Display panel and display device

Abstract

According to the display panel and the display device, the display panel comprises a substrate and a first light-emitting device, the first light-emitting device comprises a first light-emitting layer, the first light-emitting layer is located between an electron generation layer and a hole generation layer, the first light-emitting layer comprises a main material and a first light-emitting material, and the first light-emitting material is doped in the main material; wherein the main material in the first light-emitting layer comprises a first main material and a second main material which are mixed, and the band gap of the first main material is smaller than that of the second main material. According to the invention, the first light-emitting layer comprises two main materials with different band gaps, so that most of carriers are located at the first main material, most of excitons are located at the second main material, the carriers and the excitons are located on different materials, the probability of encountering and annihilating of the excitons and the carriers is further reduced, and the light-emitting efficiency is improved. Therefore, the material degradation effect of exciton annihilation on the first light-emitting layer is reduced, the service life of the first light-emitting layer is prolonged, and the light-emitting efficiency of the first light-emitting device is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display panel and a display device. Background Art

[0002] With the advancement of display technology and the expansion of display panel application areas, the requirements for higher performance of light-emitting devices in display panels are constantly being put forward. Among them, organic light-emitting diodes are a popular display technology today and a display technology with great development prospects. They have the advantages of self-luminescence, ultra-light and thin, wide viewing angle, fast response speed, low power consumption and flexible display. As the application scope of light-emitting devices increases, there are higher requirements for improving the luminous efficiency of light-emitting devices, reducing power consumption, and extending the life of light-emitting devices. Summary of the invention

[0003] In view of this, embodiments of the present application provide a display panel and a display device to solve the above problems.

[0004] In a first aspect, an embodiment of the present application provides a display panel, including a substrate and a first light-emitting device, wherein the first light-emitting device is located on one side of the substrate; the first light-emitting device includes:

[0005] An electron generating layer, the electron generating layer can generate electrons;

[0006] A hole generating layer, wherein the hole generating layer can generate holes;

[0007] A first light-emitting layer, the first light-emitting layer is located between the electron generating layer and the hole generating layer, the first light-emitting layer comprises a main material and a first light-emitting material, and the first light-emitting material is doped in the main material;

[0008] The main material in the first light-emitting layer includes a mixed first main material and a second main material, and the band gap of the first main material is smaller than the band gap of the second main material.

[0009] In a second aspect, an embodiment of the present application provides a display device, comprising a display panel provided in the first aspect.

[0010] In the embodiment of the present application, the first light-emitting layer is provided with two different main materials, which is conducive to the faster transmission of the excitons generated by the first main material, and the excitons generated by the first main material are transmitted to the first light-emitting material and the second main material respectively, which is conducive to reducing the degree of exciton annihilation at the first main material, improving the utilization rate of the first light-emitting layer for excitons, thereby reducing the power consumption of the first light-emitting device. In addition, the band gap of the first main material is set to be smaller than the band gap of the second main material, which is conducive to making the majority of the carriers in the first light-emitting layer located at the first main material, and the majority of the excitons located at the second main material, and the carriers and excitons are located on different materials respectively, which is conducive to further reducing the probability of excitons and carriers meeting and annihilating, thereby reducing the effect of exciton annihilation on the degradation of materials in the first light-emitting layer, which is conducive to improving the working life of the first light-emitting layer, and is also conducive to increasing the energy of the excitons transmitted to the first light-emitting material, thereby increasing the amount of photons generated by the first light-emitting material, and improving the luminous efficiency of the first light-emitting device, providing conditions for the first light-emitting device to be applied to more fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0012] Figure 1 A schematic diagram of the structure of a display panel provided in an embodiment of the present application;

[0013] Figure 2 A schematic diagram of particle distribution around a main material molecule in a related technology provided in an embodiment of the present application;

[0014] Figure 3 A schematic diagram of particle distribution around a main material molecule provided in an embodiment of the present application;

[0015] Figure 4 A schematic diagram of an exciton transfer path provided in an embodiment of the present application;

[0016] Figure 5 A time-brightness attenuation variation trend diagram corresponding to a first light-emitting device provided in an embodiment of the present application;

[0017] Figure 6 A variation trend diagram of current density-luminous efficiency corresponding to a first light-emitting device provided in an embodiment of the present application;

[0018] Figure 7 A triplet energy level schematic diagram provided for an embodiment of the present application;

[0019] Figure 8 A schematic diagram of the structure of another display panel provided in an embodiment of the present application;

[0020] Fig. 9 A schematic diagram of the chemical formula of a material provided in an embodiment of the present application;

[0021] Fig.10 A schematic diagram of the structure of another display panel provided in an embodiment of the present application;

[0022] Fig.11 A schematic diagram of the structure of another display panel provided in the application embodiment;

[0023] Fig.12 A schematic diagram of the structure of another display panel provided in an embodiment of the present application;

[0024] Fig.13 A schematic diagram of the structure of another display panel provided in an embodiment of the present application;

[0025] Fig.14 A schematic diagram of a display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0027] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0028] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0029] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0030] In the description of this specification, it is necessary to understand that the words such as "substantially", "approximately", "approximately", "about", "roughly", "substantially" and the like described in the claims and embodiments of the present application refer to what can be generally recognized within a reasonable process operation range or tolerance range, rather than an exact value.

[0031] It should be understood that although the terms first, second, etc. may be used to describe the light-emitting device, the light-emitting layer, the main material, etc. in the embodiments of the present application, these should not be limited to these terms. These terms are only used to distinguish the light-emitting device, the light-emitting layer, the main material, etc. from each other. For example, without departing from the scope of the embodiments of the present application, the first light-emitting device may also be referred to as the second light-emitting device, and similarly, the second light-emitting device may also be referred to as the first light-emitting device. The applicant of this case has provided a solution to the problems existing in the prior art through careful and in-depth research.

[0032] Figure 1 A schematic diagram of the structure of a display panel provided in an embodiment of the present application is shown in FIG. Figure 2 A schematic diagram of particle distribution around a main material molecule in a related technology provided in an embodiment of the present application, Figure 3 A schematic diagram of particle distribution around a main material molecule provided in an embodiment of the present application, Figure 4 A schematic diagram of an exciton transfer path provided in an embodiment of the present application.

[0033] The present application embodiment provides a display panel 100, such as Figure 1 As shown, the display panel 100 includes a substrate 10 and a first light emitting device 20, which is located on one side of the substrate 10. The first light emitting device 20 includes an electron generating layer 201, which can generate electrons E1, and a hole generating layer 202, which can generate holes E2.

[0034] The first light-emitting device 20 further includes a first light-emitting layer 203, and the first light-emitting layer 203 is located between the electron generating layer 201 and the hole generating layer 202. Optionally, the first light-emitting device 20 is an organic light-emitting diode. Optionally, the electron generating layer 201 is the cathode of the first light-emitting device 20, and the hole generating layer 202 is the anode of the first light-emitting device. During the operation of the first light-emitting device 20, the electron generating layer 201 of the first light-emitting device 20 can be electrically connected to a fixed potential, and the hole generating layer 202 thereof is electrically connected to a pixel circuit in the display panel, receiving a light-emitting driving current generated by the pixel circuit, thereby driving the first light-emitting device 20 to emit light.

[0035] During the light emission process of the first light emitting device 20, an electric field exists between the electron generating layer 201 and the hole generating layer 202, and under the action of the electric field, both the electrons E1 and the holes E2 move toward the first light emitting layer 203. The electrons E1 and the holes E2 meet in the first light emitting layer 203 to form excitons, and the energy of the excitons excites the light emitting material in the first light emitting layer 203 to generate photons, so that the first light emitting device 20 emits light.

[0036] In the related art, the material used to prepare the first light-emitting layer is usually obtained by mixing a main material host and a light-emitting material. The main function of the host material in the first light-emitting layer is to capture electrons and holes. After an electron located on the highest occupied molecular orbital (HOMO) around a molecule of the main material gains energy and is excited, it can jump from the highest occupied molecular orbital (HOMO) to the lowest unoccupied orbital (LUMO) of a higher energy level, leaving a hole on the original highest occupied molecular orbital. There is a Coulomb attraction between the excited electron and the hole it leaves behind. If the attraction between the electron and the hole overcomes the separation trend, the electron and the hole combine to form an exciton. Since the main material and the light-emitting material are mixed and evaporated in the first light-emitting layer, the distance between the main material molecules and the light-emitting material molecules is close. At this time, there is a coulomb attraction between the host material host and the light-emitting material. The energy transfer mechanism, also known as the long-range non-radiative energy transfer phenomenon, allows the excitons formed at the main material molecules to be received by the luminescent material molecules. After receiving the exciton energy, the luminescent material molecules are in an excited state. The luminescent material molecules in the excited state will return to the ground state by releasing a photon, thereby realizing the luminescence of the first luminescent layer.

[0037] It should be noted that in the related art, the paths by which a large amount of exciton energy is released mainly include non-radiative recombination (conversion into heat energy) or radiative recombination (releasing photons) and disintegration. Transferring excitons to luminescent materials to disintegrate through radiative recombination is the ideal state required to complete luminescence. Figure 2 As shown, since electrons and holes will continue to be obtained at the main material molecules to form excitons, there are multiple excitons located at the main material molecules, and some of the excitons located at the main material molecules will meet with the carriers (including electrons and holes) obtained by the main material molecules. When the excitons meet the carriers, they will annihilate each other, so that the excitons are released as heat energy. At this time, if a large number of excitons disintegrate in the form of heat energy, on the one hand, the number of excitons received by the luminescent material is reduced, which is not conducive to improving the efficiency of the luminescent material in generating photons, thereby reducing the luminous efficiency of the light-emitting device; on the other hand, the heat energy generated by the excitons can easily damage the chemical bonds between the main material host and the luminescent material, thereby depleting the service life of the luminescent layer material, and further reducing the working life of the first luminescent layer. Therefore, in the first luminescent layer, reducing the degree of annihilation of excitons is more important for improving the luminous efficiency, reducing power consumption and increasing the working life of the luminescent layer.

[0038] In the technical solution of the present application, the first light-emitting layer 203 of the first light-emitting device 20 includes a main material H1 and a first light-emitting material D1, and the first light-emitting material D1 is doped in the main material H1. The main material H1 in the first light-emitting layer 203 includes a mixed first main material H1A and a second main material H1B. The first main material H1A, the second main material H1B and the first light-emitting material D1 are mixed and evaporated to form the first light-emitting layer 203, wherein the band gap X1 of the first main material H1A is smaller than the band gap X2 of the second main material H1B. The band gap can be considered as the energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). If the electrons in the highest occupied molecular orbital want to be excited to the lowest unoccupied molecular orbital of a higher energy level, at least this energy difference is required. Neither the first main material H1A nor the second main material H1B is a luminescent material, and the excitons E3 at the first main material H1A and the second main material H1B will not disintegrate through radiative recombination (releasing photons), which provides conditions for the excitons E3 to exist relatively stably at the first main material H1A or the second main material H1B.

[0039] like Figure 3 As shown, the band gap X1 of the first main material H1A is smaller than the band gap of the second main material H1B, so the electrons located at the molecules of the first main material H1A are more easily excited to a higher energy level, and then combine with the holes E2 to form excitons E3. However, it is more difficult for the electrons E1 and holes E2 at the second main material H1B to combine to form excitons E3, and the consumption of electrons E1 and holes E2 is relatively small. Therefore, between the first main material H1A and the second main material H1B, the excitons E3 are mainly generated at the first main material H1A. Correspondingly, it is more difficult for the electrons E1 and holes E2 at the second main material H1B to combine to form excitons E3 than the first main material H1A, so the carriers flowing to the first light-emitting layer 203 are not easily obtained by the second main material H1B, which helps to reduce the probability of annihilation of the excitons E3 located at the second main material H1B. Combination Figure 4 As shown, since the distance between the first main material H1A and the second main material H1B is also close, there is a distance between the first main material H1A and the second main material H1B. The energy transfer mechanism is also called the long-range non-radiative energy transfer phenomenon. In addition to partially transferring the exciton E3 generated by the first main material H1A to the first luminescent material D1, it is also partially transferred to the second main material H1B. After the second main material H1B obtains the exciton E3, it is also in an excited state. However, due to the larger band gap X2 of the second main material H1B, the energy of the exciton E3 obtained by the electron E1 at the second main material H1B molecule is not enough to make the electron E1 at the second main material H1B jump to the lowest unoccupied orbital (LUMO), so the exciton energy at the second main material H1B can be better preserved. The distance between the second main material H1B and the first luminescent material D1 is also close. Similarly, there is a The energy transfer mechanism enables the molecules of the second main material H1B to transfer the exciton energy to the first light-emitting material D1, so that the second main material H1B returns to the ground state, and the first light-emitting material D1 generates photons after receiving the exciton E3.

[0040] In the embodiment of the present application, the first light-emitting layer 203 is provided with two different main materials H1, which is beneficial to the faster transmission of the excitons E3 generated by the first main material H1A, and the excitons E3 generated by the first main material H1A are transmitted to the first light-emitting material D1 and the second main material H1B respectively, which is beneficial to reduce the degree of annihilation of the excitons E3 at the first main material H1A, improve the utilization rate of the excitons E3 by the first light-emitting layer 203, and thus reduce the power consumption of the first light-emitting device 20. In addition, setting the band gap X1 of the first main material H1 to be smaller than the band gap X2 of the second main material H1B is beneficial to making most of the carriers in the first light-emitting layer 203 located at the first main material H1A, and most of the excitons E3 located at the second main material H1B. The carriers and the excitons E3 are located on different materials respectively, which is beneficial to further reduce the probability of annihilation of the excitons E3 and the carriers, thereby reducing the degradation effect of the exciton E3 annihilation on the material in the first light-emitting layer 203, which is beneficial to improve the working life of the first light-emitting layer 203, and is also beneficial to improve the energy of the excitons E3 transferred to the first light-emitting material D1, thereby increasing the amount of photons generated by the first light-emitting material D1, improving the luminous efficiency of the first light-emitting device 20, and providing conditions for the first light-emitting device 20 to be applied to more fields.

[0041] Figure 5 A time-brightness attenuation variation trend diagram corresponding to a first light-emitting device provided in an embodiment of the present application, Figure 6 A variation trend diagram of current density-luminous efficiency corresponding to a first light-emitting device provided in an embodiment of the present application.

[0042] like Figure 5As shown, the first function Line1 obtained by the study represents the luminance attenuation Lumi.Decay trend graph of the first light-emitting device 20 changing with time time when there is only one main material H1 in the first light-emitting device 20. Correspondingly, the second function Line2 obtained by the study represents the luminance attenuation Lumi.Decay trend graph of the first light-emitting device 20 changing with time time when two main materials are added to the first light-emitting device 20, and optionally, the two main materials are the first main material H1A and the second main material H1B. Figure 5 It can be seen that when the first main material H1A and the second main material H1B are added to the first light-emitting device 20, the brightness decay Lumi.Decay trend of the first light-emitting device 20 slows down, indicating that the addition of the second main material H1B reduces the annihilation of the exciton E3, thereby reducing the effect of the annihilation of the exciton E3 on the degradation of the light-emitting layer material, thereby improving the service life of the first light-emitting device 20.

[0043] Combination Figure 6 As shown, the third function Line3 obtained by the study represents the trend of the luminous efficiency Eff of the first light-emitting device 20 with the change of the current density Curr dens when there is only one main material H1 in the first light-emitting device 20. Correspondingly, the fourth function Line2 obtained by the study represents the trend of the luminous efficiency Eff of the first light-emitting device 20 with the change of the current density Curr dens when two main materials are added to the first light-emitting device 20, and optionally, the two main materials are the first main material H1A and the second main material H1B. Figure 6 It can be seen that when the first main material H1A and the second main material H1B are added to the first light-emitting device 20, the luminous efficiency Eff of the first light-emitting device 20 is improved, indicating that the addition of the second main material H1B reduces the annihilation of the exciton E3, thereby increasing the processing capacity of the first light-emitting material D1 for the exciton E3, thereby improving the luminous efficiency of the first light-emitting device 20.

[0044] In one embodiment of the application, the first light-emitting material D1 in the first light-emitting layer 203 is a phosphorescent material. Among the light-emitting materials, the phosphorescent material may include a heavy metal complex, and is widely used because of its wide spectrum coverage and long service life. Excitons include triplet excitons and singlet excitons, and the phosphorescent material mainly utilizes the excitation energy of triplet excitons to cause the exciton E3 to disintegrate by radiation recombination (releasing photons). The technical solution of the present application sets the first light-emitting material D1 as a phosphorescent material, which is beneficial to utilize the combined mechanism of the first main material H1A and the second main material H1B so that more excitons in the triplet state can be obtained by the phosphorescent material and then release more photons.

[0045] Optionally, in some other embodiments, the first light-emitting material D1 is a fluorescent material, and the fluorescent material mainly generates photon luminescence by using the excitation energy of singlet excitons.

[0046] Optionally, in some other embodiments, the first light-emitting material D1 is a mixed material system of a phosphorescent material and a fluorescent material.

[0047] Figure 7 A triplet energy level schematic diagram provided for an embodiment of the present application.

[0048] In one embodiment of the application, in combination Figure 4 , Figure 7 As shown, the triplet energy level of the first main material H1A in the first light-emitting layer 203 is T1, the triplet energy level of the second main material H1B is T2, and the triplet energy level of the first light-emitting material D1 is T3; wherein, T1>T2>T3. The triplet energy level of a material refers to the energy level when the electron E1 is in an excited state, and the exciton E3 is easily transferred from a material with a high triplet energy level to a material with a low triplet energy level. The embodiment of the present application is described by taking the first light-emitting material D1 as a phosphorescent material as an example.

[0049] In the embodiment of the present application, since the exciton E3 is mainly generated at the first main material H1A, T1>T2>T3 is set, which is conducive to the smooth transfer of the exciton E3 at the first main material H1A to the second main material H1B and the first light-emitting material D1 with a lower triplet energy level than the exciton E3, which is conducive to realizing that the first main material H1A mainly includes carriers and the second main material H1B mainly includes excitons E3, further reducing the annihilation of the exciton E3. Similarly, the exciton E3 located at the second main material H1B can be smoothly transferred to the first light-emitting material D1 with a lower triplet energy level than the exciton E3. In summary, the energy of the exciton E3 at the first main material H1A and the energy of the exciton E3 at the second main material H1B are ultimately transferred to the first light-emitting material D1, which is conducive to improving the utilization rate of the exciton E3 in the first light-emitting layer 203 and reducing the power consumption of the first light-emitting device 20.

[0050] In one embodiment of the application, the proportion of any one of the first main material H1A and the second main material H1B in the main material H1 is greater than or equal to 30%. The material ratio of the first main material H1A and the second main material H1B is relatively balanced, which is conducive to avoiding the large particle load of one of the two main materials caused by too large or too small proportion of one of the main materials H1A, thereby reducing the service life. For example, when the proportion of the first main material H1A is too large and the proportion of the second main material H1B is too small, it is easy to cause the second main material H1B to have insufficient carrying capacity for the exciton E3, and a large number of excitons E3 are still between the first main material H1A, and the excitons E3 are easy to be annihilated. When the proportion of the first main material H1A is too small and the proportion of the second main material H1B is too large, the ability of the first light-emitting layer 203 to obtain electrons E1 and holes E2 to generate excitons E3 becomes insufficient, and the number of excitons E3 in the first light-emitting layer 203 decreases, which easily leads to a decrease in the luminous efficiency of the first light-emitting device 20.

[0051] Optionally, the ratio of the first main material H1A to the second main material H1B in the main material H1 is set to 7:3 or 3:7. Optionally, the ratio of the first main material H1A to the second main material H1B in the main material H1 is set to 1:1. It should be noted that the ratios proposed in the embodiments of the present application are not the only ones, and in actual use, different ratios can be set as needed.

[0052] In the embodiment of the present application, the proportion of any one of the first main material H1A and the second main material H1B in the main material H1 is greater than or equal to 30%, which is beneficial to balance the material proportion of the first light-emitting layer 203, thereby ensuring the light-emitting working stability of the first light-emitting device 20 and improving the service life of the first light-emitting device 20.

[0053] In one embodiment of the application, the majority carriers in the second main material H1B are holes E2, and the proportion of the second main material H1B in the main material H1 is set to be greater than the proportion of the first main material H1A in the main material H1. When the majority carriers in the second main material H1B added to the main material H1 are holes E2, the number of electrons E1 at the second main material H1B is small, and the second main material H1B is not easy to transition to an excited state, so that the state of the second main material H1B is relatively stable and its service life is longer. In the embodiment of the present application, the proportion of the second main material H1B, which is more hole-type, is set to be greater than the proportion of the first main material H1A. From the perspective of improving the service life of the first light-emitting device 20, this is conducive to improving the stability of the main material H1, and then improving the service life of the main material H1.

[0054] Optionally, when the majority carriers of the second main material H1B are holes E2, in order to improve the working efficiency of the first light-emitting layer 203, the proportion of the second main material H1B in the main material H1 can be set to be smaller than the proportion of the first main material H1A in the main material H1.

[0055] In one embodiment of the application, the majority carriers in the second main material H1B are electrons E1, and the proportion of the second main material H1B in the main material H1 is set to be less than the proportion of the first main material H1A in the main material H1. When the majority carriers in the second main material H1B added to the main material H1 are electrons E1, the number of holes E2 at the second main material H1B is small, and the second main material H1B is easy to transition to the excited state, and its efficiency in generating excitons E3 is high, and the service life is correspondingly short. In the embodiment of the present application, the proportion of the second main material H1B with a partial electron type is set to be less than the proportion of the first main material H1A. From the perspective of increasing the service life of the first light-emitting device 20, it is beneficial to improve the stability of the main material H1, and then increase the service life of the main material H1.

[0056] Optionally, when the majority carriers of the second main material H1B are electrons E1, in order to improve the working efficiency of the first light-emitting layer 203, the proportion of the second main material H1B in the main material H1 may be set to be greater than the proportion of the first main material H1A in the main material H1.

[0057] In one embodiment of the application, the first light-emitting material D1 accounts for N1 in the first light-emitting layer 203 , wherein 6%≤N1≤12%.

[0058] In the embodiment of the present application, the proportion of the first light-emitting material D1 is set within the range of 6%≤N1≤12%. Studies have shown that when the proportion of the first light-emitting material D1 is within the range of 6%≤N1≤12%, the luminous performance of the first light-emitting device 20 is in a stable state. The low concentration of the first light-emitting material D1 can reduce the interaction between materials, thereby improving the stability and durability of the first light-emitting layer 203 and extending the working life of the first light-emitting layer 203. This is conducive to reducing the amount of the first light-emitting material D1 on the basis of ensuring the stable light emission of the first light-emitting device 20, and reducing the production cost of the first light-emitting device 20. In addition, the proportion of the first light-emitting material D1 within 6%≤N1≤12% is conducive to the uniform dispersion of the material, improving the production yield, so that the first light-emitting layer 203 maintains good luminous performance.

[0059] Of course, in some other embodiments, the proportion of the first luminescent material D1 can be set to any value within the range of 0%<N1<100% to meet the needs of luminescent work.

[0060] Figure 8 A schematic diagram of the structure of another display panel provided in an embodiment of the present application.

[0061] In one embodiment of the application, Figure 8 As shown, the display panel 100 further includes a second light emitting device 30 , which includes an electron generating layer 201 , which can generate electrons E1 , and a hole generating layer 202 , which can generate holes E2 .

[0062] The second light-emitting device 30 also includes a second light-emitting layer 301, which is located between the electron generation layer 201 and the hole generation layer 202. Similar to the first light-emitting layer 203, electrons E1 and holes E2 move toward the second light-emitting layer 301 under the action of the electric field, and electrons E1 and holes E2 meet in the second light-emitting layer 301 to form excitons E3.

[0063] The second light-emitting layer 301 includes a main material H1 and a second light-emitting material D2. The main material H1 in the second light-emitting layer 301 is the first main material H1A. Excitons are generated in the first main material H1A and then transferred to the second light-emitting material D2.

[0064] It should be noted that the electron generation layer 201 in the first light emitting device 20 and the second light emitting device 30 may be of different film structures, and the hole generation layer 202 in the first light emitting device 20 and the second light emitting device 30 may also be of different film structures. The electron generation layer 201 in the first light emitting device 20 and the second light emitting device 30 may be electrically connected to different potentials, and the hole generation layer 202 in the first light emitting device 20 and the second light emitting device 30 may also be electrically connected to different potentials, thereby providing electric fields of different intensities for the first light emitting device 20 and the second light emitting device 30, so that the first light emitting device 20 and the second light emitting device 30 generate different luminous brightness.

[0065] Alternatively, the electron generation layer 201 in the first light emitting device 20 and the second light emitting device 30 may be the same film structure, and the hole generation layer 202 in the first light emitting device 20 and the second light emitting device 30 may also be the same film structure. The electron generation layer 201 in the first light emitting device 20 and the second light emitting device 30 may be electrically connected to the same potential, and the hole generation layer 202 in the first light emitting device 20 and the second light emitting device 30 may also be electrically connected to the same potential, so that the first light emitting device 20 and the second light emitting device 30 share the electron generation layer 201 and the hole generation layer 202.

[0066] In the embodiment of the present application, the first light-emitting device 20 and the second light-emitting device 30 have different luminous colors, and the first light-emitting material D1 and the second light-emitting material D2 are used to emit light of different wavelengths, so that the first light-emitting device 20 and the second light-emitting device 30 produce different luminous colors. The number of types of the main material H1 added to the light-emitting devices of different colors is different, and the type of the added main material H1 can be adaptively adjusted in the light-emitting application, which is beneficial to reduce the cost of adding the main material H1. In addition, in the display panel 100, there is a certain difference in the luminous life of the first light-emitting device 20 and the second light-emitting device 30 of different colors. In some uses, the luminous work does not significantly damage the luminous life of the second light-emitting device 30. The main material H1 of the second light-emitting layer 301 can be set to include only the first main material H1A, which is beneficial to provide applicable conditions for the addition of the main material H1 and improve the applicability of the embodiment of the present application.

[0067] Fig. 9 A schematic diagram of the chemical formula of a material provided in an embodiment of the present application, Fig.10 A schematic diagram of the structure of another display panel provided in an embodiment of the present application.

[0068] In one embodiment of the application, the light emitting color of the first light emitting device 20 is green. When the light emitting device in the display panel 100 is an organic light emitting device, optionally, the light emitting device in the display panel 100 may include a green light emitting device, a blue light emitting device, and a red light emitting device. Among them, when the display panel 100 displays a white screen, the green light emitting device among the green light emitting device, the blue light emitting device, and the red light emitting device generates the highest amount of light, accounting for more than 80%. Therefore, in order to increase the life of the display panel 100 for white light display and ensure the stability of white light display, it is particularly important to increase the working life of the green light emitting device. In combination with the above embodiments, it can be seen that when the light emitting color of the first light emitting device 20 is green, the first main material H1A and the second main material H1B can be added to the main material H1 of the first light emitting device 20, and the band gap X1 of the first main material H1 is smaller than the band gap X2 of the second main material H1B, which is conducive to reducing the annihilation of the exciton E3 in the first light emitting device 20, thereby reducing the material loss in the first light emitting layer 203 and increasing the working life of the first light emitting device 20.

[0069] Alternatively, if Fig. 9As shown, the first luminescent material D1 used in the technical solution of the present application is (a) tris(2-phenylpyridine)iridium (Ir(ppy)3), which is a phosphorescent luminescent material widely used in organic light-emitting diodes (OLEDs) as a phosphorescent dopant because it can effectively utilize triplet excitons, thereby significantly improving the luminous efficiency of the device. At this time, the band gap of the first luminescent material D1 is 2.4eV. The first main material H1A used can be (b) 4-(3-(terphenyl-2-yl)phenyl)dibenzo[b,d]thiophene, which has a band gap of 2.8Ev. (c) 9-(30-(4,6-diphenyl-1,3,5-triazine-2-yl)-[1,10]phenanthroline-3-yl)-9H-carbazole, which has a band gap greater than that of the first main material H1A, can be used as the second main material H1B, which has a band gap of 3.5eV.

[0070] Combination Fig.10 As shown, the display panel 100 includes a first light-emitting device 20 and a second light-emitting device 30 of different colors. The main material H1 of the first light-emitting layer 203 in the first light-emitting device 20 may include a first main material H1A and a second main material H1B, and the main material H2 of the second light-emitting layer 301 in the second light-emitting device 30 includes only the first main material H1A. Using the same first main material H1A in the first light-emitting device 20 and the second light-emitting device 30 of different colors is conducive to reducing the preparation cost of the light-emitting device.

[0071] Fig.11 A schematic diagram of the structure of another display panel provided in the application embodiment, Fig.12 A schematic diagram of the structure of another display panel provided in an embodiment of the present application.

[0072] In one embodiment of the application, Fig.11 As shown, the display panel 100 further includes a third light-emitting device 40, the third light-emitting device 40 includes an electron generation layer 201, the electron generation layer 201 can generate electrons E1, and the third light-emitting device 40 further includes a hole generation layer 202, and the hole generation layer 202 can generate holes E2. The third light-emitting device 40 further includes a third light-emitting layer 401, the third light-emitting layer 401 is located between the electron generation layer 201 and the hole generation layer 202, and the third light-emitting layer 401 includes a main material H1 and a third light-emitting material D3, and the third light-emitting material D3 is doped in the main material H1.

[0073] The main material H1 in the third light-emitting layer 401 includes a mixed first main material H1A and a third main material H1C, and the band gap X1 of the first main material H1A is smaller than the band gap X3 of the third main material H1C. If the light-emitting colors of the first light-emitting device 20 and the third light-emitting device 40 are different, then the first light-emitting material D1 and the third light-emitting material D3 are also different.

[0074] The band gap X1 of the first main material H1A is smaller than the band gap X3 of the third main material H1C, and the carriers in the third light-emitting device 40 are mainly located in the first main material H1A, and the excitons E3 are mainly located in the third main material H1C, which is beneficial to reduce the exciton annihilation in the third light-emitting layer 401 and to increase the number of excitons E3 in the third light-emitting layer 401 transferred to the third light-emitting material D3, thereby improving the luminous efficiency of the third light-emitting layer 401 and increasing the working life of the third light-emitting layer 401.

[0075] In addition, if Fig.12 As shown, the display panel 100 includes a first light emitting device 20, a second light emitting device 30 and a third light emitting device 40 of different colors.

[0076] Optionally, the second main material H1B and the third main material H1C are the same. Optionally, the second main material H1B and the third main material H1C are different.

[0077] In the embodiment of the present application, the main material H1 in the third light-emitting device 40 includes a first main material H1A and a third main material H1C, which is beneficial to adjust the corresponding material configuration for light-emitting devices of different colors and adaptively adjust the luminous efficiency and service life of different light-emitting devices.

[0078] In one embodiment of the application, one of the first light emitting device 20 and the third light emitting device 40 is green, and the other is blue. Among the light emitting devices of different colors, as described in the above embodiment, when the display panel 100 displays a white screen, the green light emitting device generates the highest amount of light, accounting for more than 80%. Therefore, in order to increase the life of the display panel 100 for white light display and ensure the stability of white light display, it is particularly important to increase the working life of the green light emitting device. The main material H1 of the light emitting layer of the green light emitting device is set to the first main material H1A and the second main material H1C with different band gaps or to the first main material H1A and the second main material H1C with different band gaps. In addition, the blue light emitting device among the green light emitting device, the blue light emitting device, and the red light emitting device has a larger light emitting area and generates a larger wavelength of light, so it is also important to protect the materials in the light emitting layer of the blue light emitting device. The main material H1 of the light emitting layer of the blue light emitting device can be set to the first main material H1A and the second main material H1C with different band gaps or to the first main material H1A and the second main material H1C with different band gaps.

[0079] Fig.13 A schematic diagram of the structure of another display panel provided in an embodiment of the present application.

[0080] In one embodiment of the application, Fig.13As shown, the first light emitting device 20 further includes a fourth light emitting layer 204, and the fourth light emitting layer 204 is located on the side of the first light emitting layer 203 facing the substrate 10. The first light emitting layer 203 and the fourth light emitting layer 204 are arranged in the first light emitting device 20 at the same time, which is beneficial to improving the working efficiency of the first light emitting device 20 and improving the service life of the first light emitting device 20.

[0081] The electron generation layer 201 in the first light emitting device 20 includes a first sub-electron generation layer 201A and a second sub-electron generation layer 201B. The hole generation layer 202 in the first light emitting device 20 includes a first sub-hole generation layer 202A and a second sub-hole generation layer 202B. The first light emitting layer 203 is located between the first sub-electron generation layer 201A and the first sub-hole generation layer 202A. The fourth light emitting layer 204 is located between the second sub-electron generation layer 201B and the second sub-hole generation layer 202B.

[0082] The electrons E1 generated by the first sub-electron generation layer 201A and the holes E2 generated by the first sub-hole generation layer 202A both move toward the first light-emitting layer 203 under the action of the electric field of the first sub-electron generation layer 201A and the first sub-hole generation layer 202A. The electrons E1 generated by the second sub-electron generation layer 201B and the holes E2 generated by the second sub-hole generation layer 202B both move toward the fourth light-emitting layer 204 under the action of the electric field of the second sub-electron generation layer 201B and the second sub-hole generation layer 202B.

[0083] The fourth light-emitting layer 204 includes a main material H1 and a first light-emitting material D1, the first light-emitting material D1 is doped in the main material H1, and the main material H1 in the fourth light-emitting layer 204 includes a mixed first main material H1A and a second main material H1B. The fourth light-emitting layer 204 has the same light-emitting color as the first light-emitting layer 203, and the mixed first main material H1A and the second main material H1B are also arranged in the fourth light-emitting layer 204, which is conducive to reducing the annihilation degree of the exciton E3 in the fourth light-emitting layer 204, improving the utilization rate of the exciton E3 in the fourth light-emitting layer 204, and improving the luminous efficiency of the fourth light-emitting layer 204.

[0084] In the first light-emitting device 20, since the fourth light-emitting layer 204 is located on the side of the backlight surface of the display panel 100 compared to the first light-emitting layer 203, and the light-emitting directions of the first light-emitting layer 203 and the fourth light-emitting layer 204 are the same, both are toward the side of the light-emitting surface of the display panel 100. In the embodiment of the present application, the first sub-electron generation layer 201A is located on the side of the first light-emitting layer 203 toward the light-emitting surface of the display panel 100, the first hole generation layer 202A is located on the side of the first light-emitting layer 203 toward the substrate 10, the second electron generation layer 201B is located on the side of the fourth light-emitting layer 204 toward the light-emitting surface of the display panel 100, and the second hole generation layer 202B is located on the side of the fourth light-emitting layer 204 toward the substrate 10. When the first light-emitting device 20 emits light, in order to prevent the first light-emitting device 20 from emitting light, the first electron generation layer 201A, the second electron generation layer 201B, and the first hole generation layer 202A can be set as transparent electrodes. In order to prevent the light emitted by the first light-emitting device 20 from irradiating the circuit structure overlapping with the first light-emitting device 20, the second hole generation layer 202B can be set as a non-transparent electrode that can reflect light. The light of the first light-emitting layer 203 and the fourth light-emitting layer 204 both include part of the light emitted after being reflected by the second hole generation layer 202B. In the related art, due to the reflection of light, the fourth light-emitting layer 204 is more susceptible to more disturbances of reflected light, and photons frequently passing through the fourth light-emitting layer 204 are likely to damage the material of the fourth light-emitting layer 204.

[0085] In the embodiment of the present application, the proportion of the second main material H1B in the main material H1 arranged in the fourth light-emitting layer 204 is greater than the proportion of the second main material H1B in the main material H1 in the first light-emitting layer 203, which is beneficial to improving the material protection effect on the fourth light-emitting layer 204, reducing the annihilation of the exciton E3 on the material degradation effect, and better protecting the material in the fourth light-emitting layer 204, so that it can better cope with the influence of reflection of photons on the fourth light-emitting layer 204.

[0086] Continue to refer Fig.11 As shown, the first light-emitting device 20 further includes an electron injection layer 205, an electron transport layer 206, a hole injection layer 207, and a hole transport layer 208. The electron injection layer 205 is used to receive the electrons E1 generated by the electron generation layer 201, and then the electron transport layer 206 is used to assist the transmission of the electrons E1, and transmit the electrons E1 to the first light-emitting layer 203 or the fourth light-emitting layer 204. The hole injection layer 207 is used to receive the holes E2 generated by the hole generation layer 202, and then the hole transport layer 208 is used to assist the transmission of the holes E2, and transmit the holes E2 to the first light-emitting layer 203 or the fourth light-emitting layer 204.

[0087] Fig.14 A schematic diagram of a display device provided in an embodiment of the present application.

[0088] The present application embodiment provides a display device 200, such as Fig.14 As shown, the display device 200 includes the display panel 100 provided in the above embodiment. The display device 200 provided in the embodiment of the present application can be a device including a display function, such as a computer, a television, and a mobile phone.

[0089] In the display device 200, the first light-emitting layer 203 is provided with two different main materials H1, which is beneficial to the faster transmission of the excitons E3 generated by the first main material H1A, and the excitons E3 generated by the first main material H1A are respectively transmitted to the first light-emitting material D1 and the second main material H1B, which is beneficial to reduce the annihilation degree of the excitons E3 at the first main material H1A, improve the utilization rate of the excitons E3 by the first light-emitting layer 203, and thus reduce the power consumption of the first light-emitting device 20. In addition, setting the band gap X1 of the first main material H1 to be smaller than the band gap X2 of the second main material H1B is beneficial to making most of the carriers in the first light-emitting layer 203 located at the first main material H1A, and most of the excitons E3 located at the second main material H1B. The carriers and the excitons E3 are located on different materials respectively, which is beneficial to further reduce the probability of annihilation of the excitons E3 and the carriers, thereby reducing the degradation effect of the exciton E3 annihilation on the material in the first light-emitting layer 203, which is beneficial to improve the working life of the first light-emitting layer 203, and is also beneficial to improve the energy of the excitons E3 transferred to the first light-emitting material D1, thereby increasing the amount of photons generated by the first light-emitting material D1, improving the luminous efficiency of the first light-emitting device 20, and providing conditions for the first light-emitting device 20 to be applied to more fields.

[0090] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A display panel, characterized in that: It includes a substrate and a first light-emitting device, wherein the first light-emitting device is located on one side of the substrate; The first light emitting device comprises: An electron generating layer, wherein the electron generating layer can generate electrons; a hole generating layer, wherein the hole generating layer can generate holes; A first light-emitting layer, wherein the first light-emitting layer is located between the electron generating layer and the hole generating layer, and the first light-emitting layer comprises a main material and a first light-emitting material, wherein the first light-emitting material is doped in the main material; The main material in the first light-emitting layer includes a mixed first main material and a second main material, and the band gap of the first main material is smaller than the band gap of the second main material.

2. The display panel according to claim 1, characterized in that: The first light-emitting material is a phosphorescent material.

3. The display panel according to claim 2, characterized in that: The triplet energy level of the first main material is T1, the triplet energy level of the second main material is T2, and the triplet energy level of the first light-emitting material is T3; wherein T1>T2>T3.

4. The display panel according to claim 1, characterized in that: The proportion of any one of the first main material and the second main material in the main material is greater than or equal to 30%.

5. The display panel according to claim 4, characterized in that: The majority of carriers in the second main material are holes, and the proportion of the second main material in the main material is greater than the proportion of the first main material in the main material.

6. The display panel according to claim 4, characterized in that: The majority of carriers in the second main material are electrons, and the proportion of the second main material in the main material is smaller than the proportion of the first main material in the main material.

7. The display panel according to claim 1, characterized in that: The proportion of the first light-emitting material in the first light-emitting layer is N1; 6%≤N1≤12%.

8. The display panel according to claim 1, characterized in that: The display panel further includes a second light emitting device, wherein the second light emitting device includes: An electron generating layer, wherein the electron generating layer can generate electrons; a hole generating layer, wherein the hole generating layer can generate holes; a second light-emitting layer, wherein the first light-emitting layer is located between the electron generating layer and the hole generating layer; the second light-emitting layer comprises a main material and a second light-emitting material, and the main material in the second light-emitting layer is the first main material; and the first light-emitting device and the second light-emitting device have different light-emitting colors.

9. The display panel according to claim 1 or 8, characterized in that: The light emitting color of the first light emitting device is green.

10. The display panel according to claim 1 or 8, characterized in that: The display panel further includes a third light emitting device, and the third light emitting device includes: An electron generating layer, wherein the electron generating layer can generate electrons; a hole generating layer, wherein the hole generating layer can generate holes; A third light-emitting layer, the third light-emitting layer is located between the electron generating layer and the hole generating layer; the third light-emitting layer comprises a main material and a third light-emitting material, and the third light-emitting material is doped in the main material; The main material in the third light-emitting layer includes a mixed first main material and a third main material, the band gap of the first main material is smaller than the band gap of the third main material; and the first light-emitting device and the third light-emitting device have different light-emitting colors.

11. The display panel according to claim 10, characterized in that: One of the first light emitting device and the third light emitting device is green, and the other is blue.

12. The display panel according to claim 1, characterized in that: The first light-emitting device further includes a fourth light-emitting layer, and the fourth light-emitting layer is located on a side of the first light-emitting layer facing the substrate; The electron generation layer includes a first sub-electron generation layer and a second sub-electron generation layer; the hole generation layer includes a first sub-hole generation layer and a second sub-hole generation layer; the first light-emitting layer is located between the first sub-electron generation layer and the first sub-hole generation layer; the fourth light-emitting layer is located between the second sub-electron generation layer and the second sub-hole generation layer; The fourth light-emitting layer includes a main material and a first light-emitting material, wherein the first light-emitting material is doped in the main material; the main material in the fourth light-emitting layer includes a mixed first main material and a second main material; The proportion of the second main material in the fourth light-emitting layer in the main material is greater than the proportion of the second main material in the first light-emitting layer in the main material.

13. A display device, characterized in that: Comprising the display panel as described in claims 1-12.

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