Light-emitting device, display panel, display device and terminal equipment

Abstract

The invention relates to a light-emitting device, a display panel, a display device and terminal equipment, and the light-emitting device comprises an anode which is used for injecting a hole; the cathode is used for injecting electrons; the functional layer is located between the anode and the cathode and at least comprises a first light-emitting unit, a connecting unit and a second light-emitting unit which are sequentially arranged in a stacked mode in the direction from the anode to the cathode. The first light-emitting unit comprises a hole injection layer, a first hole transport layer, a first light-emitting layer and a first electron transport layer which are sequentially arranged along the direction from the anode to the cathode; the connection unit comprises a first charge generation layer, a connection layer and a second charge generation layer which are sequentially arranged along the direction from the anode to the cathode; the connecting layer is used for hole and / or electron transmission; the second light-emitting unit comprises a second electron transport layer, a second light-emitting layer and a second hole transport layer which are sequentially arranged in the direction from the cathode to the anode. A hole blocking layer is reduced, the level potential barrier of each layer is reduced, and the driving voltage is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting device, a display panel, a display apparatus and a terminal device. Background Art

[0002] With the development of display technology, it is applied in more and more fields. Display technology is mainly used in display devices, which can display corresponding information and meet corresponding display needs. As an important part of display technology, displays are available on various devices with display functions, and the types of displays on different devices may be different.

[0003] The display is composed of light-emitting devices, such as organic light-emitting diodes (OLED), and the display screen formed by OLED is an OLED screen. Summary of the invention

[0004] The present disclosure provides a light emitting device, a display panel, a display apparatus and a terminal device.

[0005] According to a first aspect of the embodiments of the present disclosure, a light-emitting device is provided, comprising: an anode for injecting holes; a cathode for injecting electrons; a functional layer located between the anode and the cathode, comprising at least a first light-emitting unit, a connecting unit and a second light-emitting unit which are sequentially stacked from the anode to the cathode; wherein the first light-emitting unit comprises: a hole injection layer, a first hole transport layer, a first light-emitting layer and a first electron transport layer which are sequentially arranged from the anode to the cathode; the connecting unit comprises: a first charge generation layer, a connecting layer and a second charge generation layer which are sequentially arranged from the anode to the cathode, and the connecting layer is at least used to transport the holes and / or the electrons; the second light-emitting unit comprises: a second electron transport layer, a second light-emitting layer and a second hole transport layer which are sequentially arranged from the cathode to the anode.

[0006] In one embodiment, the connection layer is a metal layer or a metal oxide layer.

[0007] In one embodiment, the metal layer includes a metal layer formed of one of lithium, ytterbium, aluminum, magnesium, gold and silver.

[0008] In one embodiment, the first charge generation layer and the first electron transport layer are a homojunction structure.

[0009] In one embodiment, the first charge generation layer is an N-type charge generation layer; the N-type charge generation layer is a doped charge generation layer; wherein the first material in the N-type charge generation layer is the same as the material of the electron transport layer; the second material is lithium or ytterbium, and the doping mass ratio of the second material doped in the first material is 1% to 3%.

[0010] In one embodiment, the second charge generation layer and the second hole transport layer are a homojunction structure.

[0011] In one embodiment, the second charge generating layer is a P-type charge generating layer; the P-type charge generating layer is a doped charge generating layer; wherein the first material in the P-type charge generating layer is the same as the material of the hole injection layer, and the doping mass ratio of the second material doped in the first material is 6% to 8%.

[0012] In one embodiment, the first light-emitting unit further includes: a first light-emitting auxiliary layer located between the first hole transport layer and the first light-emitting layer.

[0013] In one embodiment, the second light-emitting unit further includes: a second light-emitting auxiliary layer located between the second hole transport layer and the second light-emitting layer.

[0014] In one embodiment, the length of the microcavity is the sum of the thickness of the first light emitting unit, the thickness of the connecting unit, and the thickness of the second light emitting unit.

[0015] In one embodiment, it further includes: a light extraction layer connected to the cathode for extracting light spectrum.

[0016] According to a second aspect of the embodiments of the present disclosure, there is provided a display panel, comprising: a light emitting device as described in any one of the above embodiments.

[0017] According to a third aspect of the embodiments of the present disclosure, a display device is provided, comprising: the display panel described in the above embodiments.

[0018] According to a fourth aspect of the embodiments of the present disclosure, a terminal device is provided, including: the display panel described in the above embodiments.

[0019] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0020] The display device in the embodiment of the present disclosure is a series-connected fixed-emission light-emitting device. Since the hole blocking layer is reduced in multiple light-emitting units, the injection barrier of carriers in the device is reduced, and the hierarchical barrier of each film layer in each light-emitting unit is reduced, which is more conducive to the injection and transmission of carriers, improves the injection and transmission efficiency of carriers, and thus reduces the driving voltage of the light-emitting device.

[0021] In addition, by adding a connection layer for transferring carriers between the first charge generation layer and the second charge generation layer, the reduction in the injection efficiency and transfer efficiency of carriers caused by ion diffusion in the first charge generation layer and the second charge generation layer can be reduced, and the injection efficiency and transfer efficiency of carriers can be increased, thereby reducing the driving voltage of the light-emitting device. After the driving voltage is reduced, the power consumption can be reduced, thereby increasing the use time and further improving the user experience.

[0022] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0024] Figure 1 is a schematic structural diagram of a light emitting device according to an exemplary embodiment;

[0025] Figure 2 is a schematic structural diagram of another light emitting device according to an exemplary embodiment;

[0026] Figure 3 The present invention is a block diagram of a terminal device according to an exemplary embodiment. DETAILED DESCRIPTION

[0027] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the appended claims.

[0028] Active-matrix Organic Light-emitting Diode (AMOLED) is a type of OLED, and AMOLED has the characteristics of ultra-thinness, flexibility, low driving voltage, etc. Most of the AMOLEDs in the AMOLED display screen formed by AMOLED are top-emitting OLEDs.

[0029] A tandem top-emitting OLED device includes multiple light-emitting units connected in series. Compared with a non-tandem OLED device, a tandem top-emitting OLED device has a higher luminous efficiency, and the luminous efficiency increases exponentially with the number of tandem light-emitting units. Under the same current density, the degradation characteristics of a tandem top-emitting OLED device are the same as those of a non-tandem OLED device. Since the initial brightness of a tandem top-emitting OLED device is relatively high, when converted to the same initial brightness, the life of a tandem top-emitting OLED device will be longer than that of a non-tandem OLED device. The high-luminous-efficiency AMOLED has a lower driving current, which greatly reduces the power consumption of the display, allowing the entire device to be used for a longer time, and the battery capacity is lower, making the entire device thinner and lighter, which helps to improve the user experience.

[0030] However, the driving voltage of such a tandem top-emitting OLED device will increase exponentially as the number of light-emitting units increases. The increase in driving voltage has a negative impact on the application of such an OLED device in products.

[0031] refer to Figure 1 , is a schematic diagram of the structure of a light-emitting device, comprising:

[0032] Anode 1, for injecting holes;

[0033] cathode 2, for injecting electrons;

[0034] The functional layer 3 is located between the anode 1 and the cathode 2, and at least includes a first light-emitting unit 301, a connecting unit 302, and a second light-emitting unit 303 which are sequentially stacked from the anode 1 to the cathode 2;

[0035] The first light-emitting unit 301 includes: a hole injection layer 3011, a first hole transport layer 3012, a first light-emitting layer 3013 and a first electron transport layer 3014 arranged in sequence from the anode 1 to the cathode 2;

[0036] The connection unit 302 includes: a first charge generation layer 3021, a connection layer 3022 and a second charge generation layer 3023 arranged in sequence from the anode 1 to the cathode 2; the connection layer 302 is at least used for the transmission of electrons and / or holes;

[0037] The second light-emitting unit 303 includes: a second electron transport layer 3031 , a second light-emitting layer 3032 and a second hole transport layer 3033 which are sequentially arranged from the cathode 2 to the anode 1 .

[0038] Exemplarily, the light-emitting device in this embodiment is a tandem top-emitting light-emitting device, that is, a tandem top-emitting OLED.

[0039] The anode 1 may be formed of indium tin oxide (ITO) and silver (Ag), and may include a first indium tin oxide layer, a silver layer, and a second indium tin oxide layer stacked in sequence. The anode 1 is used to connect to the positive electrode of a power source for releasing and injecting holes.

[0040] The cathode 2 is a metal cathode connected to the negative electrode of the power source and is used for releasing and injecting electrons.

[0041] The functional layer 3 is located between the anode 1 and the cathode 2. The functional layer 3 includes a plurality of film layers with different functions for emitting light according to holes and electrons. The functional layer 3 includes at least two light-emitting units connected in series, namely a first light-emitting unit 301 and a second light-emitting unit 303. The first light-emitting unit 301 and the second light-emitting unit 302 are connected by a connecting unit 302.

[0042] The hole injection layer 3011 in the first light-emitting unit 301 is connected to the anode 1 , and the hole injection layer 3011 , the first hole transport layer 3012 , the first light-emitting layer 3013 and the first electron transport layer 3014 in the first light-emitting unit 301 are arranged in sequence from the anode 1 to the cathode 2 .

[0043] The second electron transport layer 3031 in the second light-emitting unit 303 is connected to the cathode 2 , and the second electron transport layer 3031 , the second light-emitting layer 3032 and the second hole transport layer 3033 in the second light-emitting unit 303 are arranged in sequence from the cathode 2 to the anode 1 .

[0044] The connecting unit 302 is located between the first light-emitting unit 301 and the second light-emitting unit 302, and is used to connect the first light-emitting unit 301 and the second light-emitting unit 302. The first charge generation layer 3021, the connecting layer 3022, and the second charge generation layer 3023 in the connecting unit 302 are sequentially arranged from the anode 1 to the cathode 2. The connecting unit 302 is also used to generate carriers for adjacent light-emitting units, and inject and transfer the carriers into the light-emitting units.

[0045] Exemplarily, the first charge generation layer 3021 and the second charge generation layer 3023 are used to generate carriers, transport carriers, and inject carriers. The carriers may include holes and electrons.

[0046] The material, thickness and type of the first charge generation layer 3021 and the second charge generation layer 3023 can be determined according to actual needs, and reference can be made to the description of the first charge generation layer 3021 and the second charge generation layer 3023 in subsequent embodiments.

[0047] The connection layer 3022 is used to connect the first charge generation layer 3021 and the second charge generation layer 3023, and has the function of transporting holes and / or electrons. The connection layer 3022 can be a metal layer, which can increase the injection efficiency and transmission efficiency of carriers, thereby reducing the driving voltage of the light-emitting device.

[0048] Exemplarily, the connecting layer 3022 is located between the first charge generating layer 3021 and the second charge generating layer 3023, and is used to connect the first charge generating layer 3021 and the second charge generating layer 3023, and helps to reduce the increase in driving voltage caused by the operation of the light-emitting device, thereby improving the stability of the light-emitting device.

[0049] Through the transport of carriers by the connecting unit 302 , electrons can be transported to the first light-emitting layer 3013 , and holes can be transported to the second light-emitting layer 3032 , so that the first light-emitting unit 301 and the second light-emitting unit 303 emit light.

[0050] The hole blocking layer can form a barrier to the migration of carriers, thereby blocking the migration of carriers. In multiple light-emitting units, the hole blocking layer is reduced, thereby reducing the injection barrier of carriers in the device, reducing the hierarchical barrier of each film layer in each light-emitting unit, and being more conducive to the injection and transmission of carriers, thereby improving the injection efficiency and transmission efficiency of carriers, and thus reducing the driving voltage of the light-emitting device.

[0051] By adding a connecting layer 3022 for transporting carriers between the first charge generation layer 3021 and the second charge generation layer 3023, the reduction in carrier injection efficiency and transport efficiency due to the mutual diffusion of ions in the first charge generation layer and the second charge generation layer can be reduced, the carrier injection efficiency and transport efficiency can be increased, and the driving voltage of the light-emitting device can be reduced.

[0052] When the driving voltage is reduced, the power consumption can be reduced, thereby increasing the usage time and further improving the user experience.

[0053] In one embodiment, the thickness of the anode 1 can be determined according to actual needs. For example, the thickness of the first indium tin oxide layer is 7 nanometers to 10 nanometers, the thickness of the silver layer is 100 nanometers to 120 nanometers, and the thickness of the second indium tin oxide layer is 8 nanometers to 12 nanometers.

[0054] In one embodiment, the anode 1 may be formed by magnetron sputtering.

[0055] In one embodiment, the cathode 2 may be a double-layer structure, for example, an ytterbium metal layer and a mixed layer, wherein the mixed layer is a mixed layer formed of magnesium metal and silver metal.

[0056] In one embodiment, the thickness of the ytterbium metal layer is 1 nanometer. The mass ratio of the magnesium metal to the silver metal in the mixed layer is 1:9.

[0057] Exemplarily, the thickness of the mixed layer is 9 nanometers to 15 nanometers.

[0058] In one embodiment, the hole injection layer 3011 is a film layer formed of an organic small molecule material, or a film layer formed of a metal material.

[0059] Exemplarily, the hole injection layer 3011 is a doped film layer, and the second material in the hole injection layer 3011 is doped into the first material at a concentration of 0.5% to 5.0%. The second material and the first material in the hole injection layer 3011 can be determined according to actual needs, for example, the first material is an organic small molecule material.

[0060] Illustratively, the thickness of the hole injection layer 3011 is 10 nanometers to 20 nanometers.

[0061] In one embodiment, the first hole transport layer 3012 is a film layer formed of a single material.

[0062] Exemplarily, the material of the first hole transport layer 3012 is the same as the first material of the hole injection layer 3011, and the first hole transport layer 3012 and the hole injection layer 3011 are a homojunction structure, which can reduce the energy level barrier between the material of the first hole transport layer 3012 and the hole injection layer 3011, and also reduce the injection barrier and transmission barrier of carriers, thereby improving the injection and transmission efficiency of carriers, thereby helping to reduce the driving voltage.

[0063] Exemplarily, the thickness of the first hole transport layer 3012 is 20 nanometers to 25 nanometers.

[0064] In one embodiment, the first light emitting layer 3013 is a doped film layer.

[0065] Exemplarily, the first light emitting layer 3013 may be a doped film layer of two materials, and the mass ratio or concentration ratio of the second material doped into the first material in the first light emitting layer 3013 is 2%. The second material in the first light emitting layer 3013 includes a fluorescent material and may also include a phosphorescent material.

[0066] Exemplarily, the thickness of the first light emitting layer 3013 is 18 nanometers to 22 nanometers.

[0067] The first electron transport layer 3014 is a single material layer. The material forming the first electron transport layer 3014 is the same as the first material in the first charge generation layer 3021 , which can be an inorganic metal oxide or 8-hydroxyquinoline lithium.

[0068] Exemplarily, the thickness of the first electron transport layer 3014 is 15 nanometers.

[0069] In one embodiment, the second electron transport layer 3031 is a doped film layer, for example, a film layer formed by doping two materials, and the doping mass ratio or doping concentration ratio of the second material in the second electron transport layer 3031 to the first material in the second electron transport layer 3031 is 20% to 40%.

[0070] Exemplarily, the doping mass ratio or doping concentration ratio of the second material in the second electron transport layer 3031 to the first material in the second electron transport layer 3031 is 20%, 25%, 30%, 35% or 40%.

[0071] Exemplarily, the second material in the second electron transport layer 3031 is 8-hydroxyquinoline lithium (Liq).

[0072] In one embodiment, the second light-emitting layer 3032 is a doped light-emitting layer, which can be a light-emitting layer formed by doping two materials. Exemplarily, the second light-emitting layer 3032 has the same structure, thickness and material as the first light-emitting layer 3013 .

[0073] In one embodiment, the second hole transport layer 3033 is a transport layer formed of a single material, and the material forming the second hole transport layer 3033 is the same as the material forming the first hole transport layer 3012 .

[0074] Exemplarily, the thickness of the second hole transport layer 3033 is 40 nanometers to 50 nanometers.

[0075] Exemplarily, the thickness of the second hole transport layer 3033 is 43 nanometers, 44 nanometers, 48 ​​nanometers, or 49 nanometers.

[0076] In one embodiment, the first charge generation layer 3021 is an N-type charge generation layer (N-Charge-Generation Layer, N-CGL).

[0077] The first charge generation layer 3021 is a doped film layer, and the first charge generation layer 3021 may be a film layer formed of two materials, and the doping mass ratio or concentration ratio of the second material in the first charge generation layer 3021 to the first material in the first charge generation layer 3021 is 1% to 3%. Exemplarily, the doping mass ratio or concentration ratio of the second material in the first charge generation layer 3021 to the first material in the first charge generation layer 3021 is 1%, 2% or 3%.

[0078] Exemplarily, the second material in the first charge generation layer 3021 is metallic lithium or ytterbium. The first material in the first charge generation layer 3021 is a single material, which is the same as the material of the first electron transport layer 3014 .

[0079] The thickness of the first charge generation layer 3021 is 10 nm or 15 nm.

[0080] In one embodiment, the second charge generation layer 3023 is a P-type charge generation layer (P-CGL). The second charge generation layer 3023 is a doped charge generation layer, and the second charge generation layer 3023 can be a film layer formed of two materials. The doping mass ratio of the second material of the second charge generation layer 3023 doped in the first material of the second charge generation layer 3023 is 6% to 8%.

[0081] Illustratively, the doping mass ratio of the second material of the second charge generation layer 3023 doped in the first material of the second charge generation layer 3023 is 6%, 7% or 8%.

[0082] Exemplarily, the material forming the P-type charge generation layer is the same as the material forming the hole injection layer 3011 , which can facilitate the injection and transmission of holes to the second light-emitting layer 3032 , thereby improving the injection efficiency and transmission efficiency of holes.

[0083] Exemplarily, the thickness of the second charge generation layer 3023 is 10 nanometers.

[0084] In one embodiment, the first material in the first charge generation layer 3021 and the first material in the second charge generation layer 3023 are different.

[0085] In one embodiment, the second material in the first charge generation layer 3021 and the second material in the second charge generation layer 3023 are different.

[0086] In one embodiment, the connection layer 3022 is a metal layer or a metal oxide layer.

[0087] Exemplarily, when the connection layer 3022 is a metal layer, it can be a film layer formed by at least one of the following metals:

[0088] Lithium, ytterbium, aluminum, magnesium, gold and silver, that is, the connection layer 3022 may be a metal layer formed of one of lithium, ytterbium, aluminum, magnesium, gold and silver.

[0089] The connecting layer 3022 is a metal layer or a metal oxide layer, which can facilitate the transport of carriers. The connecting layer 3022 can reduce the reduction in carrier injection efficiency and transport efficiency due to ion diffusion in the first charge generation layer and the second charge generation layer, thereby increasing the carrier injection efficiency and transport efficiency and reducing the driving voltage of the light-emitting device.

[0090] In one embodiment, the first charge generation layer 3021 and the first electron transport layer 3014 are in a homojunction structure. Since the first charge generation layer 3021 is connected to the first electron transport layer 3014, the hierarchical barrier between the first charge generation layer 3021 and the first electron transport layer 3014 can be reduced during the process of electrons being transported from the first charge generation layer 3021 to the first electron transport layer 301, and the injection barrier and transport barrier of electrons are also reduced, thereby helping to reduce the driving voltage.

[0091] In one embodiment, the second charge generation layer 3023 and the second hole transport layer 3033 are homojunction structures. Since the second charge generation layer 3023 is connected to the second hole transport layer 3033, the hierarchical barrier between the second charge generation layer 3023 and the second hole transport layer 3033 can be reduced during the process of holes being transported from the second charge generation layer 3023 to the second hole transport layer 3033, and the injection barrier and transport barrier of holes are also reduced, thereby helping to reduce the driving voltage.

[0092] In one embodiment, the first light emitting unit 301 further includes:

[0093] The first light-emitting auxiliary layer 3015 is located between the first hole transport layer 3012 and the first light-emitting layer 3013 .

[0094] The first light-emitting auxiliary layer 3015 may also be referred to as a first optical auxiliary layer (prime layer). The first light-emitting auxiliary layer 3015 may assist the first hole transport layer 3012, reduce the potential barrier between the first hole transport layer 3012 and the first light-emitting layer 3013, and help reduce the driving voltage of the light-emitting device, further increase the utilization rate of holes, and thus improve the light-emitting efficiency and life of the light-emitting device.

[0095] In one embodiment, when the microcavity length of the light-emitting device is the microcavity length for emitting light of a preset color, and after the film layer structure of each unit in the light-emitting device changes, the thickness of each unit changes. In order to keep the microcavity length of the light-emitting device unchanged, the thickness of the first light-emitting auxiliary layer 3015 is adjusted so that the thickness of the light-emitting device is still the microcavity length for emitting light of a preset color.

[0096] Exemplarily, the microcavity length of the light-emitting device is the microcavity length for emitting light of a preset color. After the film layer in the first light-emitting unit is reduced, the thickness of the first light-emitting unit can be kept unchanged by adding the first light-emitting auxiliary layer 3015, and the light-emitting device can continue to emit light of the preset color. Alternatively, the thickness of the first light-emitting auxiliary layer 3015 is increased on the basis of the original first light-emitting auxiliary layer 3015, so that the thickness of the first light-emitting unit remains unchanged, and the light-emitting device can continue to emit light of the preset color.

[0097] Exemplarily, the preset color may be blue.

[0098] Since the first light-emitting unit 301 in the light-emitting device reduces the hole blocking layer, the thickness of the first light-emitting unit changes. The thickness of the first light-emitting unit 1 is adjusted by the thickness of the first light-emitting auxiliary layer 3015, thereby adjusting the microcavity length of the entire light-emitting device to facilitate emitting light of a preset color.

[0099] Exemplarily, the first light-emitting auxiliary layer 3015 is a film layer formed by a single material, and the material forming the first light-emitting auxiliary layer 3015 is different from the material forming the first hole transport layer 3012 , for example, it can be a film layer formed by an organic small molecule material.

[0100] Exemplarily, the thickness of the first light-emitting auxiliary layer 3015 is 5 nanometers.

[0101] In one embodiment, the second light emitting unit 303 further includes:

[0102] The second light-emitting auxiliary layer 3034 is located between the second hole transport layer 3033 and the second light-emitting layer 3032 .

[0103] The second light-emitting auxiliary layer 3034 may also be referred to as a second optical auxiliary layer (prime layer). The second light-emitting auxiliary layer 3034 may assist the second hole transport layer 3033, reduce the potential barrier between the second hole transport layer 3033 and the second light-emitting layer 3032, and help reduce the driving voltage of the light-emitting device, further increase the utilization rate of holes, and thus improve the light-emitting efficiency and life of the light-emitting device.

[0104] In one embodiment, the microcavity length of the light-emitting device is the length of the microcavity for emitting light of a preset color, and the thickness of the second light-emitting auxiliary layer 3034 is a portion of the microcavity length.

[0105] When the microcavity length of the light-emitting device is the microcavity length for emitting light of a preset color, and after the film layer structure of each unit in the light-emitting device changes, the thickness of each unit changes. In order to keep the microcavity length of the light-emitting device unchanged, the thickness of the second light-emitting auxiliary layer 3034 is adjusted so that the thickness of the light-emitting device is still the microcavity length for emitting light of a preset color.

[0106] Exemplarily, the microcavity length of the light-emitting device is the microcavity length for emitting light of a preset color. After the film layer in the second light-emitting unit is reduced, the thickness of the second light-emitting unit can be kept unchanged by adding the second light-emitting auxiliary layer 3034, and the light-emitting device can continue to emit light of the preset color. Alternatively, the thickness of the second light-emitting auxiliary layer 3034 is increased on the basis of the original second light-emitting auxiliary layer 3034, so that the thickness of the first light-emitting unit remains unchanged, and the light-emitting device can continue to emit light of the preset color.

[0107] Exemplarily, the preset color may be blue.

[0108] Since the hole blocking layer is reduced in the second light-emitting unit 303 in the light-emitting device, the thickness of the second light-emitting unit changes. The thickness of the second light-emitting unit is adjusted by the thickness of the second light-emitting auxiliary layer 3034, thereby adjusting the microcavity length of the entire light-emitting device to facilitate light emission.

[0109] Exemplarily, the second light-emitting auxiliary layer 3034 is a film layer formed by a single material. The material forming the second light-emitting auxiliary layer 3034 is different from the material forming the first hole transport layer 3012, and is the same as the material forming the first light-emitting auxiliary layer 3015. For example, it can be a film layer formed by an organic small molecule material.

[0110] Exemplarily, the thickness of the second light-emitting auxiliary layer 3034 is 5 nanometers.

[0111] In one embodiment, the microcavity length of the light-emitting device is the sum of the thickness of the first light-emitting unit 301, the thickness of the connecting unit 302, and the thickness of the second light-emitting unit 303. After the structure or thickness of other film layers in the light-emitting device is changed, the thickness of the first light-emitting auxiliary layer 3015 and / or the thickness of the second light-emitting auxiliary layer 3034 can be adjusted to ensure that the microcavity of the light-emitting device still has a cavity length that emits light of a preset color.

[0112] Exemplarily, the light-emitting device may be a blue light-emitting device, and the cavity length of the microcavity of the blue light-emitting device is less than 190 nanometers.

[0113] Exemplarily, the microcavity length of the first light-emitting unit 301 is 50 nanometers, and the microcavity length of the second light-emitting unit 303 is 110 nanometers.

[0114] In one embodiment, reference Figure 2 , for Figure 1 A schematic structural diagram of another light-emitting device shown on the basis of the light-emitting device shown, the light-emitting device further includes:

[0115] The light extraction layer 4 is connected to the cathode 2 and is used to extract the spectrum. The light extraction layer 4 can also be called a capping layer, which can realize the selection of the spectrum to facilitate light emission.

[0116] Exemplarily, the thickness of the light extraction layer 4′ may be 40 nanometers to 80 nanometers.

[0117] In one embodiment, reference Figure 2 , the light emitting device further comprises:

[0118] The surface coating 5 is located on the side of the light extraction layer 4 away from the cathode 2 and connected to the light extraction layer 4, that is, the light extraction layer 4 is located between the surface coating 5 and the cathode 2. The surface coating 5 can be lithium fluoride (LiF), which can be used as an encapsulation layer of the light-emitting device and has good light transmittance.

[0119] Exemplarily, the thickness of the surface coating 5 is 20 nanometers to 50 nanometers.

[0120] In one embodiment, each layer in the first light-emitting unit 301 , the connecting unit 302 , and the second light-emitting unit 303 may be formed by vacuum thermal evaporation.

[0121] In one embodiment, at least one third light emitting unit may be included between the first light emitting unit and the second light emitting unit, and the structure of the third light emitting unit may be the same as that of the second light emitting unit. That is, the light emitting device includes a first light emitting unit and a plurality of second light emitting units, the first light emitting unit and the second light emitting unit are connected in series, and the plurality of second light emitting units are also connected in series. In this way, the light emitting efficiency can be improved while reducing the driving voltage.

[0122] In one embodiment, a display panel is further provided, comprising: the light emitting device in any one of the above embodiments. The display target may be an OLED display panel.

[0123] In one embodiment, a display device is further provided, comprising: the display panel in any of the above embodiments. The display device may include a display screen.

[0124] In one embodiment, a terminal device is further provided, comprising: the display panel in the above embodiment. The terminal device may be any electronic device having a display panel.

[0125] In one embodiment, reference Figure 2 , and another example of a light emitting device is also provided:

[0126] This embodiment provides an organic light emitting diode (AMOLED) for a display screen. The device is a series structure and is a blue light emitting device. Figure 2 The tandem OLED device shown has no hole blocking layer and has the following structure:

[0127] The anode 1 (Anode) structure is a first indium tin oxide layer (ITO 1), silver (Ag) and a first indium tin oxide layer (ITO 2), the thickness of the ITO 1 layer is 7nm-10nm, the thickness of the Ag layer is 100nm-120nm, and the thickness of the ITO 2 layer is 8-12nm. The anode can be formed by magnetron sputtering.

[0128] The hole injection layer (HIL) 3011 is a host-guest doped type, with a guest doping concentration mass ratio of 0.5%-5.0%; the HIL thickness is 10nm-20nm. The first material in the hole injection layer 3011 is the host material, and the second material in the hole injection layer 3011 is the guest material.

[0129] The hole transport layer (HTL1) 3012 is a single material, which is the same as the main material of the hole injection layer 3011, and has a thickness of 20-25 nm.

[0130] The first light-emitting auxiliary layer 3015 is the HTL2 layer, also known as the first optical auxiliary layer (first Prime layer), which is used to adjust the length of the device microcavity. HTL2 is a single material, which is different from the HTL1 material and has a thickness of 5 nm.

[0131] The first light-emitting layer 3013 (EML1) is a doped type of host and guest materials. The doped guest can be a fluorescent material or a phosphorescent material, and the doping mass ratio is 2%. The thickness of the first light-emitting layer 3013 is 18nm-22nm. The first material in the first light-emitting layer 3013 is the host material, and the second material in the first light-emitting layer 3013 is the guest material.

[0132] The first electron transport layer 3014 is ETL1. ETL1 is a single material that is the same as the N-CGL main material and has a thickness of 15 nm.

[0133] The hole injection layer 3011 , the first hole transport layer 3012 , the first light-emitting auxiliary layer 3015 , the first light-emitting layer 3013 and the first electron transport layer 3014 are part of the first light-emitting unit.

[0134] The first charge generation layer is an N-type charge generation layer (N-CGL). N-CGL is a doped type of host and guest materials. The host material is the same as ETL1, and the guest material is metallic lithium or metallic ytterbium. The doping mass ratio is 1%, 2% or 3%. The thickness of N-CGL is 10nm or 15nm.

[0135] The material of the connection layer 3022 is metal, such as one of Li, Yb, Al, Mg, Au, Ag, or metal oxide. The thickness of the connection layer 3022 is 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm.

[0136] The second charge generation layer 3023 is a P-type charge generation layer (P-CGL), which is a host-guest doped type, the host-guest material is the same as the hole injection layer 3011, the guest doping mass ratio is one of 6%, 7% and 8%, and the thickness of the second charge generation layer 3023 is 10nm. The first material in the P-CGL is the host material, and the second material in the P-CGL is the guest material.

[0137] The first charge generation layer 3021, the connection layer 3022, and the second charge generation layer 3023 are connecting parts of two adjacent light emitting units arranged in a stacked manner.

[0138] The second hole transport layer 3033 is the HTL of the second light emitting unit, and is a single material, the same as the material of the first hole transport layer 3012 , and has a thickness of 40-50 nm, such as 43 nm, 44 nm, 48 nm or 49 nm.

[0139] The second light-emitting auxiliary layer 3034 is the same as the first light-emitting auxiliary layer 3015, also called the Prime layer, which is used to adjust the length of the device microcavity. The material of the second light-emitting auxiliary layer 3034 can be different from the material of the first hole transport layer. The material of the second light-emitting auxiliary layer 3034 is a single material with a thickness of 5nm.

[0140] The second light-emitting layer (EML2) 3032, EML2 is a doped type of host and guest materials, and is the same as the material of the first light-emitting layer 3013. The doped guest can be a fluorescent material or a phosphorescent material, the doping mass ratio is 2%, and the thickness is 18nm-22nm.

[0141] The second electron transport layer 3031 is doped with host and guest materials, one of which is Liq, and the proportion of Liq is 40%, 35%, 30%, 25% or 20%.

[0142] The structure of the cathode 2 is a double-layer structure of Yb and a mixture of Mg and Ag, the Yb thickness is 1 nm, the Mg:Ag ratio is 1:9, and the Mg:Ag thickness is 9 nm-15 nm.

[0143] The light extraction layer 4 (CPL), CPL is a thin film formed of a single material and has a thickness of 40nm-80nm.

[0144] The surface coating 5 is a lithium fluoride (LiF) layer with a thickness of 20-50 nm.

[0145] Illustratively, the hole injection layer 3011 and the first hole transport layer 3012 are homojunction structures.

[0146] The second electron transport layer 3031 and the first charge generation layer 3021 are homojunction structures;

[0147] The second hole transport layer 3033 and the second charge generation layer 3023 have a homojunction structure.

[0148] In one embodiment, the distance between the anode 1 and the cathode 2 is the microcavity length of the light emitting device, that is, the microcavity length of the OLED device is from the hole injection layer 3011 to the second electron transport layer 3031. The microcavity length of the blue OLED device is less than 190 nanometers.

[0149] The cavity length of the first light-emitting unit is 50 nanometers; the cavity length of the second light-emitting unit is 110 nm.

[0150] Figure 1 and Figure 2 Each layer is formed by vacuum thermal evaporation, and the material is organic small molecule material or metal material.

[0151] The light-emitting device structure provided in this embodiment increases the light-emitting efficiency exponentially while reducing the voltage. The low driving voltage and low driving current help to reduce the power consumption of the AMOLED display panel, increase the user's usage time, and make the overall device design thinner and lighter, thereby comprehensively improving the user experience.

[0152] Figure 3 1 is a block diagram of a terminal device according to an exemplary embodiment. For example, the terminal device may be a mobile phone, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, a personal digital assistant, etc.

[0153] Reference Figure 3 The terminal device may include one or more of the following components: a processing component 802 , a memory 804 , a power component 806 , a multimedia component 808 , an audio component 810 , an input / output (I / O) interface 812 , a sensor component 814 , and a communication component 816 .

[0154] The processing component 802 generally controls the overall operation of the terminal device, such as operations associated with display, phone calls, data communications, camera operations, and recording operations. The processing component 802 may include one or more processors 820 to execute instructions to complete all or part of the steps of the above method. In addition, the processing component 802 may include one or more modules to facilitate the interaction between the processing component 802 and other components. For example, the processing component 802 may include a multimedia module to facilitate the interaction between the multimedia component 808 and the processing component 802.

[0155] The memory 804 is configured to store various types of data to support operations on the terminal device. Examples of such data include instructions for any application or method operating on the terminal device, contact data, phone book data, messages, pictures, videos, etc. The memory 804 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0156] The power component 806 provides power to various components of the terminal device. The power component 806 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to the terminal device.

[0157] The multimedia component 808 includes a screen that provides an output interface between the terminal device and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundaries of the touch or slide action, but also detect the duration and pressure associated with the touch or slide operation. In some embodiments, the multimedia component 808 includes a front camera and / or a rear camera. When the terminal device is in an operating mode, such as a shooting mode or a video mode, the front camera and / or the rear camera may receive external multimedia data. Each front camera and rear camera may be a fixed optical lens system or have a focal length and optical zoom capability.

[0158] The audio component 810 is configured to output and / or input audio signals. For example, the audio component 810 includes a microphone (MIC), and when the terminal device is in an operation mode, such as a call mode, a recording mode, and a speech recognition mode, the microphone is configured to receive an external audio signal. The received audio signal can be further stored in the memory 804 or sent via the communication component 816. In some embodiments, the audio component 810 also includes a speaker for outputting audio signals.

[0159] I / O interface 812 provides an interface between processing component 802 and peripheral interface modules, such as keyboards, click wheels, buttons, etc. These buttons may include but are not limited to: home button, volume button, start button, and lock button.

[0160] The sensor assembly 814 includes one or more sensors for providing various aspects of status assessment for the terminal device. For example, the sensor assembly 814 can detect the open / closed state of the terminal device, the relative positioning of components, such as the display and keypad of the terminal device, and the sensor assembly 814 can also detect the position change of the terminal device or a component of the terminal device, the presence or absence of user contact with the terminal device, the orientation or acceleration / deceleration of the terminal device, and the temperature change of the terminal device. The sensor assembly 814 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. The sensor assembly 814 may also include an optical sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 814 may also include an accelerometer, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

[0161] The communication component 816 is configured to facilitate wired or wireless communication between the terminal device and other devices. The terminal device can access a wireless network based on a communication standard, such as Wi-Fi, 4G or 5G, or a combination thereof. In an exemplary embodiment, the communication component 816 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 816 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

[0162] In an exemplary embodiment, the terminal device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the above method.

[0163] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0164] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A light emitting device, characterized in that: include: an anode for injecting holes; cathode, for injecting electrons; A functional layer, located between the anode and the cathode, at least comprising a first light-emitting unit, a connecting unit and a second light-emitting unit stacked in sequence from the anode to the cathode; Wherein, the first light-emitting unit comprises: a hole injection layer, a first hole transport layer, a first light-emitting layer and a first electron transport layer arranged in sequence from the anode to the cathode; The connection unit comprises: a first charge generation layer, a connection layer and a second charge generation layer arranged in sequence from the anode to the cathode; wherein the connection layer is at least used to transport the holes and / or the electrons; The second light-emitting unit includes: a second electron transport layer, a second light-emitting layer and a second hole transport layer are sequentially arranged along the direction from the cathode to the anode.

2. The light emitting device according to claim 1, characterized in that: The connection layer is a metal layer or a metal oxide layer.

3. The light emitting device according to claim 2, characterized in that: The metal layer comprises: A metal layer formed from one of lithium, ytterbium, aluminum, magnesium, gold and silver.

4. The light emitting device according to claim 1, characterized in that: The first charge generation layer and the first electron transport layer are in a homojunction structure.

5. The light emitting device according to claim 1, characterized in that: The first charge generation layer is an N-type charge generation layer; the N-type charge generation layer is a doped charge generation layer; The first material in the N-type charge generation layer is the same as the material of the electron transport layer; the second material is lithium or ytterbium, and the doping mass ratio of the second material doped in the first material is 1% to 3%.

6. The light emitting device according to claim 1, characterized in that: The second charge generation layer and the second hole transport layer are of a homojunction structure.

7. The light emitting device according to claim 6, characterized in that: The second charge generation layer is a P-type charge generation layer; the P-type charge generation layer is a doped charge generation layer; The first material in the P-type charge generation layer is the same as the material of the hole injection layer, and the second material is doped into the first material at a doping ratio of 6% to 8% by mass.

8. The light emitting device according to claim 1, characterized in that: The first light emitting unit further comprises: The first light-emitting auxiliary layer is located between the first hole transport layer and the first light-emitting layer.

9. The light emitting device according to claim 1, characterized in that: The second light emitting unit further comprises: The second light-emitting auxiliary layer is located between the second hole transport layer and the second light-emitting layer.

10. The light emitting device according to claim 8 or 9, characterized in that: The length of the microcavity is the sum of the thickness of the first light emitting unit, the thickness of the connecting unit, and the thickness of the second light emitting unit.

11. The light emitting device according to claim 1, characterized in that: Also includes: The light extraction layer is connected to the cathode and is used for extracting light spectrum.

12. A display panel, characterized in that: include: A light emitting device as claimed in any one of claims 1 to 11.

13. A display device, characterized in that: include: The display panel as claimed in claim 12.

14. A terminal device, characterized in that: include: The display panel as claimed in claim 12.

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