in Fig. 1B contains a high molecular weight material 131 and a guest material 132.

[0054] The high-molecular-weight material 131 contains a framework 131_1, a framework 131_2, and a framework 131_3 as structural units. Framework 131_1 and framework 131_2 are bonded or polymerized to each other via framework 131_3.

[0055] The guest material 132 may be a light-emitting organic compound, and the light-emitting organic compound is preferably a substance capable of emitting fluorescence (hereinafter also referred to as a fluorescent compound). A structure using a fluorescent compound as the guest material 132 will be described below. The guest material 132 may also be referred to as a fluorescent compound.

[0056] In the light-emitting element 150 of one embodiment of the present invention, applying a voltage between the pair of electrodes (electrodes 101 and 102) allows electrons and holes to be injected from the cathode and anode, respectively, into the EL layer 100, thereby causing a current to flow. Excitons are formed by recombination of the injected electrons and holes. The ratio of singlet excitons to triplet excitons (hereinafter referred to as exciton generation probability) generated by the recombination of carriers (electrons and holes) is approximately 1:3 according to the statistically obtained probability.Accordingly, for a light-emitting element containing a fluorescent compound, the probability of generating singlet excitons that contribute to light emission is 25%, and the probability of generating triplet excitons that do not contribute to light emission is 75%. Therefore, it is important to convert the triplet excitons that do not contribute to light emission into singlet excitons that do contribute to light emission to increase the light-emitting efficiency of the light-emitting element.

[0057] Therefore, the high molecular material 131 preferably has a function of generating the singlet excited state from the triplet excited state. <Lichtemissionsmechanismus des Licht emittierenden Elements>

[0058] Next, the light emission mechanism of the light-emitting layer 130 will be described below.

[0059] In the high-molecular-weight material 131 in the light-emitting layer 130, preferably, the framework 131_1 contains a framework with a hole-transferring function (a hole-transporting property), and the framework 131_2 contains a framework with an electron-transferring function (an electron-transporting property). Alternatively, preferably, the framework 131_1 contains a π-electron-rich heteroaromatic framework and / or an aromatic amine framework, and the framework 131_2 contains a π-electron-deficient heteroaromatic framework.

[0060] In one embodiment of the present invention, the high molecular material 131 has a function of forming an excited complex (also referred to as an excited dimer) with two high molecular chains of the high molecular material 131. Specifically, it is preferable that the framework having a hole-transport property and the framework having an electron-transport property of the high molecular material 131 form an excited complex in two high molecular chains containing the same structural units. Alternatively, it is preferable that the π-electron-rich heteroaromatic framework and / or the aromatic amine framework contained in the high molecular material 131 and the π-electron-deficient heteroaromatic framework contained in the high molecular material 131 form an excited complex in two high molecular chains containing the same structural units.Note that in this specification and the like, high molecular chains containing the same structural units are high molecular chains containing at least the same types of structural units (here, the skeleton 131_1, the skeleton 131_2, and the skeleton 131_3), and may have different bond directions, bond angles, bond lengths, and the like of the structural units. Furthermore, the structural units may contain different substituents, and different skeletons may be provided between the structural units. Furthermore, polymerization methods of the structural units may be different.

[0061] In other words, the high molecular material 131 has a function of forming an excited complex with a first high molecular chain and a second high molecular chain of the high molecular material 131. Specifically, it is preferable that the framework having a hole-transport property in the first high molecular chain and the framework having an electron-transport property in the second high molecular chain of the high molecular material 131 form an excited complex. Alternatively, it is preferable that the π-electron-rich heteroaromatic framework and / or the aromatic amine framework in the first high molecular chain of the high molecular material 131 and the π-electron-deficient heteroaromatic framework in the second high molecular chain of the high molecular material 131 form an excited complex.

[0062] In the case where the high molecular weight material 131 has the framework with a hole-transport property contained in the framework 131_1 and the framework with an electron-transport property contained in the framework 131_2, an excited donor-acceptor complex of two high molecular weight chains is easily formed; thus, it is possible to efficiently form an excited complex. Alternatively, when the high molecular weight material 131 contains the π-electron-rich heteroaromatic framework and / or the aromatic amine framework contained in the framework 131_1 and the π-electron-deficient heteroaromatic framework contained in the framework 131_2, an excited donor-acceptor complex of two high molecular weight chains is easily formed; thus, it is possible to efficiently form an excited complex.

[0063] Therefore, to enhance both the donor property and the acceptor property in the high molecular weight chains of the high molecular weight material 131, a structure in which the conjugation between the framework with a hole-transport property and the framework with an electron-transport property is reduced is preferably used. Alternatively, a structure in which the conjugation between the π-electron-deficient heteroaromatic framework and the π-electron-rich heteroaromatic framework and / or the aromatic amine framework is reduced is preferably used. Thus, an overlap between a region where the highest occupied molecular orbital (HOMO) is present and a region where the lowest unoccupied molecular orbital (LUMO) is present can be small.In addition, a difference between a singlet excitation energy level and a triplet excitation energy level of the high molecular material 131 can be reduced. Furthermore, the triplet excitation energy level of the high molecular material 131 can be high.

[0064] It should be noted that a molecular orbital describes the spatial distribution of electrons in a molecule and can indicate the probability of finding electrons. Furthermore, the molecular orbital can be used to describe the electron configuration of the molecule (the spatial distribution and energy of the electrons) in detail.

[0065] Furthermore, in the excited complex formed by the two high molecular weight chains containing the same structural units, one high molecular weight chain exhibits the HOMO, and the other high molecular weight chain exhibits the LUMO; thus, the overlap between the HOMO and the LUMO is very small. This means that in the excited complex, a difference between a singlet excitation energy level and a triplet excitation energy level is small. Therefore, in the excited complex formed by the two high molecular weight chains of the high molecular weight material 131, a difference between a singlet excitation energy level and a triplet excitation energy level is small, and preferably greater than 0 eV and less than or equal to 0.2 eV.

[0066] In the case where the high molecular weight material 131 includes the framework with a hole-transport property and the framework with an electron-transport property, the charge carrier balance can be easily controlled. As a result, a charge carrier recombination range can also be easily controlled. To achieve this, preferably, the composition ratio of the framework 131_1 (containing the framework with a hole-transport property) to the framework 131_2 (containing the framework with an electron-transport property) is in the range of 1:9 to 9:1 (molar ratio), and more preferably, the proportion of the framework 131_2 (containing the framework with an electron-transport property) is higher than the proportion of the framework 131_1 (containing the framework with a hole-transport property).

[0067] Fig. Figure 1C shows a correlation of energy levels of the high molecular material 131 and the guest material 132 in the light-emitting layer 130. The following clarifies what terms and symbols in Fig. 1C represent: Polymer (131_1 + 131_2): the skeleton 131_1 in the first high molecular chain and the skeleton 131_2 in the second high molecular chain of the high molecular material 131, which are close to each other; Guest (132): the guest material 132 (the fluorescent compound); S H : the S1 level of the high molecular weight material 131; T H : the T1 level of the high molecular weight material 131; S G : the S1 level of the guest material 132 (the fluorescent compound); T G : the T1 level of the guest material 132 (the fluorescent compound); S E : the S1 level of the excited complex; and T E: the T1 level of the excited complex.

[0068] In the light-emitting layer 130, the high-molecular material 131 is present in the highest weight fraction, and the guest material 132 (the fluorescent compound) is dispersed in the high-molecular material 131. The S1 level of the high-molecular material 131 in the light-emitting layer 130 is preferably higher than the S1 level of the guest material 132 (the fluorescent compound) in the light-emitting layer 130. The T1 level of the high-molecular material 131 in the light-emitting layer 130 is preferably higher than the T1 level of the guest material 132 (the fluorescent compound) in the light-emitting layer 130.

[0069] In the light-emitting element of one embodiment of the present invention, an excited complex is formed by the two high-molecular chains of the high-molecular material 131 contained in the light-emitting layer 130. The lowest singlet excitation energy level (S E ) of the excited complex and the lowest triplet excitation energy level (T E ) of the excited complex close to each other (see route E3 in Fig. 1C).

[0070] An excited complex is an excited state formed by two high molecular weight chains. Upon light excitation, the excited complex is formed by the interaction between one high molecular weight chain in an excited state and the other high molecular weight chain in a ground state. The two high molecular weight chains that formed the excited complex return to a ground state by emitting light, and then they serve as the original two high molecular weight chains. Upon electrical excitation, a high molecular weight chain that is brought into an excited state immediately interacts with the other high molecular weight chain to form an excited complex. Alternatively, one high molecular weight chain receives a hole and the other high molecular weight chain receives an electron to immediately form an excited complex.In this case, each of the high molecular weight chains can form an excited complex without forming an excited state with a single high molecular weight chain; thus, most excitons in the light-emitting layer 130 can exist as excited complexes. Since the excitation energy levels (p. E and T E ) of the excited complex are lower than the singlet excitation energy level (S H ) of a single high-molecular chain of the high-molecular material 131 forming the excited complex, the excited state of the high-molecular material 131 can be formed with lower excitation energy. Accordingly, the driving voltage of the light-emitting element 150 can be reduced.

[0071] Since the singlet excitation energy level (S E ) and the triplet excitation energy level (T E) of the excited complex are close to each other, the excited complex has a function to emit thermally activated delayed fluorescence. In other words, the excited complex has a function to convert triplet excitation energy into singlet excitation energy through reverse intersystem crossing (upconversion) (see route E4 in Fig. 1C). Thus, the triplet excitation energy generated in the light-emitting layer 130 is partially converted into singlet excitation energy by the excited complex. To achieve this conversion, the energy difference between the singlet excitation energy level (S E ) and the triplet excitation energy level (T E ) of the excited complex is preferably greater than 0 eV and less than or equal to 0.2 eV.

[0072] Furthermore, the singlet excitation energy level (S E) of the excited complex is preferably higher than the singlet excitation energy level (S G ) of the guest material 132. In this way, the singlet excitation energy of the formed excited complex can be determined from the singlet excitation energy level (S E ) of the excited complex to the singlet excitation energy level (S G ) of the guest material 132, so that the guest material 132 is put into the singlet excited state, which leads to light emission (see route E5 in Fig. 1C).

[0073] In order to obtain efficient light emission from the singlet excited state of the guest material 132, the fluorescence quantum yield of the guest material 132 is preferably high, in particular 50% or higher, more preferably 70% or higher, even more preferably 90% or higher.

[0074] It should be noted that the triplet excitation energy level (T E) of the excited complex formed by two high molecular weight chains is preferably lower than the triplet excitation energy level (T H ) of the single high molecular weight chain of the high molecular weight material 131 forming the excited complex to efficiently induce reverse intersystem crossing. Thus, the probability of quenching of the triplet excitation energy of the excited complex due to another high molecular weight chain(s) in the high molecular weight material 131 is reduced, leading to the efficient induction of reverse intersystem crossing.

[0075] Therefore, the triplet excitation energy level of the high molecular material 131 is preferably high, and the energy difference between the singlet excitation energy level and the triplet excitation energy level of the high molecular material 131 is preferably small.

[0076] It should be noted that since the direct transition from a singlet ground state to a triplet excited state is forbidden in the guest material 132, it is unlikely that energy transfer from the singlet excited energy level (S E ) of the excited complex to the triplet excitation energy level (T G ) of the guest material 132 becomes a major process of energy transfer.

[0077] If a transfer of the triplet excitation energy from the triplet excitation energy level (T E ) of the excited complex to the triplet excitation energy level (T G ) of the guest material 132, the triplet excitation energy is deactivated (see route E6 in Fig. 1C). Therefore, energy transfer by route E6 is preferably less likely to occur because the triplet excited state generation efficiency of the guest material 132 may be reduced and thermal deactivation may be reduced. To satisfy this condition, the weight ratio of the guest material 132 to the high molecular weight material 131 is preferably low, particularly preferably greater than or equal to 0.001 and less than or equal to 0.05, more preferably greater than or equal to 0.001 and less than or equal to 0.03, and even more preferably greater than or equal to 0.001 and less than or equal to 0.01.

[0078] It should be noted that when the direct charge carrier recombination process is dominant in the guest material 132, a large number of triplet excitons are generated in the light-emitting layer 130, resulting in reduced light emission efficiency due to thermal deactivation. Therefore, the probability of the energy transfer process through the excited complex formation process (routes E4 and E5 in Fig. 1C) is higher than the probability of the direct charge carrier recombination process in the guest material 132, because the efficiency of generating the triplet excited state of the guest material 132 may be reduced and thermal deactivation may be reduced. Therefore, as described above, the weight ratio of the guest material 132 to the high molecular weight material 131 is preferably low, particularly preferably greater than or equal to 0.001 and less than or equal to 0.05, more preferably greater than or equal to 0.001 and less than or equal to 0.03, more preferably greater than or equal to 0.001 and less than or equal to 0.01.

[0079] By efficiently performing all the energy transfer processes of the routes E4 and E5 as described above, both the singlet excitation energy and the triplet excitation energy of the high molecular material 131 can be efficiently converted into the singlet excitation energy of the guest material 132, whereby the light-emitting element 150 can emit light with a high light emission efficiency.

[0080] Since an excited complex is sometimes referred to as an "exciplex," in this specification and the like, the processes described above via routes E3, E4, and E5 may be referred to as exciplex-singlet energy transfer (ExSET) or exciplex-enhanced fluorescence (ExEF). In other words, in the light-emitting layer 130, the excitation energy is transferred from the excited complex to the guest material 132.

[0081] When the light-emitting layer 130 has the structure described above, light emission from the guest material 132 of the light-emitting layer 130 can be obtained efficiently.

[0082] A thermally activated delayed fluorescent (TADF) material is known as a material capable of generating a singlet excitation state from a triplet excitation state. The TADF material can naturally generate a singlet excitation state from a triplet excitation state through reverse intersystem crossing. In other words, the TADF material has the function of converting part of the triplet excitation energy into light emission.

[0083] Therefore, the TADF material exhibits a small difference between the triplet excitation energy level and the singlet excitation energy level, and can upconvert the triplet excitation state to a singlet excitation state with low thermal energy. Specifically, the difference between the triplet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV and less than or equal to 0.2 eV, more preferably greater than 0 eV and less than or equal to 0.1 eV.

[0084] As an example of the TADF material, a heterocyclic compound comprising a π-electron-rich heteroaromatic framework and a π-electron-poor heteroaromatic framework is given. In order for the heterocyclic compound to exhibit thermally activated delayed fluorescence emission, it is preferable to directly bond the π-electron-rich heteroaromatic framework and the π-electron-poor heteroaromatic framework, thereby increasing both the donor property of the π-electron-rich heteroaromatic framework and the acceptor property of the π-electron-poor heteroaromatic framework. Furthermore, it is preferable to reduce the conjugation between the π-electron-rich heteroaromatic framework and the π-electron-poor heteroaromatic framework, and to reduce the overlap between the HOMO and the LUMO.However, a certain overlap between the HOMO and the LUMO is preferably provided to increase the probability of transition (oscillator strength) between the HOMO and the LUMO. In this way, the difference between the singlet excitation energy level and the triplet excitation energy level can be reduced, and light emission from the singlet excitation state can be efficiently obtained.

[0085] For such a heterocyclic compound, it is preferable to use a structure in which the π-electron-rich heteroaromatic skeleton, such as an acridine skeleton, a phenazine skeleton, and a phenoxazine skeleton, has a strong twist at a portion bonded to the π-electron-poor heteroaromatic skeleton, and the conjugation between the π-electron-rich heteroaromatic skeleton and the π-electron-poor heteroaromatic skeleton is reduced. However, the molecular structure of a skeleton having such a twisted structure is limited.

[0086] Therefore, in one embodiment of the present invention, in the high molecular weight material 131, the framework 131_1 having a hole-transport property and the framework 131_2 having an electron-transport property are preferably bonded or polymerized to each other via the framework 131_3. Alternatively, in the high molecular weight material 131, the π-electron-deficient heteroaromatic framework and the π-electron-rich heteroaromatic framework and / or the aromatic amine framework are preferably bonded or polymerized to each other via the framework 131_3. Note that the details of the framework 131_3 will be described below. <Energieübertragungsmechanismus>

[0087] Next, factors controlling the processes of intermolecular energy transfer between the high molecular weight material 131 and the guest material 132 are described. Two mechanisms have been proposed for intermolecular energy transfer: the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction). Although the intermolecular process of energy transfer between the high molecular weight material 131 and the guest material 132 is described here, the same applies to a case where the high molecular weight material 131 forms an excited complex. <<Förster-Mechanismus> >

[0088] In the Förster mechanism, no direct contact between molecules is necessary for energy transfer, and the energy is transferred through a resonance phenomenon of dipole vibration between the high-molecular material 131 and the guest material 132. Through the resonance phenomenon of dipole vibration, the high-molecular material 131 transfers energy to the guest material 132, and thus the high-molecular material 131 in an excited state is converted to a ground state, and the guest material 132 in a ground state is converted to an excited state. Note that the rate constant k h*→g of the Förster mechanism is represented by formula (1). kh*→g=9000c4K2ϕIn10128π5n4NτR6∫f′h(ν)εg(ν)ν4dν

[0089] In formula (1), v represents a frequency, f' h ( V) represents a normalized emission spectrum of the high molecular weight material 131 (a fluorescence spectrum with energy transfer from a singlet excited state, and a phosphorescence spectrum with energy transfer from a triplet excited state), ε g (v) represents a molar absorption coefficient of the guest material 132, N represents the Avogadro number, n represents a refractive index of a medium, R represents an intermolecular distance between the high molecular weight material 131 and the guest material 132, τ represents a measured lifetime of an excited state (fluorescence lifetime or phosphorescence lifetime), c represents the speed of light, ϕ represents a luminescence quantum yield (a fluorescence quantum yield upon energy transfer from a singlet excited state, and a phosphorescence quantum yield upon energy transfer from a triplet excited state), and K 2represents a coefficient (0 to 4) for the orientation of a transition dipole moment between the high molecular weight material 131 and the guest material 132. It should be noted that for random orientation K 2 2 / 3 is. < <dexter-mechanismus>>

[0090] In the Dexter mechanism, the high-molecular-weight material 131 and the guest material 132 are close to a contact-effective region where their orbitals overlap, and the high-molecular-weight material 131, which is in an excited state, and the guest material 132, which is in a ground state, exchange their electrons, resulting in energy transfer. Note that the rate constant k h*→g of the Dexter mechanism is represented by formula (2). kh*→g=(2πh)K2exp(−2RL)∫f′h(ν)ε′g(ν)dv

[0091] In formula (2), h represents a Planck constant, K represents a constant with an energy dimension, v represents a frequency, f' h (v) represents a normalized emission spectrum of the high molecular weight material 131 (a fluorescence spectrum at energy transfer from a singlet excited state, and a phosphorescence spectrum at energy transfer from a triplet excited state), ε' g (v) represents a normalized absorption spectrum of the guest material 132, L represents an effective molecular radius, and R represents an intermolecular distance between the high molecular weight material 131 and the guest material 132.

[0092] Here, the efficiency of energy transfer from the high molecular material 131 to the guest material 132 (energy transfer efficiency ϕ ET ) is represented by formula (3). In the formula, k r a rate constant of a light emission process (fluorescence during energy transfer from a singlet excited state, and phosphorescence during energy transfer from a triplet excited state) of the high molecular weight material 131, k n represents a rate constant of a process without light emission (thermal deactivation or intersystem crossing) of the high molecular weight material 131, and τ represents a measured lifetime of an excited state of the high molecular weight material 131. ϕET=kh*→gkr+kn+kh*→g=kh*→g(1τ)+kh*→g

[0093] According to formula (3), it has been found that the efficiency of energy transfer ϕ ET by increasing the rate constant k h*→g in the energy transfer can be increased, so that another competing rate constant k r + k n (= 1 / τ) becomes relatively small. <<Konzept zur Förderung der Energieübertragung> >

[0094] First, energy transfer through the Förster mechanism is considered. If formula (1) is substituted into formula (3), τ can be eliminated. Thus, in the Förster mechanism, the efficiency of energy transfer ϕ depends ET does not depend on the lifetime τ of the excited state of the high molecular weight material 131. Furthermore, it can be stated that the efficiency of energy transfer ϕ ET is higher when the luminescence quantum yield ϕ (the fluorescence quantum yield, since this is the energy transfer from a singlet excited state) is higher. In general, the luminescence quantum yield of an organic compound in a triplet excited state is very low at room temperature. Therefore, when the high molecular weight material 131 is in a triplet excited state, the process of energy transfer by the Förster mechanism is negligible, and the process of energy transfer by the Förster mechanism is only considered in the case where the high molecular weight material 131 is in a singlet excited state.

[0095] Furthermore, it is preferable that the emission spectrum (the fluorescence spectrum in the case of energy transfer from a singlet excited state) of the high molecular material 131 largely overlaps the absorption spectrum (absorption corresponding to the transition from the singlet ground state to the singlet excited state) of the guest material 132. Furthermore, it is preferable that the molar absorption coefficient of the guest material 132 is also high. That is, the emission spectrum of the high molecular material 131 overlaps the absorption band of the guest material 132, which is located on the longest wavelength side. Since the direct transition from the singlet ground state to the triplet excited state of the guest material 132 is prohibited, the molar absorption coefficient of the guest material 132 in the triplet excited state is negligible.Therefore, the process of energy transfer to a triplet excited state of the guest material 132 by the Förster mechanism is negligible, and only a process of energy transfer to a singlet excited state of the guest material 132 is considered. That is, in the Förster mechanism, a process of energy transfer from the singlet excited state of the high-molecular-weight material 131 to the singlet excited state of the guest material 132 is considered.

[0096] Next, energy transfer through the Dexter mechanism is considered. According to formula (2), the rate constant k h*→g To increase the energy transfer efficiency, it is preferable that an emission spectrum of the high-molecular-weight material 131 (a fluorescence spectrum in the case of energy transfer from a singlet excited state) largely overlaps the absorption spectrum of the guest material 132 (absorption corresponding to the transition from a singlet ground state to a singlet excited state). Accordingly, the energy transfer efficiency can be optimized by ensuring that the emission spectrum of the high-molecular-weight material 131 overlaps the absorption band of the guest material 132, which is on the longest wavelength side.

[0097] If formula (2) is substituted into formula (3), it becomes clear that the efficiency of energy transfer ϕ ET in the Dexter mechanism depends on τ. In the Dexter mechanism, which is an energy transfer process based on electron exchange, energy transfer occurs from the triplet excited state of the high molecular weight material 131 to the triplet excited state of the guest material 132, as well as energy transfer from the singlet excited state of the high molecular weight material 131 to the singlet excited state of the guest material 132.

[0098] In the light-emitting element of one embodiment of the present invention, in which the guest material 132 is a fluorescent compound, the energy transfer efficiency to the triplet excited state of the guest material 132 is preferably low. That is, the energy transfer efficiency based on the Dexter mechanism from the high molecular weight material 131 to the guest material 132 is preferably low, and the energy transfer efficiency based on the Förster mechanism from the high molecular weight material 131 to the guest material 132 is preferably high.

[0099] As described above, in the Förster mechanism, the energy transfer efficiency does not depend on the lifetime τ of the excited state of the high molecular material 131. In contrast, the energy transfer efficiency in the Dexter mechanism depends on the excitation lifetime τ of the high molecular material 131. Therefore, to reduce the energy transfer efficiency in the Dexter mechanism, the excitation lifetime τ of the high molecular material 131 is preferably short.

[0100] In a similar manner to the energy transfer from the high molecular weight material 131 to the guest material 132, the energy transfer through both the Förster mechanism and the Dexter mechanism also occurs in the process of energy transfer from the excited complex to the guest material 132.

[0101] Accordingly, one embodiment of the present invention provides a light-emitting element including the high-molecular-weight material 131 in which two high-molecular-weight chains form an excited complex serving as an energy donor suitable for efficient energy transfer to the guest material 132. The excited complex formed by the two high-molecular-weight chains in the high-molecular-weight material 131 has a singlet excitation energy level and a triplet excitation energy level that are close to each other; therefore, a transition from a triplet exciton generated in the light-emitting layer 130 to a singlet exciton (reverse intersystem crossing) is likely to occur. This can increase the efficiency of generating singlet excitons in the light-emitting layer 130.Furthermore, the emission spectrum of the excited complex preferably overlaps the absorption band of the guest material 132, which is located on the longest wavelength side (lowest energy side), to promote energy transfer from the singlet excited state of the excited complex to the singlet excited state of the guest material 132, which serves as an energy acceptor. Consequently, the efficiency of generating the singlet excited state of the guest material 132 can be increased.

[0102] Furthermore, the fluorescence lifetime of a thermally activated delayed fluorescence component in light emitted from the excited complex is preferably short, and particularly preferably 10 ns or longer and 50 µs or shorter, more preferably 10 ns or longer and 30 µs or shorter.

[0103] The proportion of a thermally activated delayed fluorescence component in the light emitted by the excited complex is preferably high. In particular, the proportion of a thermally activated delayed fluorescence component in the light emitted by the excited complex is preferably greater than or equal to 5%, more preferably greater than or equal to 10%. <Strukturbeispiel 2 des Licht emittierenden Elements>

[0104] Next, a structural example of the light-emitting layer 130 which is different from that in Fig. 1B, below based on Fig. 2 described.

[0105] Fig. 2 is a schematic cross-sectional view showing another example of the light-emitting layer 130 in Fig. 1A. It should be noted that in Fig. 2 sections with functions similar to those of sections in Fig. 1B are similar, are designated by the same reference numerals and a detailed description of the sections is omitted in some cases.

[0106] The light-emitting layer 130 in Fig. 2 contains the high-molecular-weight material 131. The high-molecular-weight material 131 contains the structural units scaffold 131_1, scaffold 131_2, scaffold 131_3, and scaffold 131_4. Scaffold 131_1 and scaffold 131_2 are bonded or polymerized to each other via scaffold 131_3.

[0107] The scaffold 131_4 may be a light-emitting scaffold, and the light-emitting scaffold is preferably a scaffold capable of emitting fluorescence (hereinafter also referred to as a fluorescent scaffold). A structure using a fluorescent scaffold as the scaffold 131_4 will be described below. Note that the scaffold 131_4 can be reformulated into a fluorescent scaffold.

[0108] The framework 131_4 has a function similar to that of the guest material 132. Therefore, this structural example can be described by reformulating the guest material 132 described in Structural Example 1 of this embodiment into framework 131_4. Furthermore, for the description of functions similar to those in Structural Example 1 of this embodiment, reference can be made to Structural Example 1 of this embodiment.

[0109] That is, in the light-emitting element of one embodiment of the present invention, the high-molecular material 131 includes the framework having a hole-transport property contained in the framework 131_1 and the framework having an electron-transport property contained in the framework 131_2, and two high-molecular chains form an excited complex. Then, the excitation energy from the excited complex is transferred to the framework 131_4, thereby emitting light from the framework 131_4. Note that the framework 131_4 receiving the excitation energy from the excited complex may be included in one of the two high-molecular chains constituting the excited complex or in another high-molecular chain.

[0110] When the triplet excitation energy is transferred from the triplet excitation energy level of the excited complex formed by the scaffold 131_1 in one high molecular chain and the scaffold 131_2 in the other high molecular chain to the triplet excitation energy level of the scaffold 131_4, the triplet excitation energy is deactivated. Therefore, the composition ratio of the scaffold 131_4 to all structural units of the high molecular material 131 is preferably low, specifically, higher than or equal to 0.1 mol% and lower than or equal to 5 mol%, more preferably higher than or equal to 0.1 mol% and lower than or equal to 3 mol%, even more preferably higher than or equal to 0.1 mol% and lower than or equal to 1 mol%.

[0111] When the direct carrier recombination process is dominant in the framework 131_4, a large number of triplet excitons are generated in the light-emitting layer 130, resulting in reduced light emission efficiency due to thermal deactivation. Therefore, as described above, the composition ratio of the framework 131_4 to all structural units of the high molecular weight material 131 is preferably low, specifically, higher than or equal to 0.1 mol% and lower than or equal to 5 mol%, more preferably higher than or equal to 0.1 mol% and lower than or equal to 3 mol%, even more preferably higher than or equal to 0.1 mol% and lower than or equal to 1 mol%. <material>

[0112] Next, components of a light-emitting element of an embodiment of the present invention will be described in detail below. <<Licht emittierende Schicht> >

[0113] Next, materials that can be used for the light-emitting layer 130 are described below.

[0114] The high molecular material 131 in the light-emitting layer 130 is not particularly limited as long as two high molecular chains of the high molecular material 131 have a function of forming an excited complex; however, the high molecular material 131 preferably contains the π-electron-deficient heteroaromatic skeleton, as well as the π-electron-rich heteroaromatic skeleton and / or the aromatic amine skeleton. That is, preferably, the high molecular material 131 includes at least the skeletons 131_1, 131_2, and 131_3, the skeleton 131_1 includes the π-electron-rich heteroaromatic skeleton and / or the aromatic amine skeleton, and the skeleton 131_2 includes the π-electron-deficient heteroaromatic skeleton.

[0115] As the aromatic amine skeleton contained in the host material 131, a tertiary amine that does not have an NH bond, particularly a triarylamine skeleton, is preferably used. As the aryl group of a triarylamine skeleton, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms contained in a ring is preferably used, and examples thereof include a phenyl group, a naphthyl group, and a fluorenyl group.

[0116] As the π-electron-rich heteroaromatic skeleton contained in the high molecular weight material 131, one or more of a furan skeleton, a thiophene skeleton, and a pyrrole skeleton are preferable due to their high stability and reliability. As the furan skeleton, a dibenzofuran skeleton is preferable. As the thiophene skeleton, a dibenzothiophene skeleton is preferable. Note that as the pyrrole skeleton, an indole skeleton or a carbazole skeleton, particularly a 3-(9H-carbazol-3-yl)-9H-carbazole skeleton, is preferable. Each of these skeletons may further contain a substituent.

[0117] As examples of the above-described aromatic amine skeleton and the above-described π-electron-rich heteroaromatic skeleton, skeletons represented by the following general formulas (101) to (110) are given. Note that X in the general formulas (105) to (107) represents an oxygen atom or a sulfur atom.

[0118] Furthermore, as the π-electron-deficient heteroaromatic skeleton contained in the second skeleton (the skeleton 131_2), a pyridine skeleton, a diazine skeleton (a pyrimidine skeleton, a pyrazine skeleton, or a pyridazine skeleton), or a triazine skeleton is preferable; in particular, the diazine skeleton or the triazine skeleton is preferable due to its high stability and reliability.

[0119] As examples of the π-electron-deficient heteroaromatic framework described above, frameworks represented by the following general formulas (201) to (210) are given.

[0120] It should be noted that, as the second skeleton, instead of the π-electron-deficient heteroaromatic skeleton described above, an aromatic hydrocarbon skeleton whose triplet excitation energy is 2 eV or more, such as a biphenyl skeleton, a naphthalene skeleton, a phenanthrene skeleton, a triphenylene skeleton, or a fluorene skeleton, can be used.

[0121] Furthermore, preferably, a framework having a hole transport property contained in the first framework (the framework 131_1) (particularly the π-electron-rich heteroaromatic framework and / or the aromatic amine framework) and a framework having an electron transport property contained in the second framework (particularly the π-electron-poor heteroaromatic framework) are bonded or polymerized to each other via at least the framework 131_3.

[0122] Examples of the skeleton 131_3 (the third skeleton) include, for example, a phenylene skeleton, a biphenyldiyl skeleton, a terphenyldiyl skeleton, a naphthalenediyl skeleton, a fluorenediyl skeleton, a 9,10-dihydroanthracenediyl skeleton, a phenanthrenediyl skeleton, and an arylenevinylene skeleton (a phenylenevinylene skeleton or the like), which are skeletons represented by the following general formulas (301) to (314).

[0123] The above-described aromatic amine skeleton (e.g., the triarylamine skeleton), the above-described π-electron-rich heteroaromatic skeleton (e.g., a ring comprising the furan skeleton, the thiophene skeleton, or the pyrrole skeleton), and the above-described π-electron-poor heteroaromatic skeleton (e.g., a ring comprising the pyridine skeleton, the diazine skeleton, or the triazine skeleton), or the above-described general formulas (101) to (110), the above-described general formulas (201) to (210), and the above-described general formulas (301) to (314) may each contain a substituent.As the substituent, an alkyl group, an alkoxy group, or an alkylthio group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group or aryloxy group having 6 to 18 carbon atoms, or a heterocyclic compound group having 4 to 14 carbon atoms can also be selected. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a lauryl group, a 2-ethylhexyl group, a 3-methylbutyl group, and the like.Furthermore, specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, a 2-ethylhexyloxy group, a 3-methylbutoxy group, an isopropyloxy group, and the like. Furthermore, specific examples of the alkylthio group having 1 to 20 carbon atoms include a methylthio group, an ethylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, a laurylthio group, a 2-ethylhexylthio group, a 3-methylbutylthio group, an isopropylthio group, and the like.Specific examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a noradamantyl group, an adamantyl group, a homoadamantyl group, a tricyclodecanyl group, and the like. Specific examples of the aryl group having 6 to 18 carbon atoms include a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted pyrenyl group, and the like.In addition, specific examples of an aryloxy group having 6 to 18 carbon atoms include a substituted or unsubstituted alkoxyphenoxy group, a substituted or unsubstituted alkylphenoxy group, a substituted or unsubstituted naphthyloxy group, a substituted or unsubstituted anthracenyloxy group, a substituted or unsubstituted pyrenyloxy group, and the like. Specific examples of the heterocyclic linking group having 4 to 14 carbon atoms include a substituted or unsubstituted thienyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted pyridyl group, and the like. The above substituents may be bonded to each other to form a ring.For example, in the case where a carbon atom at the 9-position in a fluorene skeleton contains two phenyl groups as substituents, the phenyl groups are bonded to form a spirofluorene skeleton. It should be noted that an unsubstituted group is advantageous in that it is easy to synthesize and its raw material is inexpensive.

[0124] Furthermore, Ar represents an arylene group having 6 to 18 carbon atoms. The arylene group may contain one or more substituents, and the substituents may be bonded to each other to form a ring. For example, a carbon atom at the 9-position in a fluorenyl group contains two phenyl groups as substituents, and the phenyl groups are bonded to form a spirofluorene skeleton. Specific examples of the arylene group having 6 to 18 carbon atoms include a phenylene group, a naphthylene group, a biphenyldiyl group, a fluorenediyl group, an anthracenediyl group, a phenanthrenediyl group, a pyrenediyl group, a perylenediyl group, a chrysenediyl group, an alkoxyphenylene group, and the like.In the case where the arylene group contains a substituent, an alkyl group, an alkoxy group or an alkylthio group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group or a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms or a heterocyclic linking group having 4 to 14 carbon atoms can be selected as the substituent. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a lauryl group, a 2-ethylhexyl group, a 3-methylbutyl group, and the like.Furthermore, specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, a 2-ethylhexyloxy group, a 3-methylbutoxy group, an isobutoxy group, and the like. Furthermore, specific examples of the alkylthio group having 1 to 20 carbon atoms include a methylthio group, an ethylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, a laurylthio group, a 2-ethylhexylthio group, a 3-methylbutylthio group, an isopropylthio group, and the like.Specific examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a noradamantyl group, an adamantyl group, a homoadamantyl group, a tricyclodecanyl group, and the like. Specific examples of the aryl group having 6 to 18 carbon atoms include a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted pyrenyl group, and the like.Furthermore, specific examples of an aryloxy group having 6 to 18 carbon atoms include a substituted or unsubstituted alkoxyphenoxy group, a substituted or unsubstituted alkylphenoxy group, a substituted or unsubstituted naphthyloxy group, a substituted or unsubstituted anthracenyloxy group, a substituted or unsubstituted pyrenyloxy group, and the like. Specific examples of the heterocyclic linking group having 4 to 14 carbon atoms include a substituted or unsubstituted thienyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted pyridyl group, and the like.

[0125] As the arylene group represented by Ar, for example, groups represented by the following structural formulas (Ar-1) to (Ar-18) can be used. Note that the group that can be used for Ar is not limited to these.

[0126] Furthermore, R 1 and R 2 each independently represents hydrogen, an alkyl group, an alkoxy group or an alkylthio group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group or aryloxy group having 6 to 18 carbon atoms or a heterocyclic linking group having 4 to 14 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a lauryl group, a 2-ethylhexyl group, a 3-methylbutyl group and the like.Furthermore, specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, a 2-ethylhexyloxy group, a 3-methylbutoxy group, an isobutoxy group, and the like. Furthermore, specific examples of the alkylthio group having 1 to 20 carbon atoms include a methylthio group, an ethylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, a laurylthio group, a 2-ethylhexylthio group, a 3-methylbutylthio group, an isopropylthio group, and the like.Specific examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a noradamantyl group, an adamantyl group, a homoadamantyl group, a tricyclodecanyl group, and the like. Specific examples of the aryl group having 6 to 18 carbon atoms include a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted pyrenyl group, and the like.In addition, specific examples of an aryloxy group having 6 to 18 carbon atoms include a substituted or unsubstituted alkoxyphenoxy group, a substituted or unsubstituted alkylphenoxy group, a substituted or unsubstituted naphthyloxy group, a substituted or unsubstituted anthracenyloxy group, a substituted or unsubstituted pyrenyloxy group, and the like. Specific examples of the heterocyclic linking group having 4 to 14 carbon atoms include a substituted or unsubstituted thienyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted pyridyl group, and the like. The above R. 1 and R 2 may each contain a substituent, and the substituents may be bonded to each other to form a ring. The substituent may also be an alkyl group, an alkoxy group, or an alkylthio group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group or aryloxy group having 6 to 18 carbon atoms, or a heterocyclic linking group having 4 to 14 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a lauryl group, a 2-ethylhexyl group, a 3-methylbutyl group, and the like.Furthermore, specific examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, a 2-ethylhexyloxy group, a 3-methylbutoxy group, an isobutoxy group, and the like. Furthermore, specific examples of the alkylthio group having 1 to 20 carbon atoms include a methylthio group, an ethylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, a laurylthio group, a 2-ethylhexylthio group, a 3-methylbutylthio group, an isopropylthio group, and the like.Specific examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a noradamantyl group, an adamantyl group, a homoadamantyl group, a tricyclodecanyl group, and the like. Specific examples of the aryl group having 6 to 18 carbon atoms include a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted pyrenyl group, and the like.Furthermore, specific examples of an aryloxy group having 6 to 18 carbon atoms include a substituted or unsubstituted alkoxyphenoxy group, a substituted or unsubstituted alkylphenoxy group, a substituted or unsubstituted naphthyloxy group, a substituted or unsubstituted anthracenyloxy group, a substituted or unsubstituted pyrenyloxy group, and the like. Specific examples of the heterocyclic linking group having 4 to 14 carbon atoms include a substituted or unsubstituted thienyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted pyridyl group, and the like.

[0127] For example, groups represented by the following structural formulas (R-1) to (R-29) can be represented as an alkyl group or aryl group represented by R 1 and R 2 and the substituents shown in the general formulas (101) to (110), the general formulas (201) to (210), the general formulas (301) to (314), Ar, R 1 and R 2 may be included. It should be noted that the groups that can be used as an alkyl group or aryl group are not limited to this.

[0128] In the light-emitting layer 130, there is no particular limitation on the guest material 132; however, an anthracene derivative, a tetracene derivative, a chrysene derivative, a phenanthrene derivative, a pyrene derivative, a perylene derivative, a stilbene derivative, an acridone derivative, a coumarin derivative, a phenoxazine derivative, a phenothiazine derivative, or the like can be used preferably. For example, one of the following substituted or unsubstituted materials can be used.

[0129] Examples include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N-diphenyl-N,N-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N-bis(3-methylphenyl)-N,N-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-Bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diamine (abbreviation: 1,6tBu-FLPAPrn), N,N'-Diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-Bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-Carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-Tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-Phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N'-(2-tert-Butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N[4-(9,10-Diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N,N,N',N',N'',N''-Octaphenyldibenzo[g,p]chrysen-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-Diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-Bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-Diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 6, coumarin 545T, N,N-diphenylquinacridone (abbreviation: DPQd), rubrene, 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(Dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-Methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-Tetrakis(4-methylphenyl)tetracen-5,11-diamine (abbreviation: p-mPhTD), 7,14-Diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-alfluoranthen-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-Isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-12,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM) and 5,10,15,20-Tetraphenylbisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-Im]perylene.,

[0130] As described above, the efficiency of energy transfer based on the Dexter mechanism from the high molecular material 131 to the guest material 132 is preferably low. The rate constant of the Dexter mechanism is inversely proportional to the exponential function of the distance between the two molecules. Therefore, when the distance between the two molecules is approximately 1 nm or smaller, the Dexter mechanism is dominant, and when the distance is approximately 1 nm or more, the Förster mechanism is dominant. To reduce the efficiency of energy transfer in the Dexter mechanism, the distance between the high molecular material 131 and the guest material 132 is preferably large, specifically 0.7 nm or more, preferably 0.9 nm or more, and more preferably 1 nm or more. In view of the above, the guest material 132 preferably contains a substituent that prevents the approach to the high molecular material 131.The substituent is preferably an aliphatic hydrocarbon, more preferably an alkyl group, and even more preferably a branched alkyl group. In particular, the guest material 132 preferably contains at least two alkyl groups, each containing 2 or more carbon atoms. Alternatively, the guest material 132 preferably contains at least two branched alkyl groups, each containing 3 to 10 carbon atoms. Alternatively, the guest material 132 preferably contains at least two cycloalkyl groups, each containing 3 to 10 carbon atoms.

[0131] Alternatively, the guest material 132 may be a high molecular compound, for example, a compound containing a phenylene group, a naphthalenediyl group, an anthracenediyl group, a phenanthrenediyl group, a dihydrophenanthrenediyl group, a carbazolediyl group, a phenoxazinediyl group, a phenothiazinediyl group, a pyrenediyl group, or the like.

[0132] In the light-emitting layer 130, the skeleton 131_4 is not particularly limited; however, it is preferable that the skeleton 131_4 contains a light-emitting skeleton contained in the guest material 132. That is, for example, as a structural unit, it is preferable to use a structure in which one or two hydrogen atoms are removed from an aromatic ring of a skeleton of anthracene, tetracene, chrysene, phenanthrene, pyrene, perylene, stilbene, acridone, coumarin, phenoxazine, phenothiazine, or the like. As the light-emitting skeleton, one of the skeletons represented by the following general formulas (401) to (410) from which one or two hydrogen atoms are removed is used. In addition, the skeletons each contain a substituent.To suppress the Dexter transfer described above, an aliphatic hydrocarbon group, preferably an alkyl group, more preferably a branched alkyl group, can be introduced as a substituent. In particular, the guest material 131_4 preferably contains at least two alkyl groups, each containing 2 or more carbon atoms. Alternatively, the framework 131_4 preferably contains at least two branched alkyl groups, each containing 3 to 10 carbon atoms. Alternatively, the guest material 131_4 preferably contains at least two cycloalkyl groups, each containing 3 to 10 carbon atoms.

[0133] The light-emitting layer 130 may contain another material in addition to the high-molecular-weight material 131 and the guest material 132. For example, a substituted or unsubstituted material of any of the following hole-transport materials and electron-transport materials may be used. Note that any of the substituents described above may be used as the substituent.

[0134] A material that has a property of transporting more holes than electrons can be used as a hole transport material, whereby a material with a hole mobility of 1 × 10 -6 cm 2 / Vs or higher is preferable. Specifically, an aromatic amine, a carbazole derivative, an aromatic hydrocarbon, a stilbene derivative, or the like can be used. Further, the hole-transporting material can be a high-molecular compound. Furthermore, a high-molecular compound containing the hole-transporting skeleton, the π-electron-rich heteroaromatic skeleton, or the aromatic amine skeleton contained in the high-molecular material 131 can be used.

[0135] Examples of the material with a high hole transport property are N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) and the like.

[0136] Specific examples of the carbazole derivatives are 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-Naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) and the like.

[0137] Other examples of the carbazole derivative are 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene and the like.

[0138] Examples of the aromatic hydrocarbon are 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-Tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-Bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-Tetra(tert-butyl)perylene and the like. Further examples are pentacene, coronene and the like.The aromatic hydrocarbon, which has a hole mobility of 1 × 10. -6 cm 2 / Vs or higher and contains 14 to 42 carbon atoms is particularly preferred.

[0139] The aromatic hydrocarbon may contain a vinyl skeleton. Examples of aromatic hydrocarbons containing a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like.

[0140] Further examples are high molecular weight compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA) and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD).

[0141] Examples of the material with a high hole transport property are aromatic amine compounds, such as: B. 4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-Tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4''-Tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4"-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-Tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-Bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-Phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-Dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-Dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-Diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-Diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-Naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-Phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 9,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'-bifluorene (abbreviation: DPA2SF), N-[4-(9H-Carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP) and N,N'-Bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F). Further examples are amine compounds, carbazole compounds, thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, and the like, such as 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,6-Di(9H-carbazol-9-yl)-9-phenyl-9H-carbazole (abbreviation: PhCzGl), 2,8-Di(9H-carbazol-9-yl)-dibenzothiophene (abbreviation: Cz2DBT), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-Tri(dibenzothiophen-4-yl)-benzene (abbreviation: DBT3P-II), 2,8-Diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and 4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II). The substances mentioned here are mainly substances with a hole mobility of 1 × 10 -6 cm 2 / Vs or higher. It should be noted that, in addition to these substances, any substance that has the property of transporting more holes than electrons can be used.

[0142] As an electron transport material, a material having a property of transporting more electrons than holes can be used, and a material with an electron mobility of 1 × 10 -6 cm 2 / Vs or higher is preferable. As a material that readily accepts electrons (material having an electron-transport property), a π-electron-deficient heteroaromatic compound such as a nitrogen-containing heteroaromatic compound, a metal complex, or the like can be used. Specific examples include a metal complex having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, an oxadiazole derivative, a triazole derivative, a phenanthroline derivative, a pyridine derivative, a bipyridine derivative, a pyrimidine derivative, and the like. Specifically, an aromatic amine, a carbazole derivative, an aromatic hydrocarbon, a stilbene derivative, or the like can be used. Furthermore, the electron-transport material can be a high-molecular compound.Furthermore, a high molecular compound containing the electron transport skeleton or the π-electron-deficient heteroaromatic skeleton contained in the high molecular material 131 can be used.

[0143] Specific examples include metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), and the like. A metal complex having an oxazole-based or thiazole-based ligand, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Alq), bis(10-hydroxybenzo[h]quinolinolato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), and the like. B. Bis[2-(2-benzoxazolyl)phenolate]zinc(II) (abbreviation: ZnPBO) or bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can be used alternatively. In addition to such metal complexes, any of the following can be used: heterocyclic compounds, such as2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[4-(4,5-Diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviation: CzTAZ1), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), bathophenanthroline (abbreviation: BPhen) and bathocuproine (abbreviation: BCP); heterocyclic compounds with a diazine skeleton, such as2-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-Carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-[3-(3,9'-bi-9H-carbazol-9-yl)phenyl]dibenzo[fh]quinoxaline (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II) and 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm); heterocyclic compounds with a triazine skeleton, such as B.2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn); heterocyclic compounds with a pyridine skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy); and heteroaromatic compounds, such as 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs). Among the heterocyclic compounds, heterocyclic compounds with diazine skeletons (pyrimidine, pyrazine, pyridazine) or a pyridine skeleton are extremely reliable and stable and are therefore preferred. In addition, the heterocyclic compounds with the frameworks exhibit high electron transport properties, thus contributing to a reduction in the drive voltage. A high-molecular compound, such asPoly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), or poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used as alternatives. The substances described here are primarily those with an electron mobility of 1 × 10 -6 cm 2 / Vs or higher. It should be noted that other substances can also be used as long as their electron transport properties are higher than their hole transport properties.

[0144] In addition, the high molecular material 131 may have a structure in which one or two hydrogen atoms are removed from any one of the above-described hole transport materials and the above-described electron transport materials.

[0145] Furthermore, the light-emitting layer 130 may contain a thermally activated delayed fluorescent emitter in addition to the high-molecular material 131 and the guest material 132. Alternatively, a material having a function of emitting thermally activated delayed fluorescence at room temperature is preferably included. Note that a thermally activated delayed fluorescent emitter is a material that can form a singlet excited state from a triplet excited state through reverse intersystem crossing due to thermal activation. The thermally activated delayed fluorescent emitter may contain a material, such as a TADF material, that can form a singlet excited state by itself from a triplet excited state through reverse intersystem crossing.Such a material preferably has a difference between the singlet excitation energy level and the triplet excitation energy level of greater than 0 eV and less than or equal to 0.2 eV.

[0146] For example, one of the following materials can be used as a TADF material that serves as a thermally activated delayed fluorescent emitter.

[0147] First, fullerene and its derivative, an acridine derivative such as proflavin, eosin, and the like, may be mentioned. Furthermore, a metal-containing porphyrin, such as porphyrin containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), may be mentioned. Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF2(Proto IX)), a mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), a hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), a coproporphyrin-tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), an octaethylporphyrin-tin fluoride complex (SnF2(OEP)), an etioporphyrin-tin fluoride complex (SnF2(Etio I)), and an octaethylporphyrin-platinum chloride complex (PtCl2OEP).

[0148] As a thermally activated delayed fluorescent material composed of one type of material, a heterocyclic compound comprising a π-electron-rich heteroaromatic ring and a π-electron-poor heteroaromatic ring can be used. In particular, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-Dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS) or 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA) can be used.The heterocyclic compound is preferable because it contains the π-electron-rich heteroaromatic ring and the π-electron-poor heteroaromatic ring; therefore, the electron-transport property and hole-transport property are high. Note that a substance in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-poor heteroaromatic ring is particularly preferable because both the donor property of the π-electron-rich heteroaromatic ring and the acceptor property of the π-electron-poor heteroaromatic ring are enhanced, and the energy difference between the singlet excitation energy level and the triplet excitation energy level becomes small.

[0149] Alternatively, the thermally activated delayed fluorescent material may contain a combination of two types of materials forming an excited complex. As the combination of two types of materials, a combination of the above-described hole-transport material and the above-described electron-transport material is preferable. Specifically, a zinc- or aluminum-based metal complex, an oxadiazole derivative, a triazole derivative, a benzimidazole derivative, a quinoxaline derivative, a dibenzoquinoxaline derivative, a dibenzothiophene derivative, a dibenzofuran derivative, a pyrimidine derivative, a triazine derivative, a pyridine derivative, a bipyridine derivative, a phenanthroline derivative, or the like can be used. Other examples include an aromatic amine and a carbazole derivative.

[0150] As a material that can be used for the light-emitting layer 130, a material capable of being dissolved in a solvent that can dissolve the high-molecular material of one embodiment of the present invention is preferable.

[0151] The light-emitting layer 130 may have a structure in which two or more layers are stacked. For example, in the case where the light-emitting layer 130 is formed by stacking a first light-emitting layer and a second light-emitting layer in this order from the hole-transporting layer side, the first light-emitting layer is formed using a substance having a hole-transporting property as a high-molecular material, and the second light-emitting layer is formed using a substance having an electron-transporting property as a high-molecular material. < <lochinjektionsschicht>>

[0152] The hole-injection layer 111 has a function of reducing a barrier to hole injection from one of the pair of electrodes (the electrode 101 or the electrode 102) to promote hole injection, and is formed using, for example, a transition metal oxide, a phthalocyanine derivative, or an aromatic amine. As the transition metal oxide, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, or the like can be cited. As the phthalocyanine derivative, phthalocyanine, metal phthalocyanine, or the like can be cited. As the aromatic amine, a benzidine derivative, a phenylenediamine derivative, or the like can be cited. It is also possible to use a high-molecular compound such as polythiophene or polyaniline; a typical example is poly(ethylenedioxythiophene) / poly(styrenesulfonic acid), which is a self-doped polythiophene.In addition, polyvinylcarbazole and a derivative thereof, polyarylene containing an aromatic amine skeleton or a π-electron-rich heteroaromatic skeleton in a side chain or a main chain and a derivative thereof, and the like are exemplified.

[0153] As the hole-injection layer 111, a layer containing a composite material of a hole-transporting material and a material having a property of accepting electrons from the hole-transporting material can also be used. Alternatively, a layer arrangement of a layer containing a material having an electron-accepting property and a layer containing a hole-transporting material can also be used. In a stable state or in the presence of an electric field, electric charges can be transferred between these materials. As examples of the material having a property of accepting electrons, organic acceptors such as a quinodimethane derivative, a chloranil derivative, and a hexaazatriphenylene derivative can be given. A specific example is a compound having an electron-withdrawing group (a halogen group or a cyano group), such as7,7,8,8-Tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, or 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN). Alternatively, a transition metal oxide, such as an oxide of a Group 4 to Group 8 metal, can also be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, or the like can be used. In particular, molybdenum oxide is preferred because it is stable in air, has low hygroscopicity, and is easy to handle.

[0154] A material that has a property of transporting more holes than electrons can be used as a hole transport material, whereby a material with a hole mobility of 1 × 10 -6 cm 2 / Vs or higher is preferable. Specifically, any of an aromatic amine, a carbazole derivative, an aromatic hydrocarbon, a stilbene derivative, or the like, which have been described as examples of the hole-transport material that can be used in the light-emitting layer 130, can be used. Furthermore, the hole-transport material may be a high-molecular compound. < <lochtransportschicht>>

[0155] A hole-transport layer may be provided between the hole-injection layer 111 and the light-emitting layer 130. The hole-transport layer is a layer containing a hole-transport material and may be formed using any of the hole-transport materials given as examples of the material of the hole-injection layer 111. In order for the hole-transport layer to have a function of transporting holes injected into the hole-injection layer 111 to the light-emitting layer 130, the HOMO level of the hole-transport layer is preferably equal to or close to the HOMO level of the hole-injection layer 111.

[0156] As hole transport material, a substance with a hole mobility of 1 × 10 -6 cm 2 / Vs or higher can be used. Note that other than the above substances, any substance can be used as long as the hole-transport property is higher than the electron-transport property. The layer containing a substance with a high hole-transport property is not limited to a single layer, and two or more layers containing the above substances can be stacked. < <elektronentransportschicht>>

[0157] An electron transport layer may be provided between the light-emitting layer 130 and the electron injection layer 114. The electron transport layer has a function of transporting electrons injected from the other electrode of the pair of electrodes (the electrode 101 or the electrode 102) via the electron injection layer 114 to the light-emitting layer 130. A material having a property of transporting more electrons than holes may be used as the electron transport material, and a material having an electron mobility of 1 × 10 -6 cm 2 / Vs or higher is preferable. As a compound that readily accepts electrons (material with an electron-transport property), for example, a π-electron-deficient heteroaromatic compound such as a nitrogen-containing heteroaromatic compound, a metal complex, or the like can be used. Specifically, a metal complex having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, an oxadiazole derivative, a triazole derivative, a phenanthroline derivative, a pyridine derivative, a bipyridine derivative, a pyrimidine derivative, and the like, which have been described as electron-transport materials that can be used in the light-emitting layer 130, can be cited. In addition, a high-molecular compound such as polyphenylene, polyfluorene, and derivatives thereof can be used. A substance having an electron mobility of 1 × 10 -6 cm 2 / Vs or higher is preferable. Note that, in addition to these substances, any substance that has the property of transporting more electrons than holes can be used for the electron-transport layer. The electron-transport layer is not limited to a single layer, and it may be a stacked arrangement of two or more layers containing the above-mentioned substances.

[0158] Between the electron-transport layer and the light-emitting layer 130, a layer that controls the transport of electron carriers may be provided. This is a layer formed by adding a small amount of a substance with a high electron-trapping property to a material with a high electron-transport property described above, and the layer is capable of adjusting the carrier balance by suppressing the transport of electron carriers. Such a structure is very effective in preventing a problem (such as a reduction in the lifetime of the element) that arises when electrons pass through the light-emitting layer. < <elektroneninjektionsschicht>>

[0159] The electron injection layer 114 has a function of reducing a barrier to electron injection from the electrode 102 to promote electron injection, and can be formed using, for example, a Group 1 metal or a Group 2 metal, or an oxide, a halide, or a carbonate of one of the metals. Alternatively, a composite material containing an electron-transport material (described above) and a material having a property of donating electrons to the electron-transport material can also be used. As the material having a property of donating electrons, a Group 1 metal, a Group 2 metal, an oxide of any of the metals, or the like can be specified. Specifically, an alkali metal, an alkaline earth metal, or a compound thereof, such as a metal alloy, can be used.Lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF2) or lithium oxide (LiO). x ) may be used. Alternatively, a rare earth metal compound such as erbium fluoride (ErF3) may be used. An electride may also be used for the electron-injection layer 114. Examples of the electride include a substance in which electrons have been added to calcium oxide-alumina at a high concentration. The electron-injection layer 114 may be formed using the substance that can be used for the electron-transport layer 118.

[0160] A composite material in which an organic compound and an electron donor (donor) are mixed can also be used for the electron-injection layer 114. Such a composite material has excellent electron injection properties and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that can excellently transport the generated electrons. Specifically, for example, the substances listed above for forming the electron-transport layer (e.g., the metal complexes and heteroaromatic compounds) can be used. As the electron donor, a substance that has an electron-donating property with respect to the organic compound can be used.In particular, an alkali metal, an alkaline earth metal, and a rare earth metal are preferred, and lithium, cesium, magnesium, calcium, erbium, and ytterbium can be cited. Furthermore, an alkali metal oxide or an alkaline earth metal oxide is preferred, and lithium oxide, calcium oxide, barium oxide, and the like can be cited. A Lewis base such as magnesium oxide can also be used. An organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used.

[0161] Note that the light-emitting layer, the hole-injection layer, the hole-transport layer, the electron-transport layer, and the electron-injection layer described above can each be formed by an evaporation method (including a vacuum evaporation method), an inkjet method, a coating method, a jet printing method, a gravure printing method, or the like. In addition to the above-mentioned materials, an inorganic compound such as a quantum dot can be used in the light-emitting layer, the hole-injection layer, the hole-transport layer, the electron-transport layer, and the electron-injection layer.

[0162] For example, the quantum dot can be a gelatinous quantum dot, an alloyed quantum dot, a core-shell quantum dot, or a core quantum dot. The quantum dot containing elements belonging to groups 2 and 16, elements belonging to groups 13 and 15, elements belonging to groups 13 and 17, elements belonging to groups 11 and 17, or elements belonging to groups 14 and 15 can be used. Alternatively, the quantum dot containing an element such as cadmium (Cd), selenium (Se), zinc (Zn), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga), arsenic (As), or aluminum (Al) can be used.

[0163] Examples of a solvent that can be used in the case where the inkjet method, the coating method, the jet printing method, the gravure printing method or the like is used include: chlorine-based solvents such as dichloroethane, trichloroethane, chlorobenzene and dichlorobenzene; ether-based solvents such as tetrahydrofuran, dioxane, anisole and methylanisole; aromatic hydrocarbon-based solvents such as toluene, xylene, mesitylene, ethylbenzene, hexylbenzene and cyclohexylbenzene; aliphatic hydrocarbon-based solvents such as cyclohexane, methylcyclohexane, pentane, hexane, heptane, octane, nonane, decane, dodecane and bicyclohexyl; ketone-based solvents such as acetone, methyl ethyl ketone, benzophenone and acetophenone; ester-based solvents such as ethyl ketone, benzene and cyclohexylbenzene. B. ethyl acetate, butyl acetate, ethyl cellosolve acetate, methyl benzoate and phenyl acetate; polyalcohol-based solvents, such asEthylene glycol, glycerin, and hexanediol; alcohol-based solvents such as isopropyl alcohol and cyclohexanol; a sulfoxide-based solvent such as dimethyl sulfoxide; and amide-based solvents such as methylpyrrolidone and dimethylformamide. One or more materials may be used as the solvent. <<Paar von Elektroden> >

[0164] Electrodes 101 and 102 serve as the anode and cathode of each light-emitting element. Electrodes 101 and 102 can be formed using a metal, alloy, conductive compound, mixture, or layered arrangement of these, or the like.

[0165] The electrode 101 or the electrode 102 is preferably formed using a conductive material having a function of reflecting light. Examples of the conductive material include aluminum (Al), an alloy containing Al, and the like. Examples of the alloy containing Al include an alloy containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), such as an alloy containing Al and Ti, and an alloy containing Al, Ni, and La. Aluminum has low resistance and high light reflectivity. Aluminum is abundant in the earth's crust and is inexpensive; accordingly, it is possible to reduce the cost of manufacturing a light-emitting element using aluminum.Alternatively, an alloy of silver (Ag) and N (N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au)) or the like may be used. Examples of the silver-containing alloy include an alloy containing silver, palladium, and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, an alloy containing silver and nickel, an alloy containing silver and gold, an alloy containing silver and ytterbium, and the like. Besides, a transition metal such as tungsten, chromium (Cr), molybdenum (Mo), copper, or titanium may be used.

[0166] Light emitted from the light-emitting layer is taken out via the electrode 101 and / or the electrode 102. Accordingly, at least one of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of transmitting light. As the conductive material, a conductive material whose visible light transmittance is higher than or equal to 40% and lower than or equal to 100%, preferably higher than or equal to 60% and lower than or equal to 100%, and whose resistivity is lower than or equal to 1 × 10 -2 Ω·cm.

[0167] The electrodes 101 and 102 can each be formed using a conductive material having functions of transmitting light and reflecting light. As the conductive material, a conductive material whose visible light reflectance is higher than or equal to 20% and lower than or equal to 80%, preferably higher than or equal to 40% and lower than or equal to 70%, and whose resistivity is lower than or equal to 1 × 10 -2 Ω cm. For example, one or more types of conductive metals and alloys, conductive compounds, and the like can be used. Specifically, a metal oxide such as indium tin oxide (hereinafter referred to as ITO), indium tin oxide (ITSO) containing silicon or silicon oxide, indium oxide-zinc oxide (indium zinc oxide), indium oxide-tin oxide containing titanium, indium titanium oxide, or indium oxide containing tungsten oxide and zinc oxide can be used. A thin metal film having a thickness that allows light transmission (preferably a thickness greater than or equal to 1 nm and less than or equal to 30 nm) can also be used. As the metal, Ag, an alloy of Ag and Al, an alloy of Ag and Mg, an alloy of Ag and Au, an alloy of Ag and ytterbium (Yb), or the like can be used.

[0168] In this specification and the like, as the light-transmitting material, a material that transmits visible light and has conductivity is used. Examples of the material include, in addition to the above-described oxide conductor, of which ITO is a typical example, an oxide semiconductor and an organic conductor containing an organic substance. Examples of the organic conductor containing an organic substance include a composite material in which an organic compound and an electron donor (donor material) are mixed, and a composite material in which an organic compound and an electron acceptor (acceptor material) are mixed. Alternatively, an inorganic carbon-based material such as graphene may be used. The specific resistance of the material is preferably less than or equal to 1 × 10 5 Ω·cm, preferably less than or equal to 1 × 10 4 Ω cm.

[0169] Alternatively, the electrode 101 and / or the electrode 102 may be formed by stacking two or more of these materials.

[0170] Further, in order to improve light extraction efficiency, a material whose refractive index is higher than that of an electrode having a function of transmitting light may be formed in contact with the electrode. Such a material may be an electrically conductive material or a non-conductive material as long as it has a function of transmitting visible light. In addition to the oxide conductors described above, for example, an oxide semiconductor and an organic material can be exemplified. As examples of the organic material, the materials of the light-emitting layer, the hole-injection layer, the hole-transport layer, the electron-transport layer, and the electron-injection layer are given. Alternatively, an inorganic carbon-based material or a metal thin film that transmits light may be used.A plurality of layers, each formed using the material having a high refractive index and having a thickness of several nanometers to several tens of nanometers, may be stacked one on top of the other.

[0171] In the case where electrode 101 or electrode 102 serves as a cathode, the electrode preferably contains a material with a low work function (less than or equal to 3.8 eV). Examples include an element belonging to Group 1 or 2 of the Periodic Table (e.g., an alkali metal such as lithium, sodium, or cesium; an alkaline earth metal such as calcium or strontium; or magnesium); an alloy containing one of these elements (e.g., Ag-Mg or Al-Li); a rare earth metal such as europium (Eu) or Yb; an alloy containing one of these rare earth metals; an alloy containing aluminum and silver; and the like.

[0172] In the case where the electrode 101 or the electrode 102 is used as an anode, a material with a high work function (higher than or equal to 4.0 eV) is preferably used.

[0173] Alternatively, the electrodes 101 and 102 may each be a laminated structure composed of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In this case, the electrodes 101 and 102 may have a function of adjusting the optical path length so that light of a desired wavelength emitted from each light-emitting layer is oscillated and amplified; therefore, such a structure is preferable.

[0174] As a method for forming the electrode 101 and the electrode 102, a sputtering method, an evaporation method, a printing method, a coating method, a molecular beam epitaxy (MBE) method, a CVD method, a pulse laser deposition method, an atomic layer deposition (ALD) method, or the like can be used as needed. < <substrat>>

[0175] A light-emitting element of one embodiment of the present invention can be formed over a substrate made of glass, plastic, or the like. As one way to stack layers over the substrate, layers can be arranged sequentially from the electrode 101 side or sequentially from the electrode 102 side.

[0176] For the substrate over which the light-emitting element of one embodiment of the present invention can be formed, for example, glass, quartz, plastic, or the like can be used. Alternatively, a flexible substrate can be used. The flexible substrate is, for example, a substrate that can be bent, such as a plastic substrate made of polycarbonate or polyarylate. Alternatively, a film, an inorganic film formed by vapor deposition, or the like can be used. Another material can be used as long as the substrate serves as a support in a manufacturing process of the light-emitting element or an optical element, or as long as it has a function of protecting the light-emitting element or an optical element.

[0177] For example, in this specification and the like, a light-emitting element can be formed using various substrates. There is no particular limitation on the type of substrate. Examples of the substrate include a semiconductor substrate (e.g., a single-crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate containing a stainless steel foil, a tungsten substrate, a substrate containing a tungsten foil, a flexible substrate, an attachment film, cellulose nanofiber (CNF), paper containing a fiber material, a base material film, and the like. As an example of a glass substrate, a barium borosilicate glass substrate, an aluminum borosilicate glass substrate, a soda-lime glass substrate, and the like can be given.Examples of the flexible substrate, the fixing film, the base material film, and the like include substrates made of plastics, typical examples of which include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Another example is a resin such as acrylic. Further, polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride can be exemplified. Other examples include polyamide, polyimide, aramid, epoxy, an inorganic film formed by vapor deposition, paper, and the like.

[0178] Alternatively, a flexible substrate may be used as the substrate so that the light-emitting element is provided directly above the flexible substrate. As a further alternative, a separation layer may be provided between the substrate and the light-emitting element. The separation layer may be used when a part or all of the light-emitting element formed above the separation layer is separated from the substrate and transferred to another substrate. In such a case, the light-emitting element may also be transferred to a substrate with low heat resistance or to a flexible substrate. For the above separation layer, for example, a layer arrangement comprising inorganic films, namely a tungsten film and a silicon oxide film, and a structure in which a resin film of polyimide or the like is formed over a substrate can be used.

[0179] In other words, after the light-emitting element is formed using one substrate, the light-emitting element can be transferred to another substrate. Examples of the substrate to which the light-emitting element is transferred include, in addition to the above substrates, a cellophane substrate, a stone substrate, a wood substrate, a cloth substrate (including a natural fiber (e.g., silk, cotton, and hemp), a synthetic fiber (e.g., nylon, polyurethane, and polyester), a regenerated fiber (e.g., acetate, cupro, viscose, and regenerated polyester), and the like), a leather substrate, a rubber substrate, and the like. When such a substrate is used, a light-emitting element with high durability, high heat resistance, reduced weight, or reduced thickness can be formed.

[0180] For example, the light-emitting element 150 may be formed over an electrode electrically connected to a field-effect transistor (FET) formed over one of the substrates described above. In this way, an active matrix display device can be fabricated in which the FET controls the operation of the light-emitting element 150.

[0181] In Embodiment 1, one embodiment of the present invention was described. Other embodiments of the present invention will be described in Embodiments 2 to 9. Note that one embodiment of the present invention is not limited thereto. That is, one embodiment of the present invention is not limited to a specific embodiment because various embodiments of the present invention are disclosed in Embodiment 1 and Embodiments 2 to 9. Although the example in which one embodiment of the present invention is applied to a light-emitting element is described, one embodiment of the present invention is not limited thereto. For example, depending on circumstances or conditions, one embodiment of the present invention may not necessarily be applied to a light-emitting element.Although another example in which the EL layer contains the high molecular material and the guest material, the high molecular material has a structure in which the first skeleton and the second skeleton are bonded to each other via the third skeleton, and the first high molecular chain and the second high molecular chain of the high molecular material form an excited complex, is shown as one embodiment of the present invention, an embodiment of the present invention is not limited thereto. For example, depending on circumstances or conditions, in one embodiment of the present invention, the first high molecular chain and the second high molecular chain of the high molecular material may not form an excited complex. Alternatively, the structure in which the first skeleton and the second skeleton in the high molecular material are bonded to each other via the third skeleton is not necessarily provided.Although another example in which the first skeleton in the high molecular material contains the π-electron-rich heteroaromatic skeleton and / or the aromatic amine skeleton and the second skeleton contains the π-electron-deficient heteroaromatic skeleton is shown as one embodiment of the present invention, one embodiment of the present invention is not limited thereto. For example, depending on circumstances or conditions, in one embodiment of the present invention, the first skeleton does not necessarily contain the π-electron-rich heteroaromatic skeleton or the aromatic amine skeleton. Alternatively, the second skeleton does not necessarily contain the π-electron-deficient heteroaromatic skeleton.

[0182] The structures described in this embodiment may be used in a suitable combination with any of the other embodiments. (Embodiment 2)

[0183] In this embodiment, a light-emitting element having a structure different from that described in Embodiment 1 and light-emitting mechanisms of the light-emitting element will be described below with reference to Fig. 3A to Fig. 3C and Fig. 4 described. In Fig. 3A will in some cases be a section with a similar function to that in Fig. 1A by the same hatching pattern as in Fig. 1A and are not specifically identified by a reference numeral. In addition, the same reference numerals are used for sections with similar functions, and a detailed description of the sections is omitted in some cases. <Strukturbeispiel 1 des Licht emittierenden Elements>

[0184] Fig. 3A is a schematic cross-sectional view of a light-emitting element 152 of an embodiment of the present invention.

[0185] The light-emitting element 152 includes a pair of electrodes (an electrode 101 and an electrode 102) and an EL layer 100 between the pair of electrodes. The EL layer 100 includes at least one light-emitting layer 140.

[0186] Note that the electrode 101 serves as an anode and the electrode 102 serves as a cathode in the following description of the light-emitting element 152; however, the functions in the light-emitting element 152 may be interchanged.

[0187] Fig. 3B is a schematic cross-sectional view showing an example of the light-emitting layer 140 in Fig. 3A. The light-emitting layer 140 in Fig. 3B contains a high molecular weight material 141 and a guest material 142.

[0188] The high-molecular-weight material 141 contains a framework 141_1, a framework 141_2, and a framework 141_3 as structural units. Framework 141_1 and framework 141_2 are bonded or polymerized to each other via framework 141_3.

[0189] The guest material 142 may be a light-emitting organic compound, and the light-emitting organic compound is preferably a substance capable of emitting fluorescence (hereinafter also referred to as a phosphorescent compound). A structure using a phosphorescent compound as the guest material 142 will be described below. The guest material 142 may also be referred to as a phosphorescent compound. <Lichtemissionsmechanismus des Licht emittierenden Elements>

[0190] Next, the light emission mechanism of the light-emitting layer 140 will be described below.

[0191] In the high-molecular-weight material 141 in the light-emitting layer 140, preferably, the framework 141_1 contains a framework with a hole-transferring function (a hole-transporting property), and the framework 141_2 contains a framework with an electron-transferring function (an electron-transporting property). Alternatively, preferably, the framework 141_1 contains a π-electron-rich heteroaromatic framework and / or an aromatic amine framework, and the framework 141_2 contains a π-electron-deficient heteroaromatic framework.

[0192] In one embodiment of the present invention, the high molecular material 141 has a function of forming an excited complex (also referred to as an excited dimer) with two high molecular chains of the high molecular material 141. Specifically, it is preferable that the framework having a hole-transport property and the framework having an electron-transport property of the high molecular material 141 form an excited complex in two high molecular chains containing the same structural units. Alternatively, it is preferable that the π-electron-rich heteroaromatic framework and / or the aromatic amine framework contained in the high molecular material 141 and the π-electron-deficient heteroaromatic framework contained in the high molecular material 141 form an excited complex in two high molecular chains containing the same structural units.

[0193] In other words, the high molecular material 141 has a function of forming an excited complex with a first high molecular chain and a second high molecular chain of the high molecular material 141. Specifically, the framework having a hole-transport property in the first high molecular chain and the framework having an electron-transport property in the second high molecular chain of the high molecular material 141 preferably form an excited complex. Alternatively, the π-electron-rich heteroaromatic framework and / or the aromatic amine framework in the first high molecular chain of the high molecular material 141 and the π-electron-deficient heteroaromatic framework in the second high molecular chain of the high molecular material 141 preferably form an excited complex.

[0194] In the case where the high molecular weight material 141 has the framework with a hole-transport property contained in the framework 141_1 and the framework with an electron-transport property contained in the framework 141_2, an excited donor-acceptor complex of two high molecular weight chains is easily formed; thus, it is possible to efficiently form an excited complex. Alternatively, when the high molecular weight material 141 has the π-electron-rich heteroaromatic framework and / or the aromatic amine framework contained in the framework 141_1 and the π-electron-deficient heteroaromatic framework contained in the framework 141_2, an excited donor-acceptor complex of two high molecular weight chains is easily formed; thus, it is possible to efficiently form an excited complex.

[0195] Therefore, to enhance both the donor property and the acceptor property in the high molecular weight chains of the high molecular weight material 141, a structure in which the conjugation between the framework with a hole-transport property and the framework with an electron-transport property is reduced is preferably used. Alternatively, a structure in which the conjugation between the π-electron-deficient heteroaromatic framework and the π-electron-rich heteroaromatic framework and / or the aromatic amine framework is reduced is preferably used. Thus, a difference between a singlet excitation energy level and a triplet excitation energy level of the high molecular weight material 141 can be reduced. Furthermore, the triplet excitation energy level of the high molecular weight material 141 can be high.

[0196] Furthermore, in the excited complex formed by the two high molecular weight chains containing the same structural units, one high molecular weight chain exhibits the HOMO, and the other high molecular weight chain exhibits the LUMO; thus, the overlap between the HOMO and the LUMO is very small. This means that in the excited complex, a difference between a singlet excitation energy level and a triplet excitation energy level is small. Therefore, in the excited complex formed by the two high molecular weight chains of the high molecular weight material 141, a difference between a singlet excitation energy level and a triplet excitation energy level is small, and preferably greater than 0 eV and less than or equal to 0.2 eV.

[0197] In the case where the high molecular weight material 141 is the framework with a hole-transport property and the framework with an electron-transport property, the charge carrier balance can be easily controlled. As a result, a charge carrier recombination range can also be easily controlled. To achieve this, preferably, the composition ratio of the framework 141_1 (containing the framework with a hole-transport property) to the framework 141_2 (containing the framework with an electron-transport property) is in the range of 1:9 to 9:1 (molar ratio), and more preferably, the proportion of the framework 141_2 (containing the framework with an electron-transport property) is higher than the proportion of the framework 141_1 (containing the framework with a hole-transport property).

[0198] Fig. Figure 3C shows a correlation of energy levels of the high molecular material 141 and the guest material 142 in the light-emitting layer 140. The following clarifies what terms and symbols in Fig. 3C represent: Polymer (141_1 + 141_2): the skeleton 141_1 in the first high molecular chain and the skeleton 141_2 in the second high molecular chain of the high molecular material 141, which are close to each other; Guest (142): the guest material 142 (the phosphorescent compound); S PH : the S1 level of the high molecular weight material 141; T PH : the T1 level of the high molecular weight material 141; T PG : the T1 level of the guest material 142 (the phosphorescent compound); S PE : the S1 level of the excited complex; and T PE : the T1 level of the excited complex.

[0199] In the light-emitting layer 140, the high-molecular material 141 is present in the highest weight fraction, and the guest material 142 (the phosphorescent compound) is dispersed in the high-molecular material 141. The T1 level of the high-molecular material 141 in the light-emitting layer 140 is preferably higher than the T1 level of the guest material (the guest material 142) in the light-emitting layer 140.

[0200] In the light-emitting element of one embodiment of the present invention, an excited complex is formed by the two high-molecular chains of the high-molecular material 141 contained in the light-emitting layer 140. The lowest energy level (S PE ) in a singlet excited state of the excited complex and the lowest energy level (T PE ) in a triplet excited state of the excited complex close to each other (see route E7 in Fig. 3C).

[0201] In the two high-molecular-weight chains of the high-molecular-weight material 141 that are close to each other, one high-molecular-weight chain receives a hole, and the other high-molecular-weight chain receives an electron, so that they immediately form an excited complex. Alternatively, a high-molecular-weight chain that is brought into an excited state immediately interacts with the other high-molecular-weight chain to form an excited complex. Consequently, most excitons in the light-emitting layer 140 exist as excited complexes. Since the excitation energy levels (S PE and T PE ) of the excited complex are lower than the singlet excitation energy level (S PH ) of the high-molecular material 141 forming the excited complex, the excited state of the high-molecular material 141 can be formed with lower excitation energy. Accordingly, the driving voltage of the light-emitting element 152 can be reduced.

[0202] Both energies, S PE and T PE , of the excited complex are then transferred to the lowest energy level in the triplet excited state of the guest material 142 (the phosphorescent compound); thus, light emission is obtained (see routes E8 and E9 in Fig. 3C).

[0203] Furthermore, the triplet excitation energy level (T PE ) of the excited complex is preferably higher than the triplet excitation energy level (T PG ) of the guest material 142. In this way, the singlet excitation energy and the triplet excitation energy of the formed excited complex can be determined from the singlet excitation energy level (S PE ) and the triplet excitation energy level (T PE ) of the excited complex to the triplet excitation energy level (T PG ) of the guest material 142.

[0204] When the light-emitting layer 140 has the structure described above, light emission from the guest material 142 (the phosphorescent compound) of the light-emitting layer 140 can be obtained efficiently.

[0205] Since an excited complex is called an "exciplex" in some cases, in this specification and the like, the processes described above via routes E7, E8, and E9 may be referred to as exciplex-triplet energy transfer (ExTET). In other words, in the light-emitting layer 140, the excitation energy is transferred from the excited complex to the guest material 142. In this case, the efficiency of the reverse intersystem crossing of T PE to S PE and the luminescence quantum yield from the singlet excited state of S PE not necessarily high; therefore, the materials can be selected from a wide range of options.

[0206] It should be noted that the triplet excitation energy level (T PE ) of the excited complex formed by two high molecular weight chains is preferably lower than the triplet excitation energy level (T PH ) of the single high molecular weight material 141 forming the excited complex to efficiently transfer the excitation energy from the excited complex to the guest material 142. Thus, the probability of quenching of the triplet excitation energy of the excited complex due to another high molecular weight chain(s) in the high molecular weight material 141 is reduced, leading to efficient energy transfer to the guest material 142.

[0207] Furthermore, the mechanisms of the energy transfer process between the molecules of the high molecular weight material 141 and the host material 142 can be described using two mechanisms, namely the Förster mechanism (dipole-dipole interaction) and the Dexter mechanism (electron exchange interaction), as in Embodiment 1. For the Förster mechanism and the Dexter mechanism, refer to Embodiment 1. <<Konzept zur Förderung der Energieübertragung> >

[0208] In the energy transfer through the Förster mechanism, the efficiency of energy transfer ϕ ET higher as the luminescence quantum yield ϕ (the fluorescence quantum yield when energy transfer from a singlet excited state) is higher. Furthermore, it is preferable that the emission spectrum (the fluorescence spectrum when energy transfer from a singlet excited state) of the high molecular material 141 largely overlaps the absorption spectrum (absorption corresponding to the transition from the singlet ground state to the triplet excited state) of the guest material 142. Furthermore, it is preferable that the molar absorption coefficient of the guest material 142 is also high. That is, the emission spectrum of the high molecular material 141 overlaps the absorption band of the guest material 142, which is on the longest wavelength side.

[0209] In the energy transfer by the Dexter mechanism, overlaps to the rate constant k h*→g To increase the energy transfer efficiency, it is preferable that an emission spectrum of the high-molecular-weight material 141 (a fluorescence spectrum in the case of energy transfer from a singlet excited state) largely overlaps the absorption spectrum of the guest material 142 (absorption corresponding to the transition from a singlet ground state to a triplet excited state). Accordingly, the energy transfer efficiency can be optimized by ensuring that the emission spectrum of the high-molecular-weight material 141 overlaps the absorption band of the guest material 142, which is located on the longest wavelength side.

[0210] In a similar manner to the energy transfer from the high molecular weight material 141 to the guest material 142, the energy transfer through both the Förster mechanism and the Dexter mechanism also occurs in the process of energy transfer from the excited complex to the guest material 142.

[0211] Accordingly, one embodiment of the present invention provides a light-emitting element including the high-molecular material 141, in which two high-molecular chains form an excited complex serving as an energy donor suitable for efficient energy transfer to the guest material 142. The excited complex formed by the two high-molecular chains of the high-molecular material 141 has a singlet excitation energy level and a triplet excitation energy level that are close to each other; therefore, the excited complex generated in the light-emitting layer 140 can be formed only with a lower excitation energy than that of the high-molecular material 141. This can reduce the driving voltage of the light-emitting element 142.Furthermore, the emission spectrum of the excited complex preferably overlaps the absorption band of the guest material 142, which is located on the longest wavelength side (lowest energy side), to promote energy transfer from the singlet excited state of the excited complex to the triplet excited state of the guest material 142, which serves as an energy acceptor. Consequently, the efficiency of generating the triplet excited state of the guest material 142 can be increased. <Strukturbeispiel 2 des Licht emittierenden Elements>

[0212] Next, a structural example of the light-emitting layer 140 which is different from that in Fig. 3B, below based on Fig. 4 described.

[0213] Fig. 4 is a schematic cross-sectional view showing another example of the light-emitting layer 140 in Fig. 3A. It should be noted that in Fig. 4 sections with functions similar to those of sections in Fig. 3B are similar, are designated by the same reference numerals, and a detailed description of the sections is omitted in some cases.

[0214] The light-emitting layer 140 in Fig. 4 contains the high-molecular-weight material 141. The high-molecular-weight material 141 contains the structural units scaffold 141_1, scaffold 141_2, scaffold 141_3, and a scaffold 141_4. The scaffold 141_1 and the scaffold 141_2 are bonded or polymerized to each other via the scaffold 141_3.

[0215] The framework 141_4 may be a light-emitting framework, and the light-emitting framework is preferably a framework capable of emitting phosphorescence (hereinafter also referred to as a phosphorescent framework). A structure using a phosphorescent framework as the framework 141_4 will be described below. Note that the framework 141_4 can be reformulated as a phosphorescent framework.

[0216] The scaffold 141_4 has a function similar to that of the guest material 142. Therefore, this structural example can be described by reformulating the guest material 142 shown in Structural Example 1 as the scaffold 141_4. Thus, for the description of functions similar to those of Structural Example 1 of this embodiment, reference can be made to Structural Example 1 of this embodiment.

[0217] That is, the high-molecular-weight material 141 comprises the framework with hole-transport properties contained in framework 141_1 and the framework with electron-transport properties contained in framework 141_2. The two high-molecular-weight chains form an excited complex. Then, the excitation energy is transferred from the excited complex to framework 141_4, causing light to be emitted from framework 141_4. <Material, das bei den Licht emittierenden Schichten verwendet werden kann>

[0218] Next, materials that can be used in the light-emitting layer 140 are described.

[0219] The high molecular material 141 in the light-emitting layer 140 is not particularly limited as long as two high molecular chains of the high molecular material 141 have a function of forming an excited complex; however, the high molecular material 141 preferably contains a π-electron-deficient heteroaromatic skeleton and / or a π-electron-rich heteroaromatic skeleton and / or an aromatic amine skeleton. As the high molecular material 141, any of the materials described in Embodiment 1 can be used.

[0220] As the guest material 142 (phosphorescent compound), an organometallic complex or metal complex based on iridium, rhodium, or platinum can be used; particularly, an organoiridium complex such as an ortho-metalated iridium complex is preferred. As the ortho-metalated ligand, a 4H-triazole ligand, a 1H-triazole ligand, an imidazole ligand, a pyridine ligand, a pyrimidine ligand, a pyrazine ligand, an isoquinoline ligand, and the like can be cited. As the metal complex, a platinum complex with a porphyrin ligand, and the like can be cited.

[0221] Examples of the substance exhibiting an emission peak in the blue or green wavelength range include organometallic iridium complexes having a 4H-triazole skeleton, such as: B. Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-ĸN2]phenyl-ĸC}iridium(III) (abbreviation: Ir(mpptz-dmp)3), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: Ir(Mptz)3), Tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: Ir(iPrptz-3b)3) and Tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: Ir(iPrSbtz)3); organometallic iridium complexes with a 1H-triazole framework, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: Ir(Mptz1-mp)3) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: Ir(Prptz1-Me)3); organometallic iridium complexes with an imidazole framework, such asfac-Tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: Ir(iPrpmi)3) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: Ir(dmpimpt-Me)3); and organometallic iridium complexes in which a phenylpyridine derivative with an electron-withdrawing group is a ligand, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C. 2' ]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2 ]iridium(III)picolinate (abbreviation: Flrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2 }iridium(III)picolinate (abbreviation: Ir(CF3ppy)2(pic)) and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2 ]iridium(III) acetylacetonate (abbreviation: Flr(acac)). Among the materials listed above, the organometallic iridium complexes with a 4H-triazole framework exhibit high reliability and high light emission efficiency and are therefore particularly preferable.

[0222] Examples of the substance exhibiting an emission peak in the green or yellow wavelength range include organometallic iridium complexes with a pyrimidine skeleton, such asTris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(tBuppm)3), (Acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)2(acac)), (Acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: Ir(tBuppm)2(acac)), (Acetylacetonato)bis[4-(2-norbornyl)-6-phenylpyrimidinato]iridium(III) (abbreviation: Ir(nbppm)2(acac)), (Acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (Acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac)) and (Acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: Ir(dppm)2(acac)); organometallic iridium complexes with a pyrazine framework, such as(Acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: Ir(mppr-Me)2(acac)) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)); organometallic iridium complexes with a pyridine framework, such as tris(2-phenylpyridinato-N,C 2 )iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N,C 2 ')iridium(III)acetylacetonate (abbreviation: Ir(ppy)2(acac)), bis(benzo[h]quinolinato)iridium(III)acetylacetonate (abbreviation: Ir(bzq)2(acac)), tris(benzo[h]quinolinato)iridium(III) (abbreviation: Ir(bzq)3), tris(2-phenylquinolinato-N,C 2 )iridium(III) (abbreviation: Ir(pq)3) and bis(2-phenylquinolinato-N,d')iridium(III)acetylacetonate (abbreviation: Ir(pq)2(acac)); organometallic iridium complexes, such as bis(2,4-diphenyl-1,3-oxazolato-N,C 2 ')iridium(III)acetylacetonate (abbreviation: Ir(dpo)2(acac)), bis{2-[4'-(ρerfluorophenyl)phenyl]pyridinato-N,C 2}iridium(III)acetylacetonate (abbreviation: Ir(p-PF-ph)2(acac)), and bis(2-phenylbenzothiazolato-N,C 2 iridium(III) acetylacetonate (abbreviation: Ir(bt)2(acac)); and a rare earth metal complex, such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: Tb(acac)3(Phen)). Among the above-mentioned materials, the organometallic iridium complexes with a pyrimidine framework exhibit very high reliability and very high light emission efficiency and are therefore particularly preferable.

[0223] Examples of the substance exhibiting an emission peak in the yellow or red wavelength range include organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: Ir(5mdppm)2(dibm)), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(5mdppm)2(dpm)) and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1 npm)2(dpm)); organometallic iridium complexes having a pyrazine skeleton, such as B. (Acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: Ir(tppr)2(acac)), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: Ir(tppr)2(dpm)) and (Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: Ir(Fdpq)2(acac)); organometallic iridium complexes with a pyridine framework, such as tris(1-phenylisoquinolinato-N,C 2 ')iridium(III) (abbreviation: Ir(piq)3) and bis(1-phenylisoquinolinato-N,C 2 ')iridium(III) acetylacetonate (abbreviation: Ir(piq)2(acac)); a platinum complex such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: Eu(DBM)3(Phen)) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3(Phen)). Among the materials listed above, organometallic iridium complexes with a pyrimidine framework exhibit very high reliability and very high light emission efficiency and are therefore particularly preferred. Furthermore, the organometallic iridium complex with a pyrazine framework can exhibit red light emission with favorable chromaticity.

[0224] Any material can be used as the light-emitting material included in the light-emitting layer 140, as long as the material can convert triplet excitation energy into light emission. As an example of a material that can convert triplet excitation energy into light emission, in addition to a phosphorescent compound, a thermally activated delayed fluorescent (TADF) material can be cited. Accordingly, it is acceptable to replace "phosphorescent compound" with "thermally activated delayed fluorescent material" in the description.It should be noted that the thermally activated delayed fluorescent material is a material that has a small difference between the triplet excitation energy level and the singlet excitation energy level and has the function of converting the triplet excitation energy into a singlet excitation energy through reverse intersystem crossing. Thus, the TADF material can upconvert a triplet excited state to a singlet excited state using a small amount of thermal energy (i.e., reverse intersystem crossing is possible) and efficiently emit light (fluorescence) from the singlet excited state.The TADF is efficiently obtained under the condition that the energy difference between the triplet excitation energy level and the singlet excitation energy level is preferably greater than 0 eV and less than or equal to 0.2 eV, more preferably greater than 0 eV and less than or equal to 0.1 eV.

[0225] In particular, in the case where the material emitting thermally activated delayed fluorescence is formed of one kind of material, any of the thermally activated delayed fluorescent materials described in Embodiment 1 can be used.

[0226] The guest material 142 may be a high molecular compound, and for example, a high molecular compound containing an organometallic complex or iridium-, rhodium-, or platinum-based metal complex as a structural unit is preferable.

[0227] In the light-emitting layer 140, the framework 141_4 is not particularly limited; however, a light-emitting framework contained in the guest material 142 is preferably included in the framework 141_4. That is, as the structural unit, a structure in which one or two hydrogen atoms are removed from the organometallic complex or iridium-, rhodium-, or platinum-based metal complex is preferably used.

[0228] The light-emitting layer 140 may have a structure in which two or more layers are stacked. For example, in the case where the light-emitting layer 140 is formed by stacking a first light-emitting layer and a second light-emitting layer in this order from the hole-transporting layer side, the first light-emitting layer is formed using a substance having a hole-transporting property as a high-molecular material, and the second light-emitting layer is formed using a substance having an electron-transporting property as a high-molecular material.

[0229] The light-emitting layer 140 may contain another material in addition to the high-molecular material 141 and the guest material 142. Specifically, one of the materials of Embodiment 1 described above may be used.

[0230] Note that the light-emitting layer 140 can be formed by an evaporation method (including a vacuum evaporation method), an inkjet method, a coating method, a jet printing method, gravure printing, or the like. In addition to the above-mentioned materials, an inorganic compound such as a quantum dot or a high-molecular compound (e.g., an oligomer, a dendrimer, and a polymer) can be used.

[0231] The structure described in this embodiment may be used in a suitable combination with any of the structures described in the other embodiments. (Embodiment 3)

[0232] In this embodiment, examples of light-emitting elements having structures different from those described in Embodiments 1 and 2 will be described below with reference to Fig. 5A and Fig. 5B, Fig. 6A and Fig. 6B, Fig. 7A to Fig. 7C and Fig. 8A to Fig. 8C. <Strukturbeispiel 1 des Licht emittierenden Elements>

[0233] Fig. 5A and Fig. 5B are cross-sectional views each illustrating a light-emitting element of an embodiment of the present invention. In Fig. 5A and Fig. 5B, in some cases, a section with a similar function to that in Fig. 1A by the same hatching pattern as in Fig. 1A and are not specifically identified by a reference symbol. In addition, the same reference symbols are used for sections with similar functions, and a detailed description of the sections is omitted in some cases.

[0234] Light-emitting elements 260a and 260b in Fig. 5A and Fig. 5B may have a bottom-emission structure in which light is extracted via the substrate 200, or may have a top-emission structure in which light emitted from the light-emitting element is extracted in the direction opposite to the substrate 200. However, an embodiment of the present invention is not limited to this structure, and a light-emitting element having a dual-emission structure in which light emitted from the light-emitting element is extracted in both the top and bottom directions of the substrate 200 may be employed.

[0235] In the case where the light-emitting elements 260a and 260b each have a bottom-emission structure, the electrode 101 preferably has a function of transmitting light, and the electrode 102 preferably has a function of reflecting light. Alternatively, in the case where the light-emitting elements 260a and 260b each have a top-emission structure, the electrode 101 preferably has a function of reflecting light, and the electrode 102 preferably has a function of transmitting light.

[0236] The light-emitting elements 260a and 260b each include the electrode 101 and the electrode 102 above the substrate 200. Between the electrodes 101 and 102, a light-emitting layer 123B, a light-emitting layer 123G, and a light-emitting layer 123R are provided. The hole-injection layer 111, the hole-transport layer 112, the electron-transport layer 113, and the electron-injection layer 114 are also provided.

[0237] The light-emitting element 260b includes, as part of the electrode 101, a conductive layer 101a, a conductive layer 101b above the conductive layer 101a, and a conductive layer 101c below the conductive layer 101a. In other words, the light-emitting element 260b includes the electrode 101 with a structure in which the conductive layer 101a is disposed between the conductive layer 101b and the conductive layer 101c.

[0238] In the light-emitting element 260b, the conductive layer 101b and the conductive layer 101c can be formed from different materials or the same material. The electrode 101 preferably has a structure in which the conductive layer 101a is sandwiched between the layers formed from the same conductive material, in which case, patterning by etching can be easily performed.

[0239] In the light-emitting element 260b, the electrode 101 may comprise either the conductive layer 101b or the conductive layer 101c.

[0240] For each of the conductive layers 101a, 101b, and 101c included in the electrode 101, the structure and materials of the electrode 101 or 102 described in Embodiment 1 can be used.

[0241] In Fig. 5A and Fig. 5B, a partition wall 145 is provided between a region 221B, a region 221G, and a region 221R, which are located between the electrode 101 and the electrode 102. The partition wall 145 has an insulating property. The partition wall 145 covers end portions of the electrode 101 and has openings that overlap with the electrode. By the partition wall 145, the electrode 101 provided above the substrate 200 in the regions can be divided into island shapes.

[0242] Note that the light-emitting layer 123B and the light-emitting layer 123G may overlap each other in a region where they overlap the partition wall 145. The light-emitting layer 123G and the light-emitting layer 123R may overlap each other in a region where they overlap the partition wall 145. The light-emitting layer 123R and the light-emitting layer 123B may overlap each other in a region where they overlap the partition wall 145.

[0243] The partition wall 145 has an insulating property and is formed using an inorganic or organic material. Examples of the inorganic material include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride. Examples of the organic material include photosensitive resin materials such as an acrylic resin and a polyimide resin.

[0244] It should be noted that a silicon oxynitride film refers to a film in which the proportion of oxygen is higher than that of nitrogen. The silicon oxynitride film preferably contains oxygen, nitrogen, silicon, and hydrogen in the ranges of 55 atomic % to 65 atomic %, 1 atomic % to 20 atomic %, 25 atomic % to 35 atomic % and 0.1 atomic % to 10 atomic %, respectively. A silicon nitride oxide film refers to a film in which the proportion of nitrogen is higher than that of oxygen. The silicon nitride oxide film preferably contains nitrogen, oxygen, silicon, and hydrogen in the ranges of 55 atomic % to 65 atomic %, 1 atomic % to 20 atomic %, 25 atomic % to 35 atomic % and 0.1 atomic % to 10 atomic %, respectively.

[0245] Light-emitting layers 123R, 123G, and 123B preferably contain light-emitting materials with functions for emitting light of different colors. For example, when light-emitting layer 123R contains a light-emitting material with a red-emitting function, region 221R emits red light. When light-emitting layer 123G contains a light-emitting material with a green-emitting function, region 221G emits green light. When light-emitting layer 123B contains a light-emitting material with a blue-emitting function, region 221B emits blue light. The light-emitting element 260a or 260b having such a structure is used in a pixel of a display device, whereby a full-color display device can be manufactured. The thicknesses of the light-emitting layers may be the same or different from each other.

[0246] Any one or more of the light-emitting layers 123B, 123G, and 123R preferably includes the light-emitting layer 130 described in Embodiment 1 and / or the light-emitting layer 140 described in Embodiment 2, in which case a light-emitting element having a high light-emitting efficiency can be manufactured.

[0247] One or more of the light-emitting layers 123B, 123G and 123R may comprise two or more layers arranged one above the other.

[0248] When at least one light-emitting layer as described above includes the light-emitting layer described in Embodiments 1 or 2, and the light-emitting element 260a or 260b including the light-emitting layer is used in pixels of a display device, a display device with high light emission efficiency can be manufactured. The display device including the light-emitting element 260a or 260b can thus have reduced power consumption.

[0249] By providing an optical element (e.g., a color filter, a polarizing plate, and an anti-reflection film) on the light extraction side of the electrode through which light is extracted, the color purity of each of the light-emitting elements 260a and 260b can be improved. Accordingly, the color purity of a display device including the light-emitting element 260a or 260b can be improved. Alternatively, the reflection of external light from each of the light-emitting elements 260a and 260b can be reduced. Accordingly, the contrast ratio of a display device including the light-emitting element 260a or 260b can be improved.

[0250] For the other components of the light-emitting elements 260a and 260b, reference may be made to the components of the light-emitting elements in Embodiments 1 and 2. <Strukturbeispiel 2 des Licht emittierenden Elements>

[0251] Next, structural examples of the light-emitting elements that are different from those used in Fig. 5A and Fig. 5B, in the following using Fig. 6A and Fig. 6B.

[0252] Fig. 6A and Fig. 6B are cross-sectional views of a light-emitting element of an embodiment of the present invention. In Fig. 6A and Fig. 6B, in some cases, a section with a similar function to that in Fig. 5A and Fig. 5B by the same hatching pattern as in Fig. 5A and Fig. 5B and are not specifically identified by a reference numeral. In addition, the same reference numerals are used for sections with similar functions, and a detailed description of such sections is omitted in some cases.

[0253] Fig. 6A and Fig. 6B illustrate structural examples of a light-emitting element including the light-emitting layer between a pair of electrodes. A light-emitting element 262a shown in Fig. 6A has a top-emission structure in which light is taken out in a direction opposite to the substrate 200, and a light-emitting element 262b arranged in Fig. 6B has a bottom-emission structure in which light is extracted to the side of the substrate 200. However, an embodiment of the present invention is not limited to these structures, and may have a dual-emission structure in which light emitted from the light-emitting element is extracted in both the top and bottom directions with respect to the substrate 200 over which the light-emitting element is formed.

[0254] The light-emitting elements 262a and 262b each include the electrode 101, the electrode 102, an electrode 103, and an electrode 104 above the substrate 200. At least one light-emitting layer 170 is provided between the electrode 101 and the electrode 102, between the electrode 102 and the electrode 103, and between the electrode 102 and the electrode 104. The hole-injection layer 111, the hole-transport layer 112, the electron-transport layer 113, and the electron-injection layer 114 are further provided.

[0255] The electrode 101 comprises a conductive layer 101a and a conductive layer 101b over and in contact with the conductive layer 101a. The electrode 103 comprises a conductive layer 103a and a conductive layer 103b over and in contact with the conductive layer 103a. The electrode 104 comprises a conductive layer 104a and a conductive layer 104b over and in contact with the conductive layer 104a.

[0256] The light-emitting element 262a, which is in Fig. 6A, and the light-emitting element 262b shown in Fig. 6B each include a partition wall 145 between a region 222B disposed between the electrode 101 and the electrode 102, a region 222G disposed between the electrode 102 and the electrode 103, and a region 222R disposed between the electrode 102 and the electrode 104. The partition wall 145 has an insulating property. The partition wall 145 covers end portions of the electrodes 101, 103, and 104 and has openings overlapping with the electrodes. By the partition wall 145, the electrodes provided above the substrate 200 in the regions can be divided into island shapes.

[0257] The light-emitting elements 262a and 262b each include a substrate 220 provided with an optical element 224B, an optical element 224G, and an optical element 224R in the direction in which light emitted from the region 222B, the light emitted from the region 222G, and the light emitted from the region 222R are taken out. The light emitted from each region is emitted to the outside of the light-emitting element via each optical element. In other words, the light from the region 222B, the light from the region 222G, and the light from the region 222R are emitted via the optical element 224B, the optical element 224G, and the optical element 224R, respectively.

[0258] The optical elements 224B, 224G, and 224R each have a function of selectively transmitting light of a specific color of the incident light. For example, the light emitted from the region 222B via the optical element 224B is blue light, the light emitted from the region 222G via the optical element 224G is green light, and the light emitted from the region 222R via the optical element 224R is red light.

[0259] For example, a color layer (also called a color filter), a bandpass filter, a multilayer filter, or the like can be used for the optical elements 224R, 224G, and 224B. Alternatively, color conversion elements can be used as the optical elements. A color conversion element is an optical element that converts incident light into light with a longer wavelength than the incident light. Quantum dot elements can be advantageously used as the color conversion elements. The use of the quantum dot type can increase the color reproducibility of the display device.

[0260] One or more optical elements may be further disposed over each of the optical elements 224R, 224G, and 224B. As another optical element, for example, a circularly polarizing plate, an anti-reflection film, or the like may be provided. A circularly polarizing plate provided on the side where light emitted from the light-emitting element of the display device is taken out can prevent a phenomenon in which light incident from the outside of the display device is reflected inside the display device and redirected to the outside. An anti-reflection film can attenuate external light reflected from a surface of the display device. This leads to clear observation of light emitted from the display device.

[0261] It should be noted that in Fig. 6A and Fig. 6B blue light (B), green light (G) and red light (R) emitted from the areas via the optical elements are schematically represented by arrows made of dashed lines.

[0262] An opaque layer 223 is provided between the optical elements. The opaque layer 223 functions to block light emitted from the adjacent regions. Note that a structure without the opaque layer 223 may also be used.

[0263] The opaque layer 223 has a function of reducing the reflection of external light. The opaque layer 223 has a function of preventing mixing of light emitted from an adjacent light-emitting element. A metal, a resin containing a black pigment, carbon black, a metal oxide, a composite oxide containing a solid solution of a plurality of metal oxides, or the like can be used as the opaque layer 223.

[0264] Note that the optical element 224B and the optical element 224G may overlap each other in a region where they overlap the opaque layer 223. Furthermore, the optical element 224G and the optical element 224R may overlap each other in a region where they overlap the opaque layer 223. Furthermore, the optical element 224R and the optical element 224B may overlap each other in a region where they overlap the opaque layer 223.

[0265] For the structures of the substrate 200 and the substrate 220 provided with the optical elements, reference may be made to the substrate of Embodiment 1.

[0266] Furthermore, the light-emitting elements 262a and 262b have a microcavity structure. <<Mikrokavitätsstruktur> >

[0267] Light emitted from the light-emitting layer 170 oscillates between a pair of electrodes (e.g., the electrode 101 and the electrode 102). The light-emitting layer 170 is formed at a location such that it amplifies the light of a desired wavelength among light to be emitted. For example, by adjusting the optical length from a reflective portion of the electrode 101 to the light-emitting portion of the light-emitting layer 170 and the optical length from a reflective portion of the electrode 102 to the light-emitting portion of the light-emitting layer 170, the light of a desired wavelength among light emitted from the light-emitting layer 170 can be amplified.

[0268] In each of the light-emitting elements 262a and 262b, the light of a desired wavelength among the light emitted from the light-emitting layer 170 can be increased by adjusting the thicknesses of the conductive layers (the conductive layer 101b, the conductive layer 103b, and the conductive layer 104b) in each region. Note that the thickness of the hole-injection layer 111 and / or the hole-transport layer 112 may differ between regions to increase the light emitted from the light-emitting layer 170.

[0269] For example, in the case where the refractive index of the conductive material having a function of reflecting light in the electrodes 101 to 104 is lower than the refractive index of the light-emitting layer 170, the thickness of the conductive layer 101b of the electrode 101 is adjusted such that the optical length between the electrode 101 and the electrode 102 becomes m B λ B / 2 becomes (m B is a natural number and λ e is the wavelength of the light amplified in the region 222B). The thickness of the conductive layer 103b of the electrode 103 is similarly adjusted such that the optical length between the electrode 103 and the electrode 102 is m G λ G / 2 becomes (m G is a natural number and λ G is the wavelength of the light amplified in the region 222G). Furthermore, the thickness of the conductive layer 104b of the electrode 104 is adjusted such that the optical length between the electrode 104 and the electrode 102 is m R λ R / 2 becomes (m R is a natural number and λR is the wavelength of the light amplified in the range 222R).

[0270] In the case where it is difficult to precisely determine the reflective areas of the electrodes 101 to 104, the optical length for amplifying light emitted from the light-emitting layer 170 can be derived by assuming that certain areas of the electrodes 101 to 104 are the reflective areas. In the case where it is difficult to precisely determine the light-emitting area of ​​the light-emitting layer 170, the optical length for amplifying light emitted from the light-emitting layer 170 can be derived by assuming that a certain area of ​​the light-emitting layer 170 is the light-emitting area.

[0271] In the above manner, by the microcavity structure in which the optical length between the pair of electrodes is adjusted in the respective regions, scattering and absorption of light in the vicinity of the electrodes can be suppressed, resulting in high light extraction efficiency. In the above structure, the conductive layers 101b, 103b, and 104b preferably have a function of transmitting light. The materials for the conductive layers 101b, 103b, and 104b may be the same as or different from each other. Preferably, the conductive layers 101b, 103b, and 104b are formed using the same material, and patterning by etching can be easily performed. Each of the conductive layers 101b, 103b, and 104b may have a multilayer structure composed of two or more layers.

[0272] Since the light-emitting element 262a, which is Fig. 6A, has a top-emission structure, the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a have a function of reflecting light. Furthermore, the electrode 102 preferably has functions of transmitting and reflecting light.

[0273] Since the light-emitting element 262b, which is Fig. 6B, has a bottom-emission structure, the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a preferably have light transmitting and reflecting functions. Furthermore, the electrode 102 preferably has a light reflecting function.

[0274] In each of the light-emitting elements 262a and 262b, the conductive layers 101a, 103a, and 104a can be formed from different materials or the same material. If the conductive layers 101a, 103a, and 104a are formed from the same material, the manufacturing cost of the light-emitting elements 262a and 262b can be reduced. Note that each of the conductive layers 101a, 103a, and 104a may have a multilayer structure composed of two or more layers.

[0275] The light-emitting layer 170 in the light-emitting elements 262a and 262b preferably has the structure described in Embodiment 1 or 2, whereby light-emitting elements with high light emission efficiency can be manufactured.

[0276] The light-emitting layer 170 may have a multilayer structure composed of two layers. The two light-emitting layers, which contain two types of light-emitting materials (a first compound and a second compound) for emitting different colors of light, enable light emission of a variety of colors. Preferably, the light-emitting materials of the light-emitting layers are specifically selected such that white light can be obtained by combining light emissions from the light-emitting layer 170.

[0277] The light-emitting layer 170 may have a multilayer structure of three or more layers, which may include a layer that does not contain a light-emitting material.

[0278] In the manner described above, the light-emitting element 262a or 262b including at least one of the light-emitting layers having the structures described in Embodiments 1 and 2 is used in pixels of a display device, whereby a display device with high light emission efficiency can be manufactured. The display device including the light-emitting element 262a or 262b can thus have low power consumption.

[0279] For the other components of the light-emitting elements 262a and 262b, reference may be made to the components of the light-emitting elements 260a and 260b and the light-emitting elements of Embodiments 1 and 2. <Herstellungsverfahren des Licht emittierenden Elements>

[0280] Next, a method for manufacturing a light-emitting element of an embodiment of the present invention will be described below with reference to Fig. 7A to Fig. 7C and Fig. 8A to Fig. 8C. Here, a method for manufacturing the light-emitting element 262a shown in Fig. 6A.

[0281] Fig. 7A to Fig. 7C and Fig. 8A to Fig. 8C are cross-sectional views illustrating a method of manufacturing the light-emitting element of one embodiment of the present invention.

[0282] The method for manufacturing the light-emitting element 262a described below comprises first to sixth steps. <<Erster Schritt> >

[0283] In the first step, the electrodes (specifically, the conductive layer 101a of the electrode 101, the conductive layer 103a of the electrode 103 and the conductive layer 104a of the electrode 104) of the light-emitting elements are formed over the substrate 200 (see Fig. 7A).

[0284] In this embodiment, a conductive layer having a light-reflecting function is formed over the substrate 200 and processed into a desired shape, thereby forming the conductive layers 101a, 103a, and 104a. An alloy film of silver, palladium, and copper (also referred to as an Ag-Pg-Cu film or APC) is used as the conductive layer having a light-reflecting function. The conductive layers 101a, 103a, and 104a are preferably formed through a single step of processing the same conductive layer, as this can reduce manufacturing costs.

[0285] It should be noted that a plurality of transistors may be formed over the substrate 200 prior to the first step. The plurality of transistors may be electrically connected to the conductive layers 101a, 103a, and 104a. <<Zweiter Schritt> >

[0286] In the second step, the conductive layer 101b having a function of transmitting light is formed over the conductive layer 101a of the electrode 101, the conductive layer 103b having a function of transmitting light is formed over the conductive layer 103a of the electrode 103, and the conductive layer 104b having a function of transmitting light is formed over the conductive layer 104a of the electrode 104 (see Fig. 7B).

[0287] In this embodiment, conductive layers 101b, 103b, and 104b, each having a light-transmitting function, are formed over conductive layers 101a, 103a, and 104a, each having a light-reflecting function, thereby forming electrode 101, electrode 103, and electrode 104. ITSO films are used as conductive layers 101b, 103b, and 104b.

[0288] The conductive layers 101b, 103b, and 104b having a light transmitting function can be formed through a plurality of steps. When the conductive layers 101b, 103b, and 104b having a light transmitting function are formed through a plurality of steps, they can be formed to have thicknesses that enable suitable microcavity structures in the respective regions. <<Dritter Schritt> >

[0289] In the third step, the partition wall 145 covering the end portions of the electrodes of the light-emitting element is formed (see Fig. 7C).

[0290] The partition wall 145 includes an opening that overlaps the electrode. The conductive film exposed through the opening serves as the anode of the light-emitting element. A polyimide-based resin is used as the partition wall 145 in this embodiment.

[0291] In the first to third steps, various film formation methods and micromachining techniques can be used because there is no possibility of damaging the EL layer (a layer containing an organic compound). In this embodiment, a reflective conductive layer is formed by a sputtering method, a pattern is formed over the conductive layer by a lithography method, and then the conductive layer is processed into an island shape by a dry etching method or a wet etching method to form the conductive layer 101a of the electrode 101, the conductive layer 103a of the electrode 103, and the conductive layer 104a of the electrode 104.Then, a transparent conductive film is formed by a sputtering method, a pattern is formed over the transparent conductive film by a lithography method, and then the transparent conductive film is processed into an island shape by a wet etching method to form the electrodes 101, 103, and 104. <<Vierter Schritt> >

[0292] In the fourth step, the hole injection layer 111, the hole transport layer 112, the light emitting layer 170, the electron transport layer 113, the electron injection layer 114 and the electrode 102 are formed (see Fig. 8A).

[0293] The hole-injection layer 111 can be formed, for example, by spin-coating poly(ethylenedioxythiophene) / poly(styrenesulfonic acid). The hole-transport layer 112, which can be formed using a hole-transport material, can be formed, for example, by spin-coating polyvinylcarbazole. After the formation of the hole-injection layer 111 and the hole-transport layer 112, a heat treatment can be performed under an air atmosphere or an inert gas atmosphere, such as nitrogen.

[0294] The light-emitting layer 170 may be formed using a high-molecular material that emits light in at least one color selected from violet, blue, blue-green, green, yellow-green, yellow, orange, and red. A fluorescent or phosphorescent organic compound may be used as the high-molecular material. The light-emitting layer 170 may be formed by coating a solvent in which the high-molecular material is dissolved using a spin-coating method or the like. After the formation of the light-emitting layer 170, a heat treatment may be performed under an air atmosphere or an inert gas atmosphere such as nitrogen.The fluorescent or phosphorescent organic compound can be used as the guest material, and the guest material can be dispersed in a high-molecular material having a higher excitation energy than the guest material. Only the light-emitting organic compound can be deposited, or the light-emitting organic compound mixed with another material can be deposited. The light-emitting layer 170 can have a two-layer structure. In this case, the two light-emitting layers preferably contain light-emitting substances that emit light of different colors.

[0295] The electron-transport layer 113 may be formed using a substance with a high electron-transport property. The electron-injection layer 114 may be formed using a substance with a high electron-injection property. Note that the electron-transport layer 113 and the electron-injection layer 114 may be formed by an evaporation method.

[0296] The electrode 102 can be formed by stacking a reflective conductive film and a light-transmitting conductive film. The electrode 102 can have a single-layer structure or a multi-layer structure.

[0297] Through the steps described above, the light-emitting element including the region 222B, the region 222G, and the region 222R over the electrode 101, the electrode 103, and the electrode 104, respectively, is formed over the substrate 200. <<Fünfter Schritt> >

[0298] In the fifth step, the opaque layer 223, the optical element 224B, the optical element 224G and the optical element 224R are formed over the substrate 220 (see Fig. 8B).

[0299] A resin film containing a black pigment is formed as the opaque layer 223 in a desired area. Subsequently, the optical element 224B, the optical element 224G, and the optical element 224R are formed over the substrate 220 and the opaque layer 223. A resin film containing a blue pigment is formed as the optical element 224B in a desired area. A resin film containing a green pigment is formed as the optical element 224G in a desired area. A resin film containing a red pigment is formed as the optical element 224R in a desired area. <<Sechster Schritt> >

[0300] In the sixth step, the light-emitting element formed over the substrate 200 is attached to the light-opaque layer 223, the optical element 224B, the optical element 224G, and the optical element 224R formed over the substrate 220, and sealed with a sealant (not shown).

[0301] Through the steps described above, the light-emitting element 262a shown in Fig. 6A.

[0302] It should be noted that the structures described in this embodiment may be used in a suitable combination with any of the structures described in the other embodiments. (Embodiment 4)

[0303] In this embodiment, a display device of an embodiment of the present invention will be described below with reference to Fig. 9A and Fig. 9B, Fig. 10A and Fig. 10B, Fig. 11, Fig. 12A and Fig. 12B, Fig. 13A and Fig. 13B, Fig. 14, Fig. 15A and Fig. 15B, Fig. 16, Fig. 17A and Fig. 17B, Fig. 18A to Fig. 18D and Fig. 19 described. <Strukturbeispiel 1 der Anzeigevorrichtung>

[0304] Fig. 9A is a plan view illustrating a display device 600, and Fig. 9B is a cross-sectional view taken along the dashed line AB and the dashed line CD in Fig. 9A. The display device 600 includes drive circuit sections (a signal line drive circuit section 601 and a scan line drive circuit section 603) and a pixel section 602. Note that the signal line drive circuit section 601, the scan line drive circuit section 603, and the pixel section 602 have a function of controlling light emission of a light-emitting element.

[0305] The display device 600 also includes an element substrate 610, a sealing substrate 604, a sealant 605, a region 607 enclosed by the sealant 605, a lead wire 608, and an FPC 609.

[0306] Note that a lead line 608 is a line for transmitting signals input to the signal line driver circuit section 601 and the scan line driver circuit section 603, and for receiving a video signal, a clock signal, a start signal, a reset signal, and the like from the FPC 609, which serves as an external input terminal. Although only the FPC 609 is illustrated here, the FPC 609 may be provided with a printed wiring board (PWB).

[0307] As the signal line driver circuit section 601, a CMOS circuit combining an n-channel transistor 623 and a p-channel transistor 624 is formed. Various types of circuits, such as a CMOS circuit, a PMOS circuit, or an NMOS circuit, can be used as the signal line driver circuit section 601 or the scan line driver circuit section 603. Although a driver in which a driver circuit section is formed and a pixel are formed over the same surface of a substrate in the display device of this embodiment, the driver circuit section is not necessarily formed over the substrate and may be formed outside the substrate.

[0308] The pixel section 602 includes a switching transistor 611, a current control transistor 612, and a lower electrode 613 electrically connected to a drain of the current control transistor 612. Note that a partition wall 614 is formed to cover end portions of the lower electrode 613. For the partition wall 614, for example, a positive photosensitive acrylic resin film can be used.

[0309] To achieve favorable coverage by a film formed over the partition wall 614, the partition wall 614 is formed to have a curved surface with a curvature at its upper or lower end portion. For example, in the case where a positive photosensitive acrylic is used as the material of the partition wall 614, it is preferable that only the upper end portion of the partition wall 614 has a curved surface with a curvature (the radius of curvature being 0.2 μm to 3 μm). Either a negative photosensitive resin or a positive photosensitive resin can be used as the partition wall 614.

[0310] Note that there is no particular limitation on a structure of the transistors (transistors 611, 612, 623, and 624). For example, a staggered transistor may be used. Furthermore, there is no particular limitation on the polarity of these transistors. N-channel and p-channel transistors may be used for these transistors, or, for example, either n-channel transistors or p-channel transistors may be used. Furthermore, there is no particular limitation on the crystallinity of a semiconductor film used for these transistors. For example, an amorphous semiconductor film or a crystalline semiconductor film may be used. Examples of a semiconductor material include Group 14 semiconductors (e.g., a semiconductor including silicon), compound semiconductors (including oxide semiconductors), organic semiconductors, and the like.For example, an oxide semiconductor having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more, is preferably used for the transistors so that the off-state current of the transistors can be reduced. Examples of the oxide semiconductor include an In-Ga oxide and an In-M-Zn oxide (M is Al, Ga, Y, zirconium (Zr), La, cerium (Ce), Sn, hafnium (Hf), or Nd).

[0311] An EL layer 616 and an upper electrode 617 are formed over the lower electrode 613. Here, the lower electrode 613 serves as an anode, and the upper electrode 617 serves as a cathode.

[0312] Furthermore, the EL layer 616 is formed by various methods, such as an evaporation method using an evaporation mask, an inkjet method, or a spin coating method. A low-molecular compound or a high-molecular compound can be used as another material included in the EL layer 616.

[0313] Note that a light-emitting element 618 is formed including the lower electrode 613, the EL layer 616, and the upper electrode 617. The light-emitting element 618 preferably has any of the structures described in Embodiments 1 to 3. In the case where the pixel portion includes a plurality of light-emitting elements, the pixel portion may include either one of the light-emitting elements described in Embodiments 1 to 3 or a light-emitting element having a different structure.

[0314] When the sealing substrate 604 and the element substrate 610 are bonded together with the sealant 605, the light-emitting element 618 is provided in the region 607 enclosed by the element substrate 610, the sealing substrate 604, and the sealant 605. The region 607 is filled with a filler material. In some cases, the region 607 is filled with an inert gas (nitrogen, argon, or the like) or filled with a UV-curing resin or a thermosetting resin that can be used for the sealant 605. For example, a polyvinyl chloride (PVC)-based resin, an acrylic-based resin, a polyimide-based resin, an epoxy-based resin, a silicone-based resin, a polyvinyl butyral (PVB)-based resin, or an ethylene vinyl acetate (EVA)-based resin can be used.Preferably, the sealing substrate is provided with a recessed part and the desiccant is arranged in the recessed part, in which case deterioration due to the influence of moisture can be prevented.

[0315] An optical element 621 is provided under the sealing substrate 604 to overlap the light-emitting element 618. An opaque layer 622 is provided under the sealing substrate 604. The structures of the optical element 621 and the opaque layer 622 may be the same as those of the optical element and the opaque layer of Embodiment 3, respectively.

[0316] An epoxy-based resin or a glass frit is preferably used for the sealant 605. Preferably, such a material allows as little moisture or oxygen permeation as possible. A glass substrate, a quartz substrate, or a plastic substrate made of fiber-reinforced plastic (FRP), poly(vinyl fluoride) (PVF), polyester, acrylic, or the like can be used as the sealant substrate 604.

[0317] Here, a method of forming the EL layer 616 by a droplet ejection method is described based on Fig. 18A to Fig. 18D described. Fig. 18A to Fig. 18D are cross-sectional views illustrating the process of forming the EL layer 616.

[0318] First, in Fig. 18A, the element substrate 610 is shown, over which the lower electrode 613 and the partition wall 614 are formed. However, as shown in Fig. 9B, the lower electrode 613 and the partition wall 614 are formed over an insulating film over a substrate.

[0319] Next, into a portion where the lower electrode 613 is exposed and which is an opening of the partition wall 614, a droplet 684 is ejected from a droplet ejector 683 to form a composition-containing layer 685. The droplet 684 is a composition containing a solvent and adheres to the lower electrode 613 (see Fig. 18B).

[0320] It should be noted that the process for ejecting the droplet 684 may be performed under reduced pressure.

[0321] Then, the solvent is removed from the composition-containing layer 685, and the resulting layer is solidified to form the EL layer 616 (see Fig. 18C).

[0322] The solvent can be removed by drying or heating.

[0323] Next, the upper electrode 617 is formed over the EL layer 616, and the light-emitting element 618 is formed (see Fig. 18D).

[0324] When the EL layer 616 is formed by a droplet ejection method as described above, the composition can be selectively ejected, and thus, the loss of materials can be reduced. Furthermore, no lithography process or the like is required for molding, and therefore the process can be simplified and a reduction in cost can be achieved.

[0325] The droplet ejection method described above is a general term for a means comprising a nozzle provided with a composition ejecting orifice or a means for ejecting droplets such as a head having one nozzle or a plurality of nozzles.

[0326] Next, a droplet ejector used for the droplet ejection method is described by Fig. 19 described. Fig. 19 is a conceptual diagram illustrating a droplet ejector 1400.

[0327] The droplet ejection device 1400 includes a droplet ejection means 1403. In addition, the droplet ejection means 1403 is provided with a head 1405 and a head 1412.

[0328] The heads 1405 and 1412 are connected to a control means 1407, and this control means 1407 is controlled by a computer 1410; in this way, a preprogrammed pattern can be drawn.

[0329] The drawing can be performed at a time, for example, based on a mark 1411 formed over a substrate 1402. Alternatively, the reference point can be determined based on an outer edge of the substrate 1402. Here, the mark 1411 is detected by an imaging means 1404 and converted into a digital signal by an image processing means 1409. The digital signal is then perceived by the computer 1410, and a control signal is generated and transmitted to the control means 1407.

[0330] An image sensor or the like using a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) can be used for the imaging means 1404. Note that information about a pattern to be formed over the substrate 1402 is stored in a storage medium 1408, and the control signal is transmitted to the control means 1407 based on the information, whereby the head 1405 and the head 1412 of the droplet ejection means 1403 can be separately controlled. A material to be ejected is supplied to the head 1405 and the head 1412 from a material source 1413 and a material source 1414, respectively, through pipes.

[0331] In the head 1405, a space 1406 filled with a liquid material, as shown by a dashed line, and a nozzle serving as an ejection port are provided. Although not shown, an internal structure of the head 1412 is similar to that of the head 1405. When the nozzle sizes of the heads 1405 and 1412 are different from each other, patterns of different materials with different widths can be drawn simultaneously. Alternatively, one head can eject multiple types of light-emitting materials or the like and draw a pattern. When a pattern is drawn in a large area, the same material can be ejected from a plurality of nozzles simultaneously, and the pattern can be drawn to improve throughput. When a large substrate is used, the heads 1405 and 1412 can eject the substrate in the directions of arrows X, Y, and Z in Fig. 19 can be freely scanned, and the area in which a pattern is drawn can be freely set. Therefore, a plurality of the same patterns can be drawn over a substrate.

[0332] Furthermore, the composition ejection step may be performed under reduced pressure. The substrate may be heated when the composition is ejected. After the composition is ejected, a drying step and / or a baking step are / is performed. Both the drying step and the baking step are heat treatment steps; however, they are different in purpose, temperature, and time. The drying step and the baking step are each performed under normal pressure or reduced pressure by laser light irradiation, rapid thermal annealing, heating using a heating furnace, or the like. Note that there is no particular limitation on the timing and number of steps of this heat treatment.The appropriate temperature when performing the drying step and the baking step depends on the materials of the substrate and the properties of the composition.

[0333] In the above-described manner, the display device comprising any of the light-emitting elements and the optical elements described in Embodiments 1 to 3 can be obtained. <Strukturbeispiel 2 der Anzeigevorrichtung>

[0334] Next, another example of the display device is shown using Fig. 10A and Fig. 10B and Fig. 11. It should be noted that Fig. 10A and Fig. 10B and Fig. 11 are each a cross-sectional view of a display device of an embodiment of the present invention.

[0335] In Fig. 10A, a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, lower electrodes 1024R, 1024G, and 1024B of the light-emitting elements, a partition wall 1025, an EL layer 1028, an upper electrode 1026 of the light-emitting elements, a sealing layer 1029, a sealing substrate 1031, a sealant 1032, and the like are illustrated.

[0336] In Fig. 10A, examples of the optical elements, i.e., color layers (a red color layer 1034R, a green color layer 1034G, and a blue color layer 1034B), are provided on a transparent base material 1033. An opaque layer 1035 may be further provided. The transparent base material 1033, which is provided with the color layers and the opaque layer, is located on and fixed to the substrate 1001. Note that the color layers and the opaque layer are covered with a covering layer 1036. In the structure in Fig. 10A, red light, green light, and blue light are transmitted through the color layers, and thus an image can be displayed using the pixels of three colors.

[0337] Fig. 10B illustrates an example in which the color layers (the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B) as examples of the optical elements are provided between the gate insulating film 1003 and the first interlayer insulating film 1020. As in this structure, the color layers may be arranged between the substrate 1001 and the sealing substrate 1031.

[0338] Fig. 11 illustrates an example in which the color layers (the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B) as examples of the optical elements are provided between the first interlayer insulating film 1020 and the second interlayer insulating film 1021. As in this structure, the color layers may be arranged between the substrate 1001 and the sealing substrate 1031.

[0339] The display device described above has a structure in which light is taken out from the side of the substrate 1001 on which the transistors are formed (a bottom-emission structure); however, it may have a structure in which light is taken out from the side of the sealing substrate 1031 (a top-emission structure). <Strukturbeispiel 3 der Anzeigevorrichtung>

[0340] Fig. 12A and Fig. 12B are each an example of a cross-sectional view of a display device having a top-emission structure. It should be noted that Fig. 12A and Fig. 12B are each a cross-sectional view illustrating the display device of an embodiment of the present invention, and the driving circuit section 1041, the peripheral section 1042 and the like shown in Fig. 10A and Fig. 10B and Fig. 11 are not shown in these.

[0341] In this case, a substrate that does not transmit light can be used as the substrate 1001. The process up to the step of forming a connection electrode that connects the transistor and the anode of the light-emitting element is performed in a manner similar to that of the display device having a bottom emission structure. Next, a third interlayer insulating film 1037 is formed to cover an electrode 1022. This insulating film may have a planarization function. The third interlayer insulating film 1037 may be formed using a material similar to that of the second interlayer insulating film, or may be formed using other known materials.

[0342] The lower electrodes 1024R, 1024G and 1024B of the light-emitting elements each serve as anode; however, they can also serve as cathode. In the case of a Fig. 12A and Fig. In the display device having a top-emission structure shown in FIG. 12B, the lower electrodes 1024R, 1024G, and 1024B preferably further have a property of reflecting light. The upper electrode 1026 is provided above the EL layer 1028. Preferably, the upper electrode 1026 has a function of reflecting light and a function of transmitting light, and a microcavity structure may be used between the upper electrode 1026 and the lower electrodes 1024R, 1024G, and 1024B, in which case the intensity of light having a specific wavelength is increased.

[0343] In case of a Fig. In the top-emission structure illustrated in FIG. 12A, sealing may be performed with the sealing substrate 1031 on which the color layers (the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B) are provided. The sealing substrate 1031 may be provided with the opaque layer 1035 positioned between pixels. Note that a light-transmissive substrate is advantageously used as the sealing substrate 1031.

[0344] Fig. 12A exemplifies the structure provided with the light-emitting elements and the color layers for the light-emitting elements; however, the structure is not limited thereto. For example, as shown in Fig. 12B, a structure including the red color layer 1034R and the blue color layer 1034B, but no green color layer, can be used to obtain a full-color display with the three colors of red, green, and blue. Fig. The structure shown in Figure 12A, in which the light-emitting elements are provided with the color layers, is effective in suppressing the reflection of external light. In contrast, the structure shown in Fig. 12B, in which the light-emitting elements are provided with the red color layer and the blue color layer but without the green color layer, is effective for reducing power consumption due to a small energy loss of the light emitted from the green light-emitting element. <Strukturbeispiel 4 der Anzeigevorrichtung>

[0345] Although a display device comprising subpixels of three colors (red, green, and blue) has been described above, the number of colors of subpixels may be four (red, green, blue, and yellow, or red, green, blue, and white). Fig. 13A and Fig. 13B, Fig. 14 and Fig. 15A and Fig. 15B illustrate structures of display devices including the lower electrodes 1024R, 1024G, 1024B, and 1024Y, respectively. Fig. 13A and Fig. 13B and Fig. 14 each illustrate a display device having a structure in which light is taken from the side of the substrate 1001 on which transistors are formed (bottom emission structure), and Fig. 15A and Fig. 15B each illustrates a display device having a structure in which light is taken out from the sealing substrate 1031 side (top emission structure).

[0346] Fig. 13A illustrates an example of a display device in which optical elements (the color layer 1034R, the color layer 1034G, the color layer 1034B, and a color layer 1034Y) are provided on the transparent base material 1033. Fig. 13B illustrates an example of a display device in which optical elements (the color layer 1034R, the color layer 1034G, the color layer 1034B, and the color layer 1034Y) are provided between the gate insulating film 1003 and the first interlayer insulating film 1020. Fig. 14 illustrates an example of a display device in which optical elements (the color layer 1034R, the color layer 1034G, the color layer 1034B, and the color layer 1034Y) are provided between the first interlayer insulating film 1020 and the second interlayer insulating film 1021.

[0347] The color layer 1034R transmits red light, the color layer 1034G transmits green light, and the color layer 1034B transmits blue light. The color layer 1034Y transmits yellow light or light of a variety of colors selected from blue, green, yellow, and red. When the color layer 1034Y can transmit light of a variety of colors selected from blue, green, yellow, and red, the light transmitted by the color layer 1034Y can be white light. Since the light-emitting element that emits yellow or white light has high light emission efficiency, the display device including the color layer 1034Y can have low power consumption.

[0348] The top emission indicators used in Fig. 15A and Fig. 15B, a light-emitting element including the lower electrode 1024Y preferably has a microcavity structure between the upper electrode 1026 and the lower electrodes 1024R, 1024G, 1024B, and 1024Y, as in the display device shown in Fig. 12A. In the display device shown in Fig. 15A, sealing can be performed with the sealing substrate 1031 on which the color layers (the red color layer 1034R, the green color layer 1034G, the blue color layer 1034B, and the yellow color layer 1034Y) are provided.

[0349] Light emitted via the microcavity and the yellow color layer 1034Y has an emission spectrum in a yellow region. Since yellow is a color with a high luminance factor, a light-emitting element that emits yellow light has high light emission efficiency. Consequently, the display device can be Fig. 15A reduce power consumption.

[0350] Fig. 15A exemplifies the structure provided with the light-emitting elements and the color layers for the light-emitting elements; however, the structure is not limited thereto. For example, as shown in Fig. 15B, a structure comprising the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B, but no yellow color layer, can be used to obtain a full-color display with the four colors of red, green, blue, and yellow, or red, green, blue, and white. Fig. The structure shown in Figure 15A, in which the light-emitting elements are provided with the color layers, is effective for suppressing the reflection of external light. In contrast, the structure shown in Fig. 15B, in which the light-emitting elements are provided with the red color layer, the green color layer, and the blue color layer but without the yellow color layer, is effective for reducing power consumption due to a small energy loss of the light emitted from the yellow or white light-emitting element. <Strukturbeispiel 5 der Anzeigevorrichtung>

[0351] Next, a display device of another embodiment of the present invention will be described with reference to Fig. 16 described. Fig. 16 is a cross-sectional view taken along the dash-dotted line AB and the dash-dotted line CD in Fig. 9A. It should be noted that in Fig. 16 sections with functions similar to those of the sections in Fig. 9B, with the same reference numerals as in Fig. 9B, and a detailed description of the sections is omitted.

[0352] The display device 600 in Fig. 16 includes a sealing layer 607a, a sealing layer 607b, and a sealing layer 607c in a region 607 enclosed by the element substrate 610, the sealing substrate 604, and the sealant 605. For one or more of the sealing layer 607a, the sealing layer 607b, and the sealing layer 607c, a resin such as a polyvinyl chloride (PVC)-based resin, an acrylic-based resin, a polyimide-based resin, an epoxy-based resin, a silicone-based resin, a polyvinyl butyral (PVB)-based resin, or an ethylene vinyl acetate (EVA)-based resin may be used. Alternatively, an inorganic material such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, or aluminum nitride may be used. The formation of the sealing layers 607a, 607b and 607c can prevent the light-emitting element 618 from deteriorating due to impurities such asWater, which is preferable. In the case where the sealing layers 607a, 607b, and 607c are formed, the sealant 605 is not necessarily provided.

[0353] Alternatively, any one or two of the sealing layers 607a, 607b, and 607c may be provided, or four or more sealing layers may be formed. When the sealing layer has a multi-layer structure, contaminants such as water can be effectively prevented from penetrating from the outside of the display device 600 into the light-emitting element 618 located inside the display device. In the case where the sealing layer has a multi-layer structure, a resin and an organic material are preferably stacked. <Strukturbeispiel 6 der Anzeigevorrichtung>

[0354] Although the display devices in Structural Examples 1 to 4 in this embodiment each have a structure including optical elements, an embodiment of the present invention does not necessarily include an optical element.

[0355] Fig. 17A and Fig. 17B each illustrates a display device having a structure in which light is taken out from the sealing substrate 1031 side (a top-emission display device). Fig. 17A illustrates an example of a display device including a light-emitting layer 1028R, a light-emitting layer 1028G, and a light-emitting layer 1028B. Fig. 17B illustrates an example of a display device including a light-emitting layer 1028R, a light-emitting layer 1028G, a light-emitting layer 1028B, and a light-emitting layer 1028Y.

[0356] The light-emitting layer 1028R has a red light emitting function, the light-emitting layer 1028G has a green light emitting function, and the light-emitting layer 1028B has a blue light emitting function. The light-emitting layer 1028Y has a yellow light emitting function or a multi-color light emitting function selected from blue, green, and red. The light-emitting layer 1028Y can emit white light. Since the light-emitting element that emits yellow or white light has high light emission efficiency, the display device including the light-emitting layer 1028Y can have low power consumption.

[0357] Each of the display devices in Fig. 17A and Fig. 17B does not necessarily include color layers serving as optical elements, since EL layers emitting lights of different colors are included in subpixels.

[0358] For the sealing layer 1029, a resin such as a polyvinyl chloride (PVC)-based resin, an acrylic-based resin, a polyimide-based resin, an epoxy-based resin, a silicone-based resin, a polyvinyl butyral (PVB)-based resin, or an ethylene vinyl acetate (EVA)-based resin can be used. Alternatively, an inorganic material such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, or aluminum nitride can be used. The formation of the sealing layer 1029 can prevent the light-emitting element from deteriorating due to impurities such as water, which is preferable.

[0359] Alternatively, the sealing layer 1029 may have a single-layer or a double-layer structure, or four or more sealing layers may be formed as the sealing layer 1029. When the sealing layer has a multi-layer structure, contaminants such as water can be effectively prevented from penetrating from the outside of the display device into the interior of the display device. In the case where the sealing layer has a multi-layer structure, a resin and an organic material are preferably stacked.

[0360] Note that the sealing substrate 1031 has a function of protecting the light-emitting element. Thus, a flexible substrate or a flexible film can be used for the sealing substrate 1031.

[0361] It should be noted that the structures described in this embodiment may be appropriately combined with any of the other structures of this embodiment and the other embodiments. (Embodiment 5)

[0362] In this embodiment, a display device including a light-emitting element of one embodiment of the present invention is described with reference to Fig. 20A and Fig. 20B, Fig. 21A and Fig. 21B and Fig. 22A and Fig. 22B.

[0363] Fig. 20A is a block diagram illustrating the display device of an embodiment of the present invention, and Fig. 20B is a circuit diagram illustrating a pixel circuit of the display device of one embodiment of the present invention. <Beschreibung der Anzeigevorrichtung>

[0364] The display device, which is Fig. 20A includes a region including pixels of display elements (hereinafter, the region is referred to as a pixel section 802), a circuit section provided outside the pixel section 802 and including circuits for driving the pixels (hereinafter, the section is referred to as a drive circuit section 804), circuits having a function of protecting elements (hereinafter, the circuits are referred to as protection circuits 806), and a terminal section 807. Note that the protection circuits 806 are not necessarily provided.

[0365] Preferably, part or all of the driver circuit section 804 is formed over a substrate over which the pixel section 802 is formed, in which case the number of components and the number of terminals can be reduced. If part or all of the driver circuit section 804 is not formed over the substrate over which the pixel section 802 is formed, part or all of the driver circuit section 804 can be assembled by COG or tape-automated bonding (TAB).

[0366] The pixel section 802 includes a plurality of circuits for driving the display elements arranged in X rows (X is a natural number greater than or equal to 2) and Y columns (Y is a natural number greater than or equal to 2) (hereinafter, such circuits are referred to as pixel circuits 801). The drive circuit section 804 includes drive circuits such as a circuit for supplying a signal (scanning signal) to select a pixel (hereinafter, the circuit is referred to as a scan line drive circuit 804a) and a circuit for supplying a signal (data signal) to drive a display element in a pixel (hereinafter, the circuit is referred to as a signal line drive circuit 804b).

[0367] The scanning line driver circuit 804a includes a shift register or the like. Via the terminal portion 807, the scanning line driver circuit 804a receives a signal for driving the shift register and outputs a signal. For example, the scanning line driver circuit 804a receives a start pulse signal, a clock signal, or the like and outputs a pulse signal. The scanning line driver circuit 804a has a function of controlling the potentials of lines to which scanning signals are supplied (hereinafter, such lines are referred to as scanning lines GL_1 to GL_X). Note that a plurality of scanning line driver circuits 804a may be provided to separately control the scanning lines GL_1 to GL_X. Alternatively, the scanning line driver circuit 804a has a function of supplying an initialization signal. Without being limited thereto, the scanning line driver circuit 804a may supply another signal.

[0368] The signal line driver circuit 804b includes a shift register or the like. Via the terminal portion 807, the signal line driver circuit 804b receives a signal (image signal) from which a data signal is derived and a signal for driving the shift register. The signal line driver circuit 804b has a function of generating a data signal to be written into the pixel circuit 801 based on the image signal. The signal line driver circuit 804b further has a function of controlling an output of a data signal in response to a pulse signal generated by inputting a start pulse, a clock signal, or the like. The signal line driver circuit 804b also has a function of controlling the potentials of lines to which data signals are supplied (hereinafter, such lines are referred to as data lines DL_1 to DL_Y).Alternatively, the signal line driver circuit 804b has a function of supplying an initialization signal. Without being limited thereto, the signal line driver circuit 804b may supply another signal.

[0369] The signal line driver circuit 804b includes, for example, a plurality of analog switches or the like. The signal line driver circuit 804b can output signals obtained by time-dividing the image signal as data signals by sequentially turning on the plurality of analog switches. The signal line driver circuit 804b may include a shift register or the like.

[0370] A pulse signal and a data signal are input to each of the plurality of pixel circuits 801 via one of the plurality of scan lines GL to which scan signals are supplied, and one of the plurality of data lines DL to which data signals are supplied, respectively. The writing and holding of the data signal in each of the plurality of pixel circuits 801 are controlled by the scan line driver circuit 804a. For example, to the pixel circuit 801 in the m-th row and the n-th column (m is a natural number less than or equal to X, and n is a natural number less than or equal to Y), a pulse signal is input from the scan line driver circuit 804a via the scan line GL_m, and a data signal is input from the signal line driver circuit 804b via the data line DL_n according to the potential of the scan line GL_m.

[0371] The Fig. For example, the protection circuit 806 shown in FIG. 20A is connected to the scanning line GL between the scanning line driver circuit 804a and the pixel circuit 801. The protection circuit 806 is alternatively connected to the data line DL between the signal line driver circuit 804b and the pixel circuit 801. The protection circuit 806 may alternatively be connected to a line between the scanning line driver circuit 804a and the terminal portion 807. The protection circuit 806 may alternatively be connected to a line between the signal line driver circuit 804b and the terminal portion 807. Note that the terminal portion 807 denotes a portion having terminals through which power, control signals, and image signals from external circuits are input to the display device.

[0372] The protection circuit 806 is a circuit that electrically connects a line connected to the protection circuit to another line when a potential outside a certain range is applied to the line connected to the protection circuit.

[0373] As in Fig. As shown in FIG. 20A, the protection circuits 806 are provided for the pixel section 802 and the driver circuit section 804, so that the resistance of the display device to an overcurrent generated by electrostatic discharge (ESD) or the like can be improved. Note that the configuration of the protection circuits 806 is not limited thereto; for example, a configuration in which the protection circuits 806 are connected to the scanning line driver circuit 804a or a configuration in which the protection circuits 806 are connected to the signal line driver circuit 804b may be employed. The protection circuits 806 may alternatively be configured to be connected to the terminal section 807.

[0374] In Fig. 20A shows an example in which the driver circuit section 804 includes the scan line driver circuit 804a and the signal line driver circuit 804b; however, the structure is not limited to this. For example, only the scan line driver circuit 804a may be formed, and a separately prepared substrate on which a signal line driver circuit is formed (e.g., a driver circuit substrate formed of a single-crystal semiconductor film or a polycrystalline semiconductor film) may be mounted. <Strukturbeispiel der Pixelschaltung>

[0375] Each of the plurality of pixel circuits 801 in Fig. 20A can, for example, be a Fig. 20B shown structure.

[0376] The Fig. Pixel circuit 801 shown in Figure 20B includes transistors 852 and 854, a capacitor 862, and a light-emitting element 872.

[0377] Either a source electrode or a drain electrode of transistor 852 is electrically connected to a line to which a data signal is supplied (a data line DL_n). A gate electrode of transistor 852 is electrically connected to a line to which a gate signal is supplied (a scan line GL_m).

[0378] Transistor 852 has a function to control whether a data signal is written.

[0379] One of a pair of electrodes of the capacitor 862 is electrically connected to a line to which a potential is supplied (hereinafter referred to as a potential supply line VL_a), and the other is electrically connected to the other of the source electrode and the drain electrode of the transistor 852.

[0380] The capacitor 862 serves as a storage capacitor to store the written data.

[0381] Either a source electrode or a drain electrode of transistor 854 is electrically connected to the potential supply line VL_a. A gate electrode of transistor 854 is further electrically connected to the other of the source electrode and the drain electrode of transistor 852.

[0382] Either an anode or a cathode of the light-emitting element 872 is electrically connected to a potential supply line VL_b, and the other is electrically connected to the other of the source electrode and the drain electrode of the transistor 854.

[0383] As the light-emitting element 872, any of the light-emitting elements described in Embodiments 1 to 3 can be used.

[0384] Note that a high power supply potential VDD is supplied to either the potential supply line VL_a or the potential supply line VL_b, and a low power supply potential VSS is supplied to the other line.

[0385] For example, in the display device having the pixel circuits 801 in Fig. 20B, the pixel circuits 801 by the scanning line driver circuit 804a in Fig. 20A is selected sequentially row by row, turning on transistors 852 and writing a data signal.

[0386] When transistors 852 are turned off, pixel circuits 801 into which the data has been written are placed in a hold state. The magnitude of the current flowing between the source and drain electrodes of transistor 854 is further controlled according to the potential of the written data signal. Light-emitting element 872 emits light with a luminance corresponding to the magnitude of the flowing current. This operation is performed sequentially line by line; thus, an image is displayed.

[0387] Alternatively, the pixel circuit may have a function of compensating for fluctuations in threshold voltages or the like of a transistor. Fig. 21A and Fig. 21B and Fig. 22A and Fig. 22B show examples of the pixel circuit.

[0388] The pixel circuit, which is Fig. 21A, comprises six transistors (transistors 303_1 to 303_6), a capacitor 304 and a light-emitting element 305. The pixel circuit shown in Fig. 21A is electrically connected to lines 301_1 to 301_5 and lines 302_1 and 302_2. Note that, for example, p-channel transistors can be used as transistors 303_1 to 303_6.

[0389] The pixel circuit, which is Fig. 21B has a configuration in which the pixel circuit shown in Fig. 21A, a transistor 303_7 is added. The pixel circuit shown in Fig. 21B, is electrically connected to lines 301_6 and 301_7. Lines 301_5 and 301_6 may be electrically connected to each other. Note that, for example, a p-channel transistor may be used for transistor 303_7.

[0390] The pixel circuit, which is Fig. 22A includes six transistors (transistors 308_1 to 308_6), the capacitor 304 and the light-emitting element 305. The pixel circuit shown in Fig. 22A, is electrically connected to lines 306_1 through 306_3 and lines 307_1 through 307_3. Lines 306_1 and 306_3 may be electrically connected to each other. Note that, for example, p-channel transistors may be used for transistors 308_1 through 308_6.

[0391] The pixel circuit, which is Fig. 22B, comprises two transistors (transistors 309_1 and 309_2), two capacitors (capacitors 304_1 and 304_2) and the light-emitting element 305. The pixel circuit shown in Fig. 22B, is electrically connected to lines 311_1 to 311_3 and lines 312_1 and 312_2. With the configuration of the pixel circuit shown in Fig. As shown in Figure 22B, the pixel circuit may be driven by a voltage inputting current driving method (also referred to as CVCC). Note that, for example, p-channel transistors may be used for transistors 309_1 and 309_2.

[0392] A light-emitting element of one embodiment of the present invention can be used for an active matrix method in which an active element is included in a pixel of a display device, or for a passive matrix method in which no active element is included in a pixel of a display device.

[0393] In the active matrix method, not only a transistor but also various active elements (nonlinear elements) can be used as the active element (nonlinear element). For example, a metal-insulator-metal (MIM), a thin-film diode (TFD), or the like can also be used. Since these elements can be formed with a fewer number of manufacturing steps, manufacturing costs can be reduced or yield can be improved. Alternatively, since the size of these elements is small, the aperture ratio can be improved, so that power consumption can be reduced or higher luminance can be achieved.

[0394] In addition to the active matrix method, the passive matrix method, which does not use an active element (non-linear element), can also be used. Since no active element (non-linear element) is used, the number of manufacturing steps is reduced, so manufacturing costs can be reduced or yield can be improved. Alternatively, since no active element (non-linear element) is used, the aperture ratio can be improved, so that, for example, power consumption can be reduced or luminance can be increased.

[0395] The structure described in this embodiment may be used in a suitable combination with the structure described in any of the other embodiments. (Embodiment 6)

[0396] In this embodiment, a display device including a light-emitting element of one embodiment of the present invention and an electronic device in which the display device is provided with an input device are described with reference to Fig. 23A and Fig. 23B, Fig. 24A to Fig. 24C, Fig. 25A and Fig. 25B, Fig. 26A and Fig. 26B and Fig. 27 described. <Beschreibung 1 des Touchscreens>

[0397] In this embodiment, a touchscreen 2000 including a display device and an input device will be described as an example of an electronic device. An example in which a touch sensor is used as an input device will also be described.

[0398] Fig. 23A and Fig. 23B are perspective views of the touch screen 2000. It should be noted that Fig. 23A and Fig. 23B only shows the main components of the touchscreen 2000 for the sake of simplicity.

[0399] The touchscreen 2000 includes a display device 2501 and a touch sensor 2595 (see Fig. 23B). The touchscreen 2000 further includes a substrate 2510, a substrate 2570, and a substrate 2590. The substrate 2510, the substrate 2570, and the substrate 2590 each exhibit flexibility. It should be noted that one or all of the substrates 2510, 2570, and 2590 may be inelastic.

[0400] The display device 2501 includes a plurality of pixels above the substrate 2510 and a plurality of lines 2511 through which signals are supplied to the pixels. The plurality of lines 2511 extend to a peripheral portion of the substrate 2510, and portions of the plurality of lines 2511 form a terminal 2519. The terminal 2519 is electrically connected to an FPC 2509(1). The plurality of lines 2511 can supply signals to the plurality of pixels from a signal line driver circuit 2503s(1).

[0401] The substrate 2590 includes the touch sensor 2595 and a plurality of leads 2598 electrically connected to the touch sensor 2595. The plurality of leads 2598 extend to a peripheral portion of the substrate 2590, and portions of the plurality of leads 2598 form a terminal. The terminal is electrically connected to an FPC 2509(2). It should be noted that in Fig. 23B Electrodes, leads, and the like of the touch sensor 2595 provided on the back side of the substrate 2590 (the side facing the substrate 2510) are shown by solid lines for clarity.

[0402] A capacitive touch sensor can be used as the touch sensor 2595. Examples of capacitive touch sensors include a surface capacitive touch sensor and a projected capacitive touch sensor.

[0403] Examples of projected capacitive touch sensors include self-capacitive touch sensors and mutual capacitive touch sensors, which differ primarily in their control method. Mutual capacitive touch sensors are preferred because they can detect multiple points simultaneously.

[0404] It should be noted that the touch sensor 2595 used in Fig. 23B is an example in which a projected capacitive touch sensor is used.

[0405] It should be noted that various sensors that can detect the approach or touch of a sensing object such as a finger can be used as the touch sensor 2595.

[0406] The projected capacitive touch sensor 2595 includes electrodes 2591 and electrodes 2592. The electrodes 2591 are electrically connected to one of the plurality of lines 2598, and the electrodes 2592 are electrically connected to one of the other lines 2598.

[0407] The electrodes 2592 each have a shape of a plurality of quadrilaterals arranged in one direction, with a corner of one quadrilateral connected to a corner of another quadrilateral, as shown in Fig. 23A and Fig. 23B.

[0408] The electrodes 2591 each have a quadrangular shape and are arranged in a direction that crosses the direction in which the electrodes 2592 extend.

[0409] A line 2594 electrically connects two electrodes 2591, between which the electrode 2592 is positioned. The sectional area of ​​the electrode 2592 and the line 2594 is preferably as small as possible. Such a structure enables a reduction in the area of ​​a region where the electrodes are not provided, thereby reducing fluctuations in light transmittance. As a result, the fluctuations in the luminance of light passing through the touch sensor 2595 can be reduced.

[0410] Note that the shapes of the electrodes 2591 and the electrodes 2592 are not limited thereto, and they may have any of various shapes. For example, a structure may be adopted in which the plurality of electrodes 2591 are arranged so as to minimize gaps between the electrodes 2591, and the electrodes 2592 are arranged separately from the electrodes 2591 with an insulating layer therebetween to have regions that do not overlap the electrodes 2591. In this case, it is preferable that a dummy electrode electrically insulated from these electrodes be provided between two adjacent electrodes 2592, since this can reduce the area of ​​regions having different light transmittances. <Beschreibung der Anzeigevorrichtung>

[0411] Next, the display device 2501 will be described in detail with reference to Fig. 24A. Fig. 24A corresponds to a cross-sectional view along the dashed line X1-X2 in Fig. 23B.

[0412] The display device 2501 includes a plurality of pixels arranged in a matrix. Each of the pixels includes a display element and a pixel circuit for driving the display element.

[0413] In the following description, an example in which a light-emitting element that emits white light is used as a display element is described; however, the display element is not limited to such an element. For example, light-emitting elements that emit light of different colors may be included, so that light of different colors can be emitted from adjacent pixels.

[0414] For the substrate 2510 and the substrate 2570, for example, a flexible material having a water vapor permeability of less than or equal to 1 × 10 -5 g m -2 ·Day -1 , preferably less than or equal to 1 × 10 -6 g m -2 ·Day -1 , can be advantageously used. Alternatively, materials are preferably used for the substrate 2510 and the substrate 2570 whose thermal expansion coefficients are substantially equal to one another. For example, the linear expansion coefficients of the materials are preferably less than or equal to 1 × 10 -3 / K, preferably less than or equal to 5 × 10 -5 / K and more preferably less than or equal to 1 × 10 -5 / K.

[0415] Note that the substrate 2510 is a layered assembly of an insulating layer 2510a for preventing impurities from diffusing into the light-emitting element, a flexible substrate 2510b, and an adhesive layer 2510c for attaching the insulating layer 2510a to the flexible substrate 2510b. The substrate 2570 is a layered assembly of an insulating layer 2570a for preventing impurities from diffusing into the light-emitting element, a flexible substrate 2570b, and an adhesive layer 2570c for attaching the insulating layer 2570a to the flexible substrate 2570b.

[0416] For the adhesive layer 2510c and the adhesive layer 2570c, for example, polyester, polyolefin, polyamide (e.g., nylon, aramid), polyimide, polycarbonate, or an acrylic, urethane, or epoxy can be used. Alternatively, a material containing a resin with a siloxane bond can be used.

[0417] A sealing layer 2560 is provided between the substrate 2510 and the substrate 2570. The sealing layer 2560 preferably has a higher refractive index than air. In the case where light, as in Fig. 24A, to the side of the sealing layer 2560, the sealing layer 2560 can also serve as an optical adhesive layer.

[0418] A sealant may be formed in the peripheral portion of the sealing layer 2560. Using the sealant, a light-emitting element 2550R may be provided in a region enclosed by the substrate 2510, the substrate 2570, the sealing layer 2560, and the sealant. Note that an inert gas (such as nitrogen or argon) may be used instead of the sealing layer 2560. A desiccant may be provided in the inert gas to adsorb moisture or the like. Alternatively, a resin such as an acrylic or an epoxy may be used instead of the sealing layer 2560. An epoxy-based resin or a glass frit is preferably used for the sealant. As the material used for the sealant, a material that does not permeate moisture or oxygen is preferably used.

[0419] The display device 2501 includes a pixel 2502R. The pixel 2502R includes a light-emitting module 2580R.

[0420] Pixel 2502R includes light-emitting element 2550R and a transistor 2502T that can supply electrical power to light-emitting element 2550R. Note that transistor 2502T serves as part of the pixel circuit. Light-emitting module 2580R includes light-emitting element 2550R and a color layer 2567R.

[0421] The light-emitting element 2550R includes a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. Any of the light-emitting elements described in Embodiments 1 to 3 can be used as the light-emitting element 2550R.

[0422] A microcavity structure can be used between the lower electrode and the upper electrode so that the intensity of light with a specific wavelength can be increased.

[0423] In the case where the sealing layer 2560 is provided on the light extraction side, the sealing layer 2560 is in contact with the light-emitting element 2550R and the color layer 2567R.

[0424] The color layer 2567R is positioned in an area overlapping the light-emitting element 2550R. Accordingly, a part of the light emitted by the light-emitting element 2550R passes through the color layer 2567R and is emitted to the outside of the light-emitting module 2580R, as shown by an arrow in Fig. 24A shows.

[0425] The display device 2501 includes an opaque layer 2567BM on the light extraction side. The opaque layer 2567BM is arranged to enclose the color layer 2567R.

[0426] The 2567R color layer is a color layer with a function of transmitting light in a specific wavelength range. For example, a color filter for transmitting light in a red wavelength range, a color filter for transmitting light in a green wavelength range, a color filter for transmitting light in a blue wavelength range, a color filter for transmitting light in a yellow wavelength range, or the like can be used. Each color filter can be formed with any of various materials by a printing method, an inkjet method, an etching method using a photolithography technique, or the like.

[0427] An insulating layer 2521 is provided in the display device 2501. The insulating layer 2521 covers the transistor 2502t. Note that the insulating layer 2521 has a function of covering unevenness caused by the pixel circuit. The insulating layer 2521 may also have a function of suppressing impurity diffusion. This can prevent the reliability of the transistor 2502t or the like from being reduced due to impurity diffusion.

[0428] The light-emitting element 2550R is formed over the insulating layer 2521. A partition wall 2528 is provided to overlap with an end portion of the lower electrode of the light-emitting element 2550R. Note that a spacer for controlling the distance between the substrate 2510 and the substrate 2570 may be formed over the partition wall 2528.

[0429] A scan line driver circuit 2503g(1) includes a transistor 2503t and a capacitor 2503c. Note that the driver circuit can be formed in the same process and over the same substrate as the pixel circuits.

[0430] Lines 2511, through which signals can be supplied, are provided above the substrate 2510. Terminal 2519 is provided above the lines 2511. FPC 2509(1) is electrically connected to terminal 2519. FPC 2509(1) has a function of supplying a video signal, a clock signal, a start signal, a reset signal, or the like. Note that FPC 2509(1) can be provided with a PWB.

[0431] The display device 2501 can use transistors with various structures. Fig. 24A illustrates an example in which bottom-gate transistors are used; however, the present invention is not limited to this example, and top-gate transistors may be used in the display device 2501 as shown in Fig. 24B.

[0432] Furthermore, there is no particular limitation on the polarity of transistor 2502t and transistor 2503t. N-channel and p-channel transistors can be used for these transistors, or, for example, either n-channel transistors or p-channel transistors can be used. Furthermore, there is no particular limitation on the crystallinity of a semiconductor film used for transistors 2502t and 2503t. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. Examples of semiconductor materials include Group 14 semiconductors (e.g., a semiconductor including silicon), compound semiconductors (including oxide semiconductors), organic semiconductors, and the like.Preferably, an oxide semiconductor having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more, is used for one or both of the transistors 2502t and 2503t, so that the off-state current of the transistors can be reduced. Examples of the oxide semiconductors include an In-Ga oxide, an In-M-Zn oxide (M represents Al, Ga, Y, Zr, La, Ce, Sn, Hf, or Nd), and the like. <Beschreibung des Berührungssensors>

[0433] Next, the 2595 touch sensor will be described in detail using Fig. 24C described. Fig. 24C corresponds to a cross-sectional view along the dashed line X3-X4 in Fig. 23B.

[0434] The touch sensor 2595 includes the electrodes 2591 and the electrodes 2592 arranged in a staggered arrangement on the substrate 2590, an insulating layer 2593 covering the electrodes 2591 and the electrodes 2592, and the lead 2594 electrically connecting the adjacent electrodes 2591.

[0435] The electrodes 2591 and the electrodes 2592 are formed using a light-transmitting conductive material. A conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium has been added can be used as the light-transmitting conductive material. Note that a film containing graphene can also be used. The film containing graphene can be formed, for example, by reducing a film containing graphene oxide. As the reduction method, a method using heat or the like can be used.

[0436] The electrodes 2591 and the electrodes 2592 may be formed, for example, by depositing a light-transmitting conductive material on the substrate 2590 by a sputtering method and then removing an unnecessary part by any of various patterning techniques such as photolithography.

[0437] Examples of a material for the insulating layer 2593 include a resin such as an acrylic resin or an epoxy resin, a resin having a siloxane bond, and an inorganic insulating material such as silicon oxide, silicon oxynitride, or aluminum oxide.

[0438] Openings reaching the electrodes 2591 are formed in the insulating layer 2593, and the wiring 2594 electrically connects the adjacent electrodes 2591. A light-transmitting conductive material can be advantageously used for the wiring 2594 because the aperture ratio of the touchscreen can be increased. Furthermore, a material with higher conductivity than the electrodes 2591 and 2592 can be advantageously used for the wiring 2594 because the electrical resistance can be reduced.

[0439] An electrode 2592 extends in one direction, and a plurality of electrodes 2592 are provided in a strip shape. The line 2594 crosses the electrode 2592.

[0440] Adjacent electrodes 2591 are provided, with an electrode 2592 disposed therebetween. Lead 2594 electrically connects the adjacent electrodes 2591.

[0441] It should be noted that the plurality of electrodes 2591 are not necessarily arranged in the direction orthogonal to an electrode 2592 and may be arranged to cross an electrode 2592 at an angle of more than 0° and less than 90°.

[0442] Lead 2598 is electrically connected to one of electrodes 2591 and 2592. A portion of lead 2598 serves as a terminal. Lead 2598 may be a metal material such as aluminum, gold, platinum, silver, nickel, titanium, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy material containing any of these metal materials.

[0443] Note that an insulating layer covering the insulating layer 2593 and the lead 2594 may be provided to protect the touch sensor 2595.

[0444] An interconnect layer 2599 electrically connects the line 2598 to the FPC 2509(2).

[0445] Any of various anisotropic conductive films (ACF), anisotropic conductive pastes (ACP), and the like can be used as the interconnect layer 2599. <Beschreibung 2 des Touchscreens>

[0446] Next, the Touchscreen 2000 will be described in detail using Fig. 25A. Fig. 25A corresponds to a cross-sectional view along the dashed line X5-X6 in Fig. 23A.

[0447] In the Touchscreen 2000, which is Fig. 25A, the display device 2501, which is based on Fig. 24A, and the touch sensor 2595, which is described with reference to Fig. 24C, attached to each other.

[0448] The touch sensor 2000, which is Fig. 25A, includes, in addition to the components identified by Fig. 24A and Fig. 24C, an adhesive layer 2597 and an anti-reflection layer 2567p.

[0449] The adhesive layer 2597 is provided in contact with the lead 2594. Note that the adhesive layer 2597 bonds the substrate 2590 to the substrate 2570 such that the touch sensor 2595 overlaps the display device 2501. The adhesive layer 2597 preferably has a light transmittance property. A thermosetting resin or a UV-curing resin can be used for the adhesive layer 2597. For example, an acrylic resin, a urethane-based resin, an epoxy-based resin, or a siloxane-based resin can be used.

[0450] The 2567p anti-reflection layer is positioned in an area that overlaps pixels. A circularly polarizing plate, for example, can be used as the 2567p anti-reflection layer.

[0451] Next, a touchscreen with a structure different from that used in Fig. 25A, differentiates, based on Fig. 25B.

[0452] Fig. 25B is a cross-sectional view of a touchscreen 2001. The touchscreen 2001, which is shown in Fig. 25B is different from the touchscreen 2000 shown in Fig. 25A, in the relative position of the touch sensor 2595 to the display device 2501. Different parts will be described in detail below, and for the other similar parts, reference is made to the above description of the touch screen 2000.

[0453] The color layer 2567R is positioned in an area that overlaps the light-emitting element 2550R. The light-emitting element 2550R, which is Fig. 25B, emits light to the side where the transistor 2502t is provided. Accordingly, a part of the light emitted from the light-emitting element 2550R passes through the color layer 2567R and is emitted to the outside of the light-emitting module 2580R, as shown by an arrow in Fig. 25B shows.

[0454] The touch sensor 2595 is provided on the substrate 2510 side of the display device 2501.

[0455] The adhesive layer 2597 is provided between the substrate 2510 and the substrate 2590 and fixes the touch sensor 2595 to the display device 2501.

[0456] As in Fig. 25A or Fig. 25B, light may be emitted from the light-emitting element via the substrate 2510 and / or the substrate 2570. <Beschreibung eines Verfahrens zum Ansteuern des Touchscreens>

[0457] Next, an example of a method for controlling a touch screen is shown using Fig. 26A and Fig. 26B.

[0458] Fig. Figure 26A is a block diagram showing the structure of a mutual capacitive touch sensor. Fig. 26A illustrates a pulse voltage output circuit 2601 and a current detection circuit 2602. It should be noted that in Fig. 26A, six lines X1 to X6 represent the electrodes 2621 to which a pulse voltage is applied, and six lines Y1 to Y6 represent the electrodes 2622 which detect the changes in current. Fig. 26A also illustrates capacitors 2603, each formed in a region where electrodes 2621 and 2622 overlap. Note that functional interchange between electrodes 2621 and 2622 is possible.

[0459] Pulse voltage output circuit 2601 is a circuit for sequentially applying a pulse voltage to lines X1 to X6. Applying a pulse voltage to lines X1 to X6 generates an electric field between electrodes 2621 and 2622 of capacitor 2603. When the electric field between the electrodes is shielded, a change (mutual capacitance, for example) occurs in capacitor 2603. The approach or contact of a detection object can be detected by utilizing this change.

[0460] Current detection circuit 2602 is a circuit for detecting changes in the current flowing through wirings Y1 to Y6 caused by the change in the mutual capacitance in capacitor 2603. No change in the current value is detected in wirings Y1 to Y6 when there is no approach or contact of a detection object, while a decrease in the current value is detected when the mutual capacitance is reduced by the approach or contact of a detection object. Note that an integrator circuit or the like is used to detect the current values.

[0461] Fig. 26B is a timing chart showing input and output waveforms of the Fig. 26A shows the mutually capacitive touch sensor. In Fig. 26B, a detection of a detection object is carried out in all rows and columns in one frame period. Fig. Figure 26B shows a period in which no detection object is detected (no touch) and a period in which a detection object is detected (touch). The detected current values ​​of the lines Y1 to Y6 are shown in Fig. 26B as waveforms of the voltage values.

[0462] A pulse voltage is applied sequentially to lines X1 to X6, and the waveforms of lines Y1 to Y6 change according to the pulse voltage. When there is no approach or contact of a detection object, the waveforms of lines Y1 to Y6 change according to the changes in the voltages of lines X1 to X6. The current value decreases at the point where a detection object approaches or contacts, and the voltage waveform changes accordingly.

[0463] By detecting a change in mutual capacitance in this way, the approach or contact of a sensing object can be detected. <Beschreibung der Sensorschaltung>

[0464] Although Fig. 26A shows a passive matrix touch sensor in which only the capacitor 2603 is provided as a touch sensor at the crossing point of the lines, an active matrix touch sensor including a transistor and a capacitor may also be used. Fig. Figure 27 illustrates an example of a sensor circuit included in an active matrix touch sensor.

[0465] The sensor circuit in Fig. 27 includes capacitor 2603 and transistors 2611, 2612 and 2613.

[0466] A signal G2 is input to a gate of transistor 2613. A voltage VRES is applied to one terminal of the source and drain of transistor 2613, and one electrode of capacitor 2603 and a gate of transistor 2611 are electrically connected to the other terminal of the source and drain of transistor 2613. One terminal of the source and drain of transistor 2611 is electrically connected to one terminal of the source and drain of transistor 2612, and a voltage VSS is applied to the other terminal of the source and drain of transistor 2611. A signal G1 is input to a gate of transistor 2612, and a line ML is electrically connected to the other terminal of the source and drain of transistor 2612. The voltage VSS is applied to the other electrode of capacitor 2603.

[0467] Next, the operation of the sensor circuit in Fig. 27. First, a potential for turning on the transistor 2613 is supplied as a signal G2, and a potential related to the voltage VRES is thus applied to the node n connected to the gate of the transistor 2611. Subsequently, a potential for turning off the transistor 2613 is applied as a signal G2, thereby holding the potential of the node n.

[0468] Thereafter, the mutual capacitance of the capacitor 2603 changes due to the approach or contact of a sensing object, such as a finger; accordingly, the potential of the node n of VRES is changed.

[0469] During a read operation, a potential for turning on transistor 2612 is supplied as signal G1. According to the potential of node n, a current flowing through transistor 2611, that is, a current flowing through line ML, is changed. By detecting this current, the approach or contact of a detection object can be detected.

[0470] In each of the transistors 2611, 2612, and 2613, an oxide semiconductor layer is preferably used as a semiconductor layer in which a channel region is formed. In particular, such a transistor is preferably used for the transistor 2613 so that the potential of the node n can be held for a long time and the frequency of an operation for re-supplying VRES to the node n (refresh operation) can be reduced.

[0471] The structures described in this embodiment may be used in a suitable combination with any of the structures described in the other embodiments. (Embodiment 7)

[0472] In this embodiment, a display module and electronic devices including a light-emitting element of one embodiment of the present invention are described with reference to Fig. 28, Fig. 29A to Fig. 29G, Fig. 30A to Fig. 30D and Fig. 31A and Fig. 31B. <Erläuterung des Anzeigemoduls>

[0473] For a display module 8000 in Fig. 28, a touch sensor 8004 connected to an FPC 8003, a display device 8006 connected to an FPC 8005, a frame 8009, a printed circuit board 8010, and a battery 8011 are arranged between an upper cover 8001 and a lower cover 8002.

[0474] The light-emitting element of one embodiment of the present invention can be used, for example, for the display device 8006.

[0475] The shapes and sizes of the upper cover 8001 and the lower cover 8002 can be changed as needed according to the sizes of the touch sensor 8004 and the display device 8006.

[0476] The touch sensor 8004 may be a resistive touch sensor or a capacitive touch sensor and may be configured to overlap the display device 8006. A counter substrate (sealing substrate) of the display device 8006 may have a touch sensor function. A photosensor may be provided in each pixel of the display device 8006, thereby obtaining an optical touch sensor.

[0477] The frame 8009 protects the display device 8006 and also serves as an electromagnetic shield to block electromagnetic waves generated by the operation of the printed circuit board 8010. The frame 8009 can serve as a radiation plate.

[0478] The printed circuit board 8010 includes a power supply circuit and a signal processing circuit for outputting a video signal and a clock signal. As a power source for supplying power to the power supply circuit, an external AC power source or the battery 8011, which is provided separately, can be used. The battery 8011 can be omitted if an AC power source is used.

[0479] The display module 8000 may additionally be provided with a component such as a polarizing plate, a retardation plate or a prism film. <Beschreibung von elektronischen Geräten>

[0480] Fig. 29A to Fig. 29G represent electronic devices. These electronic devices may include a housing 9000, a display section 9001, a speaker 9003, operation buttons 9005 (including a power button or an operation switch), a connection terminal 9006, a sensor 9007 (a sensor having a function of measuring or detecting force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared ray), a microphone 9008, and the like. In addition, the sensor 9007 may have a function of measuring biological information, such as a pulse sensor and a fingerprint sensor.

[0481] The electronic devices used in Fig. 29A to Fig. 29G may have various functions, such as a function of displaying various data (a still image, a moving image, a text image, and the like) on the display section, a touch sensor function, a function of displaying a calendar, the date, the time, and the like, a function of controlling processing with various types of software (programs), a wireless communication function, a function of connecting to various computer networks using a wireless communication function, a function of transmitting and receiving various data using a wireless communication function, a function of reading a program or data stored in a storage medium and displaying the program or data on the display section, and the like. It should be noted that functions that can be provided for the electronic devices described in Fig. 29A to Fig. 29G are not limited to those described above and the electronic devices may have additional functions. Although in Fig. 29A to Fig. 29G, the electronic devices may include a plurality of display sections. The electronic devices may have a camera or the like and a function for capturing a still image, a function for capturing a moving image, a function for storing the captured image in a storage medium (an external storage medium or a storage medium built into the camera), a function for displaying the captured image on the display section, or the like.

[0482] The electronic devices used in Fig. 29A to Fig. 29G are described in detail below.

[0483] Fig. 29A is a perspective view of a portable information terminal 9100. The display section 9001 of the portable information terminal 9100 is flexible. Therefore, the display section 9001 can be installed along a curved surface of a curved case 9000. The display section 9001 further includes a touch sensor, and an operation can be performed by touching the screen with a finger, a stylus, or the like. For example, when an icon displayed on the display section 9001 is touched, an application can be launched.

[0484] Fig. 29B is a perspective view of a portable information terminal 9101. The portable information terminal 9101 serves, for example, as one or more of a telephone set, a laptop, and an information search system. In particular, the portable information terminal can be used as a smartphone. Note that the speaker 9003, the connection terminal 9006, the sensor 9007, and the like shown in Fig. 29B, in the portable information terminal 9101 as in the portable information terminal 9100 shown in Fig. 29A. The portable information terminal 9101 can display characters and image information on its plurality of surfaces. For example, three operation buttons 9050 (also referred to as operation icons, or simply as icons) may be displayed on one surface of the display section 9001. In addition, information 9051 represented by dashed rectangles may be displayed on another surface of the display section 9001. Examples of the information 9051 include a display indicating the arrival of an incoming email, a message from a social networking service (SNS), a call, and the like, the subject and sender of an email and an SNS message, the date, time, remaining battery capacity, and the reception strength of an antenna.Instead of the information 9051, the operation buttons 9050 or the like may be displayed at the position where the information 9051 is displayed.

[0485] Fig. 29C is a perspective view of a portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display section 9001. Here, information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, a user of the portable information terminal 9102 can view the display (here, information 9053) with the portable information terminal 9102 placed in a breast pocket of his / her shirt. Specifically, the telephone number, name, or the like of a caller of an incoming call can be displayed in a position visible from above the portable information terminal 9102. Therefore, the user can view the display without taking the portable information terminal 9102 out of the pocket and decide whether to answer the call.

[0486] Fig. 29D is a perspective view of a wristwatch-shaped portable information terminal 9200. The portable information terminal 9200 can perform various applications, such as mobile phone calls, sending and receiving emails, displaying and editing texts, playing music, Internet communication, and computer games. The display surface of the display section 9001 is curved, and images can be displayed on the curved display surface. The portable information terminal 9200 can utilize short-range communication according to an existing communication standard. For example, in this case, mutual communication can be performed between the portable information terminal 9200 and a headset capable of wireless communication, thereby enabling hands-free telephone conversation.The portable information terminal 9200 includes the connection port 9006, and data can be directly sent and received to / from another information terminal via a connector. Charging with power through the connection port 9006 is possible. Note that charging can be performed without the connection port 9006 by wireless power supply.

[0487] Fig. 29E, Fig. 29F and Fig. 29G are perspective views of a foldable portable information terminal 9201. Fig. 29E is a perspective view illustrating the portable information terminal 9201 being opened. Fig. Fig. 29F is a perspective view illustrating the portable information terminal 9201 being opened or folded. Fig. 29G is a perspective view illustrating the portable information terminal 9201 being folded. The portable information terminal 9201 is highly portable when folded. When the portable information terminal 9201 is opened, a seamless large display area is well browsed. The display section 9001 of the portable information terminal 9201 is supported by three cases 9000 connected to each other by hinges 9055. By folding the portable information terminal 9201 at a junction between two cases 9000 at the hinges 9055, the shape of the portable information terminal 9201 can be reversibly changed from an opened state to a folded state. For example, the portable information terminal 9201 can be bent with a radius of curvature greater than or equal to 1 mm and less than or equal to 150 mm.

[0488] Examples of electronic devices include a television set (also called a TV or TV receiver), a monitor for a computer or the like, a camera such as a digital camera and a digital video camera, a digital photo frame, a mobile phone (also called a cell phone or portable telephone device), video glasses (a head-mounted display), a portable game console, a portable information terminal, an audio playback device, and a large gaming machine such as a pachinko machine.

[0489] Fig. 30A shows an example of a television set. In the television set 9300, the display section 9001 is installed in the housing 9000. Here, the housing 9000 is supported by a stand 9301.

[0490] The 9300 television, which was Fig. 30A can be operated by means of an operation switch of the housing 9000 or by means of a separate remote control 9311. The display section 9001 may include a touch sensor. The television 9300 can be operated by touching the display section 9001 with a finger or the like. The remote control 9311 may be provided with a display section for displaying data output from the remote control 9311. By operation buttons or a touch screen of the remote control 9311, the television channels or the volume can be controlled, and images displayed on the display section 9001 can be controlled.

[0491] The 9300 television is equipped with a receiver, a modem, and the like. The receiver can receive general television broadcasts. When the television is connected to a communications network via a modem, either wirelessly or wirelessly, unidirectional (from a transmitter to a receiver) or bidirectional (between a transmitter and a receiver, or between receivers) data communication can be performed.

[0492] The electronic device or lighting apparatus of one embodiment of the present invention has flexibility and can therefore be integrated along a curved interior / exterior wall surface of a house or building or along a curved interior / exterior surface of a car.

[0493] Fig. Figure 30B is an exterior view of a 9700 vehicle. Fig. 30C illustrates a driver's seat of the vehicle 9700. The vehicle 9700 includes a body 9701, wheels 9702, a dashboard 9703, headlights 9704, and the like. The display device, the light-emitting device, or the like of one embodiment of the present invention may be used in a display section or the like of the vehicle 9700. For example, the display device, the light-emitting device, or the like of one embodiment of the present invention may be used in display sections 9710 to 9715 shown in Fig. 30C can be used.

[0494] The display portion 9710 and the display portion 9711 are each a display device provided in the car windshield. The display device, light-emitting device, or the like of one embodiment of the present invention may be a transparent display device through which the opposite side can be seen by using a light-transmitting conductive material for its electrodes and leads. Such a transparent display portion 9710 or 9711 does not obstruct the driver's view while driving the vehicle 9700. Accordingly, the display device, light-emitting device, or the like of one embodiment of the present invention may be provided in the windshield of the vehicle 9700.It should be noted that when a transistor or the like is provided for driving the display device, the light-emitting device, or the like, a transistor having a light transmitting property, such as an organic transistor using an organic semiconductor material or a transistor using an oxide semiconductor, is preferably used.

[0495] The display section 9712 is a display device provided on a pillar section. For example, an image captured by an image sensing unit provided in the vehicle body is displayed on the display section 9712, thereby compensating for the view obstructed by the pillar section. The display section 9713 is a display device provided on the instrument panel. For example, an image captured by an image sensing unit provided in the vehicle body is displayed on the display section 9713, thereby compensating for the view obstructed by the instrument panel. That is, blind spots can be eliminated and safety can be enhanced by displaying an image captured by an image sensing unit provided on the exterior of the vehicle.By displaying an image to compensate for the area a driver cannot see, the driver can easily and conveniently check safety.

[0496] Fig. 30D illustrates the interior of a car in which bench seats are used as the driver's seat and the passenger's seat. A display section 9721 is a display device provided in a door section. For example, an image captured by an image pickup unit provided in the body is displayed on the display section 9721, thereby compensating for the view obstructed by the door. A display section 9722 is a display device provided in a steering wheel. A display section 9723 is a display device provided in the center of a seating surface of the bench seat. Note that the display device can be used as a seat warmer by providing the display device on the seating surface or the back cushion and by using the heat generation of the display device as a heat source.

[0497] The display section 9714, the display section 9715, and the display section 9722 can provide a variety of information, such as navigation data, a speedometer, a tachometer, a mileage indicator, a fuel gauge, a shift point indicator, and the air conditioning setting. The content, layout, or the like of the display on the display sections can be freely changed by a user as needed. The information listed above can also be displayed on the display sections 9710 to 9713, 9721, and 9723. The display sections 9710 to 9715 and 9721 to 9723 can also be used as lighting devices. The display sections 9710 to 9715 and 9721 to 9723 can also be used as heating devices.

[0498] Furthermore, the electronic device of one embodiment of the present invention may include a secondary battery. Preferably, the secondary battery can be charged by contactless energy transfer.

[0499] Examples of the secondary battery include a lithium-ion secondary battery such as a lithium polymer battery (lithium-ion polymer battery) using a gel electrolyte, a lithium-ion battery, a nickel-hydride battery, a nickel-cadmium battery, an organic radical battery, a lead-acid battery, an air secondary battery, a nickel-zinc battery, and a silver-zinc battery.

[0500] The electronic device of one embodiment of the present invention may include an antenna. When a signal is received from the antenna, the electronic device can display an image, data, or the like on a display section. If the electronic device includes a secondary battery, the antenna can be used for contactless power transmission.

[0501] A display device 9500 which is Fig. 31A and Fig. 31B includes a plurality of display panels 9501, a hinge 9511, and a bracket 9512. The plurality of display panels 9501 each includes a display region 9502 and a light-emitting region 9503.

[0502] Each of the plurality of display panels 9501 is flexible. Two adjacent display panels 9501 are provided so as to partially overlap each other. For example, the light-transmitting regions 9503 of the two adjacent display panels 9501 may overlap each other. A display device with a large screen can be obtained with the plurality of display panels 9501. The display device is very versatile because the display panels 9501 can be wound depending on their intended use.

[0503] Although the display areas 9502 of the adjacent display fields 9501 in Fig. 31A and Fig. 31B are separated from each other, the display areas 9502 of the adjacent display panels 9501 may, without being limited to this structure, further overlap each other without a space, for example, so that a continuous display area 9502 is obtained.

[0504] The electronic devices described in this embodiment each include the display portion for displaying certain types of data. Note that the light-emitting element of one embodiment of the present invention can also be applied to an electronic device that does not have a display portion. The structure in which the display portion of the electronic device described in this embodiment is flexible and in which display can be performed on the curved display surface, or the structure in which the display portion of the electronic device is foldable, have been described as examples; however, the structure is not limited to this, and a structure in which the display portion of the electronic device is not flexible and display is performed on a flat portion may be employed.

[0505] The structure described above in this embodiment may be used in a suitable combination with the structure described in any of the other embodiments. (Embodiment 8)

[0506] In this embodiment, a light-emitting device including the light-emitting element of one embodiment of the present invention is described with reference to Fig. 32A to Fig. 32C and Fig. 33A to Fig. 33D described.

[0507] Fig. 32A is a perspective view of a light-emitting device 3000 shown in this embodiment, and Fig. 32B is a cross-sectional view taken along the dashed line EF in Fig. 32A. It should be noted that in Fig. 32A some components are represented by dashed lines to avoid complicating the drawing.

[0508] The light emitting device 3000, which is in Fig. 32A and Fig. 32B includes a substrate 3001, a light-emitting element 3005 over the substrate 3001, a first sealing region 3007 provided around the light-emitting element 3005, and a second sealing region 3009 provided around the first sealing region 3007.

[0509] Light is emitted from the light-emitting element 3005 via the substrate 3001 and / or a substrate 3003. In Fig. 32A and Fig. 32B, a structure in which light is emitted from the light-emitting element 3005 toward the lower side (the substrate 3001 side) is illustrated.

[0510] As in Fig. 32A and Fig. 32B, the light-emitting device 3000 has a double sealing structure in which the light-emitting element 3005 is enclosed by the first sealing region 3007 and the second sealing region 3009. With the double sealing structure, the entry of impurities (e.g., water, oxygen, and the like) from the outside into the light-emitting element 3005 can be advantageously suppressed. Note that it is unnecessary to provide both the first sealing region 3007 and the second sealing region 3009. For example, only the first sealing region 3007 may be provided.

[0511] It should be noted that in Fig. 32B, the first sealing region 3007 and the second sealing region 3009 are provided in contact with the substrate 3001 and the substrate 3003, respectively. However, without being limited to such a structure, for example, the first sealing region 3007 and / or the second sealing region 3009 may be provided in contact with an insulating film or a conductive film provided on the substrate 3001. Alternatively, the first sealing region 3007 and / or the second sealing region 3009 may be provided in contact with an insulating film or a conductive film provided on the substrate 3003.

[0512] The substrate 3001 and the substrate 3003 may have structures similar to those of the substrate 200 and the substrate 220 described in Embodiment 3, respectively. The light-emitting element 3005 may have a structure similar to that of any of the light-emitting elements described in the above embodiments.

[0513] For the first sealing portion 3007, a material containing glass (e.g., a glass frit, a glass ribbon, and the like) can be used. For the second sealing portion 3009, a material containing a resin can be used. By using the material containing glass for the first sealing portion 3007, productivity and sealing performance can be improved. Furthermore, by using the material containing a resin for the second sealing portion 3009, impact resistance and heat resistance can be improved. However, the materials used for the first sealing portion 3007 and the second sealing portion 3009 are not limited to these, and the first sealing portion 3007 can be formed using the material containing a resin, and the second sealing portion 3009 can be formed using the material containing glass.

[0514] The glass frit may contain, for example, magnesium oxide, calcium oxide, strontium oxide, barium oxide, cesium oxide, sodium oxide, potassium oxide, boron oxide, vanadium oxide, zinc oxide, tellurium oxide, aluminum oxide, silicon dioxide, lead oxide, tin oxide, phosphorus oxide, ruthenium oxide, rhodium oxide, iron oxide, copper oxide, manganese dioxide, molybdenum oxide, niobium oxide, titanium oxide, tungsten oxide, bismuth oxide, zirconium oxide, lithium oxide, antimony oxide, lead borate glass, tin phosphate glass, vanadate glass, or borosilicate glass. The glass frit preferably contains at least one type of transition metal to absorb infrared light.

[0515] For the above glass frits, for example, a frit paste is applied to a substrate and subjected to heat treatment, laser light irradiation, or the like. The frit paste contains the glass frit and a resin (also called a binder) diluted with an organic solvent. Note that an absorbent that absorbs light having the wavelength of the laser light may be added to the glass frit. For example, an Nd:YAG laser or a semiconductor laser is preferably used as the laser. The shape of the laser light may be circular or square.

[0516] For the above material containing a resin, for example, materials containing polyester, polyolefin, polyamide (e.g., nylon, aramid), polyimide, polycarbonate, or an acrylic resin, urethane, an epoxy resin, or a resin having a siloxane bond can be used.

[0517] Note that in the case where the material containing glass is used for the first sealing portion 3007 and / or the second sealing portion 3009, the material containing glass preferably has a thermal expansion coefficient close to that of the substrate 3001. With the above structure, the formation of a crack in the material containing glass or the substrate 3001 due to thermal stress can be suppressed.

[0518] For example, the following advantageous effects can be obtained in the case where the material containing glass is used for the first sealing portion 3007 and the material containing a resin is used for the second sealing portion 3009.

[0519] The second sealing portion 3009 is provided closer to an outer portion of the light-emitting device 3000 than the first sealing portion 3007. In the light-emitting device 3000, deformation due to external force or the like increases toward the outer portion. Accordingly, the outer portion of the light-emitting device 3000, where a greater amount of deformation occurs, that is, the second sealing portion 3009, is sealed using the material containing a resin, and the first sealing portion 3007, which is provided on a more inner side than the second sealing portion 3009, is sealed using the material containing glass, whereby the light-emitting device 3000 is less likely to be damaged even if deformation due to external force or the like occurs.

[0520] Furthermore, as in Fig. 32B, a first region 3011 corresponds to the region enclosed by the substrate 3001, the substrate 3003, the first sealing region 3007, and the second sealing region 3009. A second region 3013 corresponds to the region enclosed by the substrate 3001, the substrate 3003, the light-emitting element 3005, and the first sealing region 3007.

[0521] The first region 3011 and the second region 3013 are preferably filled with an inert gas such as an inert gas or a nitrogen gas, a resin such as an acrylic resin or an epoxy resin, or the like. Note that for the first region 3011 and the second region 3013, a reduced pressure state is preferable to an atmospheric pressure state.

[0522] Fig. Figure 32C shows a modification example of the structure in Fig. 32B. Fig. 32C is a cross-sectional view illustrating the modification example of the light-emitting device 3000.

[0523] Fig. Fig. 32C illustrates a structure in which a desiccant 3018 is provided in a recessed portion provided in a part of the substrate 3003. The other components are the same as those of the structure shown in Fig. 32B is shown.

[0524] As the desiccant 3018, a substance that adsorbs moisture and the like by chemical adsorption or a substance that adsorbs moisture and the like by physical adsorption can be used. Examples of the substance that can be used as the desiccant 3018 include alkali metal oxides, an alkaline earth metal oxide (such as calcium oxide, barium oxide, and the like), sulfate, metal halides, perchlorate, zeolite, silica gel, and the like.

[0525] Next, modification examples of the light-emitting device 3000 shown in Fig. 32B, using Fig. 33A to Fig. 33D. It should be noted that Fig. 33A to Fig. 33D are cross-sectional views showing the modification examples of the light-emitting device 3000 shown in Fig. 32B.

[0526] For each of the light-emitting devices used in Fig. 33A to Fig. 33D, the second sealing region 3009 is not provided, but only the first sealing region 3007 is provided. Furthermore, in each of the light-emitting devices shown in Fig. 33A to Fig. 33D, an area 3014 instead of the second area 3013 shown in Fig. 32B is provided.

[0527] For example, materials containing polyester, polyolefin, polyamide (e.g., nylon or aramid), polyimide, polycarbonate, an acrylic resin, an epoxy resin, urethane, or a resin with a siloxane bond can be used for the 3014 range.

[0528] When the above-described material is used for the region 3014, a so-called tightly sealed light-emitting device can be obtained.

[0529] In the light-emitting device used in Fig. 33B, a substrate 3015 is formed on the side of the light-emitting device substrate 3001 shown in Fig. 33A is provided.

[0530] The substrate 3015 has, as in Fig. 33B, an unevenness. With a structure in which the substrate 3015 is provided with an unevenness on the side through which light emitted from the light-emitting element 3005 is extracted, the light extraction efficiency from the light-emitting element 3005 can be improved. It should be noted that instead of the structure with an unevenness shown in Fig. 33B, a substrate having a function as a diffusion plate can be provided.

[0531] In the light-emitting device used in Fig. 33C, light is emitted in contrast to the light-emitting device shown in Fig. 33A and in which light is taken out via the side of the substrate 3001, taken out via the side of the substrate 3003.

[0532] The light-emitting device used in Fig. 33C, includes the substrate 3015 on the side of the substrate 3003. The other components are similar to those of the light-emitting device shown in Fig. 33B is shown.

[0533] In the light-emitting device used in Fig. 33D, the substrate 3003 and the substrate 3015 used in the light-emitting device shown in Fig. 33C, but a substrate 3016 is provided.

[0534] The substrate 3016 includes a first unevenness positioned closer to the light-emitting element 3005 and a second unevenness positioned farther from the light-emitting element 3005. With the structure shown in Fig. 33D, the efficiency of light extraction from the light-emitting element 3005 can be further improved.

[0535] Accordingly, the use of the structure described in this embodiment can provide a light-emitting device in which deterioration of a light-emitting element due to impurities such as moisture and oxygen is suppressed. Alternatively, the structure described in this embodiment can provide a light-emitting device with high light extraction efficiency.

[0536] It should be noted that the structure described above in this embodiment can be suitably used with the structure described in any of the other embodiments. (Embodiment 9)

[0537] In this embodiment, examples in which the light-emitting element of one embodiment of the present invention is used for various lighting devices and electronic devices will be explained with reference to Fig. 34A to Fig. 34C and Fig. 35 described.

[0538] An electronic device or a lighting apparatus having a light-emitting region with a curved surface can be obtained by using the light-emitting element of one embodiment of the present invention, which is fabricated over a substrate having flexibility.

[0539] Furthermore, a light-emitting device to which an embodiment of the present invention is applied can also be applied to a lighting device for vehicles; examples include a lighting device for an instrument panel, a windshield, a vehicle ceiling, and the like.

[0540] Fig. 34A is a perspective view illustrating a surface of a multi-function connector 3500, and Fig. 34B is a perspective view illustrating the other surface of the multi-function connector 3500. A housing 3502 of the multi-function connector 3500 houses a display section 3504, a camera 3506, an illuminator 3508, and the like. The light-emitting device of one embodiment of the present invention can be used for the illuminator 3508.

[0541] The illuminator 3508, which includes the light-emitting device of one embodiment of the present invention, serves as a planar light source. Accordingly, the illuminator 3508 can provide low-directivity light emission, unlike a point light source, of which an LED is a typical example. For example, when the illuminator 3508 and the camera 3506 are used in combination, image capture can be performed by the camera 3506 with the illuminator 3508 flashing or blinking. Because the illuminator 3508 serves as a planar light source, a photograph can be taken in the same way as under natural light.

[0542] It should be noted that the multifunction connector 3500, which is used in Fig. 34A and Fig. 34B, as in the electronic devices used in Fig. 29A to Fig. 29G can have a variety of functions.

[0543] The housing 3502 may include a speaker, a sensor (a sensor with a function for measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone, and the like. If a detection device including a sensor such as a gyroscope or an acceleration sensor for detecting inclination is provided within the multi-function terminal 3500, the display on the screen of the display section 3504 can be automatically changed by determining the orientation of the multi-function terminal 3500 (whether the multi-function terminal is arranged horizontally or vertically in a landscape or portrait orientation).

[0544] The display section 3504 can serve as an image sensor. For example, an image of a palm print, a fingerprint, or the like is captured when the palm or finger touches the display section 3504, thereby enabling personal authentication. Furthermore, by providing a backlight or a scanning light source that emits near-infrared light in the display section 3504, an image of a finger vein, a palm vein, or the like can be captured. Note that the light-emitting device of one embodiment of the present invention can be used for the display section 3504.

[0545] Fig. 34C is a perspective view of a security light 3600. The security light 3600 includes an illuminator 3608 on the outside of the housing 3602, and a speaker 3610 and the like are installed in the housing 3602. The light-emitting device of one embodiment of the present invention can be used for the illuminator 3608.

[0546] The safety light 3600 emits light when the light 3608 is grasped or held, for example. An electronic circuit that can control the type of light emission from the safety light 3600 can be provided in the housing 3602. The electronic circuit can be a circuit that allows light emission once or periodically multiple times, or can be a circuit that can adjust the amount of light emitted by controlling the current value for the light emission. A circuit can be incorporated that emits a loud audible alarm from the speaker 3610 simultaneously with the light emission from the light 3608.

[0547] The security light 3600 can emit light in various directions; thus, it is possible to intimidate a criminal or the like with light, or light and noise. Furthermore, the security light 3600 can include a camera, such as a digital still camera, to have a photography function.

[0548] Fig. 35 illustrates an example in which a light-emitting element is used for an indoor lighting device 8501. Since the light-emitting element can have a larger area, a lighting device with a large area can also be formed. In addition, a lighting device 8502 in which a light-emitting region has a curved surface can also be formed using a housing with a curved surface. A light-emitting element described in this embodiment is in the form of a thin film, which makes it possible to design the housing more freely. Consequently, the lighting device can be artistically designed in various ways. Furthermore, a wall of the room can be provided with a large lighting device 8503.Touch sensors may be arranged in the lighting devices 8501, 8502 and 8503 to control the switching on or off of the lighting devices.

[0549] Furthermore, when the light-emitting element is used for the surface side of a table, a lighting device 8504 having a function as a table can be obtained. When the light-emitting element is used as part of another piece of furniture, a lighting device having a function as a piece of furniture in question can be obtained.

[0550] As described above, lighting devices and electronic devices can be obtained using the light-emitting device of one embodiment of the present invention. Note that the light-emitting device for electronic devices can be used in various fields, without being limited to the lighting devices and electronic devices described in this embodiment.

[0551] It should be noted that the structures described in this embodiment may be used in a suitable combination with any of the structures described in the other embodiments. Explanation of reference symbols

[0552] 100: EL layer, 101: electrode, 101a: conductive lay...

Claims

[1] A light-emitting device comprising a light-emitting element (150; 152) comprising: a high-molecular material (131; 141) comprising a first high-molecular chain and / or a second high-molecular chain; and a guest material (132; 142), where both the first high molecular weight chain and the second high molecular weight chain comprise: a first framework (131_1; 141_1) having a hole transport property; a second framework (131_2; 141_2) with an electron transport property; and a third scaffold (131_3; 141_3), wherein the first frame (131_1; 141_1) and the second frame (131_2; 141_2) are connected to each other via the third frame (131_3; 141_3), and wherein the first high molecular weight chain and the second high molecular weight chain are configured to form an excited complex. [2] A light-emitting device comprising a light-emitting element (150; 152) comprising: a high-molecular material (131; 141) comprising a first high-molecular chain and / or a second high-molecular chain; and a guest material (132; 142), where both the first high molecular weight chain and the second high molecular weight chain comprise: a first framework (131_1; 141_1) comprising a π-electron-rich heteroaromatic framework and / or an aromatic amine framework; a second framework (131_2; 141_2) comprising a π-electron-deficient heteroaromatic framework; and a third scaffold (131_3; 141_3), wherein the first frame (131_1; 141_1) and the second frame (131_2; 141_2) are connected to each other via the third frame (131_3; 141_3), and wherein the first high molecular weight chain and the second high molecular weight chain are configured to form an excited complex. [3] The light-emitting device according to claim 2, wherein the π-electron-rich heteroaromatic skeleton comprises a thiophene skeleton and / or a furan skeleton and / or a pyrrole skeleton. [4] The light-emitting device according to claim 2, wherein the π-electron-deficient heteroaromatic skeleton comprises a pyridine skeleton and / or a diazine skeleton and / or a triazine skeleton. [5] The light-emitting device according to claim 1 or 2, wherein the guest material (132; 142) is a compound that emits fluorescence. [6] The light-emitting device according to claim 1 or 2, wherein the guest material (132; 142) is a compound that converts triplet excitation energy into light emission. [7] High molecular weight material (131; 141) which includes: a first high molecular weight chain and / or a second high molecular weight chain, where both the first high molecular weight chain and the second high molecular weight chain comprise: a first framework (131_1; 141_1) having a hole transport property; a second framework (131_2; 141_2) with an electron transport property; a third scaffold (131_3; 141_3); and a fourth framework (131_4; 141_4) that emits light, wherein the first frame (131_1; 141_1) and the second frame (131_2; 141_2) are connected to each other via the third frame (131_3; 141_3), and wherein the first high molecular weight chain and the second high molecular weight chain are configured to form an excited complex. [8] High molecular weight material (131; 141) which includes: a first high molecular weight chain and / or a second high molecular weight chain, where both the first high molecular weight chain and the second high molecular weight chain comprise: a first framework (131_1; 141_1) comprising a π-electron-rich heteroaromatic framework and / or an aromatic amine framework; a second framework (131_2; 141_2) comprising a π-electron-deficient heteroaromatic framework; a third scaffold (131_3; 141_3); and a fourth framework (131_4; 141_4) that emits light, wherein the first frame (131_1; 141_1) and the second frame (131_2; 141_2) are connected to each other via the third frame (131_3; 141_3), and wherein the first high molecular weight chain and the second high molecular weight chain are configured to form an excited complex. [9] High molecular weight material (131; 141) according to claim 8, wherein the π-electron-rich heteroaromatic skeleton comprises a thiophene skeleton and / or a furan skeleton and / or a pyrrole skeleton. [10] High molecular weight material (131; 141) according to claim 8, wherein the π-electron-deficient heteroaromatic skeleton comprises a pyridine skeleton and / or a diazine skeleton and / or a triazine skeleton. [11] The high molecular material (131; 141) according to claim 7 or 8, wherein the fourth framework (131_4; 141_4) emits fluorescence. [12] The high molecular material (131; 141) according to claim 7 or 8, wherein the fourth framework (131_4; 141_4) converts a triplet excitation energy of the high molecular material (131; 141) into light emission. [13] A light-emitting device comprising the high-molecular material (131; 141) according to claims 7 to 12 in a light-emitting layer (130; 140). [14] The light-emitting device according to any one of claims 1, 2 and 13, wherein the third framework (131_3; 141_3) comprises a biphenyl framework and / or a fluorene framework. [15] The light-emitting device according to any one of claims 1, 2 and 13, wherein the first high molecular chain and the second high molecular chain are configured to form the excited complex with the first scaffold (131_1; 141_1) in the first high molecular chain and the second scaffold (131_2; 141_2) in the second high molecular chain. [16] A light-emitting device according to any one of claims 1, 2 and 13, wherein the excited complex emits thermally activated delayed fluorescence at room temperature. [17] An electronic device comprising the light-emitting device according to any one of claims 1 to 6 and 13 and 16.

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