CN115377306A - Organic light emitting diode, manufacturing method thereof and display device - Google Patents

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 includes an electron donor layer and a triplet-state- The triplet annihilation layer, the electron donor layer and the triplet-triplet annihilation layer are stacked; between the electron donor layer and the opposite surface of the triplet-triplet annihilation layer can be formed For an exciplex that emits yellow light, 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 _of the exciplex energy level. An exciplex is accumulated between the electron donor layer of the light-emitting layer and the opposite face of the triplet-triplet annihilation layer, and the yellow light generated by the exciplex is complementary to the blue light generated by the triplet-triplet annihilation layer. For white light, compared with the traditional technology, the invention has fewer layers and simpler manufacturing process.

Description

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

technical field

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

Background technique

OLED (Organic Light Emitting Diode) is a current-type organic light-emitting device, specifically referring to the phenomenon that organic semiconductor materials and light-emitting materials are driven by an electric field to achieve light emission through carrier injection and recombination. Compared with liquid crystal display, OLED has the advantages of thinner and thinner, high brightness, low power consumption, fast response, high definition, good flexibility, and high luminous efficiency, and its performance advantages in the display field are very prominent.

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 and pads, OLED has gradually occupied the high-end and mid-range markets; while in medium and large-size display fields, such as desktop computers and TVs, OLED still occupies a small share. The superficial reason is that the price is high and the production capacity is insufficient, and the deeper reason is that the traditional large-size OLED panel mainly uses a white light OLED and a filter structure. The white light OLED is a stacked red, green and blue structure. The charge generating layers are connected, the structure is complex, the number of layers is large, the manufacturing 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 popularization and application of OLED display technology.

Contents of the invention

Based on this, the present invention aims to provide an organic light-emitting diode that can replace the complex stacked structure and its manufacturing method, as well as a display device using the organic light-emitting diode.

The present invention provides an organic light-emitting diode, comprising a bottom electrode layer, a top electrode layer, and a light-emitting layer disposed between the bottom electrode layer and the top electrode layer; the light-emitting layer includes an electron donor layer and a triplet- The triplet annihilation layer, the electron donor layer and the triplet-triplet annihilation layer are stacked; between the electron donor layer and the opposite surface of the triplet-triplet annihilation layer can be formed For an exciplex emitting yellow light, 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 of the exciplex energy level.

In one embodiment, 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 triplet-triplet annihilation layer material is 2.2eV-2.4eV.

In one embodiment, the emission wavelength of the triplet-triplet annihilation layer is 460nm-475nm, and the organic light emitting diode is an organic light emitting diode emitting white light.

In one embodiment, the electron donor layer has a thickness of 10 nm to 50 nm, and the triplet-triplet annihilation layer has a thickness of 10 nm to 30 nm.

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

In one of the embodiments, the T ₁ energy level of the material of the triplet-triplet annihilation layer < the T ₁ energy level of the material of the interface layer < the T ₁ energy level of the exciplex, and the The S ₁ energy level of the material of the interface layer > the S ₁ energy level of the material of the triplet-triplet annihilation layer.

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

In one embodiment, 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.

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˜6:4.

In one embodiment, it further 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.

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

A bottom electrode layer, a light-emitting layer, and a top electrode layer are sequentially formed on the substrate in the thickness direction, the light-emitting layer includes an electron donor layer and a triplet-triplet annihilation layer, the electron donor layer and the A triplet-triplet annihilation layer is stacked; an exciplex for yellow light emission can be formed between the electron donor layer and the opposite faces of the triplet-triplet annihilation layer, the triplet - The triplet annihilation layer is used to emit blue light, the T ₁ energy level of the material of the triplet-triplet annihilation layer is < the T ₁ energy level of the exciplex.

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

In the above organic light emitting diode, a light emitting layer composed of an electron donor layer and a triplet-triplet annihilation layer is arranged between the bottom electrode layer and the top electrode layer. The electrons and holes injected from the electrode layers at both ends, after being transported, will accumulate between the electron donor layer of the light-emitting layer and the opposite surface of the triplet-triplet annihilation layer to form exciplex excitons, wherein A part of the excitons undergo radiative recombination to produce yellow light, and the other part of the excitons, because the T ₁ energy level (the first excited triplet state energy level) of the material of the triplet-triplet annihilation layer is higher than the T ₁ energy level of the exciplex Small, so it will be transferred to the triplet-triplet annihilation layer. In the triplet-triplet annihilation layer, the process of triplet fusion to generate a singlet state occurs, and singlet excitons are generated and radiatively recombined to produce blue light. Exciplexes produce The yellow light and the blue light produced by the triplet-triplet annihilation layer complement each other to form white light. Compared with the organic light emitting diode structure connected by R/G/B sub-light-emitting units in the conventional technology, the above-mentioned organic light-emitting diode has fewer layers and a simpler manufacturing process.

Description of drawings

FIG. 1 is a schematic structural diagram of a white organic light emitting diode according to an embodiment.

FIG. 2 is a schematic diagram of the structure of a light-emitting layer according to an embodiment.

FIG. 3 is a schematic diagram of the structure of the light-emitting layer in another embodiment.

Reference signs:

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 ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As shown in FIG. 1 , an embodiment of the present invention provides an organic light emitting diode 10, including a bottom electrode layer 12, a top electrode layer 13 arranged on a substrate 11, and an organic light emitting diode layer 13 arranged between the bottom electrode layer 12 and the top electrode layer 13. The luminescent layer 14.

As shown in FIG. 2 , 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 the electrons and holes are transported through the electron donor layer 141 and the triplet-triplet annihilation layer 142, a layer for emitting yellow light can be formed between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142. The triplet-triplet annihilation layer 142 is used to emit blue light, and the T ₁ energy level of the material of the triplet-triplet annihilation layer 142 is less than the T ₁ energy level of the exciplex.

In a specific example, the energy range 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˜2.4 eV. Within this range, the fast and stable transport of electrons and holes to the opposite faces of the electron donor layer 141 and the triplet-triplet annihilation layer 142 can be effectively promoted, and the excimer recombination can be made within this energy level difference range. The object glows yellow.

In a specific example, the wavelength of the light emitted by the exciplex is 540nm-580nm. In this wavelength range, exciplexes are capable of emitting yellow light. The wavelength of light emitted by the triplet-triplet annihilation layer 142 is 460 nm to 475 nm. In this wavelength range, the triplet-triplet annihilation layer 142 can emit blue light. The blue light emitted by the triplet-triplet annihilation layer 142 is complementary to 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-670nm.

In the light-emitting layer 14 in the above-mentioned embodiment, the excitons of the exciton complex formed by accumulating between the opposite surfaces of the electron donor layer 141 and the triplet-triplet annihilation layer 142, some of the excitons undergo radiative recombination to generate yellow light , another part of excitons, because the T ₁ energy level of the material of the triplet-triplet annihilation layer 142 is smaller than the T ₁ energy level of the exciplex, so it will be transferred to the triplet-triplet annihilation layer 142, in the triplet In the state-triplet annihilation layer 142, the process of triplet fusion to generate a singlet state occurs, and singlet excitons are generated and radiatively recombined to generate blue light, and the yellow light generated by the exciplex is complementary to the blue light generated by the triplet-triplet annihilation layer 142 constitute white light.

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

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

LUMO=2.7eV, T ₁ =1.7eV, S ₁ =2.85eV) and MADN (2-methyl-9,10-bis(naphthalen-2-yl) anthracene, HOMO=5.9eV, LUMO=2.9eV, T ₁ =1.8eV, S ₁ =2.9eV) or a combination of several.

The total cavity length of the organic light-emitting diode 10 has an important influence on the luminous effect of the light-emitting device. The thickness of a single functional layer in the light-emitting layer 14 has little effect on the luminous efficiency, but it will affect the total cavity length of the light-emitting device. In a specific example, the electron donor layer 141 has a thickness of 10 nm˜50 nm, and the triplet-triplet annihilation layer 142 has a thickness of 10 nm˜30 nm. 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.

Further, the present invention finds that although white light can be generated by setting the light-emitting layer 14 composed of the electron donor layer 141 and the triplet-triplet annihilation layer 142, the blue light excitons generated by the triplet-triplet annihilation layer 142 The energy will be reversely transferred to the yellow light excitons of the exciplex, therefore, the yellow light component in the emission spectrum of the organic light emitting diode 10 will be too high and the blue light component will be insufficient. In order to solve this problem, as shown in FIG. 3 , in another embodiment of the present invention, an interface layer 143 is provided between the electron donor layer 141 and the triplet-triplet annihilation layer 142 of the light emitting layer 14 . The interfacial layer 143 does not hinder the accumulation of exciton excitons between the electron donor layer 141 and the opposing faces of the triplet-triplet annihilation layer 142, nor does it impede the exciton exciton transition to the triplet- The triplet annihilation layer 142 transmits, but can block the triplet-triplet annihilation layer 142 excitons reversely transfer to the exciplex, so as to improve the blue light component of the light emitting layer 14 .

In a specific example, the _T1 energy level of the material of the triplet-triplet annihilation layer 142 < the T1 energy level of the material of the interface layer ₁₄₃ < the _T1 energy level of the exciplex, and the material of the interface layer 143 The S ₁ energy level of > the S ₁ energy level of the material of the triplet-triplet annihilation layer 142 . Therefore, the triplet excitons of the exciplex can be transmitted to the triplet-triplet annihilation layer 142 unhindered, and at the same time, the singlet excitons of the triplet-triplet annihilation layer 142 are restricted by the interface layer 143 , avoiding the energy transfer of the blue light excitons to the yellow light excitons, which is beneficial to increase the blue light component of the light emitting layer 14 .

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

In a specific example, the electron donor layer 141 has a thickness of 10 nm-50 nm, the interface layer 143 has a thickness of 3 nm-5 nm, and the triplet-triplet annihilation layer 142 has a thickness of 10 nm-20 nm. Therefore, 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 interface layer 143 can be, but not limited to, 3nm, 3.5nm , 4nm, 4.5nm, 5nm, etc. The thickness of the triplet-triplet annihilation layer 142 can be, but not limited to, 10nm, 13nm, 15nm, 18nm, 20nm, etc. Since the total cavity length of the organic light-emitting diode 10 has an important influence on the luminous effect of the light-emitting device, although the thickness of the single functional layers such as the electron donor layer 141, the interface layer 143, and the triplet-triplet annihilation layer 142 in the light-emitting layer It has little effect on the luminous efficiency, but it will affect the total cavity length of the light emitting device.

Due to the small thickness of the interface layer 143, the holes and electrons injected from the electrode layers at both ends can still accumulate between the opposite faces of the electron donor layer 141 and the triplet-triplet annihilation layer 142 to form exciplexes, Yellow light is generated, and a part of the energy of the exciplex excitons is transferred to the triplet-triplet annihilation layer 142, so that the triplet-triplet annihilation layer 142 generates blue light. The existence of the interface layer 143 does not affect the transport of electrons and holes, nor does the existence of the interface layer 143 affect the transport of exciton energy of the exciplex to the triplet-triplet annihilation layer 142 .

Furthermore, the present invention also finds that although the above invention can produce an organic light emitting diode that emits 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 set as a mixed material layer formed by mixing the electron donor material and the material of the triplet-triplet annihilation layer 142 . The method of adopting the mixed material layer can widen the exciton recombination region, can widen the interface between the electron donor layer 141 forming the exciplex and the triplet-triplet annihilation layer 142, and help reduce the organic light emitting diode 10. Efficiency roll-off improves the brightness of the OLED 10 .

Specifically, the molar ratio of the electron donor material to the material of the triplet-triplet annihilation layer 142 in the mixed material layer is 9:1˜6:4. Within this range, not only can the organic light emitting diode 10 emit white light, but also the luminous brightness can be improved, and the efficiency roll-off can be reduced.

The organic light emitting diode 10 shown in FIG. 1 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 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 examples, and the electron transport layer 17 may be provided between the top electrode layer 13 and the light emitting layer 14 . A hole injection layer 16 may also be provided between the bottom electrode layer 12 and the hole transport layer 15 . Understandably, an electron injection layer may also be provided between the top electrode layer 13 and the electron transport layer 17 .

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

A bottom electrode layer 12, a light-emitting layer 14, and a top electrode layer 13 are sequentially formed on the substrate 11 in the thickness direction. The light-emitting layer 14 includes 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; between the electron donor layer 141 and the opposite surface of the triplet-triplet annihilation layer 142, an exciplex for yellow light emission can be formed, and the triplet- The triplet annihilation layer 142 is used to emit blue light, and the T ₁ energy level of the material of the triplet-triplet annihilation layer 142 is smaller than the T ₁ energy level of the exciplex.

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˜2.4 eV.

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

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

Further, in order to improve the problem that the yellow light component is too high and the blue light component is insufficient in the luminescence spectrum of the organic light emitting diode 10 prepared by the above-mentioned specific example method, the electron donor layer 141 and the triplet-triplet annihilation layer 142 can also be An interface layer 143 is provided therebetween. The interface layer 143 is very thin, can still form exciplexes to generate yellow light, and can also undergo a triplet-triplet annihilation process, so that the triplet-triplet annihilation layer 142 can generate blue light without loss of blue light.

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 formed by mixing the electron donor material and the material of the triplet-triplet annihilation layer 142 Mixed material layers. The mixed material layer can widen the exciton recombination region, which is beneficial to reduce the efficiency roll-off of the device and improve the brightness.

The organic light emitting diode 10 in any of the above specific examples can be used in various types of 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 examples. The light-emitting side of the diode 10. Compared with the organic light emitting diode structure in the conventional technology in which R/G/B sub-light-emitting units are stacked and connected, the above-mentioned organic light-emitting diode 10 has fewer layers and a simpler manufacturing process.

The following are specific examples.

Example 1

(1) Use the transparent conductive film ITO as the bottom electrode layer with a thickness of 50nm;

(2) Deposit MoO ₃ as a hole injection layer on the ITO by evaporation method, with a thickness of 10nm;

(3) m-MTDATA is deposited as a hole transport layer by vapor deposition on the hole injection layer, with a thickness of 40nm;

(4) m-MTDATA is deposited as an electron donor layer by vapor deposition on the hole transport layer, with a thickness of 15nm;

(5) Deposit MADN:BCzVBi (3%) on the electron donor layer as a triplet-triplet annihilation layer with a thickness of 15nm, wherein MADN is a triplet-triplet annihilation material, and BCzVBi is a fluorescent object;

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

(7) Depositing Al as a top electrode layer on the electron transport layer by evaporation method, with a thickness of 100 nm.

Example 2:

(1) Use the transparent conductive film ITO as the bottom electrode layer with a thickness of 50nm;

(2) Deposit MoO ₃ as a hole injection layer on the ITO by evaporation method, with a thickness of 10nm;

(3) m-MTDATA is deposited as a hole transport layer by vapor deposition on the hole injection layer, with a thickness of 40nm;

(4) m-MTDATA is deposited as an electron donor layer by vapor deposition on the hole transport layer, with a thickness of 15nm;

(5) Depositing 4PPIAN as an interface layer by vapor deposition on the electron donor layer, with a thickness of 3nm;

(6) Deposit MADN:BCzVBi (3%) on the interface layer as a triplet-triplet annihilation layer with a thickness of 15nm, wherein MADN is a triplet-triplet annihilation material, and BCzVBi is a fluorescent object;

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

(8) Depositing Al as a top electrode layer on the electron transport layer by evaporation method, with a thickness of 100 nm.

Example 3:

(1) Use the transparent conductive film ITO as the bottom electrode layer with a thickness of 50nm;

(2) Deposit MoO ₃ as a hole injection layer on the ITO by evaporation method, with a thickness of 10nm;

(3) Depositing m-MTDATA as a hole transport layer by vapor deposition on the hole injection layer, with a thickness of 35nm;

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

(5) Deposit 4PPIAN as an interface layer by evaporation method on the mixed layer, with a thickness of 3nm;

(6) Deposit MADN:BCzVBi (3%) on the interface layer as a triplet-triplet annihilation layer with a thickness of 15nm, wherein MADN is a triplet-triplet annihilation material, and BCzVBi is a fluorescent object;

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

(8) Depositing Al as a top electrode layer on the electron transport layer by evaporation method, with a thickness of 100 nm.

The devices of Embodiment 1 to Embodiment 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 as follows in Table 1:

Among them, color coordinate @1000cd/m ² : indicates the color coordinate of the device at 1000cd/m ² ; maximum brightness (cd/m ² ): indicates the maximum brightness of the device.

Table 1

Example Color coordinates @1000cd/m² Maximum Brightness (cd/m²) Example 1 0.36,0.47 17000 Example 2 0.33,0.35 13000 Example 3 0.34,0.37 22000

It can be seen from Table 1 that, compared with Example 1, in Example 2, after the interface layer is added between the electron donor layer and the triplet-triplet annihilation layer, the data on the x-axis and y-axis of the color coordinates are both reduced, indicating that the blue light component improve. In Example 3, 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 is significantly enhanced.

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

The above examples only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as limiting the scope of the patent for the invention. It should be pointed out that those skilled in the art can make several modifications and improvements 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 for the present invention should be based on the appended claims.

Claims (12)

1. The organic light emitting diode comprises a bottom electrode layer,A top electrode layer and a light emitting layer disposed between the bottom electrode layer and the top electrode layer; the light-emitting layer includes an electron donor layer and a triplet-triplet annihilation layer, the electron donor layer and the triplet-triplet annihilation layer being disposed in a stack; an exciplex for emitting yellow light can be formed between the facing faces of the electron donor layer and the triplet-triplet annihilation layer for emitting blue light, the triplet-triplet annihilation layer being of a material of which T ₁ Energy level < T of the exciplex ₁ Energy level.

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

3. The organic light-emitting diode according to claim 1, wherein the triplet-triplet annihilation layer emits light at a wavelength of 460nm to 475nm, and the organic light-emitting diode is a white light-emitting organic light-emitting diode.

4. The organic light-emitting diode of claim 1, wherein the electron donor layer has a thickness of 10nm to 50nm, and the triplet-triplet annihilation layer has a thickness of 10nm to 30nm.

5. The organic light-emitting diode according to any one of claims 1 to 4, wherein the light-emitting layer further comprises an interface layer disposed between the electron donor layer and the triplet-triplet annihilation layer.

6. The OLED of claim 5, wherein T of the material of the triplet-triplet annihilation layer ₁ Energy level < T of the material of the interface layer ₁ Energy level < T of the exciplex ₁ Energy level, and S of the material of the interface layer ₁ Energy level > S of the material of the triplet-triplet annihilation layer ₁ Energy level.

7. The OLED as claimed in claim 5, wherein the thickness of the electron donor layer is 10nm to 50nm, the thickness of the interface layer is 3nm to 5nm, and the thickness of the triplet-triplet annihilation layer is 10nm to 20nm.

8. The organic light-emitting diode according to any one of claims 1 to 4 and 6 to 7, wherein the electron donor layer is a mixed material layer formed by mixing an electron donor material with a material of the triplet-triplet annihilation layer.

9. The organic light-emitting diode according to claim 8, wherein the molar ratio of the electron donor material to the material of the triplet-triplet annihilation layer in the mixed material layer is from 9 to 6.

10. The organic light-emitting diode according to any one of claims 1 to 4, 6 to 7 and 9, further comprising at least one of a hole transport layer, a hole injection layer, an electron transport layer and an electron injection layer between the light-emitting layer and the corresponding electrode layer.

11. A manufacturing method of an organic light emitting diode is characterized by comprising the following steps:

sequentially forming a bottom electrode layer, a light-emitting layer and a top electrode layer which are stacked in a thickness direction 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 the facing faces of the electron donor layer and the triplet-triplet annihilation layer for emitting blue light, the T of the material of the triplet-triplet annihilation layer ₁ Energy level < T of the exciplex ₁ Energy level.

12. A display device comprising a filter and the organic light emitting diode according to any one of claims 1 to 10, wherein the filter is located on a light emitting side of the organic light emitting diode.

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