Organic light emitting diode and manufacturing method thereof, and display device

Abstract

The present invention relates to an organic light emitting diode, comprising a bottom electrode layer, a top electrode layer and a light emitting layer arranged between the bottom electrode layer and the top electrode layer; the light emitting layer comprises an electron donor layer and a triplet-triplet annihilation layer, the electron donor layer and the triplet-triplet annihilation layer are stacked; an exciplex for emitting yellow light can be formed between the opposite surfaces of the electron donor layer and the triplet-triplet annihilation layer, the triplet-triplet annihilation layer is used to emit blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the exciplex. Exciplexes are accumulated between the electron donor layer of the light emitting layer and the opposite surfaces of the triplet-triplet annihilation layer, and the yellow light generated by the exciplexes complements the blue light generated by the triplet-triplet annihilation layer to form white light. Compared with the conventional technology, the present invention has fewer layers and a simpler process.

Description

Technical Field

[0001] The present invention relates to the field of light emission, and in particular to an organic light emitting diode and a manufacturing method thereof, and a display device. Background Art

[0002] OLED (Organic Light Emitting Diode) is a current-type organic light-emitting device, specifically refers to the phenomenon that organic semiconductor materials and light-emitting materials emit light through carrier injection and recombination under the drive of an electric field. Compared with liquid crystal displays, OLED has the advantages of being lighter, brighter, lower power consumption, faster response, higher clarity, better flexibility, and higher luminous efficiency. Its performance advantages in the display field are very prominent.

[0003] After decades of development, OLED display technology is constantly replacing liquid crystal display technology and gradually becoming the mainstream. At present, in small-size display scenarios, such as mobile phones, pads, etc., OLED has gradually occupied the high-end and mid-end markets; while in the field of medium and large-size displays, such as desktop computers, TVs, etc., OLED still occupies a small share. The main surface reason is that the price is high and the production capacity is insufficient. The deeper reason is that the traditional large-size OLED panel mainly adopts white light OLED and filter structure, in which white light OLED is a stacked red, green and blue structure connected by a charge generation layer in the middle. The structure is complex, the number of layers is large, the process is complex, and the driving voltage is large and the brightness is low. Therefore, simplifying the structure of large-size OLED panels is of great significance to the promotion and application of OLED display technology. Summary of the invention

[0004] Based on this, the present invention aims to provide an organic light emitting diode and a manufacturing method thereof that can replace the complex stacked structure, and provide a display device using the organic light emitting diode.

[0005] The present invention provides an organic light emitting diode, comprising a bottom electrode layer, a top electrode layer and a light emitting layer arranged between the bottom electrode layer and the top electrode layer; the light emitting layer comprises an electron donor layer and a triplet-triplet annihilation layer, and the electron donor layer and the triplet-triplet annihilation layer are stacked; an exciplex for emitting yellow light can be formed between opposite surfaces of the electron donor layer and the triplet-triplet annihilation layer, the triplet-triplet annihilation layer is used to emit blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the exciplex.

[0006] In one embodiment, the energy difference between the HOMO energy level of the electron donor material in the electron donor layer and the LUMO energy level of the material of the triplet-triplet annihilation layer is 2.2 eV to 2.4 eV.

[0007] In one of the embodiments, the wavelength of light emitted by the triplet-triplet annihilation layer is 460 nm to 475 nm, and the organic light emitting diode is an organic light emitting diode that emits white light.

[0008] In one embodiment, the thickness of the electron donor layer is 10 nm to 50 nm, and the thickness of the triplet-triplet annihilation layer is 10 nm to 30 nm.

[0009] In one embodiment, the light-emitting layer further includes an interface layer disposed between the electron donor layer and the triplet-triplet annihilation layer.

[0010] In one embodiment, the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the material of the interface layer and less than the T1 energy level of the excited complex, and the S1 energy level of the material of the interface layer is greater than the S1 energy level of the material of the triplet-triplet annihilation layer.

[0011] In one embodiment, the thickness of the electron donor layer is 10 nm to 50 nm, the thickness of the interface layer is 3 nm to 5 nm, and the thickness of the triplet-triplet annihilation layer is 10 nm to 20 nm.

[0012] In one embodiment, the electron donor layer is a mixed material layer formed by mixing an electron donor material with a material of a triplet-triplet annihilation layer.

[0013] In one embodiment, the molar ratio of the electron donor material in the mixed material layer to the material of the triplet-triplet annihilation layer is 9:1 to 6:4.

[0014] In one embodiment, the invention further comprises at least one of a hole transport layer, a hole injection layer, an electron transport layer and an electron injection layer located between the light-emitting layer and the corresponding electrode layer.

[0015] The present invention also provides a method for manufacturing an organic light emitting diode, comprising the following steps:

[0016] A bottom electrode layer, a light-emitting layer and a top electrode layer stacked in the thickness direction are sequentially formed on a substrate, the light-emitting layer comprises an electron donor layer and a triplet-triplet annihilation layer, the electron donor layer and the triplet-triplet annihilation layer are stacked; an excited radical complex for emitting yellow light can be formed between opposite surfaces of the electron donor layer and the triplet-triplet annihilation layer, the triplet-triplet annihilation layer is used to emit blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the excited radical complex.

[0017] The present invention further provides a display device, comprising a filter and an organic light emitting diode as described in any one of the above embodiments, wherein the filter is located on the light emitting side of the organic light emitting diode.

[0018] The organic light-emitting diode has a light-emitting layer composed of an electron donor layer and a triplet-triplet annihilation layer disposed between the bottom electrode layer and the top electrode layer. Electrons and holes injected from the electrode layers at both ends, after transmission, will accumulate between the electron donor layer and the opposite surface of the triplet-triplet annihilation layer of the light-emitting layer to form excitons of exciplexes, wherein a part of the excitons undergo radiative recombination to generate yellow light, and the other part of the excitons, because the T1 energy level (first excited triplet energy level) of the material of the triplet-triplet annihilation layer is smaller than the T1 energy level of the exciplexes, will be transferred to the triplet-triplet annihilation layer, and a process of triplet fusion to generate singlets will occur in the triplet-triplet annihilation layer, generating singlet excitons and radiative recombination to generate blue light, and the yellow light generated by the exciplexes and the blue light generated by the triplet-triplet annihilation layer complement each other to form white light. Compared with the organic light emitting diode structure in which R / G / B sub-light emitting units are stacked and connected in the conventional technology, the organic light emitting diode has fewer layers and a simpler manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 4 is a schematic structural diagram of a white organic light emitting diode according to an embodiment of the present invention.

[0020] Figure 2 FIG. 4 is a schematic diagram of the structure of a light-emitting layer according to an embodiment of the present invention.

[0021] Figure 3 FIG. 4 is a schematic diagram of the structure of a light-emitting layer according to another embodiment.

[0022] Reference numerals:

[0023] 10: organic light emitting diode; 11: substrate 12: bottom electrode layer; 13: top electrode layer; 14: light emitting layer; 141: electron donor layer; 142: triplet-triplet annihilation layer; 143: interface layer; 15: hole transport layer; 16: hole injection layer; 17: electron transport layer. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] like Figure 1 As shown, an embodiment of the present invention provides an organic light emitting diode 10 , including a bottom electrode layer 12 and a top electrode layer 13 disposed on a substrate 11 , and a light emitting layer 14 disposed between the bottom electrode layer 12 and the top electrode layer 13 .

[0027] like Figure 2 As shown, the light-emitting layer 14 includes an electron donor layer 141 and a triplet-triplet annihilation layer 142, and the electron donor layer 141 and the triplet-triplet annihilation layer 142 are stacked. After electrons and holes are transmitted through the electron donor layer 141 and the triplet-triplet annihilation layer 142, an exciplex for emitting yellow light can be formed between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142, and the triplet-triplet annihilation layer 142 is used to emit blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer 142 is less than the T1 energy level of the exciplex.

[0028] In a specific example, the energy difference between the HOMO energy level of the electron donor material in the electron donor layer 141 and the LUMO energy level of the material of the triplet-triplet annihilation layer 142 is 2.2 eV to 2.4 eV. Within this range, it is possible to effectively promote the rapid and stable transmission of electrons and holes between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142, and within this energy level difference range, the exciplex can emit yellow light.

[0029] In a specific example, the wavelength of the light emitted by the exciplex is 540nm to 580nm. Within this wavelength range, the exciplex can emit yellow light. The wavelength of the light emitted by the triplet-triplet annihilation layer 142 is 460nm to 475nm. Within this wavelength range, the triplet-triplet annihilation layer 142 can emit blue light. The blue light emitted by the triplet-triplet annihilation layer 142 complements the yellow light emitted by the exciplex, so that the organic light emitting diode 10 emits white light, and the emission wavelength of the white light is 410nm to 670nm.

[0030] In the light-emitting layer 14 in the above embodiment, the excitons of the exciton complex accumulated between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142, a part of the excitons undergo radiative recombination to generate yellow light, and the other part of the excitons are transferred to the triplet-triplet annihilation layer 142 because the T1 energy level of the material of the triplet-triplet annihilation layer 142 is smaller than the T1 energy level of the exciton complex. In the triplet-triplet annihilation layer 142, triplet fusion occurs to generate singlet states, singlet excitons are generated, and radiative recombination is performed to generate blue light. The yellow light generated by the exciton complex and the blue light generated by the triplet-triplet annihilation layer 142 complement each other to form white light.

[0031] Alternatively, the material of the electron donor layer 141 may be, but is not limited to, m-MTDATA (4,4',4"-Tris[(3-methylphenyl)phenylamino]triphenylamine, HOMO=5.1 eV, LUMO=2.0 eV).

[0032] Optionally, the material of the triplet-triplet annihilation layer 142 may be, but is not limited to, PhPC (9-(4-(10-phenylanthracene-9-yl)phenyl)-9H-carbazole, HOMO=5.8 eV,

[0033] One or a mixture of the following: LUMO=2.7eV, T1=1.7eV, S1=2.85eV) and MADN (2-methyl-9,10-bis(naphthalen-2-yl)anthracene, HOMO=5.9eV, LUMO=2.9eV, T1=1.8eV, S1=2.9eV).

[0034] The total cavity length of the organic light emitting diode 10 has an important influence on the light emitting effect of the light emitting device. The thickness of a single functional layer in the light emitting layer 14 has little effect on the light emitting efficiency, but it will affect the total cavity length of the light emitting device. In a specific example, the thickness of the electron donor layer 141 is 10nm to 50nm, and the thickness of the triplet-triplet annihilation layer 142 is 10nm to 30nm. Specifically, the thickness of the electron donor layer 141 can be, but not limited to, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc., and the thickness of the triplet-triplet annihilation layer 142 can be, but not limited to, 10nm, 15nm, 20nm, 25nm, 30nm, etc.

[0035] Furthermore, the present invention has found that although white light can be generated by providing the light-emitting layer 14 composed of the electron donor layer 141 and the triplet-triplet annihilation layer 142, the energy of the blue light excitons generated by the triplet-triplet annihilation layer 142 will be reversely transferred to the yellow light excitons of the exciplex, thus causing the yellow light component in the light emission spectrum of the organic light-emitting diode 10 to be too high and the blue light component to be insufficient. In order to solve this problem, as Figure 3 As shown, in another embodiment of the present invention, an interface layer 143 is further provided between the electron donor layer 141 and the triplet-triplet annihilation layer 142 of the light-emitting layer 14. The interface layer 143 does not hinder the accumulation of excitons of the exciplex between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142, nor does it hinder the transfer of the excitons of the exciplex to the triplet-triplet annihilation layer 142, but can block the reverse transfer of the excitons of the triplet-triplet annihilation layer 142 to the exciplex, thereby facilitating the improvement of the blue light component of the light-emitting layer 14.

[0036] In a specific example, the T1 energy level of the material of the triplet-triplet annihilation layer 142 is less than the T1 energy level of the material of the interface layer 143 and less than the T1 energy level of the exciplex, and the S1 energy level of the material of the interface layer 143 is greater than the S1 energy level of the material of the triplet-triplet annihilation layer 142. Therefore, the triplet excitons of the exciplex can be transferred to the triplet-triplet annihilation layer 142 without hindrance, and at the same time, the singlet excitons of the triplet-triplet annihilation layer 142 are blocked and restricted by the interface layer 143, thereby avoiding the transfer of blue light exciton energy to yellow light exciton, which is beneficial to increase the blue light component of the light-emitting layer 14.

[0037] Optionally, the material of the interface layer 143 may be, but is not limited to, 4PPIAN (9,10-bis(2,5-dimethyl-5'-phenyl-[1,1':3'1"-terphenyl]-4-yl)anthracene, HOMO=5.9 eV, LUMO=2.8 eV, T1=1.84 eV, S1=3 eV).

[0038] In a specific example, the thickness of the electron donor layer 141 is 10 nm to 50 nm, the thickness of the interface layer 143 is 3 nm to 5 nm, and the thickness of the triplet-triplet annihilation layer 142 is 10 nm to 20 nm. Therefore, specifically, the thickness of the electron donor layer 141 may be, but not limited to, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc., the thickness of the interface layer 143 may be, but not limited to, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, etc., and the thickness of the triplet-triplet annihilation layer 142 may be, but not limited to, 10 nm, 13 nm, 15 nm, 18 nm, 20 nm, etc. Since the total cavity length of the organic light-emitting diode 10 has an important influence on the light-emitting effect of the light-emitting device, although the thickness of the specific electron donor layer 141, the interface layer 143, the triplet-triplet annihilation layer 142 and other single functional layers in the light-emitting layer has little effect on the light-emitting efficiency, it will affect the total cavity length of the light-emitting device.

[0039] Since the thickness of the interface layer 143 is small, the holes and electrons injected from the electrode layers at both ends can still accumulate between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142 to form an exciplex, generate yellow light, and a portion of the energy of the excitons of the exciplex is transferred to the triplet-triplet annihilation layer 142, so that the triplet-triplet annihilation layer 142 generates blue light. The presence of the interface layer 143 will not affect the transmission of electrons and holes, nor will the presence of the interface layer 143 affect the transmission of the energy of the excitons of the exciplex to the triplet-triplet annihilation layer 142.

[0040] Furthermore, the present invention also found that although the above invention can produce an organic light-emitting diode that can emit white light, the organic light-emitting diode 10 still has the defects of efficiency roll-off and insufficient brightness. In order to overcome this technical defect, in another embodiment of the present invention, the electron donor layer 141 is configured to be a mixed material layer formed by mixing the electron donor material with the material of the triplet-triplet annihilation layer 142. The method of using a mixed material layer can widen the exciton recombination zone, and can widen the interface between the electron donor layer 141 and the triplet-triplet annihilation layer 142 that form the exciton complex, which helps to reduce the efficiency roll-off of the organic light-emitting diode 10 and improve the brightness of the organic light-emitting diode 10.

[0041] Specifically, the molar ratio of the electron donor material in the mixed material layer to the material of the triplet-triplet annihilation layer 142 is 9:1 to 6:4. Within this range, the organic light emitting diode 10 can emit white light, and the luminance can be increased and the efficiency roll-off can be reduced.

[0042] like Figure 1The organic light emitting diode 10 shown may further include at least one of a hole transport layer 15, a hole injection layer 16, an electron transport layer 17, and an electron injection layer located between the light emitting layer 14 and the corresponding electrode layer. For example, the hole transport layer 15 may be provided between the bottom electrode layer 12 and the light emitting layer 14 in the above example, and the electron transport layer 17 may be provided between the top electrode layer 13 and the light emitting layer 14. The hole injection layer 16 may also be provided between the bottom electrode layer 12 and the hole transport layer 15. It is understandable that an electron injection layer may also be provided between the top electrode layer 13 and the electron transport layer 17.

[0043] The present invention also provides a method for manufacturing an organic light emitting diode 10, comprising the following steps:

[0044] A bottom electrode layer 12, a light-emitting layer 14 and a top electrode layer 13 which are stacked in the thickness direction are sequentially formed on a substrate 11, the light-emitting layer 14 comprises an electron donor layer 141 and a triplet-triplet annihilation layer 142, the electron donor layer 141 and the triplet-triplet annihilation layer 142 are stacked; an excited radical complex for emitting yellow light can be formed between opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142, the triplet-triplet annihilation layer 142 is used for emitting blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer 142 is less than the T1 energy level of the excited radical complex.

[0045] In a specific example, the energy level difference between the HOMO energy level of the electron donor material in the electron donor layer 141 and the LUMO energy level of the material of the triplet-triplet annihilation layer 142 is 2.2 eV to 2.4 eV.

[0046] In a specific example, the wavelength of the light emitted by the triplet-triplet annihilation layer 142 is 460 nm to 475 nm.

[0047] The organic light emitting diode 10 prepared by the above method has a light emitting layer composed of light emitting from the exciplex and light emitting from the triplet-triplet annihilation layer 142 , wherein the exciplex emits yellow light and the triplet-triplet annihilation layer 142 emits blue light, which complement each other to form white light.

[0048] Furthermore, in order to improve the problem that the yellow light component is too high and the blue light component is insufficient in the light emission spectrum of the organic light emitting diode 10 prepared by the method of the above specific example, an interface layer 143 can be provided between the electron donor layer 141 and the triplet-triplet annihilation layer 142. The interface layer 143 is very thin, and can still form an exciplex to generate yellow light, and can also cause a triplet-triplet annihilation process, so that the triplet-triplet annihilation layer 142 generates blue light, and can make the blue light substantially without loss.

[0049] Furthermore, on the basis of preparing the organic light-emitting diode 10 according to the above specific example method, the electron donor layer 141 can be further optimized to be a mixed material layer formed by mixing the electron donor material with the material of the triplet-triplet annihilation layer 142. The mixed material layer can widen the exciton recombination zone, which is beneficial to reducing the efficiency roll-off of the device and improving the brightness.

[0050] The organic light emitting diode 10 in any of the above specific examples can be used in various light emitting display devices. For example, the present invention also provides a display device, including a filter and the organic light emitting diode 10 in the above example, wherein the filter is located on the light emitting side of the organic light emitting diode 10. Compared with the organic light emitting diode structure connected by stacking R / G / B sub-light emitting units in the conventional technology, the organic light emitting diode 10 has fewer layers and a simpler manufacturing process.

[0051] The following are specific embodiments.

[0052] Example 1

[0053] (1) Using transparent conductive film ITO as the bottom electrode layer with a thickness of 50nm;

[0054] (2) MoO3 was deposited on ITO by evaporation method as a hole injection layer with a thickness of 10 nm;

[0055] (3) m-MTDATA was deposited on the hole injection layer by evaporation method as a hole transport layer with a thickness of 40 nm;

[0056] (4) m-MTDATA was deposited on the hole transport layer by evaporation as an electron donor layer with a thickness of 15 nm;

[0057] (5) depositing MADN:BCzVBi (3%) as a triplet-triplet annihilation layer on the electron donor layer by evaporation method with a thickness of 15 nm, wherein MADN is a triplet-triplet annihilation material and BCzVBi is a fluorescent guest;

[0058] (6) depositing TPBi:Liq as an electron transport layer on the triplet-triplet annihilation layer by evaporation with a thickness of 30 nm;

[0059] (7) Al was deposited on the electron transport layer by evaporation as a top electrode layer with a thickness of 100 nm.

[0060] Embodiment 2:

[0061] (1) Using transparent conductive film ITO as the bottom electrode layer with a thickness of 50nm;

[0062] (2) MoO3 was deposited on ITO by evaporation method as a hole injection layer with a thickness of 10 nm;

[0063] (3) m-MTDATA was deposited on the hole injection layer by evaporation method as a hole transport layer with a thickness of 40 nm;

[0064] (4) m-MTDATA was deposited on the hole transport layer by evaporation as an electron donor layer with a thickness of 15 nm;

[0065] (5) 4PPIAN was deposited on the electron donor layer by evaporation as an interface layer with a thickness of 3 nm;

[0066] (6) depositing MADN:BCzVBi (3%) as a triplet-triplet annihilation layer on the interface layer by evaporation method with a thickness of 15 nm, wherein MADN is a triplet-triplet annihilation material and BCzVBi is a fluorescent guest;

[0067] (7) depositing TPBi:Liq as an electron transport layer on the triplet-triplet annihilation layer by evaporation with a thickness of 30 nm;

[0068] (8) Al was deposited on the electron transport layer by evaporation as a top electrode layer with a thickness of 100 nm.

[0069] Embodiment 3:

[0070] (1) Using transparent conductive film ITO as the bottom electrode layer with a thickness of 50nm;

[0071] (2) MoO3 was deposited on ITO by evaporation method as a hole injection layer with a thickness of 10 nm;

[0072] (3) m-MTDATA was deposited on the hole injection layer by evaporation method as a hole transport layer with a thickness of 35 nm;

[0073] (4) depositing m-MTDATA:MADN (molar ratio of 7:3) as a mixed layer on the hole transport layer by evaporation with a thickness of 20 nm;

[0074] (5) 4PPIAN was deposited on the mixed layer by evaporation as an interface layer with a thickness of 3 nm;

[0075] (6) depositing MADN:BCzVBi (3%) as a triplet-triplet annihilation layer on the interface layer by evaporation method with a thickness of 15 nm, wherein MADN is a triplet-triplet annihilation material and BCzVBi is a fluorescent guest;

[0076] (7) depositing TPBi:Liq as an electron transport layer on the triplet-triplet annihilation layer by evaporation with a thickness of 30 nm;

[0077] (8) Al was deposited on the electron transport layer by evaporation as a top electrode layer with a thickness of 100 nm.

[0078] The devices of Examples 1 to 3 were tested by a special IVL test system to obtain performance parameters such as device current, brightness, and color coordinates. The test results are shown in Table 1 below:

[0079] Among them, the color coordinates @1000cd / m 2 : indicates 1000cd / m 2 Color coordinates of the device below; maximum brightness (cd / m 2 ): Indicates the maximum brightness of the device.

[0080] Table 1

[0081] Example <![CDATA[Color coordinates @ 1000 cd / m 2 > <![CDATA[Maximum brightness (cd / m 2 )]]> Example 1 0.36,0.47 17000 Example 2 0.33,0.35 13000 Example 3 0.34,0.37 22000

[0082] As can be seen from Table 1, compared with Example 1, after adding an interface layer between the electron donor layer and the triplet-triplet annihilation layer, the data of the color coordinate x-axis and y-axis are reduced in Example 2, indicating that the blue light component is improved. Compared with Example 2, when the electron donor layer is a mixed material layer formed by mixing the electron donor material and the material of the triplet-triplet annihilation layer 142, the brightness of Example 3 is significantly enhanced.

[0083] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An organic light emitting diode, characterized in that: The invention comprises a bottom electrode layer, a top electrode layer and a light-emitting layer arranged between the bottom electrode layer and the top electrode layer; the light-emitting layer comprises an electron donor layer and a triplet-triplet annihilation layer, and the electron donor layer and the triplet-triplet annihilation layer are stacked; an exciplex for emitting yellow light can be formed between opposite surfaces of the electron donor layer and the triplet-triplet annihilation layer, the triplet-triplet annihilation layer is used to emit blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the exciplex; The light-emitting layer further comprises an interface layer disposed between the electron donor layer and the triplet-triplet annihilation layer; the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the material of the interface layer and less than the T1 energy level of the exciplex, and the S1 energy level of the material of the interface layer is greater than the S1 energy level of the material of the triplet-triplet annihilation layer; The electron donor layer is a mixed material layer formed by mixing the electron donor material with the material of the triplet-triplet annihilation layer.

2. The organic light emitting diode according to claim 1, characterized in that: The energy level difference between the HOMO energy level of the electron donor material in the electron donor layer and the LUMO energy level of the material of the triplet-triplet annihilation layer is 2.2 eV to 2.4 eV.

3. The organic light emitting diode according to claim 1, characterized in that: The wavelength of light emitted by the triplet-triplet annihilation layer is 460nm-475nm, and the organic light emitting diode is an organic light emitting diode that emits white light.

4. The organic light emitting diode according to claim 1, characterized in that: The thickness of the electron donor layer is 10 nm to 50 nm, and the thickness of the triplet-triplet annihilation layer is 10 nm to 30 nm.

5. The organic light emitting diode according to claim 1, characterized in that: The thickness of the electron donor layer is 10 nm to 50 nm, the thickness of the interface layer is 3 nm to 5 nm, and the thickness of the triplet-triplet annihilation layer is 10 nm to 20 nm.

6. The organic light emitting diode according to claim 1, characterized in that: The molar ratio of the electron donor material in the mixed material layer to the material of the triplet-triplet annihilation layer is 9:1 to 6:

4.

7. The organic light emitting diode according to any one of claims 1 to 6, characterized in that: The invention also includes at least one of a hole transport layer, a hole injection layer, an electron transport layer and an electron injection layer located between the light-emitting layer and the corresponding electrode layer.

8. A method for manufacturing an organic light emitting diode, characterized in that: The steps include: A bottom electrode layer, a light-emitting layer and a top electrode layer stacked in the thickness direction are sequentially formed on a substrate, wherein the light-emitting layer comprises an electron donor layer and a triplet-triplet annihilation layer, and the electron donor layer and the triplet-triplet annihilation layer are stacked; an exciplex for emitting yellow light can be formed between opposite surfaces of the electron donor layer and the triplet-triplet annihilation layer, the triplet-triplet annihilation layer is used to emit blue light, and the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the exciplex; The light-emitting layer further comprises an interface layer disposed between the electron donor layer and the triplet-triplet annihilation layer; the T1 energy level of the material of the triplet-triplet annihilation layer is less than the T1 energy level of the material of the interface layer and less than the T1 energy level of the exciplex, and the S1 energy level of the material of the interface layer is greater than the S1 energy level of the material of the triplet-triplet annihilation layer; The electron donor layer is a mixed material layer formed by mixing the electron donor material with the material of the triplet-triplet annihilation layer.

9. A display device, characterized in that: The invention comprises a filter and an organic light emitting diode as claimed in any one of claims 1 to 7, wherein the filter is located at a light emitting side of the organic light emitting diode.

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