Organic light-emitting device and display panel

Abstract

The invention relates to an organic light-emitting device and a display panel. The organic light-emitting device comprises a first electrode and a second electrode which are oppositely arranged, and a light-emitting layer arranged between the first electrode and the second electrode; wherein the light-emitting layer comprises a host material, a guest material and a sensitizer, the host material comprises an n-type host material and a p-type host material, and the mass ratio of the n-type host material in the light-emitting layer is smaller than or equal to the mass ratio of the p-type host material in the light-emitting layer; according to the organic light-emitting device, the sensitizer is doped in the light-emitting layer, so that the light-emitting efficiency of the organic light-emitting device is improved; meanwhile, the ratio of the n-type main body material to the p-type main body material in the double-main body material is selected and designed, so that the light-emitting efficiency of the organic light-emitting device is further improved, and the service life of the organic light-emitting device is further prolonged.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to an organic light-emitting device and a display panel. Background Art

[0002] As a new generation of display technology, organic light-emitting diode (OLED) display devices have attracted much attention due to their excellent display performance, such as high contrast ratio, vivid colors, thin and light design, and good flexibility. However, the low luminous efficiency and short lifespan still restrict their wide application.

[0003] The light-emitting layer is the core factor determining the luminous efficiency of OLED display devices. Currently, the mainly applied light-emitting material system is the host-guest doping system, but the main bottleneck faced by simple host-guest doping is that it is difficult to improve the device efficiency and lifespan. Summary of the Invention

[0004] Embodiments of the present application provide an organic light-emitting device and a display panel, which can improve the luminous efficiency and lifespan of the organic light-emitting device.

[0005] Embodiments of the present application provide an organic light-emitting device, which includes a first electrode and a second electrode arranged oppositely, and a light-emitting layer arranged between the first electrode and the second electrode;

[0006] Wherein, the light-emitting layer includes a host material, a guest material, and a sensitizer, the host material includes an n-type host material and a p-type host material, and the mass ratio of the n-type host material in the light-emitting layer is less than or equal to the mass ratio of the p-type host material in the light-emitting layer.

[0007] In an embodiment of the present application, in the light-emitting layer, the mass ratio of the p-type host material to the n-type host material is greater than or equal to 1 and less than or equal to 4.

[0008] In an embodiment of the present application, the mass ratio of the sensitizer in the light-emitting layer is greater than or equal to 0.2% and less than or equal to 0.8%.

[0009] In an embodiment of the present application, the mass ratio of the guest material in the light-emitting layer is greater than or equal to 5% and less than or equal to 12%.

[0010] In an embodiment of the present application, the host material includes an electron-donating group;

[0011] Alternatively, the host material includes the electron-donating group and an electron-accepting group, and the mass ratio of the electron-donating group in the host material is greater than the mass ratio of the electron-accepting group in the host material.

[0012] In one embodiment of the present application, the electron mobility of the light-emitting layer is less than the hole mobility of the light-emitting layer.

[0013] In one embodiment of the present application, the energy gap of the sensitizer is less than the energy gap of the guest material.

[0014] In one embodiment of the present application, the difference between the energy gap of the guest material and the energy gap of the sensitizer is greater than or equal to 0.05 eV.

[0015] In one embodiment of the present application, the energy gap of the sensitizer is greater than or equal to 2 eV and less than or equal to 2.3 eV, and the guest material is a green light-emitting guest material.

[0016] According to the above object of the present application, an embodiment of the present application further provides a display panel, and the display panel includes the organic light-emitting device.

[0017] The present application provides an organic light-emitting device and a display panel. By doping a sensitizer in the light-emitting layer, the light-emitting efficiency of the organic light-emitting device is improved; at the same time, the ratio of the n-type host material and the p-type host material in the double host material is also selected and designed to further improve the light-emitting efficiency and lifespan of the organic light-emitting device.

[0018] Other features and advantages of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] In order to more completely understand the present application and its beneficial effects, the following will be described in conjunction with the drawings, where the same reference numerals in the following description represent the same parts.

[0021] Figure 1 It is a schematic structural diagram of an organic light-emitting device provided by an embodiment of the present application;

[0022] Figure 2 It is another schematic structural diagram of an organic light-emitting device provided by an embodiment of the present application;

[0023] Figure 3 It is a first carrier migration schematic diagram of an organic light-emitting device provided by an embodiment of the present application;

[0024] Figure 4 The second carrier migration schematic diagram of the organic light-emitting device provided by the embodiment of the present application;

[0025] Figure 5 The third carrier migration schematic diagram of the organic light-emitting device provided by the embodiment of the present application;

[0026] Figure 6 The energy transfer structure schematic diagram provided by the embodiment of the present application;

[0027] Figure 7 The relationship curve graph of the host material ratio and efficiency in the organic light-emitting device provided by the embodiment of the present application;

[0028] Figure 8 The relationship curve graph of the device efficiency and current density in the organic light-emitting device provided by the embodiment of the present application;

[0029] Figure 9 A structure schematic diagram of the display panel provided by the embodiment of the present application.

[0030] Explanation of reference numerals:

[0031] 10. Organic light-emitting device; 11. First electrode; 12. Second electrode; 13. Light-emitting layer; 14. Hole injection layer; 15. Hole transport layer; 16. Electron transport layer; 17. Electron injection layer; 20. Array substrate; 200. Display panel. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a 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 those skilled in the art without creative efforts fall within the protection scope of the present application.

[0033] Please refer to Figure 1 , the embodiment of the present application provides an organic light-emitting device 10, and the organic light-emitting device 10 includes a first electrode 11 and a second electrode 12 which are oppositely arranged and a light-emitting layer 13 arranged between the first electrode 11 and the second electrode 12.

[0034] Among them, the light-emitting layer 13 includes a host material, a guest material and a sensitizer. The host material includes an n-type host material and a p-type host material, and the mass ratio of the n-type host material in the light-emitting layer 13 is less than or equal to the mass ratio of the p-type host material in the light-emitting layer 13.

[0035] During the application process of the embodiments, in the embodiments of the present application, the sensitizer is doped in the light-emitting layer 13 to improve the light-emitting efficiency of the organic light-emitting device 10; at the same time, the ratio of the n-type host material and the p-type host material in the double host material is also selected and designed to further improve the light-emitting efficiency and lifespan of the organic light-emitting device 10.

[0036] Specifically, please continue to refer to Figure 1 , in the organic light-emitting device 10, one of the first electrode 11 and the second electrode 12 is an anode, and the other of the first electrode 11 and the second electrode 12 is a cathode; in the embodiments of the present application, taking the first electrode 11 as the anode and the second electrode 12 as the cathode as an example for illustration.

[0037] It can be understood that the first electrode 11 is used to inject holes, the second electrode 12 is used to inject electrons, and the holes and electrons recombine in the light-emitting layer 13 to emit light, so as to realize the light emission of the organic light-emitting device.

[0038] In some embodiments, please refer to Figure 2 , the organic light-emitting device 10 further includes a light-emitting auxiliary layer stacked with the light-emitting layer 13 between the first electrode 11 and the second electrode 12; and the light-emitting auxiliary layer may include a hole injection layer 14, a hole transport layer 15, an electron transport layer 16, and an electron injection layer 17; wherein, the hole injection layer 14 is disposed on the first electrode 11, the hole transport layer 15 is disposed on a side of the hole injection layer 14 away from the first electrode 11, the light-emitting layer 13 is disposed on a side of the hole transport layer 15 away from the hole injection layer 14, the electron transport layer 16 is disposed on a side of the light-emitting layer 13 away from the hole transport layer 15, the electron injection layer 17 is disposed on a side of the electron transport layer 16 away from the light-emitting layer 13, and the second electrode 12 is disposed on a side of the electron injection layer 17 away from the electron transport layer 16.

[0039] It should be noted that in other embodiments of the present application, at least one of the hole injection layer 14, the hole transport layer 15, the electron transport layer 16, and the electron injection layer 17 may not be provided. For example, the electron injection layer 17 is not provided in the organic light-emitting device 10, and the second electrode 12 is disposed on a side of the electron transport layer 16 away from the light-emitting layer 13.

[0040] In some embodiments, the first electrode 11 is a hole-injecting electrode. For example, the first electrode 11 injects holes into the hole injection layer 14, the hole transport layer 15, or the light-emitting layer 13. The first electrode 11 may include at least one of a conductive metal, a conductive metal oxide, or a conductive polymer. Preferably, the absolute value of the difference between the work function of the first electrode 11 and the HOMO (Highest Occupied Molecular Orbital) energy level or valence band energy level of the p-type semiconductor material serving as the hole injection layer, or the HOMO (Highest Occupied Molecular Orbital) energy level or valence band energy level of the p-type semiconductor material in the hole injection layer and the hole transport layer or the electron blocking layer is less than 0.5 eV, preferably less than 0.3 eV, and more preferably less than 0.2 eV. The material of the first electrode 11 includes, but is not limited to, at least one of Al, Cu, Au, Ag, Mg, Fe, Co, Ni, Mn, Pd, Pt, ITO (Indium Tin Oxide), aluminum-doped zinc oxide (AZO), etc., or other suitable and known anode materials, which can be easily selected and used by those of ordinary skill in the art. The material of the first electrode 11 can be deposited using any suitable technique, such as a suitable physical vapor deposition method, including radio frequency magnetron sputtering, vacuum thermal evaporation, electron beam (e-beam), etc. In some embodiments, the first electrode 11 can be pattern-structured. For example, a patterned ITO conductive substrate is commercially available and can be used to fabricate the organic light-emitting device 10 of the present application.

[0041] In some embodiments, the second electrode 12 is an electrode for injecting electrons. For example, the second electrode 12 injects electrons into the electron injection layer 17, the electron transport layer 16, or the light-emitting layer 13. The second electrode 12 may include at least one of a conductive metal or a conductive metal oxide. Preferably, the absolute value of the difference between the work function of the second electrode 12 and the LUMO (Lowest Unoccupied Molecular Orbital) energy level or the conduction band energy level of the n-type semiconductor material serving as the electron injection layer, or the LUMO (Lowest Unoccupied Molecular Orbital) energy level or the conduction band energy level of the n-type semiconductor material of the electron injection layer and the electron transport layer or the hole blocking layer is less than 0.5 eV, preferably less than 0.3 eV, and more preferably less than 0.2 eV. All materials that can be used as the cathode of an organic electronic device may be used as the cathode material of the device of the present application. The material of the second electrode 12 includes, but is not limited to, at least one of Al, Au, Ag, Ca, Ba, Mg, LiF / Al, MgAg alloy, BaF2 / Al, Cu, Fe, Co, Ni, Mn, Pd, Pt, ITO, etc. The material of the second electrode 12 can be deposited using any suitable technique, such as suitable physical vapor deposition methods, including radio frequency magnetron sputtering, vacuum thermal evaporation, electron beam (e-beam), etc.

[0042] In some embodiments, the hole injection layer 14 is used to facilitate the injection of holes from the anode into the light-emitting layer 13, and the hole injection layer 14 includes a hole injection material, which is a material that can receive holes injected from the positive electrode at a low voltage. And, preferably, the highest occupied molecular orbital (HOMO) of the hole injection material is between the work function of the material of the first electrode 11 and the HOMO of the functional material of the film layer on the side of the hole injection layer away from the first electrode 11 (such as the hole transport material of the hole transport layer). The hole injection material includes, but is not limited to, at least one of metal porphyrins, oligothiophenes, arylamine-based organic materials, hexanitrile hexaazatriphenylene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinone, polyaniline-based and polythiophene-based conductive polymers, etc.

[0043] In some embodiments, the hole transport layer 15 can be used to transport holes to the light-emitting layer 13. The hole transport layer 15 includes a hole transport material that receives holes transported from the first electrode 11 or the hole injection layer 14 and transfers the holes to the light-emitting layer 13. The hole transport material is a material known in the art to have a high hole mobility, and the hole transport material can include, but is not limited to, at least one of arylamine-based organic materials, conductive polymers, block copolymers having both a conjugated portion and a non-conjugated portion, etc.

[0044] In some embodiments, the electron transport layer 16 is used to transport electrons. The electron transport layer 16 includes an electron transport material that receives electrons injected from the second electrode 12 and transfers the electrons to the light-emitting layer 13. The electron transport material is a material known in the art to have a high electron mobility, and the electron transport material can include, but is not limited to, at least one of an Al complex of 8-hydroxyquinoline, a complex containing Alq3, an organic radical compound, a hydroxyflavone-metal complex, lithium 8-hydroxyquinolate (LiQ), and a benzimidazole-based compound.

[0045] In some embodiments, the electron injection layer 17 is used to inject electrons. The electron injection layer 17 includes an electron injection material that preferably has the ability to transport electrons, has the effect of injecting electrons from the negative second electrode 12, has an excellent effect of injecting electrons into the light-emitting layer 13 or the light-emitting material, has the ability to prevent excitons generated by the light-emitting layer 13 from moving to the hole injection layer, and also has an excellent ability to form a thin film. The electron injection material includes, but is not limited to, at least one of lithium 8-hydroxyquinolate (LiQ), fluorenone, anthraquinone dimethane, biphenylquinone, thiopyran dioxide, pyrazole, diazole, triazole, imidazole, perylene tetracarboxylic acid, fluoreneylidene methane, anthrone, and their derivatives, metal complex compounds, nitrogen-containing 5-membered ring derivatives, etc.

[0046] In the embodiments of the present application, the material of the light-emitting layer 13 includes a host material, a guest material, and a sensitizer, and the host material includes a p-type host material and an n-type host material; it should be noted that the electron mobility of the light-emitting layer 13 is less than the hole mobility of the light-emitting layer 13, that is, the light-emitting layer 13 in the embodiments of the present application is hole-biased. Therefore, the mass ratio of the n-type host material in the light-emitting layer 13 is less than or equal to the mass ratio of the p-type host material in the light-emitting layer 13. Furthermore, the mobility of holes and electrons can be balanced by controlling the ratio of the p-type host material and the n-type host material, so as to improve the recombination efficiency of holes and electrons in the light-emitting layer 13, and thus effectively improve the light-emitting efficiency of the light-emitting layer 13.

[0047] In some embodiments, in the light-emitting layer 13, the mass ratio of the p-type host material to the n-type host material is greater than or equal to 1 and less than or equal to 4. For example, the mass ratio of the p-type host material to the n-type host material can be 1, 2, 3, or 4. It can be understood that, in combination with Figure 3 , Figure 4 and Figure 5 , the electron injection efficiency can be improved by increasing the proportion of the n-type host material, and then the recombination efficiency of electrons and holes in the light-emitting layer 13 can be increased, thereby improving the device efficiency, as shown in Figure 3 and Figure 4 ; however, when the proportion of the n-type host material is too high, the generation rate of excitons is greater than the radiative recombination rate of excitons, resulting in exciton quenching and reducing the lifetime of the organic light-emitting device 10, as shown in Figure 5 ; therefore, it is necessary to appropriately adjust the proportion of the n-type host material and the p-type host material to increase the device lifetime while improving the efficiency of the organic light-emitting device 10.

[0048] In some embodiments, the p-type host material may be selected from compounds containing two carbazole groups; for example, the p-type host material may be selected from at least one of the following compounds:

[0049]

[0050] The above p-type host materials can be seen in Patent CN102869659B.

[0051] In some embodiments, the p-type host material may also be selected from at least one of mCP (9,9'-(1,3-phenylene)di-9H-carbazole), CBP (4,4'-bis(9-carbazolyl)biphenyl), TCTA (4,4',4”-tris(carbazol-9-yl)triphenylamine), TAPC (4-[1-[4-[bis(4-methylphenyl)amino]phenyl]cyclohexyl]-N-(3-methylphenyl)-N-(4-methylphenyl)aniline), NPB (N-[1,1'-biphenyl]-4-yl-dibenzothiophene-4-amine), TmPyPB (1,3,5-tris[(3-pyridyl)-3-phenyl]benzene), and MADN (2-methyl-9,10-di(2-naphthyl)anthracene).

[0052] In some embodiments, the n-type host material may be selected from compounds containing one carbazole group and one triazine group; for example, the n-type host material may be selected from at least one of the following compounds:

[0053]

[0054]

[0055] The above N-type host materials can be seen in patent CN117327056A.

[0056] In some embodiments, the N-type host material can also be selected from at least one of Alq3 (aluminum 8-hydroxyquinoline), B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), Bphen (4,7-diphenyl-1,10-phenanthroline), Balq (bis(2-methyl-8-hydroxyquinolinato-N1,O8)-(1,1'-biphenyl-4-ol)aluminum), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), and TPBi (1,3,5-tris(1-phenyl-1H-benzoimidazol-2-yl)benzene).

[0057] In some embodiments, the host material can include an electron-donating group; or, the host material includes the electron-donating group and an electron-withdrawing group, and the mass ratio of the electron-donating group in the host material is greater than the mass ratio of the electron-withdrawing group in the host material; thereby, the electron injection efficiency can be improved, and further, the recombination efficiency of electrons and holes in the light-emitting layer 13 can be increased, thus improving the device efficiency.

[0058] In some embodiments, the electron-donating group can include amino, methoxy, hydroxy, alkoxy, aromatic amine (such as triphenylamine), etc. The electron-withdrawing group can include cyano, nitro, carbonyl, trifluoromethyl, pyridine ring, etc.

[0059] In addition, the material of the light-emitting layer 13 further includes a guest material, and the mass ratio of the guest material in the light-emitting layer 13 is greater than or equal to 5% and less than or equal to 12%; for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11% or 12%.

[0060] In some embodiments, the guest material can be selected from Ir phosphorescent materials; for example, the guest material can be selected from at least one of the following compounds:

[0061]

[0062] The above guest materials can be seen in patent US9193745B2.

[0063] In some embodiments, the guest material may also be selected from at least one of Ir(ppy)3 (iridium(III) tris(2-phenylpyridine)), Ir(mppy)3 (iridium(III) tris[2-(p-tolyl)pyridine]), Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N) acetylacetonate), and Firpic (iridium(III) bis(4,6-difluorophenylpyridine-N,C2) picolinate).

[0064] Furthermore, the material of the light-emitting layer 13 further includes a sensitizer, and the energy gap of the sensitizer is smaller than the energy gap of the guest material.

[0065] It should be noted that, please refer to Figure 6 , S0 represents the ground state energy level, S1 and T1 represent the excited state energy levels, and ISC represents Intersystem Crossing, specifically a non-radiative transition process in which the electrons of an excited state molecule undergo a spin inversion, causing a change in the multiplicity of the molecule.

[0066] Among them, since energy always transfers from a higher energy level to a lower energy level, when the energy level of the sensitizer is lower than that of the guest material, the energy will transfer from the guest material to the sensitizer, and the guest material acts as an intermediate layer to transfer energy, forming a cascade energy transfer structure of the host material - the guest material - the sensitizer; adding the sensitizer in the light-emitting layer 13 can transfer the energy from the host material to the guest material. At the same time, the singlet exciton lifetime of the sensitizer is short and the conversion efficiency is higher. Therefore, when the energy transfers to the sensitizer, it can effectively promote exciton transfer and reduce exciton annihilation, thereby achieving the effect of high-efficiency conversion and light emission, and thus improving the light-emitting efficiency of the organic light-emitting device.

[0067] In some embodiments, the difference between the energy gap of the guest material and the energy gap of the sensitizer is greater than or equal to 0.05 eV.

[0068] In some embodiments, the energy gap of the sensitizer is greater than or equal to 2 eV and less than or equal to 2.3 eV. The guest material is a green light guest material with an energy gap of 2.35 eV.

[0069] In some embodiments, the sensitizer is selected from boron-nitrogen materials. For example, the sensitizer may be selected from at least one of the following compounds:

[0070]

[0071]

[0072] The above sensitizers can be seen in Patent CN115093437A.

[0073] Furthermore, the embodiments of the present application provide Embodiment 1 to Embodiment 4 to verify the device efficiency of the mass ratio of the p-type host material to the n-type host material under different conditions.

[0074] In Embodiment 1, the p-type host material is mCP (9,9'-(1,3-phenylene)bis-9H-carbazole), and the mass (volume) concentration is 13.725 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 9.15 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L; the sensitizer is: And the mass (volume) concentration is 0.125 g / L. And in Embodiment 1, the mass ratio of the p-type host material to the n-type host material is 6:4.

[0075] In Embodiment 2, the p-type host material is mCP (9,9'-(1,3-phenylene)bis-9H-carbazole), and the mass (volume) concentration is 16.0125 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 6.8625 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L; the sensitizer is: And the mass (volume) concentration is 0.125 g / L. And in Embodiment 2, the mass ratio of the p-type host material to the n-type host material is 7:3.

[0076] In Embodiment 3, the p-type host material is mCP (9,9'-(1,3-phenylene)bis-9H-carbazole), and the mass (volume) concentration is 13.725 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 9.15 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L; the sensitizer is: And the mass (volume) concentration is 0.125 g / L. And in Embodiment 3, the mass ratio of the p-type host material to the n-type host material is 6:4.

[0077] In Example 4, the p-type host material is mCP (9,9'-(1,3-phenylene)di-9H-carbazole), and the mass (volume) concentration is 11.4375 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 11.4375 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L; the sensitizer is: and the mass (volume) concentration is 0.125 g / L. In Example 4, the mass ratio of the p-type host material to the n-type host material is 5:5.

[0078] Continuing from the above, the curve as shown in Figure 7 is obtained; wherein, the abscissa represents the light color, the ordinate represents the device efficiency, and it can be seen from Figure 7 that by comparing the device efficiencies at the same light color, it can be seen that as the proportion of the n-type host material increases, the device efficiency at the same light color gradually increases, that is, it shows that in the embodiments of the present application, by selecting and controlling the mass ratio of the p-type host material to the n-type host material, the luminous efficiency and lifespan of the organic light-emitting device can be effectively improved.

[0079] Furthermore, the embodiments of the present application also provide a comparative example, Example 5, and Example 6, and verify the device efficiencies corresponding to whether the sensitizer is doped in the light-emitting layer 13. Among them, in the comparative example, the sensitizer is not doped in the light-emitting layer 13, while different sensitizers are doped in Example 5 and Example 6.

[0080] Specifically, in the comparative example, the p-type host material is CBP (4,4'-bis(9-carbazolyl)biphenyl), and the mass (volume) concentration is 16.1 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 6.9 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L.

[0081] In Example 5, the p-type host material is CBP (4,4'-bis(9-carbazolyl)biphenyl), and the mass (volume) concentration is 16.0125 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-bis(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 6.8625 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L; the sensitizer is: and the mass (volume) concentration is 0.125 g / L.

[0082] In Example 6, the p-type host material is CBP (4,4'-bis(9-carbazolyl)biphenyl), and the mass (volume) concentration is 16.0125 g / L; the n-type host material is B3PYMPM (4,6-bis(3,5-bis(3-pyridyl)phenyl)-2-methylpyrimidine), and the mass (volume) concentration is 6.8625 g / L; the guest material is Ir(ppy)2acac (iridium(III) bis(2-phenylpyridine-C2,N)acetylacetonate), and the mass (volume) concentration is 2 g / L; the sensitizer is: and the mass (volume) concentration is 0.125 g / L.

[0083] Continuing from the above, the curve as shown in Figure 8 is obtained; wherein, Figure 8 the abscissa is the current density and the ordinate is the device efficiency; it can be seen from Figure 8 that the luminous efficiency of the organic light-emitting device 10 in Example 5 and Example 6 is significantly higher than that of the organic light-emitting device 10 in the comparative example, which indicates that by doping the sensitizer in the light-emitting layer 13 in the embodiments of the present application, the luminous efficiency of the organic light-emitting device can be effectively improved.

[0084] In some embodiments, the mass ratio of the sensitizer in the light-emitting layer is greater than or equal to 0.2% and less than or equal to 0.8%.

[0085] In summary, the embodiments of the present application improve the luminous efficiency of the organic light-emitting device 10 by doping the sensitizer in the light-emitting layer 13; at the same time, the ratio of the n-type host material and the p-type host material in the double host material is also selected and designed to further improve the luminous efficiency and lifespan of the organic light-emitting device 10.

[0086] In addition, please refer to Figure 9 , the embodiments of the present application also provide a display panel 200, and the display panel 200 includes the organic light-emitting device 10 described in the above embodiments.

[0087] In some embodiments, the display panel 200 further includes an array substrate 20, the organic light-emitting device 10 is disposed on the array substrate 20, and the array substrate 20 includes a plurality of thin-film transistors, and the organic light-emitting device 10 is connected to the thin-film transistors.

[0088] In some embodiments, the array substrate 20 includes a substrate and a thin-film transistor layer disposed on the substrate.

[0089] In some embodiments, the substrate may be a rigid substrate, such as a glass substrate; or, the substrate may be a flexible substrate, such as a substrate formed of polyimide. When the substrate is a flexible substrate, the substrate may be formed of multiple sub-substrates with the same material such as polyimide, and adjacent sub-substrates are bonded by an adhesive sub-layer.

[0090] In some embodiments, the thin-film transistor layer includes thin-film transistors, the thin-film transistors include a semiconductor located on the substrate, and the semiconductor may be formed of polysilicon or a metal oxide (such as indium gallium zinc oxide). Wherein, the semiconductor is divided into a channel region and a source region and a drain region formed on both sides of the channel region. The thin-film transistor layer further includes a first gate insulating layer that covers the semiconductor. The thin-film transistor further includes a first gate formed on the first gate insulating layer, and the first gate overlaps with the channel region. The first gate may be formed as multiple layers or a single layer including a low-resistance material such as Al, Ti, Mo, Cu, Ni, or an alloy thereof, or a material with high anti-corrosion performance. The thin-film transistor layer further includes a second gate insulating layer that covers the first gate. The thin-film transistor further includes a second gate located on the second gate insulating layer, and the second gate overlaps with the first gate, and the second gate may be formed as multiple layers or a single layer including a low-resistance material such as Al, Ti, Mo, Cu, Ni, or an alloy thereof, or a material with high anti-corrosion performance. The thin-film transistor layer further includes a first interlayer insulating layer formed on the second gate. Wherein, the first interlayer insulating layer and the first gate insulating layer and the second gate insulating layer include a source contact hole and a drain contact hole, and the source region and the drain region are respectively exposed through the source contact hole and the drain contact hole.

[0091] The thin film transistor further includes a source electrode and a drain electrode which are disposed in the same layer. Both the source electrode and the drain electrode are formed on the first interlayer insulating layer. The source electrode passes through the source contact hole to be connected to the source region, and the drain electrode passes through the drain contact hole to be connected to the drain region. Wherein, the source electrode and the drain electrode can be multiple layers or a single layer formed of a low-resistance material such as Al, Ti, Mo, Cu, Ni, or an alloy thereof, or a material with high anti-corrosion performance. For example, the source electrode and the drain electrode can be a triple layer such as Ti / Cu / Ti, Ti / Ag / Ti, Ti / Al / Ti or Mo / Al / Mo, or other single layer or multi-layer structures.

[0092] In some embodiments, the array substrate 20 further includes a planarization layer on a side of the first interlayer insulating layer away from the substrate, and the planarization layer covers the source electrode and the drain electrode.

[0093] Further, the organic light emitting device 10 is disposed on the planarization layer, and the first electrode 11 in the organic light emitting device 10 can be connected to the source electrode or the drain electrode to achieve signal transmission.

[0094] In summary, in the embodiments of the present application, the electron mobility of the light emitting layer 13 is less than the hole mobility of the light emitting layer 13, that is, the light emitting layer 13 in the embodiments of the present application is hole-biased. Therefore, the mass ratio of the n-type host material in the light emitting layer 13 is less than or equal to the mass ratio of the p-type host material in the light emitting layer 13. Furthermore, the hole and electron mobilities can be balanced by controlling the ratio of the p-type host material and the n-type host material, so as to improve the recombination efficiency of holes and electrons in the light emitting layer 13, and further effectively improve the light emitting efficiency of the light emitting layer 13. Further, in the embodiments of the present application, the electron injection efficiency can be improved by increasing the ratio of the n-type host material, and further the recombination efficiency of electrons and holes in the light emitting layer 13 can be increased, thereby improving the device efficiency; however, when the ratio of the n-type host material is too high, the exciton generation rate is greater than the exciton radiative recombination rate, resulting in exciton quenching and reducing the lifetime of the organic light emitting device 10; therefore, in the embodiments of the present application, by adjusting the ratio of the n-type host material and the p-type host material, the efficiency of the organic light emitting device 10 is improved while the device lifetime is increased.

[0095] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0096] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0097] Among the embodiments, implementation manners, and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0098] The above are only the preferred embodiments of the present application and do not impose any formal limitations on the present application. However, any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. An organic light emitting device, characterized in that, The organic light-emitting device includes a first electrode and a second electrode disposed opposite to each other, and a light-emitting layer disposed between the first electrode and the second electrode; Wherein, the light-emitting layer includes a host material, a guest material, and a sensitizer, the host material includes an n-type host material and a p-type host material, and the mass ratio of the n-type host material in the light-emitting layer is less than or equal to the mass ratio of the p-type host material in the light-emitting layer.

2. The organic light-emitting device according to claim 1, characterized in that, In the light-emitting layer, the mass ratio of the p-type host material to the n-type host material is greater than or equal to 1 and less than or equal to 4.

3. The organic light-emitting device according to claim 1, characterized in that, The mass ratio of the sensitizer in the light-emitting layer is greater than or equal to 0.2% and less than or equal to 0.8%.

4. The organic light-emitting device according to claim 1, characterized in that, The mass ratio of the guest material in the light-emitting layer is greater than or equal to 5% and less than or equal to 12%.

5. The organic light-emitting device according to any one of claims 1 to 4, characterized in that, The host material includes an electron-donating group; Alternatively, the host material includes the electron-donating group and an electron-accepting group, and the mass ratio of the electron-donating group in the host material is greater than the mass ratio of the electron-accepting group in the host material.

6. The organic light emitting device according to any one of claims 1 to 4, characterized in that, The electron mobility of the light-emitting layer is less than the hole mobility of the light-emitting layer.

7. The organic light-emitting device according to any one of claims 1 to 4, characterized in that, The energy gap of the sensitizer is less than the energy gap of the guest material.

8. The organic light-emitting device according to claim 7, characterized in that, The difference between the energy gap of the guest material and the energy gap of the sensitizer is greater than or equal to 0.05 eV.

9. The organic light emitting device according to claim 7, wherein The energy gap of the sensitizer is greater than or equal to 2 eV and less than or equal to 2.3 eV, and the guest material is a green light-emitting guest material.

10. A display panel, characterized in that, The display panel includes the organic light-emitting device according to any one of claims 1 to 9.

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