Power-generating light-emitting element and display device

Abstract

The present invention provides a power-generating light-emitting element and a display device that can be used continuously without having to carry a separate power generation device. [Solution] A power-generating light-emitting element 100 is characterized by being formed by stacking a transparent solar cell 200 having a visible light transmittance of 40% or more and an organic electroluminescent element 300 having a power-generating function, and a display device is characterized by comprising such a power-generating light-emitting element 100.

Description

[Technical Field]

[0001] The present invention relates to a light-emitting element having a power generation function (hereinafter referred to as "power-generating light-emitting element") and a display device equipped therewith. [Background technology]

[0002] During major earthquakes and other emergencies, smartphones and other information terminals are indispensable devices not only during emergency evacuations but also during life in evacuation centers, and it is essential that they remain usable at all times. However, numerous cases have been reported where their use is restricted due to emergency evacuations to places where charging is impossible, such as rooftops, or due to power shortages in evacuation centers. Display devices (displays), which account for a large portion of the power consumption of information terminals, require further reductions in power consumption and improved power supply methods in the future.

[0003] As a technology for reducing the driving voltage of display devices, in recent years, efforts have been made to enable organic electroluminescence (hereinafter, electroluminescence (field emission) may be written as "EL") elements to emit light at low applied voltages by utilizing the triplet-triplet annihilation of organic light-emitting materials, thereby extracting the triplet excited state as light emitted from the singlet excited state. For example, it has been reported that by using rubrene, a tetracene derivative, as a donor and fullerene, which has a high electron affinity, as an acceptor, the energy of the excited complex (excyplex) formed at the interface can be extracted as light emitted from the singlet excited state of rubrene in an organic EL element via triplet-triplet annihilation (see, for example, Non-Patent Literature 1).

[0004] In an organic electroluminescence device combining this rubrene and an acceptor, the energy difference between the ionization potential, which is the energy of the highest occupied molecular orbital (HOMO) of rubrene, and the energy of the lowest unoccupied molecular orbital (LUMO) of fullerene as the acceptor is small, and an excited state can be formed with this small energy difference. Therefore, an excited state that contributes to light emission can be generated at a low applied voltage. In a general organic EL device, since charge recombination occurs in one molecule, an applied voltage corresponding to the energy of the bandgap is required to generate an excited state that contributes to light emission. However, in an organic EL device using an excited complex of rubrene and an acceptor, light emission can be obtained at a lower voltage.

[0005] However, when tetracene derivatives such as rubrene are used as materials where triplet-triplet annihilation occurs, the peak wavelength of the material becomes 550 nm or more, so only orange or red light emission can be obtained. In order to obtain blue or green light emission, a condensed ring compound with a shorter emission wavelength, such as an anthracene derivative, is required. On the other hand, the inventors have developed an anthracene derivative with a greater electron affinity and developed a low-driving-voltage blue light-emitting organic EL device for further reduction of the voltage (Patent Document 1).

[0006] On the other hand, by fabricating a transparent organic solar cell using an absorption spectrum that largely depends on the molecular structure characteristic of an organic material, the development of a low-cost and transparent organic optoelectronic (OPV) device that can be incorporated into the windows of homes, high-rise buildings, and automobiles has been attempted (Patent Document 2). Since these transparent solar cells mainly use ultraviolet and infrared rays for power generation, it is possible to add a power generation function without impairing the aesthetics.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Non-Patent Literature

[0008]

Non-Patent Literature 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, the transparent solar cell described in Patent Document 2 etc. above has problems such as hardly being able to generate electricity indoors where there is no ultraviolet light in the LED main body, and having to reduce the film thickness of the power generation layer in order to ensure transparency and power generation performance, and not being able to completely absorb the wavelength used for power generation.

[0010] In addition, in a device that combines the transparent solar cell described in Patent Document 2 etc. with a normal organic EL display, power generation cannot be performed indoors, while in the case of using a colored solar cell, it cannot be mounted on the display surface, and it is necessary to carry the colored solar cell separately and connect it.

[0011] Therefore, an object of the present invention is to provide a light-emitting element having a power generation function (that is, a power generation and light-emitting element) that can continue to use a display device without having to carry a separate power generation facility during an emergency such as a disaster, and can be applied to the display surface of a smartphone or the like. Another object of the present invention is to provide a display device that can continue to be used without having to carry a separate power generation facility.

Means for Solving the Problems

[0012] The inventors of the present invention have conceived that the above problems can be solved by laminating a transparent solar cell that mainly generates electricity with ultraviolet rays and infrared rays on an organic EL element having a function capable of generating electricity using light having a wavelength of visible light other than light emission, and have reached the present invention in which power generation and light emission are possible on one display surface. The gist of the present invention's power-generating light-emitting element and display device, which solve the above problems, is as follows.

[0013] [1] A power-generating light-emitting element characterized by comprising a transparent solar cell having a visible light transmittance of 40% or more and an organic electroluminescent element having a power-generating function, stacked together. The power-generating light-emitting element of the present invention described in [1] above can be used continuously without having to carry a separate power generation device, and can also be applied to the display surface of a smartphone or the like.

[0014] [2] A display device characterized by comprising the power-generating light-emitting element described in [1]. The display device of the present invention described in [2] above can be used continuously without having to carry a separate power generation device. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a power-generating light-emitting element that can be used continuously in emergencies such as disasters without having to carry separate power generation equipment, and that can also be applied to the display surface of a smartphone or the like. Furthermore, according to the present invention, it is possible to provide a display device that can be used continuously without having to carry around separate power generation equipment. [Brief explanation of the drawing]

[0016] [Figure 1] This document shows a perspective view and a side view of one embodiment of the power-generating light-emitting element of the present invention, as well as an image diagram of the emission wavelength and power generation wavelength. [Figure 2] This is a schematic diagram showing an example of the structure of an organic EL element constituting the power-generating light-emitting element of the present invention. [Figure 3] This is a schematic diagram showing the energy levels within an example of an organic EL element constituting the power-generating light-emitting element of the present invention. [Figure 4] This is a schematic diagram illustrating an example of the luminescence mechanism of anthracene derivatives, showing luminescence from a singlet excited state utilizing energy transfer from the excited complex and triplet-triplet annihilation. [Figure 5] This is a schematic diagram showing an example of the structure of a typical organic EL element and its energy levels. [Figure 6] This is a schematic diagram showing another example of the structure of an organic EL element constituting the power generation and light-emitting element of the present invention. [Figure 7] This schematic diagram illustrates another example of the luminescence mechanism of anthracene derivatives, showing luminescence utilizing energy transfer from the excited complex, triplet-triplet annihilation, and energy transfer from the singlet excited state. [Figure 8] This is a schematic diagram showing an example of a transparent solar cell that constitutes the power-generating light-emitting element of the present invention. [Modes for carrying out the invention]

[0017] The power-generating light-emitting element and display device of the present invention will be described in detail below based on their embodiments. Furthermore, combinations of two or more of the individual preferred embodiments of the present invention described below are also preferred embodiments of the present invention.

[0018] <Electrification light-emitting element> The present invention is characterized by comprising a transparent solar cell having a visible light transmittance of 40% or more and an organic electroluminescent element having a power generation function, stacked together.

[0019] In the power-generating light-emitting element of the present invention, a transparent solar cell that primarily generates electricity using ultraviolet and infrared light is used outdoors, while an organic electroluminescent element that has the function of generating electricity using light of visible wavelengths other than light emission is used indoors, where LEDs are the main component. Therefore, the power-generating light-emitting element of the present invention can be used continuously without having to carry separate power generation equipment. Furthermore, the power-generating light-emitting device of the present invention consists of a transparent solar cell laminated on an organic electroluminescent element, and since the transparent solar cell does not obstruct the light emitted from the organic electroluminescent element, the light emitted from the organic electroluminescent element can be visually observed. For this reason, the power-generating light-emitting device of the present invention can also be applied to the display surface of a smartphone or the like.

[0020] One embodiment of the power-generating light-emitting element of the present invention will be described in detail below with reference to the drawings. Figure 1 shows a perspective view and a side view of one embodiment of the power-generating light-emitting element of the present invention, and an image diagram of the emission wavelength and power generation wavelength. More specifically, Figure 1(a) is a perspective view of one embodiment of the power-generating light-emitting element of the present invention, Figure 1(b) is a side view of one embodiment of the power-generating light-emitting element of the present invention, Figure 1(c) is an image diagram in which an example of the spectrum of sunlight is superimposed with an example of the absorption region of a transparent solar cell and an example of the absorption region of an organic electroluminescent element, Figure 1(d) is an image diagram in which an example of the spectrum of sunlight after passing through a transparent solar cell is superimposed with an example of the emission spectrum and absorption spectrum of a red pixel, Figure 1(e) is an image diagram in which an example of the spectrum of sunlight after passing through a transparent solar cell is superimposed with an example of the emission spectrum and absorption spectrum of a green pixel, and Figure 1(f) is an image diagram in which an example of the spectrum of an LED is superimposed with an example of the absorption region of a transparent solar cell and an example of the absorption region of an organic electroluminescent element.

[0021] In the power-generating light-emitting element 100 shown in Figures 1(a) and 1(b), a transparent solar cell 200 and an organic EL element 300 are stacked. The organic EL element 300 comprises a substrate 310, a TFT 320 mounted on the substrate 310, and red pixels 330, green pixels 340, and blue pixels 350 formed on the TFT 320, respectively. As shown in Figure 1(b), the power-generating light-emitting element 100 receives sunlight and generates electricity using both the transparent solar cell 200 and the organic EL element 300. Here, as shown in Figure 1(c), sunlight contains light of a wide range of wavelengths including ultraviolet, visible, and infrared light. The transparent solar cell 200 mainly generates electricity using ultraviolet and infrared light, while the organic EL element 300 generates electricity using visible light wavelengths other than those used for emission. For example, as shown in Figure 1(d), the red pixel 330 (a red-emitting organic EL element) generates electricity using light with wavelengths in the green and blue regions, and as shown in Figure 1(e), the green pixel 340 (a green-emitting organic EL element) generates electricity using light with wavelengths in the blue region. As shown in Figure 1(f), the wavelength of LEDs is mainly visible light in the 400-700 nm range, and the transparent solar cell 200 cannot generate enough electricity, but the organic EL element 300, which has a power generation function, can generate electricity using light with wavelengths of visible light other than those emitted. Therefore, the power-generating light-emitting element 100 can be used continuously without carrying separate power generation equipment, as the transparent solar cell 200 primarily generates power outdoors, while the organic EL element 300 primarily generates power indoors where LEDs are the main component.

[0022] (Organic electroluminescent element) The power-generating light-emitting device of the present invention comprises an organic electroluminescent element having a power-generating function. The organic electroluminescent element is not particularly limited as long as it has a power-generating function.

[0023] In one embodiment, the organic electroluminescent element having a power generation function comprises an anode, a light-emitting layer, and a cathode in this order, wherein the light-emitting layer is based on the following general formula (1): [ka] In general formula (1), X 1 , X 2 and X 3 are each independently R or a cyano group, provided that any two of X 1 are cyano groups, any two of X 2 are cyano groups, and any two of X 3 are cyano groups, R is each independently hydrogen, or a monovalent substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, and a substituted or unsubstituted aromatic 6-membered heterocyclic group having 3 to 30 carbon atoms, and adjacent substituents may combine to form a ring.], and includes an anthracene derivative (condensed ring compound) represented by [].

[0024] The anthracene derivative represented by the above general formula (1) has a structure in which three phthalonitrile moieties (benzene rings having two cyano groups) are directly or indirectly connected to the anthracene ring, has a large electron affinity (for example, the calculated value of the electron affinity is 2 eV or more), and has excellent light emission characteristics. And in the organic electroluminescence device, since the anthracene derivative represented by the above general formula (1) has a large electron affinity, it is possible to obtain light emission at a low applied voltage by including the anthracene derivative represented by the general formula (1) in the light emitting layer.

[0025] In the above general formula (1), X 1 , X 2 and X 3 are each independently R or a cyano group, provided that any two of X 1 are cyano groups, any two of X 2 are cyano groups, and any two of X 3 are cyano groups. Incidentally, R as an option for X 1 , X 2 and X 3 is synonymous with R in general formula (1), and R will be described later. By linking a phthalonitrile moiety, which has two acceptor substituents (cyano groups), to the anthracene ring, the electron affinity is increased, resulting in an anthracene derivative with excellent luminescence properties.

[0026] Also, the five X's 1 Any two of these may be cyano groups, but the X at the meta position relative to the bond to the anthracene ring 1 Preferably, at least one of them is a cyano group, and the X at the meta position 1 It is even more preferable that both are cyano groups. On the other hand, five X 1 The other three of these are R, but the three Rs may be the same or different.

[0027] Also, the five X's 2 Any two of these may be cyano groups, but the X at the meta position relative to the bond position to the benzene ring 2 Preferably, at least one of them is a cyano group, and the X at the meta position 2 It is even more preferable that both are cyano groups. On the other hand, five X 2 The other three of these are R, but the three Rs may be the same or different.

[0028] Also, the five X's 3 Any two of these may be cyano groups, but the X at the meta position relative to the bond position to the benzene ring 3 Preferably, at least one of them is a cyano group, and the X at the meta position 2 It is even more preferable that both are cyano groups. On the other hand, five X 3 The other three of these are R, but the three Rs may be the same or different.

[0029] In the above general formula (1), R is independently hydrogen, or a monovalent substituent selected from the group consisting of a C1-C10 alkyl group, a C1-C10 alkoxy group, a C1-C10 alkylthio group, a C1-C10 alkylamino group, a C2-C10 acyl group, a C7-C20 aralkyl group, a substituted or unsubstituted C6-C30 aromatic hydrocarbon group, and a substituted or unsubstituted C3-C30 aromatic 6-membered heterocyclic group, and adjacent substituents may form a ring together.

[0030] Here, examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and nonyl groups. Examples of alkoxy groups having 1 to 10 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy, hexyloxy, heptyloxy, and octyloxy groups. Examples of alkylthio groups having 1 to 10 carbon atoms include methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, octylthio, and nonylthio groups. Examples of alkylamino groups having 1 to 10 carbon atoms include methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, heptylamino, and octylamino groups. Examples of carbon-neutral groups include the no group and nonylamino group. Examples of carbon-neutral acyl groups with 2 to 10 carbon atoms include the acetyl group, propionyl group, and butyryl group. Examples of carbon-neutral aralkyl groups with 7 to 20 carbon atoms include the benzyl group, phenethyl group, phenylpropyl group, and naphthylmethyl group. Examples of substituted or unsubstituted carbon-neutral aromatic hydrocarbon groups with 6 to 30 carbon atoms include the phenyl group, 2,6-xylyl group, mesityl group, duryl group, biphenyl group, terphenyl group, naphthyl group, anthryl group, pyrenyl group, toluyl group, anisyl group, fluorophenyl group, diphenylaminophenyl group, dimethylaminophenyl group, diethylaminophenyl group, pyridylphenyl group, and phenanthrenyl group. Examples of substituted or unsubstituted carbon-neutral 6-membered aromatic heterocyclic groups with 3 to 30 carbon atoms include the pyridyl group, pyrazinyl group, pyrimidinyl group, pyridadinyl group, and triazinyl group.

[0031] Specifically, examples of anthracene derivatives represented by the above formula (1) include the compounds shown in the following structural formulas (1-1) to (1-3). [ka]

[0032] The anthracene derivative represented by the above general formula (1) can be obtained by known methods. The method for synthesizing the anthracene derivative represented by general formula (1) is not particularly limited, but one example is shown below.

[0033] First, a benzene derivative having two carboxyl groups is prepared. Examples of such benzene derivatives include phthalic acid, isophthalic acid, and terephthalic acid. Next, the benzene derivative is halogenated to obtain a benzene derivative having a halogen group (also called a "halogeno group") and two carboxyl groups. Next, the carboxyl groups of the benzene derivative having the halogen group and two carboxyl groups are chlorinated to obtain a carboxylic acid chloride (acid chloride). Here, oxalyl chloride [(COCl)2], thionyl chloride (SOCl2), etc. can be used for chlorinating the carboxyl groups. Next, the carboxylic acid chloride is amidated to obtain an amide compound. Here, an amine compound such as t-butylamine can be used for the amidation of the carboxylic acid chloride. Next, the amide compound is nitrified to obtain a benzene derivative having a halogen group and two cyano groups. Here, thionyl chloride (SOCl2) or the like can be used for nitrifying the amide compound. Next, a boryl group, such as a pinacolate boryl group, is introduced into the benzene derivative having the halogen group and two cyano groups to obtain an organoboron compound having two cyano groups. Here, bis(pinacolate)diboron or the like can be used to introduce the boryl group. Examples of organoboron compounds having two cyano groups include 3,5-dicyanophenylboronic acid pinacol ester.

[0034] On the other hand, a six-membered ring compound with three halogen groups bonded to it is prepared. Here, since a boron compound having an anthracene ring will be bonded to one of the three halogen groups in a later step, it is preferable that one of the three halogen groups be of a different type. For example, it is preferable to have two bromo groups and one iodine group, or two chloro groups and one iodine group, or two chloro groups and one bromo group. The six-membered ring compound is a compound having a benzene ring as the six-membered ring. An example of a six-membered ring compound with three halogen groups bonded to it is 1,3-dibromo-5-iodobenzene. By performing Suzuki coupling between the six-membered ring compound with three halogen groups bonded to it and a boron compound having an anthracene ring such as 9-anthraceneboronic acid, an anthracene derivative having a six-membered ring moiety with two halogen groups bonded to it is obtained. Next, the anthracene derivative having a six-membered ring moiety to which the two halogen groups are bonded is brominated with N-bromosuccinimide (NBS) or the like to obtain an anthracene derivative having a six-membered ring moiety to which the two halogen groups are bonded and a bromo group.

[0035] An anthracene derivative represented by the above general formula (1) can be produced by performing a Suzuki coupling between the organoboron compound having two cyano groups obtained as described above and an anthracene derivative having a six-membered ring moiety to which two halogen groups are bonded and a bromo group. Here, the Suzuki coupling between the organoboron compound having two cyano groups and the anthracene derivative having a six-membered ring moiety to which two halogen groups are bonded and a bromo group can be carried out, for example, in the presence of a ligand such as S-Phos{dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-2-yl)phosphine}, a palladium catalyst, and a base.

[0036] Furthermore, the Suzuki coupling can be carried out in the presence of a palladium catalyst such as palladium acetate [Pd(OAc)2], Pd2(dba)3, Pd(Ph3P)4, or Pd(dppf)Cl2, and a base such as tripotassium phosphate, sodium carbonate, or sodium bicarbonate.

[0037] In the organic electroluminescent element having a power generation function, it is preferable that the light-emitting layer further contains a material having a lower ionization energy than the anthracene derivative. Furthermore, it is also preferable that the organic electroluminescent element having a power generation function further includes a hole transport layer between the anode and the light-emitting layer, and that the hole transport layer contains a material having a lower ionization energy than the anthracene derivative. In the aforementioned organic electroluminescent device, since the anthracene derivative represented by the general formula (1) has a large electron affinity, it is possible to obtain light emission at a lower applied voltage by placing adjacent materials (i.e., the light-emitting layer contains the anthracene derivative represented by the general formula (1), and a layer adjacent to the light-emitting layer, such as a hole transport layer, contains a material with a lower ionization energy than the anthracene derivative) or by mixing them (i.e., the light-emitting layer contains the anthracene derivative represented by the general formula (1) and a material with a lower ionization energy than the anthracene derivative) so that the anthracene derivative and a material with a lower ionization energy than the anthracene derivative form an excited complex.

[0038] Furthermore, an organic electroluminescent element using the anthracene derivative as the donor and a material with a lower ionization energy than the anthracene derivative as the acceptor, with a small energy difference between the donor's highest occupied orbital (HOMO) and the acceptor's lowest unoccupied orbital (LUMO), can generate electricity when irradiated with light while not emitting light, by appropriately designing the energy difference. Therefore, the organic electroluminescent element can emit light at a low driving voltage and generate electricity through photoelectric conversion. Here, the ionization energy (also called the "ionization potential (IP)") of the anthracene derivative represented by general formula (1) and the ionization energy of a material with a lower ionization energy than the anthracene derivative are calculated values, mainly calculated using density functional theory with the Gaussian 09 program, under the following conditions [B3LYP / 6-31G (d,p)].

[0039] Next, one embodiment of the organic electroluminescent element constituting the power-generating light-emitting element of the present invention will be described in detail with reference to the drawings. Figure 2 is a schematic diagram showing an example of the structure of the organic EL element constituting the power-generating light-emitting element of the present invention. The organic EL element 1 shown in Figure 2 has a laminated structure in which an anode 3, a hole injection layer 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, and a cathode 9 are formed in this order on a substrate 2.

[0040] Furthermore, Figure 3 shows the energy levels within the organic electroluminescent element 1 shown in Figure 2. In the organic EL element 1, electrons injected into the anthracene derivative (emissive layer 6) and holes injected into the hole transport layer 5, which has a lower ionization potential than the anthracene derivative, form an excited complex, causing an electric current to flow and light to be emitted. At this time, the voltage required for light emission is determined by the energy difference between the electron affinity of the anthracene derivative and the ionization potential of the material of the hole transport layer 5. However, because the electron affinity of the anthracene derivative, which is the emissive layer 6, is large, this energy difference becomes small, and the externally applied voltage required for light emission decreases. When this energy difference is 2.5 eV or less, the power generation capacity of the organic EL element 1 is improved.

[0041] Next, Figure 4 shows the energy transfer process from the formation of the excited complex to luminescence. Since the external voltage required for the formation of the excited complex is small, the energy of the resulting light from the excited complex is not large. However, if the triplet energy of the anthracene derivative involved in the formation of the excited complex is smaller than the energy of the excited state of this excited complex, the energy of the excited complex is transferred to the triplet excited state of the anthracene derivative. Since it is well known that anthracene derivatives can generate a singlet excited state by utilizing triplet-triplet annihilation, this property can be used to generate a singlet excited state and obtain luminescence from it. Here, the luminescence from the singlet excited state has higher energy than the light from the excited complex.

[0042] Next, Figure 5 shows the configuration and energy levels of a typical organic electroluminescent element that does not utilize the formation of excitation complexes. The organic electroluminescent element shown in Figure 5 has a layered structure in which an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an emissive layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode are formed in this order on a substrate. In a typical organic electroluminescent element, electrons and holes are directly recombined in the emissive layer material to form an excited state, so it is necessary to apply an external voltage close to the band gap of the emissive layer material. This external voltage is higher than the voltage required for light emission in the organic EL elements shown in Figures 2 to 4. Also, if many materials with different energy levels are used in an organic EL element, an energy difference will occur within the device, leading to an increase in voltage. Therefore, to lower the voltage, it is effective to use excitation complexes of anthracene derivatives and other materials as shown in Figures 2 to 4. However, since the anthracene derivative is expected to show high luminescence efficiency, it can also be used in the emissive layer, etc., in the form shown in Figure 5.

[0043] In this embodiment, the organic EL element 1 may be an inverted organic EL element having a cathode 9 on a substrate 2, as shown in Figure 6. The organic EL element 1 shown in Figure 6 has a laminated structure in which a cathode 9, an electron injection layer 8, an electron transport layer 7, an emissive layer 6, a hole transport layer 5, a hole injection layer 4, and an anode 3 are formed on the substrate 2 in this order.

[0044] Furthermore, in this embodiment, the organic EL element 1 may be an organic-inorganic hybrid type organic electroluminescent element (HOILED element) in which a part of the layer constituting the organic EL element is formed using an inorganic compound.

[0045] "substrate" Examples of materials for substrate 2 include resin materials and glass materials. Examples of resin materials used for the substrate 2 include polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate. Using a resin material for the substrate 2 is preferable because it allows for the production of an organic EL element 1 with excellent flexibility. Examples of glass materials used for substrate 2 include quartz glass and soda glass.

[0046] If the organic EL element 1 is a bottom-emission type, a transparent substrate is used as the material for the substrate 2. If the organic EL element 1 is of the top-emission type, the substrate 2 may be made of an opaque substrate as well as a transparent substrate. Examples of opaque substrates include substrates made of ceramic materials such as alumina, substrates in which an oxide film (insulating film) is formed on the surface of a metal plate such as stainless steel, and substrates made of resin materials.

[0047] The average thickness of substrate 2 can be determined according to the material of substrate 2, and is preferably 0.1 to 30 mm, and more preferably 0.1 to 10 mm. The average thickness of substrate 2 can be measured using a digital multimeter or calipers.

[0048] "anode" The anode 3 shown in Figure 2 is formed in direct contact with the substrate 2, but in the case of an organic EL element with an inverted structure as shown in Figure 6, it does not have to be formed in direct contact with the substrate 2. Examples of conductive oxide materials for anode 3 include ITO (indium tin oxide), IZO (indium zinc oxide), FTO (fluorinated tin oxide), In2O3, SnO2, Sb-containing SnO2, and Al-containing ZnO. Among these, ITO, IZO, and FTO are preferred as the material for anode 3. The average thickness of anode 3 is not particularly limited, but is preferably 10 to 500 nm, and more preferably 100 to 200 nm. The average thickness of anode 3 can be measured by a stylus step meter or spectroscopic ellipsometry.

[0049] "Hole injection layer" The hole injection layer 4 may be made of an inorganic material or an organic material. Since inorganic materials are more stable than organic materials, it is easier to obtain higher resistance to oxygen and water compared to when organic materials are used. The inorganic material is not particularly limited, but for example, one or more metal oxides such as vanadium oxide (V2O5), molybdenum oxide (MoO3), and ruthenium oxide (RuO2) can be used. Organic materials such as dipyradino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonnitrile (HAT-CN) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4-TCNQ) can be used. Polymer materials such as poly(3,4-ethylenedioxythiophene) (PEDOT) can also be used. The average thickness of the hole injection layer 4 is not particularly limited, but is preferably 1 to 1000 nm, and more preferably 5 to 50 nm. The average thickness of the hole injection layer 4 can be measured during film formation using a quartz crystal film thickness gauge.

[0050] "Hole transport layer" As described above, the hole transport layer 5 preferably contains an organic compound that forms an excitation complex with an anthracene derivative, and more preferably contains a material with a lower ionization energy than the anthracene derivative represented by the general formula (1) above. As will be described later, when the light-emitting layer 6 contains an anthracene derivative represented by the general formula (1) above, and the hole transport layer 5 contains a material with a lower ionization energy than the anthracene derivative, an excitation complex is formed at the interface between the light-emitting layer 6 and the hole transport layer 5, and the driving voltage of the organic EL element 1 can be further reduced.

[0051] As the hole-transporting organic material used in the hole transport layer 5, it is preferable to use a material that forms an excitation complex and has a small ionization potential (IP) and electron affinity (EA) (a material with high donor potential). Specifically, materials containing molecular structures with high donor potential, such as triarylamines, carbazoles, phenoxazines, phenazines, acridines, azadibenzopyrenes, and juloridine skeletons, are preferred. More specifically, the following are preferred: m-MTDATA, TPT-1, TAPC, TPDI, HN-D1, HN-D2, N-TPA, EH44, PHZ-2Naph, TBDI, HT-01, N-DPA, spiro-MeO-TAD, Tris-PCz, α-NPD, TcTa, 2-SF-DMAC, 2-SF-PHX, SF-BCz, FATPA, etc.

[0052] [ka] [ka] [ka]

[0053] The organic compound contained in the hole transport layer 5 preferably has an ionization potential (IP) of 3.74 to 5.08 eV calculated using density functional theory, or an experimentally measured ionization potential (IP) of 4.4 to 5.8 eV. The average thickness of the hole transport layer 5 is not particularly limited, but is preferably 10 to 150 nm, and more preferably 20 to 100 nm. The average thickness of the hole transport layer 5 can be measured, for example, by a stylus step meter or spectroscopic ellipsometry.

[0054] "Luminescent layer (luminescent layer and power generation layer)" As described above, the light-emitting layer (light-emitting layer and power-generating layer) 6 contains an anthracene derivative represented by the general formula (1) above. Furthermore, the light-emitting layer 6 may also contain a material having a lower ionization energy than the anthracene derivative. When the light-emitting layer 6 contains an anthracene derivative represented by the general formula (1) above and a material having a lower ionization energy than the anthracene derivative, an excited complex is formed.

[0055] Materials with a lower ionization energy than the aforementioned anthracene derivatives are preferred, and materials with low IP and EA (materials with high donor potential) as listed in the "Hole Transport Layer 5" section are preferred, with m-MTDATA, TPT-1, TAPC, TPDI, HN-D1, HN-D2, N-TPA, EH44, PHZ-2Naph, TBDI, HT-01, N-DPA, spiro-MeO-TAD, Tris-PCz, α-NPD, TcTa, 2-SF-DMAC, 2-SF-PHX, SF-BCz, FATPA, etc. being even more preferred. Here, the content of the material having a lower ionization energy than the anthracene derivative in the light-emitting layer 6 is preferably in the range of 10 to 50% by mass relative to the anthracene derivative.

[0056] In the light-emitting layer 6, the luminescence of an anthracene derivative can be extracted as shown in Figure 4, while as shown in Figure 7, it is also possible to use the anthracene derivative (or excited complex) as a host in the light-emitting layer 6 to extract the luminescence of another light-emitting dopant. In this case, phosphorescent materials such as iridium complexes and platinum complexes, fluorescent materials, thermally activated delayed fluorescence materials, etc., may be mixed into the light-emitting layer 6 as dopants for the host. The mixing ratio of the dopant is preferably 20% by mass or less, and more preferably 10% by mass or less, relative to the anthracene derivative (or excited complex).

[0057] The aforementioned fluorescent luminescent materials include various metal complexes such as 8-hydroxyquinoline aluminum (Alq3), tris(4-methyl-8-quinolinoleate)aluminum(III) (Almq3), and 8-hydroxyquinoline zinc (Znq2); benzene compounds such as distyrylbenzene (DSB) and diaminodistyrylbenzene (DADSB); naphthalene compounds such as naphthalene and Nile Red; phenanthrene compounds such as phenanthrene; and chrysene compounds such as chrysene and 6-nitrochrysene. Compounds; Perylene compounds such as perylene and N,N'-bis(2,5-di-t-butylphenyl)-3,4,9,10-perylene-di-carboximide (BPPC); Coronene compounds such as coronene; Anthracene compounds such as anthracene and bis-styrylanthracene; Pyrene compounds such as pyrene and BD-1; Pyrane compounds such as 4-(di-cyanomethylene)-2-methyl-6-(para-dimethylaminostyryl)-4H-pyran (DCM); Acridine compounds such as acridine; Styrene compounds Stilbene compounds such as ruben; thiophene compounds such as 2,5-dibenzoxazolethiophene; benzoxazole compounds such as benzoxazole; benzimidazole compounds such as benzimidazole; benzothiazole compounds such as 2,2'-(para-phenylenedivinylene)-bisbenzothiazole; butadiene compounds such as bistyryl(1,4-diphenyl-1,3-butadiene) and tetraphenylbutadiene; naphthalimide compounds such as naphthalimide; coumarin Examples include coumarin compounds such as perinone; perinone compounds such as perinone; oxadiazole compounds such as oxadiazole; aldazine compounds; cyclopentadiene compounds such as 1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene (PPCP); quinacridone compounds such as quinacridone and quinacridone red; pyridine compounds such as pyrrolopyridine and thiadiazolopyridine; and spiro compounds such as 2,2',7,7'-tetraphenyl-9,9'-spirobifluorene.

[0058] Examples of the aforementioned thermally activated delayed fluorescence materials include 2,4,5,6-tetra(9-carbazole)-isophthalonitrile (4CzIPN), 4,5-di(9-carbazole)-phthalonitrile (2CzPN), 3,4,5,6-tetra(9-carbazole)-phthalonitrile (4CzPN), 2,3,5,6-tetra(9-carbazole)-terephthalonitrile (4CzTPN), 2,3,5,6-tetra(3,6-dimethyl-9-carbazole)-terephthalonitrile (4CzTPN-Me), 2,3,5,6-tetra(3,6-diphenyl-9-carbazole)-terephthalonitrile (4CzTPN-Ph), and compounds described in Japanese Patent Publication No. 2012-193352 and International Publication No. 2011 / 070963.

[0059] The average thickness of the light-emitting layer 6 is not particularly limited, but is preferably 10 to 150 nm, and more preferably 20 to 100 nm. The average thickness of the light-emitting layer 6 may be measured using a stylus-type step meter, or it may be measured using a quartz crystal thickness meter during the deposition of the light-emitting layer 6.

[0060] "Electron transport layer" Any material that can be commonly used as an electron transport layer material may be used for the electron transport layer 7. Specifically, the materials for the electron transport layer 7 include phosphine oxide derivatives such as phenyl-dipyrenylphosphine oxide (POPy2), pyridine derivatives such as tris-1,3,5-(3'-(pyridin-3”-yl)phenyl)benzene (TmPhPyB), quinoline derivatives such as 2-(3-(9-carbazolyl)phenyl)quinoline (mCQ), pyrimidine derivatives such as 2-phenyl-4,6-bis(3,5-dipyridylphenyl)pyrimidine (BPyPPM), pyrazine derivatives, and phenanthroline such as bathophenanthroline (BPhen). Triolin derivatives, triazine derivatives such as 2,4-bis(4-biphenyl)-6-(4'-(2-pyridinyl)-4-biphenyl)-[1,3,5]triazine (MPT), triazole derivatives such as 3-phenyl-4-(1'-naphthyl)-5-phenyl-1,2,4-triazole (TAZ), oxazole derivatives, oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl-1,3,4-oxadiazole) (PBD), 2,2',2”-(1,3,5-bentriyl)-tris(1-phenyl Imidazole derivatives such as nyl-1-H-benzimidazole (TPBI), aromatic ring tetracarboxylic anhydrides such as naphthalene and perylene, various metal complexes represented by bis[2-(2-hydroxyphenyl)benzothiazolat]zinc (Zn(BTZ)2) and tris(8-hydroxyquinolinate)aluminum (Alq3), organosilane derivatives represented by silole derivatives such as 2,5-bis(6'-(2',2”-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), and the above general formula (1) Examples include anthracene derivatives such as 9-(1-naphthyl)-10-(2-naphthyl)anthracene (1,2-ADN), boron-containing compounds described in Japanese Patent Publication No. 2013-239691, International Publication No. 2014 / 133141, Japanese Patent Publication No. 2016-172728, Japanese Patent Publication No. 2016-199507, and Japanese Patent Publication No. 2016-199508, and one or more of these can be used. Among these, the use of anthracene derivatives as the material for the electron transport layer 7 is particularly preferred.

[0061] The average thickness of the electron transport layer 7 is not particularly limited, but is preferably 10 to 150 nm, and more preferably 20 to 100 nm. The average thickness of the electron transport layer 7 can be measured, for example, by a stylus step meter or spectroscopic ellipsometry.

[0062] "Electron injection layer" The electron injection layer 8 can be made of materials with low work functions in general, such as alkali metals and alkaline earth metals; compounds containing metals with low work functions, such as lithium quinoline, lithium fluoride, cesium carbonate, and calcium carbonate; hexahydropyrimidopyrimidine compounds having a structure represented by the following general formula (2); or compounds having a structure represented by the following general formula (3).

[0063] [ka] (In general formula (2), R 1 n represents an aromatic hydrocarbon group which may have substituents, an aromatic heterocyclic group, an arylalkylene group, a 2- to 4-valent linear or cyclic hydrocarbon group, or a group formed by combining two or more of these groups, or a group formed by combining one or more of these groups with a nitrogen atom. 1 (This is an integer between 1 and 4.)

[0064] [ka] (In general formula (3), X 1 , X 2 represents a nitrogen atom, oxygen atom, sulfur atom, or divalent linking group, which may have substituents, either identical or different. L represents a direct bond or a p-valent linking group. 2 'p' represents a number that is either 0 or 1, and 'p' represents a number from 1 to 4. 'q' represents a number that is either 0 or 1, and when 'p' is 1, 'q' is 0. R 2 ~R 4 m represents a monovalent substituent that is identical or different. 1 ~m 3 These represent numbers from 0 to 3, which are either the same or different. 2 ~R 4 X1 , X 2 It may bond with R to form a ring structure. 2 If there are multiple R 2 They may be bonded together to form a ring structure. Also, R 3 If there are multiple R 3 They may be bonded together to form a ring structure. Also, R 4 If there are multiple R 4 They may be bonded together to form a ring structure.

[0065] By including a hexahydropyrimidopyrimidine compound having the structure represented by general formula (2) or a compound having the structure represented by general formula (3) in the electron injection layer 8, direct electron injection from the cathode 9 to the electron transport layer 7 made of an acceptor material becomes possible, enabling the realization of a simple organic EL device. Furthermore, when the electron injection layer 8 includes a hexahydropyrimidopyrimidine compound having the structure represented by general formula (2) or a compound having the structure represented by general formula (3), the electron injection layer 8 may use these materials individually or in mixtures with other materials.

[0066] In the above general formula (2), R 1 This represents an aromatic hydrocarbon group which may have substituents, an aromatic heterocyclic group, an arylalkylene group, a 2- to 4-valent linear or cyclic hydrocarbon group, or a group formed by combining two or more of these groups, or a group formed by combining one or more of these groups with a nitrogen atom. The aromatic hydrocarbon group and aromatic heterocyclic group are preferably those having 3 to 30 carbon atoms, more preferably those having 4 to 24 carbon atoms, and even more preferably those having 5 to 20 carbon atoms. Aromatic hydrocarbon groups include compounds consisting of only one aromatic ring, such as benzene; compounds in which multiple aromatic rings are directly bonded to one carbon atom, such as biphenyl and diphenylbenzene; and groups formed by removing one to four hydrogen atoms from any of the aromatic rings of fused ring aromatic hydrocarbon compounds, such as naphthalene, anthracene, phenanthrene, and pyrene. Aromatic heterocyclic groups include compounds consisting of only one aromatic heterocyclic ring, such as thiophene, furan, pyrrole, oxazole, oxadiazole, thiazole, thiadiazole, imidazole, pyridine, pyrimidine, pyrazine, and triazine; compounds in which multiple of these compounds consisting of only one aromatic heterocyclic ring are directly bonded to each other by a single carbon atom (such as bipyridine); and groups formed by removing 1 to 4 hydrogen atoms from any aromatic heterocyclic ring of fused cyclic heteroaromatic hydrocarbon compounds such as quinoline, quinoxaline, benzothiophene, benzothiazole, benzimidazole, benzoxazole, indole, carbazole, dibenzofuran, dibenzothiophene, acridine, and phenanthroline. Examples of arylalkylene groups include groups that combine the above-mentioned aromatic hydrocarbon group with an alkylene group having 1 to 3 carbon atoms. The 2-4 valent linear or cyclic hydrocarbon group is preferably one with 1 to 12 carbon atoms, more preferably one with 1 to 6 carbon atoms, and even more preferably one with 1 to 4 carbon atoms. The linear hydrocarbon group may be linear or branched. Also, R 1 This may also be a group formed by combining two or more of the above-mentioned aromatic hydrocarbon groups, aromatic heterocyclic groups, arylalkylene groups, or divalent to tetravalent chain hydrocarbon groups. Furthermore, R 1 The group may be formed by combining one or more of the above-mentioned aromatic hydrocarbon groups, aromatic heterocyclic groups, arylalkylene groups, or 2- to 4-valent linear hydrocarbon groups with a nitrogen atom. Examples of such groups include trialkylamines such as trimethylamine and groups formed by removing 1 to 4 hydrogen atoms from triphenylamine.

[0067] The above-mentioned aromatic hydrocarbon group, aromatic heterocyclic group, or arylalkylene group may have one or more monovalent substituents. Monovalent substituents include fluorine atoms; haloalkyl groups such as fluoromethyl, difluoromethyl, and trifluoromethyl groups; linear or branched alkyl groups with 1 to 20 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl groups; cyclic alkyl groups with 5 to 7 carbon atoms such as cyclopentyl, cyclohexyl, and cycloheptyl groups; methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy, hexyloxy, and heptyloxy groups. Linear or branched alkoxy groups with 1 to 20 carbon atoms, such as oxy groups and octyloxy groups; nitro groups; cyano groups; alkylamino groups with alkyl groups with 1 to 10 carbon atoms, such as methylamino groups, ethylamino groups, dimethylamino groups, and diethylamino groups; cyclic amino groups such as pyrrolidino groups, piperidino groups, and morpholino groups; diarylamino groups such as diphenylamino groups and carbazolyl groups; acyl groups such as acetyl groups, propionyl groups, and butyryl groups; alkenyl groups with 2 to 30 carbon atoms, such as styryl groups; halogen atoms such as fluorine atoms, and alkyl groups with 1 to 20 carbon atoms, alkoxy groups A C5-C20 aryl group (specific examples of aryl groups are the same as those for aromatic hydrocarbon groups above) which may be substituted with a C1 group, an amino group, etc.; a C4-C40 heterocyclic group containing one or more C1-C4 nitrogen, sulfur, or oxygen atoms which may be substituted with a halogen atom such as a fluorine atom, or a C1-C20 alkyl group, an alkoxy group, an amino group, etc. (The heterocyclic group may consist of only one ring, or may be a compound in which multiple compounds consisting of only one aromatic heterocyclic ring are directly bonded to each other by a single carbon atom, or may be a fused heterocyclic group. Specific examples of heterocyclic groups are as follows: This includes specific examples of aromatic heterocyclic groups such as thiophene rings, furan rings, pyrrole rings, benzothiophene rings, benzofuran rings, indole rings, dibenzothiophene rings, dibenzofuran rings, carbazole rings, thiazole rings, benzothiazole rings, oxazole rings, benzoxazole rings, imidazole rings, benzimidazole rings, pyridine rings, pyrimidine rings, pyrazine rings, pyridazine rings, triazine rings, quinoline rings, isoquinoline rings, quinoxaline rings, benzothiadiazole rings, and phenanthridine rings. Examples include ester groups and thioether groups.These groups may also be substituted with halogen atoms, heteroatoms, alkyl groups, aromatic rings, etc.

[0068] n in the general formula (2) above 1 This is an integer from 1 to 4, but is preferably 2 or 3.

[0069] X in the general formula (3) above 1 , X 2 This represents a nitrogen atom, oxygen atom, sulfur atom, or divalent linking group, which may have substituents, and are identical or different. Examples of divalent linking groups include divalent hydrocarbon groups and groups in which some of the carbon atoms of a hydrocarbon group are replaced by heteroatoms of nitrogen, oxygen, or sulfur. The hydrocarbon group is preferably one having 1 to 6 carbon atoms, and more preferably one having 1, 2, or 6 carbon atoms. The hydrocarbon group may be linear, branched, cyclic, or a combination of these. The divalent hydrocarbon group may be an alkylene group, which is a saturated hydrocarbon group, or an unsaturated hydrocarbon group such as an alkenylene group or an alkylylene group.

[0070] In the general formula (3) above, L represents either a direct bond or a p-valent linking group. Note that L is a direct bond only when p is 2. Examples of p-valent linking groups include nitrogen atoms, oxygen atoms, sulfur atoms, and carbon atoms, as well as groups formed by removing p hydrogen atoms from hydrocarbon groups or groups in which some of the carbon atoms of a hydrocarbon group are replaced by heteroatoms of nitrogen, oxygen, or sulfur atoms. When the p-valent linking group has a carbon atom, it is preferable that it has 1 to 30 carbon atoms. More preferably, it has 1 to 20 carbon atoms. The hydrocarbon group may be linear, branched, cyclic, or a combination of these. The hydrocarbon group may be a saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aromatic hydrocarbon group. Aromatic hydrocarbon groups include those formed by removing hydrogen atoms from aromatic compounds such as benzene rings, naphthalene rings, anthracene rings, tetracene rings, pentacene rings, triphenylene rings, pyrene rings, fluorene rings, and indene rings.

[0071] In the above general formula (3), R 2 ~R 4 represents a monovalent substituent that is identical or different. Also, m 1 ~m 3 These represent numbers from 0 to 3, which are either the same or different. Monovalent substituents include fluorine atoms; haloalkyl groups such as fluoromethyl, difluoromethyl, and trifluoromethyl groups; linear or branched alkyl groups with 1 to 20 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl groups; cyclic alkyl groups with 5 to 7 carbon atoms such as cyclopentyl, cyclohexyl, and cycloheptyl groups; methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy, hexyloxy, and heptyloxy groups. Linear or branched alkoxy groups with 1 to 20 carbon atoms, such as oxy groups and octyloxy groups; nitro groups; cyano groups; alkylamino groups with alkyl groups with 1 to 10 carbon atoms, such as methylamino groups, ethylamino groups, dimethylamino groups, and diethylamino groups; cyclic amino groups such as pyrrolidino groups, piperidino groups, and morpholino groups; diarylamino groups such as diphenylamino groups and carbazolyl groups; acyl groups such as acetyl groups, propionyl groups, and butyryl groups; alkenyl groups with 2 to 30 carbon atoms, such as styryl groups; halogen atoms such as fluorine atoms, and alkyl groups with 1 to 20 carbon atoms, alkoxy groups A C5-C20 aryl group (specific examples of aryl groups are the same as those for aromatic hydrocarbon groups above) which may be substituted with a C1 group, an amino group, etc.; a C4-C40 heterocyclic group containing one or more C1-C4 nitrogen, sulfur, or oxygen atoms which may be substituted with a halogen atom such as a fluorine atom, or a C1-C20 alkyl group, an alkoxy group, an amino group, etc. (The heterocyclic group may consist of only one ring, or may be a compound in which multiple compounds consisting of only one aromatic heterocyclic ring are directly bonded to each other by a single carbon atom, or may be a fused heterocyclic group. Specific examples of heterocyclic groups are as follows: This includes specific examples of aromatic heterocyclic groups such as thiophene rings, furan rings, pyrrole rings, benzothiophene rings, benzofuran rings, indole rings, dibenzothiophene rings, dibenzofuran rings, carbazole rings, thiazole rings, benzothiazole rings, oxazole rings, benzoxazole rings, imidazole rings, benzimidazole rings, pyridine rings, pyrimidine rings, pyrazine rings, pyridazine rings, triazine rings, quinoline rings, isoquinoline rings, quinoxaline rings, benzothiadiazole rings, and phenanthridine rings. Examples include ester groups and thioether groups.These groups may also be substituted with halogen atoms, heteroatoms, alkyl groups, aromatic rings, etc.

[0072] In the general formula (3) above, p represents a number from 1 to 4, but it is preferable that it be a number from 1 to 3. Furthermore, n in the general formula (3) above 2 This represents a number that is either 0 or 1, but it is preferably 0.

[0073] The average thickness of the electron injection layer 8 is preferably 0.5 to 100 nm, and more preferably 1 to 10 nm. The electron injection layer 8 can be formed by applying a coating composition or by co-deposition using a vacuum deposition method. The average thickness of the electron injection layer 8 can be measured, for example, by a stylus step meter or spectroscopic ellipsometry.

[0074] "cathode" Materials used for cathode 9 include ITO, IZO, Au, Pt, Ag, Cu, Al, or alloys containing these materials. Among these, it is preferable to use ITO, IZO, Au, Ag, or Al as the material for cathode 9. The average thickness of the cathode 9 is not particularly limited, but is preferably 10 to 1000 nm, and more preferably 30 to 150 nm. Furthermore, even when an opaque material is used as the material for the cathode 9, by setting the average thickness to, for example, about 10 to 30 nm, it can be used as a transparent cathode in a top-emission type organic EL device. The average thickness of cathode 9 can be measured during film deposition using a quartz crystal film thickness gauge.

[0075] In particular, in the inverted structure of the organic EL element shown in Figure 6, a layer made of inorganic oxide deposited on the cathode 9 is also treated as part of the cathode. The oxide used in this case is a layer of a semiconductor or insulating multilayer thin film. Specifically, it may be a layer made of a single metal oxide, a layer made of a mixture of two or more metal oxides and a layer made of a single metal oxide (either one or both), or a layer made of a mixture of two or more metal oxides.

[0076] Metal elements that make up metal oxides, which form inorganic oxides, include magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, indium, gallium, iron, cobalt, nickel, copper, zinc, cadmium, aluminum, and silicon.

[0077] When a layer made of inorganic oxides includes a layer made of a mixture of two or more metal oxides, it is preferable that at least one of the metal elements constituting the metal oxide is magnesium, aluminum, calcium, zirconium, hafnium, silicon, titanium, or zinc. If the layer consisting of an inorganic oxide is a layer consisting of an elemental metal oxide, it is preferable that the layer is made of a metal oxide selected from the group consisting of magnesium oxide, aluminum oxide, zirconium oxide, hafnium oxide, silicon oxide, titanium oxide, and zinc oxide.

[0078] If the inorganic oxide layer is a layer formed by laminating either a layer of a mixture of two or more metal oxides or a layer of a single metal oxide, or both, or if it is a layer of a mixture of two or more metal oxides, examples include a layered and / or mixed combination of two metal oxides selected from titanium oxide / zinc oxide, titanium oxide / magnesium oxide, titanium oxide / zirconium oxide, titanium oxide / aluminum oxide, titanium oxide / hafnium oxide, titanium oxide / silicon oxide, zinc oxide / magnesium oxide, zinc oxide / zirconium oxide, zinc oxide / hafnium oxide, zinc oxide / silicon oxide, calcium oxide / aluminum oxide, etc., or a layered and / or mixed combination of three metal oxides selected from titanium oxide / zinc oxide / magnesium oxide, titanium oxide / zinc oxide / zirconium oxide, titanium oxide / zinc oxide / aluminum oxide, titanium oxide / zinc oxide / hafnium oxide, titanium oxide / zinc oxide / silicon oxide, indium oxide / gallium oxide / zinc oxide, etc.

[0079] The inorganic oxide may include IGZO (indium gallium zinc oxide), an oxide semiconductor that exhibits good properties as a special composition, and / or 12CaO·7Al2O3, an electride. The average thickness of an inorganic oxide film is not particularly limited, but is preferably 1 to 1000 nm, and more preferably 2 to 100 nm. The average thickness of the inorganic oxide layer can be measured by a stylus step meter or spectroscopic ellipsometry.

[0080] "Sealing" The organic EL element 1 may be sealed if necessary. For example, the organic EL element 1 may be sealed by a sealing container (not shown) having a concave space for housing the organic EL element 1, and by an adhesive that bonds the edge of the sealing container to the substrate 2. Alternatively, the organic EL element 1 may be housed in the sealing container and then sealed by filling it with a sealing material made of ultraviolet (UV) curing resin or the like.

[0081] When sealing the organic EL element 1 using a sealing container or sealing member, a desiccant that absorbs moisture may be placed inside the sealing container or on the inside of the sealing member. Alternatively, a material that absorbs moisture may be used as the sealing container or sealing member. Furthermore, a space may be formed inside the sealed sealing container or on the inside of the sealing member.

[0082] When encapsulating the organic EL element 1, the material of the encapsulating container or encapsulating member can be a resin material, a glass material, or the like. Examples of resin materials and glass materials used for the encapsulating container or encapsulating member are the same as those used for the substrate 2.

[0083] "Manufacturing method for organic EL elements" Next, the manufacturing method of the organic EL element 1 will be described. To manufacture the organic EL element 1, first, an anode 3 is formed on the substrate 2. Anode 3 can be formed by sputtering, vacuum deposition, sol-gel deposition, spray pyrolysis (SPD), atomic layer deposition (ALD), vapor deposition, liquid deposition, etc. A method of joining metal foils may also be used to form anode 3.

[0084] Next, a hole injection layer 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, and an electron injection layer 8 are formed on the anode 3 in this order. The method for forming the hole injection layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, and electron injection layer 8 is not particularly limited, and various conventionally known formation methods can be used as appropriate in accordance with the characteristics of the materials used for each of the hole injection layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, and electron injection layer 8. Specifically, methods for forming the hole injection layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, and electron injection layer 8 include coating methods that involve applying an organic compound solution containing the organic compounds that will form the hole injection layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7, and electron injection layer 8, as well as vacuum deposition methods and ESDUS (Evaporative Spray Deposition from Ultra-dilute Solution) methods.

[0085] Next, a cathode 9 is formed on the electron injection layer 8. The cathode 9 can be formed, for example, in the same manner as the anode 3.

[0086] When fabricating the inverted organic EL element shown in Figure 6, the order is reversed. In the inverted organic EL element shown in Figure 6, when forming a layer of inorganic oxide on the cathode 9, the oxide is formed using methods such as spray pyrolysis, sol-gel method, sputtering method, or vacuum deposition method. Through the above process, an organic EL element 1 is obtained.

[0087] "Sealing method" When encapsulating the organic EL element 1, it can be encapsulated using a standard method used for encapsulating organic EL elements.

[0088] (transparent solar cell) The power-generating light-emitting device of the present invention comprises a transparent solar cell having a visible light transmittance of 40% or more. The transparent solar cell is not particularly limited as long as it has a visible light transmittance of 40% or more. In one embodiment, the transparent solar cell comprises a pair of electrodes (cathode, anode) and a photoelectric conversion layer located between them.

[0089] Next, the transparent solar cell that constitutes the power-generating light-emitting element of the present invention will be described in detail with examples. Figure 8 is a schematic cross-sectional view illustrating an example of a transparent solar cell that constitutes a power-generating light-emitting element of the present invention. The transparent solar cell 11 shown in Figure 8 has a power-generating layer (photoelectric conversion layer) consisting of a donor layer 15 and an acceptor layer 16 between the anode (electrode) 13 and the cathode (electrode) 18. The transparent solar cell 11 shown in Figure 8 has a laminated structure in which an anode 13, a hole extraction layer 14, a donor layer 15, an acceptor layer 16, an electron extraction layer 17, a cathode 18, and an optical adjustment layer 19 are formed in this order on a substrate 12. Note that the transparent solar cell constituting the power-generating light-emitting element of the present invention may also be an inverted structure type in which the configuration from cathode to anode is reversed.

[0090] "substrate" A transparent substrate is used as the substrate 12. The material of the substrate 12 may include resin materials or glass materials. Examples of resin materials used for the substrate 12 include polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate. Examples of glass materials used for the substrate 12 include quartz glass and soda glass. The average thickness of the substrate 12 can be determined according to the material of the substrate 12, and is preferably 0.1 to 30 mm, and more preferably 0.1 to 10 mm. The average thickness of the substrate 12 can be measured using a digital multimeter or calipers.

[0091] "anode" The anode 13 shown in Figure 8 is formed in direct contact with the substrate 12. Examples of materials for the anode 13 include conductive oxides such as ITO (indium tin oxide), IZO (indium zinc oxide), FTO (fluorinated tin oxide), In2O3, SnO2, Sb-containing SnO2, and Al-containing ZnO. Among these, ITO, IZO, and FTO are preferred as the material for the anode 13. The average thickness of the anode 13 is not particularly limited, but is preferably 10 to 500 nm, and more preferably 30 to 200 nm. The average thickness of the anode 13 can be measured by a stylus step meter or spectroscopic ellipsometry.

[0092] "Hole extraction layer" The hole extraction layer 14 may be made of an inorganic material or an organic material. The inorganic material is not particularly limited, but for example, one or more metal oxides such as vanadium oxide (V2O5), molybdenum oxide (MoO3), and ruthenium oxide (RuO2) can be used. As for the organic material, low molecular weight materials such as dipyradino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonite (HAT-CN) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4-TCNQ) or high molecular weight materials such as poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT:PSS) can be used. The average thickness of the hole extraction layer 14 is not particularly limited, but is preferably 1 to 1000 nm, and more preferably 5 to 50 nm. The average thickness of the hole extraction layer 14 can be measured, for example, by a stylus step meter or spectroscopic ellipsometry.

[0093] "Donor population" The donor layer 15 is composed of donor materials (electron donors). The donor materials include arylcycloalkane compounds such as N4,N4'-bis(dibenzo[b,d]thiophen-4-yl)-N4,N4'-diphenylbiphenyl-4,4'-diamine (DBTPB), 1,1-bis(4-di-para-triaminophenyl)cyclohexane, 1,1'-bis(4-di-para-tolylaminophenyl)-4-phenyl-cyclohexane, 4,4',4”-trimethyltriphenylamine, N,N,N',N'-tetraphenyl-1,1'-biphenyl-4,4'-diamine, and N,N'-diphenyl-N Arylamine compounds such as N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD1), N,N'-diphenyl-N,N'-bis(4-methoxyphenyl)-1,1'-biphenyl-4,4'-diamine (TPD2), N,N,N',N'-tetrakis(4-methoxyphenyl)-1,1'-biphenyl-4,4'-diamine (TPD3), N,N'-di(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (α-NPD), TPTE, and N,N,N',N'-te Phenylenediamine compounds such as traphenyl-p-phenylenediamine, N,N,N',N'-tetra(p-tolyl)-p-phenylenediamine, and N,N,N',N'-tetra(meth-tolyl)-meth-phenylenediamine (PDA); carbazole compounds such as carbazole, N-isopropylcarbazole, and N-phenylcarbazole; stilbene compounds such as stilbene and 4-di-p-tolylaminostilbene; oxazole compounds such as OxZ; and triphenylmethane compounds such as triphenylmethane and m-MTDATA. Pyrazoline compounds such as 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline, benzine (cyclohexadiene) compounds, triazole compounds such as triazole, imidazole compounds such as imidazole, oxadiazole compounds such as 1,3,4-oxadiazole and 2,5-di(4-dimethylaminophenyl)-1,3,4-oxadiazole, anthracene compounds such as anthracene, 9-(4-diethylaminostyryl)anthracene, fluorenone, 2,4,7-trinitro-9-fluorenone, 2,Fluorenone compounds such as 7-bis(2-hydroxy-3-(2-chlorophenylcarbamoyl)-1-naphthylazo)fluorenone, phenoxazine compounds such as 3,3'-bi[1,4]benzoxazino[2,3,4-kl]phenoxazine (HN-D2), aniline compounds such as polyaniline, silane compounds, pyrrole compounds such as 1,4-dithioketo-3,6-diphenyl-pyrrolo-(3,4-c)pyrrolopyrrole, fluorene compounds such as fluorene, porphyrins, porphyrins such as metal tetraphenylporphyrins Phthalocyanine compounds such as quinacridone, metallic or metal-free phthalocyanine compounds such as phthalocyanine, copper phthalocyanine, tetra(t-butyl)copper phthalocyanine, and iron phthalocyanine, metallic or metal-free naphthalocyanine compounds such as copper naphthalocyanine, vanadyl naphthalocyanine, and monochlorogallium naphthalocyanine, and benzidine compounds such as N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine and N,N,N',N'-tetraphenylbenzidine can be used.

[0094] The average thickness of the donor layer 15 is preferably 2 to 30 nm, and more preferably 4 to 20 nm. The average thickness of the donor layer 15 may be measured using a stylus-type step meter, or it may be measured using a quartz crystal thickness meter during the deposition of the donor layer 15.

[0095] "Acceptor layer" The acceptor layer 16 is composed of acceptor materials (electron acceptors). Acceptor materials include bis[2-(o-hydroxyphenylbenzothiazole]zinc(II)(ZnBTZ2), boron-containing compounds, pyridine derivatives such as tris-1,3,5-(3'-(pyridine-3”-yl)phenyl)benzene (TmPyPhB), quinoline derivatives such as (2-(3-(9-carbazolyl)phenyl)quinoline (mCQ)), 2-phenyl-4,6-bis(3,5-dipyridylphenyl)pyrimidine (BPyPPM), and 4,6-bis(3,5-di(pyridyl Pyrimidine derivatives such as ₄-4-yl)phenyl)-2-methylpyrimidine (B4PYMPM), pyrazine derivatives, phenanthroline derivatives such as vasophenanthroline (BPhen), triazine derivatives such as 2,4-bis(4-biphenyl)-6-(4'-(2-pyridinyl)-4-biphenyl)-[1,3,5]triazine (MPT), triazole derivatives such as 3-phenyl-4-(1'-naphthyl)-5-phenyl-1,2,4-triazole (TAZ), oxazole derivatives, Oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl-1,3,4-oxadiazole) (PBD), imidazole derivatives such as 2,2',2”-(1,3,5-bentriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBI), aromatic ring tetracarboxylic anhydrides such as naphthalene and perylene, bis[2-(2-hydroxyphenyl)benzothiazolat]zinc (Zn(BTZ)2), tris(8-hydroxyquinolinato) Various metal complexes such as luminium (Alq3), organosilane derivatives such as silole derivatives like 2,5-bis(6'-(2',2"-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), and boron-containing compounds described in Japanese Patent Publication No. 2013-239691, International Publication No. 2014 / 133141, Japanese Patent Publication No. 2016-172728, Japanese Patent Publication No. 2016-199507, and Japanese Patent Publication No. 2016-199508 can be used.

[0096] The average thickness of the acceptor layer 16 is preferably 8 to 120 nm, and more preferably 16 to 80 nm. The average thickness of the acceptor layer 16 may be measured using a stylus-type step meter, or it may be measured using a quartz crystal film thickness meter during the deposition of the acceptor layer 16.

[0097] "Electron extraction layer" The electron extraction layer 17 improves the rate of electron injection and electron transport from the cathode 18 to the acceptor layer 16. The material of the electron extraction layer 17 may be an organic compound or an inorganic compound. If the electron extraction layer 17 is made of an inorganic compound, for example, alkali metals, alkaline earth metals, lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, cesium carbonate, etc. can be used. If the electron extraction layer 17 is made of an organic compound, for example, 8-quinolinolatritium (Liq), a hexahydropyrimidopyrimidine compound having the structure represented by the general formula (2) described in the section on the electron injection layer 8 of the organic EL element 1, or a compound having the structure represented by the general formula (3), etc. can be used.

[0098] The average thickness of the electron extraction layer 17 is preferably 0.5 to 100 nm, and more preferably 1 to 50 nm. The electron extraction layer 17 can be formed by applying a coating composition or by deposition using a vacuum deposition method. The average thickness of the electron extraction layer 17 can be measured, for example, by a stylus step meter or spectroscopic ellipsometry.

[0099] "cathode" Materials used for the cathode 18 include ITO, IZO, Au, Pt, Ag, Cu, Al, Mg, or alloys containing these materials. Among these, it is preferable to use ITO, IZO, Au, Ag, or Al as the material for the cathode 18. The average thickness of the cathode 18 is not particularly limited, but is preferably 1 to 1000 nm, and more preferably 10 to 150 nm. Furthermore, even when an opaque material is used as the material for the cathode 18, it can be used as a transparent cathode by setting the average thickness to, for example, about 10 to 30 nm. The average thickness of the cathode 18 can be measured during film deposition using a quartz crystal film thickness gauge.

[0100] "Optical adjustment layer" The optical adjustment layer 19 is provided as appropriate to improve visible light transmittance. The optical adjustment layer 19 may have either an organic compound or an inorganic compound as its main component, and if necessary, the layers constituting the optical adjustment layer 19 may be configured by laminating multiple layers.

[0101] "Sealing" The transparent solar cell 11 shown in Figure 8 may be sealed if necessary. For example, the transparent solar cell 11 shown in Figure 8 may be sealed by a sealing container (not shown) having a concave space for housing the transparent solar cell 11, and by an adhesive that bonds the edge of the sealing container to the substrate 12. Alternatively, the transparent solar cell 11 may be housed in the sealing container and then sealed by filling it with a sealing material made of ultraviolet (UV) curing resin or the like.

[0102] "Manufacturing method for transparent solar cells" Next, as an example of a method for manufacturing the transparent solar cell, we will describe the manufacturing method of the transparent solar cell 11 shown in Figure 8. To manufacture the transparent solar cell 11 shown in Figure 8, first, an anode 13 is formed on the substrate 12. The anode 13 can be formed by sputtering, vacuum deposition, sol-gel deposition, spray pyrolysis (SPD), atomic layer deposition (ALD), vapor deposition, liquid deposition, etc. A method of joining metal foils may also be used to form the anode 13.

[0103] Next, a hole extraction layer 14, a donor layer 15, an acceptor layer 16, and an electron extraction layer 17 are formed on the anode 13 in this order. The method for forming the hole extraction layer 14, donor layer 15, acceptor layer 16, and electron extraction layer 17 is not particularly limited, and various conventionally known formation methods can be appropriately used in accordance with the properties of the materials used for each of the hole extraction layer 14, donor layer 15, acceptor layer 16, and electron extraction layer 17.

[0104] Specifically, methods for forming the hole extraction layer 14, donor layer 15, acceptor layer 16, and electron extraction layer 17 include coating methods, vacuum deposition methods, and ESDUS (Evaporative Spray Deposition from Ultra-dilute Solution) methods, among others.

[0105] Next, the cathode 18 is formed. The cathode 18 can be formed, for example, in the same manner as the anode 13.

[0106] Next, an optical adjustment layer 19 is formed. Through the above process, the transparent solar cell 11 shown in Figure 8 is obtained.

[0107] "Visible light transmittance" The transparent solar cell constituting the power-generating light-emitting element of the present invention has a visible light transmittance of 40% or more, preferably 50% or more. If the visible light transmittance is 40% or more, it becomes a sufficiently transparent solar cell, and even when stacked on an organic EL element, the light emitted from the organic EL element can be clearly seen. In this specification, the visible light transmittance of a transparent solar cell is the average value obtained by calculating the transmittance for each wavelength (380-780 nm) from the absorption spectrum of the transparent solar cell.

[0108] <Display device> The display device of the present invention is characterized by comprising the above-described power-generating light-emitting element. Since the display device of the present invention is equipped with the above-mentioned power-generating light-emitting element, it can be used continuously without having to carry a separate power generation device. The display device of the present invention offers excellent productivity due to its simple element structure and low driving voltage. [Examples]

[0109] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0110] <Synthesis of 3,5-dicyanophenylboronic acid pinacol ester> The compound represented by formula (4-5) was synthesized according to the following reaction scheme. [ka]

[0111] "Synthesis process of the compound represented by formula (4-1)" Isophthalic acid (100g, 0.602mol, 1.0eq.) and concentrated sulfuric acid (300mL) were added to a 1L reactor, and the temperature was raised to a bath temperature of 80°C and an internal temperature of 65°C. NBS (128g) was added to this suspension in four portions of 32g each, every 15 minutes. After the addition, the mixture was stirred at the same temperature for 30 minutes, then allowed to cool. This solution was slowly added to ice water (2L) and stirred vigorously for 15 minutes. The precipitated solid was filtered off, the filter bed was washed with tap water and IPE, and then dried under high vacuum at 70°C to obtain a white powder of the compound represented by formula (4-1) (144g, 0.587mol, 97%).

[0112] "Synthesis process of the compound represented by formula (4-2)" Under an argon atmosphere, 60 g, 245 mmol, 1.0 eq. of the compound represented by formula (4-1), 360 mL of anhydrous toluene, 70 mL, 979 mmol, 4.0 eq. of thionyl chloride, and 0.1 mL of DMF were added to a 1 L reactor. The temperature was then raised to 100 °C, and the mixture was heated and stirred at the same temperature for 16 hours. This solution was concentrated to obtain 70 g of the compound represented by formula (4-2), which was a brown liquid. This was then used directly in the next step.

[0113] "Synthesis process of the compound represented by formula (4-3)" Under an argon atmosphere, t-butylamine (65 mL, 613 mmol, 2.5 eq.), triethylamine (102 mL, 735 mmol, 3.0 eq.), and anhydrous THF (600 mL) were added to a 2 L reactor. Under ice cooling at 5°C, 70 g of the compound represented by formula (4-2), diluted with THF (200 mL), was added dropwise over 15 minutes. After removing the cooling bath, the mixture was stirred at room temperature for 3 hours. Tap water (1 L) was added to this brown suspension, and it was extracted with ethyl acetate (500 mL x 2). The organic layers were washed together with tap water and saturated brine, dried, and concentrated to obtain a brown solid (89 g). This was heated and dispersed with ethanol, allowed to cool, filtered, the filter bed was washed with methanol, and dried under high vacuum at 80°C to obtain a colorless solid of the compound represented by formula (4-3) (76.3 g, 214 mmol, 87%).

[0114] "Synthesis process of the compound represented by formula (4-4)" Under an argon atmosphere, the compound represented by formula (4-3) (76.3 g, 214 mmol, 1.0 eq.), toluene (310 mL), and thionyl chloride (309 mL, 4.28 mol, 20 eq.) were added to a 1 L reactor and heated and stirred at a bath temperature of 100 °C for 50 hours. After cooling, this brown solution was concentrated, and the residue was azeotropically dissolved in toluene (300 mL x 2). Heptane (200 mL) was added to this light brown solid, heated to 70 °C, dispersed and washed, cooled, and filtered. THF (250 mL) was added to the filterd product, and after complete dissolution at 70 °C, IPE (200 mL) was slowly added to precipitate the solid. After cooling and filtering, the mixture was dried under high vacuum at 40 °C to obtain a colorless solid of the compound represented by formula (4-4) (39 g, 188 mmol, 88%).

[0115] "Synthesis process of the compound represented by formula (4-5)" Under an argon atmosphere, the compound represented by formula (4-4) (29 g, 140 mmol, 1.0 eq.), bispinacol diborane (46.2 g, 182 mmol, 1.3 eq.), Pd(dppf)Cl2 (1.14 g, 1.40 mmol, 0.01 eq.), potassium acetate (27.5 g, 280 mmol, 2.0 eq.), and degassed isopropyl acetate (725 mL) were added to a 2 L reactor and heated and stirred at a bath temperature of 100 °C for 5 hours. After cooling, this dark brown suspension was filtered by Celite filtration, the filter bed was washed with ethyl acetate, and the filtrate was concentrated to obtain a dark brown solid (68 g). This was purified by column (SiO2 = 350 g, hexane / ethyl acetate = 2 / 1 → 1 / 1) to obtain a viscous solid (28 g). This was dispersed in IPE (120 mL), heated and washed at 50°C, allowed to cool, filtered to remove the solid, washed the filter bed with ethanol, and dried under high vacuum at 50°C to obtain a colorless solid compound represented by formula (4-5) (21.7 g, 85.4 mmol, 60%).

[0116] <Synthesis of Anthracene Derivatives 1> An anthracene derivative represented by formula (1-1) was synthesized according to the following reaction scheme. [ka]

[0117] "Synthesis steps for compounds represented by formula (4-11)" Under an argon atmosphere, 1,3-dibromo-5-iodobenzene (2.5g, 6.91 mmol, 1.0 eq.), 9-anthraceneboronic acid (1.53g, 6.91 mmol, 1.0 eq.), Pd(Ph3P)4 (0.16g, 0.138 mmol, 0.02 eq.), sodium carbonate (2.2g, 20.7 mmol, 3.0 eq.), degassed toluene (25mL), degassed distilled water (25mL), and degassed ethanol (13mL) were added to a 200mL reactor. This suspension was heated and stirred at a bath temperature of 85°C for 12 hours. After cooling, 50 mL of 10% ammonium chloride aqueous solution was added to the brown suspension and stirred. Insoluble matter was filtered out, and the filter bed was separated into two layers. The aqueous layer was extracted with toluene (50 mL), and the organic layers were washed sequentially with tap water and saturated brine. After drying and concentration, a dark brown solid (2.34 g) was obtained. This was purified by column (SiO2 = 90 g, heptane only → heptane / toluene = 20 / 1 → 10 / 1) to obtain a colorless solid (1.98 g). This was ultrasonically dispersed and washed with ethanol, filtered, rinsed with ethanol, and dried at 80°C under high vacuum to obtain a colorless powder of the compound represented by formula (4-11) (1.68 g, 4.07 mmol, 58%).

[0118] "Synthesis process of the compound represented by formula (4-12)" In a 100 mL reactor, the compound represented by formula (4-11) (1.68 g, 4.07 mmol, 1.0 eq.), NBS (0.94 g, 5.30 mmol, 1.3 eq.), and chloroform (25 mL) were added. This suspension was heated and stirred at a bath temperature of 65 °C for 6 hours and confirmed by TLC, but a large amount of starting material remained, so NBS (0.21 g, 1.18 mmol, 0.3 eq.) and distilled water (1 mL) were added, and the mixture was stirred at the same temperature for a further 10 hours. After cooling, a 2% hydrosulfide aqueous solution (50 mL) was added to the suspension, and after stirring, the insoluble matter was filtered by Celite filtration, the filter bed was washed with tap water and chloroform, and the filtrate was separated into two layers. The aqueous layer was extracted with chloroform (20 mL), and the organic layers were washed together with tap water and saturated brine, dried, and concentrated to obtain a yellow solid (2.51 g). This was ultrasonically washed with acetone (20 mL), methanol (10 mL) was added, the precipitated solid was filtered, the filter bed was washed with methanol, and dried at 80°C under high vacuum to obtain a pale yellow powder of the compound represented by formula (4-12) (1.86 g, 3.79 mmol, 93%).

[0119] "Synthesis process for anthracene derivatives represented by formula (1-1)" Under an argon atmosphere, a 300 mL reactor was filled with the compounds represented by formulas (4-12) (1.85 g, 3.76 mmol, 1.0 eq.), (4-5) (3.83 g, 15.1 mmol, 4.0 eq.), tripotassium phosphate (6.4 g, 30.1 mmol, 8.0 eq.), and degassed toluene (55 mL). After degassing this suspension under reduced pressure, S-Phos (185 mg, 0.452 mmol, 0.12 eq.) and Pd2(dba)3 (138 mg, 0.151 mmol, 0.04 eq.) were added, the mixture was degassed again, and distilled water (0.1 mL) was added. The bath temperature was then raised to 110 °C, and the mixture was heated and stirred for 14 hours. To this brown suspension, toluene (100 mL) was added and stirred at 80°C for 30 minutes. Then, SiO2 (50 g) was added, and the mixture was concentrated to obtain a silica-supported crude material. This was purified by column (SiO2 = 150 g, heated toluene only → heated toluene / ethyl acetate = 20 / 1 → 10 / 1) to obtain a pale yellow solid (1.55 g). This was dispersed and washed with heated ethyl acetate (30 mL), filtered, dispersed and washed again with heated diethyl ketone, filtered, the filter bed was washed with methanol, and dried at 80°C under high vacuum to obtain an anthracene derivative represented by formula (1-1) (1.37 g, 2.16 mmol, 57%, HPLC 99.0%).

[0120] "Example 1" (Fabrication of organic EL elements with power generation capabilities) An organic EL element 1 with power generation capabilities was manufactured and evaluated using the method described below.

[0121] [Process 1] As substrate 2, a commercially available transparent glass substrate with an average thickness of 0.7 mm and an electrode (anode 3) made of ITO patterned to a width of 3 mm was prepared. Then, the substrate 2 having the anode 3 was scrubbed using an alkaline cleaning agent and pure water, followed by cleaning with two fluids. After drying with nitrogen blowing and rotation at 1200 rpm, UV ozone cleaning was performed for 20 minutes.

[0122] [Process 2] In [Step 1], the substrate 2 on which the cleaned anode 3 is formed was set in a spin coater, and Heraeus' hole injection material "Clevios HIL1.3N" was spin-coated as the hole injection layer 4. The material was then heat-treated in air to deposit a 10 nm hole injection layer 4.

[0123] [Process 3] Next, the substrate 2, on which each layer up to the hole injection layer 4 was formed, was fixed to the substrate holder of the vacuum deposition apparatus. -5 The pressure was reduced until it reached Pa. First, the hole transport layer 5 is formed on the hole injection layer 4, with the following structural formula: [ka] DMAC-Phenox-DMAC, represented by [formula], and NovaRed's p-type dopant NDP-9 were deposited at a mass ratio of 9:1 at a wavelength of 30 nm, followed by a 10 nm deposition of DMAC-Phenox-DMAC.

[0124] Furthermore, as the light-emitting layer 6, a 5 nm layer of an anthracene derivative represented by the above structural formula (1-1) was deposited, and a 35 nm mixed film was formed using the anthracene derivative as the host material for the light-emitting layer and containing 1 mass% of CzBN (2,6-bis(9H-carbazole-9-yl)boron) manufactured by Ossila Limited as the light-emitting material (dopant material).

[0125] Next, a 30 nm film of the anthracene derivative represented by the above structural formula (1-1) was deposited as the electron transport layer 7.

[0126] After forming the electron transport layer 7, the electron injection layer 8 is formed using the following structural formula (2-1); [ka] A compound represented by [formula] was deposited at a 3nm depth.

[0127] The compound represented by the above structural formula (2-1) was synthesized according to the method described in T. Sasaki, M. Hasegawa, K. Inagaki, H. Ito, K. Suzuki, T. Oono, K. Morii, T. Shimizu and H. Fukagawa, Nature Communications, 12, pp. 2706.1, DOI: 10.1038 / s41467-021-23067-2.

[0128] Next, a cathode 9 made of aluminum with a thickness of 100 nm was deposited on the substrate 2, which had the electron injection layer 8 formed on it, by vacuum deposition. Furthermore, the cathode 9 was formed using a stainless steel deposition mask so that the deposition surface was in the shape of a 3 mm wide strip, and the light-emitting area of ​​the fabricated organic EL element was 9 mm². 2 That's what I decided.

[0129] [Step 4] Next, the substrate 2, on which each layer up to the cathode 9 was formed, was placed in a glass cap (sealing container) having a concave space, and sealed by filling it with a sealing material made of ultraviolet (UV) curing resin to obtain the organic EL element 1.

[0130] (Fabrication of transparent solar cells) Transparent solar cells 11 were manufactured and evaluated using the method described below.

[0131] [Process 1] As substrate 12, a commercially available transparent glass substrate with an average thickness of 0.7 mm and electrodes (anodes 13) made of ITO patterned to a width of 3 mm was prepared. Then, the substrate 12 having the anode 13 was scrubbed using an alkaline cleaning agent and pure water, and subsequently cleaned with two fluids. After drying with nitrogen blowing and rotation at 1200 rpm, UV ozone cleaning was performed for 20 minutes.

[0132] [Process 2] In [Step 1], the substrate 12 on which the anode 13 has been cleaned was set in a spin coater, and poly(3,4-ethylenedioxythiophene) (PEDOT) was spin-coated as a hole extraction layer 14. The layer was then heat-treated in air to form a hole extraction layer 14 with a thickness of 60 nm.

[0133] Next, the substrate 12 on which the hole extraction layer 14 is formed is fixed to the substrate holder of the vacuum deposition apparatus, and the inside of the chamber of the vacuum deposition apparatus is 1 × 10 -5 The pressure was reduced to Pa. First, a donor layer 15 was placed on the hole extraction layer 14, with the following structural formula; [ka] HN-D2, represented by [formula], was deposited to a thickness of 40 nm.

[0134] Next, the acceptor layer 16 has the following structure: [ka] B4PYMPM, represented by [formula], was deposited to a thickness of 20 nm.

[0135] After forming the acceptor layer 16, a compound represented by the above structural formula (2-1) (i.e., the same compound as the electron injection layer 8 of the organic EL element 1) was deposited to a thickness of 3 nm as the electron extraction layer 17.

[0136] Next, a cathode 18 made of magnesium and silver with a thickness of 10 nm was deposited on the substrate 12, which had the electron extraction layer 17 formed on it, by vacuum deposition. The cathode 18 was formed using a stainless steel deposition mask so that the deposition surface was in the shape of a 3 mm wide strip, and the area of ​​the power generation portion of the fabricated transparent solar cell 11 was 9 mm². 2 That's what I decided. Next, an optical adjustment layer 19 was deposited on the cathode 18 at a thickness of 60 nm.

[0137] [Step 4] Next, the substrate 12 on which each layer up to the optical adjustment layer 19 was formed was placed in a glass cap (sealing container) having a concave space, and sealed by filling it with a sealing material made of ultraviolet (UV) curing resin to produce a transparent solar cell 11. Furthermore, the transparent solar cell 11 was stacked with the organic EL element 1 to form the element (power-generating light-emitting element) of Example 1.

[0138] "Comparative Example 1" A transparent solar cell, fabricated in the same manner as in Example 1, and a general organic EL element that does not have power generation capabilities were stacked to create the element of Comparative Example 1. A typical organic EL was fabricated in the same manner as in Example 1, except that Tris-PCz(9,9'-diphenyl-6-(9-phenyl-9H-carbazole-3-yl)-9H,9'H-3,3'-bicarbazole) was used as the material for the hole transport layer, mCBP(3,3'-di(9H-carbazole-9-yl)-1,1'-biphenyl) was used instead of an anthracene derivative as the material for the light-emitting layer, and SF3-TRZ(2-(9,9'-spirobio(fluorene)-3-yl)-4,6-diphenyl-1,3,5-triazine) was used as the material for the electron transport layer.

[0139] "Comparative Example 2" Only organic EL elements with power generation capabilities fabricated in the same manner as in Example 1 were used as the elements for Comparative Example 2.

[0140] "Comparative Example 3" Only transparent solar cells fabricated in the same manner as in Example 1 were used as the elements for Comparative Example 3.

[0141] (Visible light transmittance of transparent solar cells) The transparent solar cell portion of the element (power-generating light-emitting element) of Example 1 obtained as described above, and the element (transparent solar cell only) of Comparative Example 3 were measured using a PerkinElmer Lambda950 spectrophotometer (380-780nm) to determine the visible light transmittance, which was found to be 60% (average value across the entire visible light spectrum).

[0142] (Evaluation of power generation and light emission characteristics) For each element in the examples and comparative examples obtained as described above, the power generation efficiency (conversion efficiency) was investigated by measuring the current when the voltage was swept using a Keithley 2400 source meter while irradiating it with AM1.5 light using a Spectrometer Solar Simulator. Furthermore, for luminescence performance, a voltage was applied using a Keithley 2400 source meter, and the brightness was measured using a Konica Minolta LS-100, with the voltage at 100 nits being measured. For the element in Example 1, the power generation efficiency of each device was measured in a stacked state and then summed.

[0143] [Table 1]

[0144] Table 1 shows that the element of Example 1 has improved power generation efficiency (conversion efficiency) compared to the elements of Comparative Examples 1, 2, and 3. Furthermore, since the element of Example 1 operates at a significantly lower voltage than the element of Comparative Example 1, its light-emitting performance is also improved. This demonstrates that the configuration of the present invention makes it possible to realize a low-voltage driven organic EL element while improving power generation performance. [Explanation of symbols]

[0145] 100: Light-emitting element 200: Transparent solar cell 300: Organic EL element 310: Circuit board 320: TFT 330: Red pixels 340: Green pixels 350: Blue pixels 1: Organic EL element 2: Circuit board 3: Anode 4: Hole injection layer 5: Hole transport layer 6: Emitting layer 7:Electron transport layer 8:Electron injection layer 9: Cathode 11: Transparent solar cell 12: Circuit board 13: Anode 14: Hole extraction layer 15: Donor Layer 16: Acceptor Layer 17:Electron extraction layer 18: Cathode 19: Optical adjustment layer

Claims

1. A power-generating light-emitting element characterized by comprising a transparent solar cell having a visible light transmittance of 40% or more and an organic electroluminescent element having a power-generating function, stacked together.

2. A display device characterized by comprising the power-generating light-emitting element described in claim 1.

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