Organic light emitting device, display panel and display device

Abstract

The application discloses an organic light-emitting device, a display panel and a display device, and belongs to the technical field of display. The organic light-emitting device comprises a first light-emitting layer, a second light-emitting layer, a hole blocking layer and an electron transport layer. The electron transport layer in the organic light-emitting device can have a deeper lowest unoccupied molecular orbital energy level relative to the hole blocking layer and a shallower lowest unoccupied molecular orbital energy level relative to the first electron-type host material. Therefore, the first light-emitting layer and the second light-emitting layer can achieve better carrier balance. By regulating the material selection of the electron transport layer, the organic light-emitting device can realize the sharing of the first light-emitting layer and the second light-emitting layer, so that the efficiency and the service life of the organic light-emitting device prepared by using different light-emitting layers are both high, and the display effect of the display panel is better.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an organic light emitting device, a display panel and a display device. BACKGROUND

[0002] Organic light emitting diode (OLED) has been praised as the next generation display device due to its self-emission, high efficiency, bright color, thinness, power saving and rollability, and has attracted more and more attention in recent years.

[0003] The OLED display panel usually includes a driving backplane and a plurality of light emitting devices on one side of the driving backplane. The light emitting device includes an anode layer, an organic light emitting layer and a cathode layer which are stacked. Under the action of the electric field formed between the anode layer and the cathode layer, the holes generated by the anode layer and the electrons generated by the cathode layer can move towards the organic light emitting layer, and the holes and the electrons can combine into excitons in the organic light emitting layer to emit light.

[0004] However, the red organic light emitting layer and the green light emitting layer using super fluorescent system can meet the display purpose of the display device, but the blue light emitting layer generally still uses fluorescent system. Due to the large difference in the intrinsic mechanism between the super fluorescent light emitting layer and the fluorescent light emitting layer, the super fluorescent light emitting layer and the fluorescent light emitting layer will cause great difference in the efficiency and the service life of the display device when they are used together, thereby resulting in poor display effect of the OLED display panel. SUMMARY

[0005] The present application provides an organic light emitting device, a display panel and a display device. The problem of poor display effect of the display panel can be solved, and the technical solution is as follows:

[0006] In one aspect, an organic light emitting device is provided, including: a first light emitting layer, a second light emitting layer, a hole blocking layer and an electron transport layer;

[0007] The first light emitting layer and the second light emitting layer are arranged side by side, the hole blocking layer is located on the same side of the first light emitting layer and the second light emitting layer, and the electron transport layer is located on the side of the hole blocking layer away from the first light emitting layer and the second light emitting layer;

[0008] The first light emitting layer includes a hole type host material, a first electron type host material and a first guest material; and the second light emitting layer includes a second electron type host material and a second guest material.

[0009] The hole blocking layer has a higher triplet first excited state energy relative to the first electron-type host material and the second electron-type host material, a deeper highest occupied molecular orbital energy level relative to the first electron-type host material and the second electron-type host material, and a shallower lowest unoccupied molecular orbital energy level relative to the first electron-type host material and the second electron-type host material.

[0010] The electron transport layer has a deeper lowest unoccupied molecular orbital energy level relative to the hole blocking layer and a shallower lowest unoccupied molecular orbital energy level relative to the first electron-type host material.

[0011] Optionally, the first light-emitting layer comprises a red light-emitting layer and a green light-emitting layer arranged side by side, and the second light-emitting layer comprises a blue light-emitting layer.

[0012] Optionally, the red light-emitting layer comprises a red hole-type host material, a red electron-type host material, and a red guest material.

[0013] The electron transport layer satisfies:

[0014] 2 x LUMO(P) - LUMO(S) - LUMO(B) ≧ 0.6 eV.

[0015] LUMO(P) represents a lowest unoccupied molecular orbital energy level of a material of the hole blocking layer (300), LUMO(S) represents a lowest unoccupied molecular orbital energy level of a material of the electron transport layer (400), and LUMO(B) represents a lowest unoccupied molecular orbital energy level of the red electron-type host material.

[0016] Optionally, the red light-emitting layer satisfies:

[0017] △Est = S1(B) - T1(B) < 0.3 eV.

[0018] T1(A) > T1(B) > T1(C).

[0019] S1(B) represents a singlet first excited state energy of the red electron-type host material, T1(A) represents a triplet first excited state energy of the red hole-type host material, T1(B) represents a triplet first excited state energy of the red electron-type host material, and T1(C) represents a triplet first excited state energy of the red guest material.

[0020] Optionally, the green light-emitting layer comprises a green hole-type host material, a green electron-type host material, and a green guest material.

[0021] The electron transport layer satisfies:

[0022] 2 x LUMO(P) - LUMO(S) - LUMO(H) ≧ 0.6 eV;

[0023] wherein LUMO(P) represents a lowest unoccupied molecular orbital energy level of a material of the hole blocking layer (300), LUMO(S) represents a lowest unoccupied molecular orbital energy level of a material of the electron transport layer (400), and LUMO(H) represents a lowest unoccupied molecular orbital energy level of the green electron-type host material.

[0024] Optionally, the green light-emitting layer satisfies:

[0025] △Est = S1(H) - T1(H) < 0.3 eV;

[0026] T1(G) > T1(H) > T1(J);

[0027] wherein S1(H) represents a singlet first excited state energy of the green electron-type host material, T1(G) represents a triplet first excited state energy of the green hole-type host material, T1(H) represents a triplet first excited state energy of the green electron-type host material, and T1(J) represents a triplet first excited state energy of the green guest material.

[0028] Optionally, the red light-emitting layer comprises a red hole-type host material, a red electron-type host material, and a red guest material; the green light-emitting layer comprises a green hole-type host material, a green electron-type host material, and a green guest material; the blue light-emitting layer comprises a blue electron-type host material and a blue guest material; and the hole blocking layer satisfies:

[0029] T1(P) - T1(B) ≧ 0.1 eV;

[0030] T1(P) - T1(H) ≧ 0.1 eV;

[0031] T1(P) - T1(R) ≧ 0.1 eV;

[0032] wherein T1(P) represents a triplet first excited state energy of a material of the hole blocking layer (300), T1(B) represents a triplet first excited state energy of the red electron-type host material, T1(H) represents a triplet first excited state energy of the green electron-type host material, and T1(R) represents a triplet first excited state energy of the blue electron-type host material.

[0033] Optionally, the hole blocking layer satisfies:

[0034] HOMO(B) - HOMO(P) > 0.2 eV;

[0035] HOMO(H) - HOMO(P) > 0.2 eV;

[0036] HOMO(R) - HOMO(P) > 0.2 eV;

[0037] wherein HOMO(P) represents a highest occupied molecular orbital energy level of a material of the hole blocking layer (300), HOMO(B) represents a highest occupied molecular orbital energy level of the red electron-type host material, HOMO(H) represents a highest occupied molecular orbital energy level of the green electron-type host material, and HOMO(R) represents a highest occupied molecular orbital energy level of the blue electron-type host material.

[0038] Optionally, the hole blocking layer satisfies:

[0039] LUMO(P) - LUMO(B) > 0.2 eV;

[0040] LUMO(P) - LUMO(H) > 0.2 eV;

[0041] LUMO(P) - LUMO(R) > 0.2 eV;

[0042] wherein LUMO(P) represents a lowest unoccupied molecular orbital energy level of a material of the hole blocking layer (300), LUMO(B) represents a lowest unoccupied molecular orbital energy level of the red electron-type host material, LUMO(H) represents a lowest unoccupied molecular orbital energy level of the green electron-type host material, and LUMO(R) represents a lowest unoccupied molecular orbital energy level of the blue electron-type host material.

[0043] Optionally, the first guest material comprises a fluorescent guest material; and the first electron-type host material comprises one of a metal complex material and a thermally activated delayed fluorescence material.

[0044] Optionally, in a case where the first electron-type host material comprises the metal complex material, the first guest material further comprises a third electron-type host material.

[0045] wherein the electron transport layer further has a lowest unoccupied molecular orbital energy level shallower than the third electron-type host material.

[0046] Optionally, the first guest material and the second guest material both comprise boron element.

[0047] In another aspect, a display panel is provided, which comprises a driving backplate and a plurality of organic light emitting devices located on one side of the driving backplate, the organic light emitting device being any of the above-mentioned organic light emitting devices.

[0048] Optionally, when the display surface of the display panel is irradiated by 500 nm light, the organic light emitting device can emit light with a spectral peak wavelength in the range of 515 nm to 540 nm; when the display surface of the display panel is irradiated by 600 nm light, the organic light emitting device can emit light with a spectral peak wavelength in the range of 615 nm to 640 nm.

[0049] In yet another aspect, a display device is provided, which comprises a driving assembly and a display panel electrically connected to the driving assembly, the display panel being the above-mentioned display panel.

[0050] The technical scheme provided by the embodiments of the present application has at least the following beneficial effects:

[0051] An organic light emitting device comprises a first light emitting layer, a second light emitting layer, a hole blocking layer and an electron transport layer. The electron transport layer in the organic light emitting device can have a deeper lowest unoccupied molecular orbital energy level relative to the hole blocking layer and a shallower lowest unoccupied molecular orbital energy level relative to the first electron-type host material. Therefore, the first light emitting layer and the second light emitting layer can both achieve better carrier balance. By regulating the material selection of the electron transport layer, the organic light emitting device can achieve the sharing of the first light emitting layer and the second light emitting layer, so as to ensure that the organic light emitting devices prepared by using different light emitting layers both have high efficiency and long service life, and thus the display effect of the display panel is good. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical schemes in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0053] Figure 1 is a film layer structure schematic diagram of an organic light emitting device provided by the embodiments of the present application;

[0054] Figure 2 is a film layer structure schematic diagram of another organic light emitting device provided by the embodiments of the present application;

[0055] Figure 3 is a film layer structure schematic diagram of still another organic light emitting device provided by the embodiments of the present application;

[0056] Figure 4 is a schematic diagram of a film layer structure of another organic light-emitting device provided by an embodiment of the present application;

[0057] Figure 5 is a voltage and current density characteristic curve of a red single-carrier device provided by an embodiment of the present application;

[0058] Figure 6 is a voltage and current density characteristic curve of a green single-carrier device provided by an embodiment of the present application;

[0059] Figure 7 is a voltage and current density characteristic curve of a blue single-carrier device provided by an embodiment of the present application;

[0060] Figure 8 is a comparison diagram of physical property parameters of a material of an organic light-emitting device provided by an embodiment of the present application;

[0061] Figure 9 is a comparison diagram of physical property parameters of a material of another organic light-emitting device provided by an embodiment of the present application;

[0062] Figure 10 is a comparison diagram of physical property parameters of a material of yet another organic light-emitting device provided by an embodiment of the present application;

[0063] Figure 11 is a curve of change of mobility of an electron transport layer material with voltage provided by an embodiment of the present application;

[0064] Figure 12 is a comparison diagram of physical property parameters of a material of another organic light-emitting device provided by an embodiment of the present application;

[0065] Figure 13 is a comparison diagram of physical property parameters of a material of an organic light-emitting device provided by another embodiment of the present application;

[0066] Figure 14 is a schematic diagram of a film layer structure of a display panel provided by an embodiment of the present application;

[0067] Figure 15 is a schematic diagram of a film layer structure of another display panel provided by an embodiment of the present application. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0069] Reference should be made to Figure 1 , Figure 1is a schematic diagram of a film layer structure of an organic light-emitting device provided by an embodiment of the present application. The organic light-emitting device 000 can include a first light-emitting layer 100, a second light-emitting layer 200, a hole blocking layer 300, and an electron transport layer 400.

[0070] The first light-emitting layer 100 and the second light-emitting layer 200 in the organic light-emitting device 000 can be arranged side by side. Here, the organic light-emitting device 000 can be arranged on a driving backplane, and the driving backplane can have a plurality of pixel driving circuits corresponding to the plurality of organic light-emitting devices 000 one by one. Among them, the driving backplane can transmit a driving signal to the anode layer in the corresponding organic light-emitting device 000 through each pixel driving circuit, so that the first light-emitting layer 100 and the second light-emitting layer 200 in the corresponding organic light-emitting device 000 can emit light outward.

[0071] The first light-emitting layer 100 in the organic light-emitting device 000 can include a hole type host material, a first electron type host material, and a first guest material.

[0072] Among them, the hole mobility of the hole type host material can be higher than the electron mobility of the hole type host material. The first electron type host material can include a material with a long excited state lifetime property, for example, the first electron type host material can have a long excited state lifetime of more than 100 nanoseconds, and the electron mobility of the first electron type host material can be higher than the hole mobility of the first electron type host material. In the present application, the first guest material can include a fluorescent guest material. In other possible implementation manners, the first guest material can include a phosphorescent guest material.

[0073] The second light-emitting layer 200 in the organic light-emitting device 000 can include a second electron type host material and a second guest material. Among them, the electron mobility of the second electron type host material can be at least one order of magnitude higher than the hole mobility of the second electron type host material.

[0074] The hole blocking layer 300 in the organic light-emitting device 000 can be located on the same side of the first light-emitting layer 100 and the second light-emitting layer 200. Here, the hole blocking layer 300 can be a continuously distributed film layer structure. That is, the hole blocking layer 300 can be a shared layer of the first light-emitting layer 100 and the second light-emitting layer 200. Among them, the hole blocking layer 300 can reduce the probability of leakage of holes in the first light-emitting layer 100 and the second light-emitting layer 200 to one side of the electron transport layer 400. For example, the material of the hole blocking layer 300 can include triazine and its derivatives. In one possible implementation manner, the material of the hole blocking layer 300 can contain deuterium elements.

[0075] The electron transport layer 400 in the organic light emitting device 000 can be located on the side of the hole blocking layer 300 facing away from the first light emitting layer 100 and the second light emitting layer 200. Here, the electron transport layer 400 can be used to transport electrons to the first light emitting layer 100 and the second light emitting layer 200. For example, the material of the electron transport layer 400 can be a material having a structure of triazine and its derivatives, etc. In one possible implementation, the electron transport layer 400 can be formed by blending a material having a structure of triazine and its derivatives, etc. with lithium quinolate (LIQ) in a certain ratio.

[0076] In the organic light emitting device 000, the electron transport layer 400 can also have a continuous distribution film layer structure. Here, the continuous distribution film layer structure means that the film layer structure is continuously connected at each position, and the film layer structure can be obtained by evaporation using an open mask. For example, the hole blocking layer 300 can include a first blocking portion corresponding to the first light emitting layer 100, a second blocking portion corresponding to the second light emitting layer 200, and a third blocking portion connecting the first blocking portion and the second blocking portion. Similarly, the electron transport layer 400 can include a first transport portion corresponding to the first light emitting layer 100, a second transport portion corresponding to the second light emitting layer 200, and a third transport portion connecting the first transport portion and the second transport portion.

[0077] In the present application, the hole blocking layer 300 in the organic light emitting device 000 can have a higher triplet first excited state energy relative to the first electron type host material and the second electron type host material. In this way, by having a hole blocking layer 300 with a higher triplet first excited state energy, the excitons formed in the first light emitting layer 100 and the second light emitting layer 200 can be prevented from leaking along the side facing the electron transport layer 400, thereby improving the light emitting efficiency of the organic light emitting device 000.

[0078] The hole blocking layer 300 in the organic light emitting device 000 can have a deeper highest occupied molecular orbital energy level relative to the first electron type host material and the second electron type host material. In this way, by having a hole blocking layer 300 with a deeper highest occupied molecular orbital energy level, the holes in the first light emitting layer 100 and the second light emitting layer 200 can be effectively inhibited from leaking along the side facing the electron transport layer 400, thereby ensuring that the holes can combine with the electrons in the first light emitting layer 100 and the second light emitting layer 200 as much as possible, and further ensuring that more excitons can be generated in the first light emitting layer 100 and the second light emitting layer 200.

[0079] The hole blocking layer 300 in the organic light emitting device 000 can also have a lower unoccupied molecular orbital energy level than the first electron-type host material and the second electron-type host material. In this way, by having a hole blocking layer 300 with a lower unoccupied molecular orbital energy level, the transmission speed of the electrons transmitted to the first light emitting layer 100 and the second light emitting layer 200 can be reduced to ensure that the first light emitting layer 100 and the second light emitting layer 200 are less likely to have an electron excess.

[0080] In the embodiments of the present application, the electron transport layer 400 in the organic light emitting device 000 can have a lower unoccupied molecular orbital energy level than the hole blocking layer 300 and a lower unoccupied molecular orbital energy level than the first electron-type host material. In this case, the first light emitting layer 100 and the second light emitting layer 200 can both achieve a better carrier balance, and by regulating the material selection of the electron transport layer 400, the organic light emitting device can achieve the sharing of the first light emitting layer 100 and the second light emitting layer 200, so as to ensure that the organic light emitting device 000 prepared by using different light emitting layers has a high efficiency and a long service life, and thus the display effect of the display panel can be better.

[0081] In summary, the organic light emitting device provided in the embodiments of the present application includes a first light emitting layer, a second light emitting layer, a hole blocking layer and an electron transport layer. The electron transport layer in the organic light emitting device can have a lower unoccupied molecular orbital energy level than the hole blocking layer and a lower unoccupied molecular orbital energy level than the first electron-type host material. Therefore, the first light emitting layer and the second light emitting layer can both achieve a better carrier balance. Moreover, by regulating the material selection of the electron transport layer, the organic light emitting device can achieve the sharing of the first light emitting layer and the second light emitting layer, so as to ensure that the organic light emitting device prepared by using different light emitting layers has a high efficiency and a long service life, and thus the display effect of the display panel can be better.

[0082] In the embodiments of the present application, please refer to Figure 2 , Figure 2 is a film layer structure schematic diagram of another organic light emitting device provided in the embodiments of the present application. The first light emitting layer 100 can include a red light emitting layer 101 and a green light emitting layer 102 arranged side by side, and the second light emitting layer 200 can include a blue light emitting layer 201.

[0083] It should be noted that the hole-type host material in the first light-emitting layer 100 can include a red hole-type host material and a green hole-type host material; the first electron-type host material in the first light-emitting layer 100 can include a red electron-type host material and a green electron-type host material; and the first guest material in the first light-emitting layer 100 can include a red guest material and a green guest material. Therefore, the red light-emitting layer 101 in the first light-emitting layer 100 can include the red hole-type host material A, the red electron-type host material B, and the red guest material C. The green light-emitting layer 102 in the first light-emitting layer 100 can include the green hole-type host material G, the green electron-type host material H, and the green guest material J.

[0084] In the present application, the mole ratio of the red hole-type host material A in the red light-emitting layer 101 in the first light-emitting layer 100 needs to be the highest, and the mole ratio of the red guest material C in the red light-emitting layer 101 needs to be no higher than 3%. In this way, it can be ensured that there are more red hole-type host materials A distributed in the red light-emitting layer 101, so as to improve the light-emitting efficiency of the organic light-emitting device 000 for emitting red light.

[0085] Here, the hole mobility of the red hole-type host material A is at least one order of magnitude higher than its electron mobility, the electron mobility of the red electron-type host material B is at least one order of magnitude higher than its hole mobility, and the hole mobility of the red hole-type host material A is within one order of magnitude of the electron mobility of the red electron-type host material B. In this way, through the cooperation of the red hole-type host material A and the red electron-type host material B, the charge transmission in the red light-emitting layer 101 can be ensured to be relatively balanced.

[0086] In the present application, in the red light-emitting layer 101, the single state first excitation state energy S1(B) of the red electron-type host material and the triplet state first excitation state energy T1(B) need to satisfy: △Est=S1(B)-T1(B)<0.3eV.

[0087] The triplet state first excitation state energy T1(A) of the red hole-type host material, the triplet state first excitation state energy T1(B) of the red electron-type host material, and the triplet state first excitation state energy T1(C) of the red guest material need to satisfy: T1(A)>T1(B)>T1(C).

[0088] In the present application, the absorption spectrum of the red guest material C and the emission spectrum of the red electron-type host material B can have a large overlapping area. In this way, the red guest material C can be ensured to emit light more fully. It should be noted that the overlapping area of the absorption spectrum of the red guest material C and the emission spectrum of the red electron-type host material B should be not less than 55% of the area of the emission spectrum of the red electron-type host material B. For example, the wavelength range of the absorption spectrum of the red guest material C can be 580 nm to 610 nm, and the wavelength range of the emission spectrum of the red electron-type host material B can be 615 nm to 640 nm.

[0089] For example, the red hole-type host material A can be a carbazole derivative; the red electron-type host material B can be a “carbazole-triazine” or “carbazole-cyan” derivative with a D-A structure, or a metal complex material; and the red guest material C can be a fluoroboron material or a boron-nitrogen material, etc. In one possible implementation, the red guest material C can be a common fluorescent material or a delayed fluorescent material, which is not limited in the embodiments of the present application.

[0090] In the embodiments of the present application, the electron transport layer 400 in the organic light-emitting device 000 can satisfy:

[0091] 2 x LUMO(P) - LUMO(S) - LUMO(B) >= 0.6 eV

[0092] Wherein, LUMO(P) represents the lowest unoccupied molecular orbital energy level of the material of the hole blocking layer 300, LUMO(S) represents the lowest unoccupied molecular orbital energy level of the material of the electron transport layer 400, and LUMO(B) represents the lowest unoccupied molecular orbital energy level of the red electron-type host material.

[0093] Here, since the electron transport layer 400 in the organic light-emitting device 000 can have a lower unoccupied molecular orbital energy level relative to the hole blocking layer 300 and a higher unoccupied molecular orbital energy level relative to the red electron-type host material B. In this case, a better carrier balance can be achieved in the red light-emitting layer 101, so as to ensure that the efficiency and the service life of the organic light-emitting device 000 for emitting red light are both high.

[0094] In the present application, the mole percentage of the green hole-type host material G in the green light-emitting layer 102 in the first light-emitting layer 100 needs to be the highest, and the mole percentage of the green guest material J in the green light-emitting layer 102 needs to be not higher than 3%. In this way, it can be ensured that there is more green hole-type host material G distributed in the green light-emitting layer 102, so as to improve the light-emitting efficiency of the green organic light-emitting device 000.

[0095] Here, the hole mobility of the green hole-transporting host material G is at least one order of magnitude higher than the electron mobility thereof, the electron mobility of the green electron-transporting host material H is at least one order of magnitude higher than the hole mobility thereof, and the hole mobility of the green hole-transporting host material G is within one order of magnitude of the electron mobility of the green electron-transporting host material H. In this way, the charge transport in the green light-emitting layer 102 can be ensured to be relatively balanced through the cooperation of the green hole-transporting host material G and the green electron-transporting host material H.

[0096] In the embodiment of the present application, in the green light-emitting layer 102, the singlet first excited state energy S1(H) of the green electron-transporting host material and the triplet first excited state energy T1(H) thereof need to satisfy: ΔEst=S1(H)-T1(H)<0.3eV.

[0097] The triplet first excited state energy T1(G) of the green hole-transporting host material, the triplet first excited state energy T1(H) of the green electron-transporting host material, and the triplet first excited state energy T1(J) of the green guest material need to satisfy: T1(G)>T1(H)>T1(J).

[0098] In the present application, the absorption spectrum of the green guest material J and the emission spectrum of the green electron-transporting host material H can have a relatively large overlapping area. In this way, the green guest material J can be ensured to emit light more fully. It should be noted that the overlapping area of the absorption spectrum of the green guest material J and the emission spectrum of the green electron-transporting host material H needs to be no less than 50% of the emission spectrum area of the green electron-transporting host material H. For example, the wavelength range of the absorption spectrum of the green guest material J can be 490 nm to 510 nm, and the wavelength range of the emission spectrum of the green electron-transporting host material H can be 515 nm to 540 nm.

[0099] For example, the green hole-transporting host material G can be a carbazole derivative; the green electron-transporting host material H can be a "carbazole-triazine" or "carbazole-cyan" derivative having a D-A structure, or a metal complex material; and the green guest material J can be a fluoroboron material or a boron-nitrogen material, etc. In one possible implementation manner, the green guest material J can be a common fluorescent material or a delayed fluorescent material, and the present embodiment is not limited in this regard.

[0100] In the embodiment of the present application, the electron transport layer 400 in the organic light-emitting device 1000 can satisfy:

[0101] 2×LUMO(P)-LUMO(S)-LUMO(H)≧0.6eV

[0102] LUMO (P) - LUMO (S) > 0.1 eV; LUMO (P) - LUMO (H) > 0.1 eV; and LUMO (P) - LUMO (R) > 0.1 eV.

[0103] Here, the electron transport layer 400 in the organic light emitting device 000 can have a lower unoccupied molecular orbital energy level relative to the hole blocking layer 300 and a higher unoccupied molecular orbital energy level relative to the green electron-type host material H. In this case, a better carrier balance can be achieved in the green light emitting layer 102, thereby ensuring that the efficiency and lifetime of the organic light emitting device 000 for emitting green light are both high.

[0104] In the embodiment of the present application, the blue light emitting layer 201 in the second light emitting layer 200 can include a blue electron-type host material R and a blue guest material S. Here, the electron mobility of the blue electron-type host material R is at least one order of magnitude higher than its hole mobility. For example, the blue electron-type host material R can include anthracene, fluorene, pyrene derivatives. The blue guest material S can include fluorene, pyrene, boron-nitrogen materials, etc. Here, the doping concentration range of the blue guest material S can be 0.5% to 5%.

[0105] In the present application, the hole blocking layer 300 can satisfy:

[0106] T1 (P) - T1 (B) > 0.1 eV; T1 (P) - T1 (H) > 0.1 eV; and T1 (P) - T1 (R) > 0.1 eV.

[0107] T1 (P) - T1 (B) > 0.1 eV; T1 (P) - T1 (H) > 0.1 eV; and T1 (P) - T1 (R) > 0.1 eV.

[0108] T1 (P) - T1 (B) > 0.1 eV; T1 (P) - T1 (H) > 0.1 eV; and T1 (P) - T1 (R) > 0.1 eV.

[0109] T1 (P) - T1 (B) > 0.1 eV; T1 (P) - T1 (H) > 0.1 eV; and T1 (P) - T1 (R) > 0.1 eV.

[0110] Here, it can be seen from the above inequalities that the material P of the hole blocking layer 300 in the organic light emitting device 000 has a higher first excited triplet state energy relative to the red electron-type host material B, the green electron-type host material H and the blue electron-type host material R. In this way, the triplet excitons formed in the red light emitting layer 101, the green light emitting layer 102 and the blue light emitting layer 201 can not easily leak along the side towards the electron transport layer 400, thereby improving the light emitting efficiency of the organic light emitting device 000.

[0111] In the embodiments of the present application, the hole blocking layer 300 can satisfy:

[0112] HOMO(B) - HOMO(P) > 0.2 eV;

[0113] HOMO(H) - HOMO(P) > 0.2 eV;

[0114] HOMO(R) - HOMO(P) > 0.2 eV;

[0115] wherein HOMO(P) represents the highest occupied molecular orbital energy level of the material of the hole blocking layer 300, HOMO(B) represents the highest occupied molecular orbital energy level of the red electron-transporting host material, HOMO(H) represents the highest occupied molecular orbital energy level of the green electron-transporting host material, and HOMO(R) represents the highest occupied molecular orbital energy level of the blue electron-transporting host material.

[0116] Here, it can be seen from the above inequalities that the material P of the hole blocking layer 300 in the organic light-emitting device 000 has a deeper highest occupied molecular orbital energy level than the red electron-transporting host material B, the green electron-transporting host material H and the blue electron-transporting host material R. In this way, the leakage of holes in the red light-emitting layer 101, the green light-emitting layer 102 and the blue light-emitting layer 201 towards the side of the electron-transporting layer 400 can be effectively inhibited, so that the holes in the light-emitting layer can be combined with the electrons in the light-emitting layer as much as possible, and thus more excitons can be generated in the red light-emitting layer 101, the green light-emitting layer 102 and the blue light-emitting layer 201. In this way, the light-emitting efficiency of the organic light-emitting device 000 can be improved.

[0117] In the embodiments of the present application, the hole blocking layer 300 can also satisfy:

[0118] LUMO(P) - LUMO(B) > 0.2 eV;

[0119] LUMO(P) - LUMO(H) > 0.2 eV;

[0120] LUMO(P) - LUMO(R) > 0.2 eV;

[0121] wherein LUMO(P) represents the lowest unoccupied molecular orbital energy level of the material of the hole blocking layer 300, LUMO(B) represents the lowest unoccupied molecular orbital energy level of the red electron-transporting host material, LUMO(H) represents the lowest unoccupied molecular orbital energy level of the green electron-transporting host material, and LUMO(R) represents the lowest unoccupied molecular orbital energy level of the blue electron-transporting host material.

[0122] Here, it can be seen from the above inequality that the material P of the hole blocking layer 300 in the organic light-emitting device 000 has a shallower lowest unoccupied molecular orbital energy level than the red electron-type host material B, the green electron-type host material H, and the blue electron-type host material R. In this way, the transmission speed of the electrons transmitted to the red light-emitting layer 101, the green light-emitting layer 102, and the blue light-emitting layer 201 can be reduced, so that the red light-emitting layer 101, the green light-emitting layer 102, and the blue light-emitting layer 201 can be prevented from being prone to electron excess.

[0123] In the present application, the first guest material in the first light-emitting layer 100 can include a fluorescent guest material; and the first electron-type host material in the first light-emitting layer 100 can include one of a metal complex material and a thermally activated delayed fluorescence material.

[0124] Here, in the case where the first electron-type host material in the first light-emitting layer 100 includes a metal complex material, the first guest material in the first light-emitting layer 100 can further include a third electron-type host material X. In this case, the electron transport layer 400 in the organic light-emitting device 000 can have a lower lowest unoccupied molecular orbital energy level than the third electron-type host material X. In this way, the transmission speed of the electrons transmitted to the first light-emitting layer 100 can be reduced, so that the first light-emitting layer 100 can be prevented from being prone to electron excess, and thus the organic light-emitting device 000 can have high light-emitting efficiency and long service life.

[0125] In the embodiments of the present application, please refer to Figure 3 , Figure 3 is another film layer structure schematic diagram of an organic light-emitting device provided by the embodiments of the present application. The organic light-emitting device 000 can further include a first anode 501, a second anode 502, a hole injection layer 600, a hole transport layer 700, a first electron blocking layer 801, a second electron blocking layer 802, a microcavity adjustment layer 900, an electron injection layer 1000, a cathode layer 1100, and an optical cover layer 1200.

[0126] The electron injection layer 1000 in the organic light-emitting device 000 can be located on the side of the electron transport layer 400 away from the first light-emitting layer 100 and the second light-emitting layer 200. The electron injection layer 1000 can be used to improve the injection efficiency of the electrons. For example, the electron injection layer 1000 can be formed by evaporation of a material such as lithium, calcium, ytterbium, or lithium fluoride, which has a low work function. The thickness of the electron injection layer 1000 can be in the range of 0.5 nanometers to 2 nanometers.

[0127] The cathode layer 1100 in the organic light emitting device 000 can be located on the side of the electron injection layer 1000 facing away from the electron transport layer 400. Among them, the first anode 501, the second anode 502 and the cathode layer 1100 can be used to apply a driving voltage to achieve electrical driving of the organic light emitting device 000. For example, the material of the cathode layer 1100 can include a lower work function metal aluminum, magnesium, silver, etc., or an alloy containing a low work function metal material. For example, the thickness of the cathode layer 1100 can range from 10 nanometers to 20 nanometers.

[0128] The first electron blocking layer 801 in the organic light emitting device 000 can be arranged corresponding to the first light emitting layer 100, and can be located on the side of the first light emitting layer 100 facing away from the hole blocking layer 300. Among them, the first electron blocking layer 801 can be used to transport holes, and can block excitons generated in the red light emitting layer 101 and the green light emitting layer 102. For example, the material of the first electron blocking layer 801 can be a hole type material, such as carbazole and the like.

[0129] It should be noted that the triplet first excited state energy of the material of the first electron blocking layer 801 can be greater than the triplet first excited state energy of the first electron type host material in the first light emitting layer 101. For example, the difference between the triplet first excited state energy of the material of the first electron blocking layer 801 and the triplet first excited state energy of the first electron type host material can be greater than 0.2 electron volts. It should also be noted that the difference between the highest occupied molecular orbital energy level of the material of the first electron blocking layer 801 and the energy level of the hole type host material can be less than or equal to 0.3 electron volts, and the difference between the highest occupied molecular orbital energy level of the material of the first electron blocking layer 801 and the highest occupied molecular orbital energy level of the material of the hole transport layer 700 can range from 0.2 electron volts to 0.4 electron volts.

[0130] The second electron blocking layer 802 in the organic light emitting device 000 can be arranged corresponding to the second light emitting layer 200, and can be located on the side of the second light emitting layer 200 facing away from the hole blocking layer 300. Among them, the second electron blocking layer 802 can be used to transport holes, and can block excitons generated in the blue light emitting layer 201.

[0131] It should be noted that the triplet first excited state energy of the material of the second electron blocking layer 802 can be greater than the triplet first excited state energy of the second electron-type host material in the second light-emitting layer 200. For example, the difference between the triplet first excited state energy of the material of the second electron blocking layer 802 and the triplet first excited state energy of the second electron-type host material can be greater than 0.1 electron volts. It should also be noted that the lowest unoccupied molecular orbital energy level of the material of the second electron blocking layer 802 can be less than the lowest unoccupied molecular orbital energy level of the second electron-type host material. For example, the difference between the lowest unoccupied molecular orbital of the material of the second electron blocking layer 802 and the lowest unoccupied molecular orbital of the second electron-type host material can be greater than 0.3 electron volts.

[0132] The microcavity adjustment layer 900 in the organic light-emitting device 000 can be arranged corresponding to the first light-emitting layer 100, and can be located on the side of the first electron blocking layer 801 away from the first light-emitting layer 100. Here, the microcavity adjustment layer 900 can include a first microcavity adjustment layer 901 arranged corresponding to the red light-emitting layer 101 and a second microcavity adjustment layer 902 arranged corresponding to the green light-emitting layer 102. The first microcavity adjustment layer 901 and the second microcavity adjustment layer 902 can generally be formed of a hole transport type material with high hole mobility. For example, the material of the first microcavity adjustment layer 901 and the second microcavity adjustment layer 902 can be a carbazole type material.

[0133] It should be noted that according to the principle of micro resonant cavity, on the basis of setting a fixed thickness of the hole transport layer 700, the color coordinates of the red light-emitting layer 101 can be adjusted by adjusting the thickness of the first microcavity adjustment layer 901. Similarly, the color coordinates of the green light-emitting layer 102 can be adjusted by adjusting the thickness of the second microcavity adjustment layer 902. The thickness of the first microcavity adjustment layer 901 can be greater than the thickness of the second microcavity adjustment layer 902.

[0134] It should also be noted that the difference between the highest occupied molecular orbital energy level of the material of the first microcavity adjustment layer 901 and the highest occupied molecular orbital energy level of the material of the first electron blocking layer 801 can be less than or equal to 0.2 electron volts. Similarly, the difference between the highest occupied molecular orbital energy level of the material of the second microcavity adjustment layer 902 and the highest occupied molecular orbital energy level of the material of the second electron blocking layer 802 can be less than or equal to 0.2 electron volts.

[0135] The hole transport layer 700 in the organic light emitting device 000 can be located on the side of the microcavity adjustment layer 900 and the second electron blocking layer 802 facing away from the hole blocking layer 300. Here, the hole transport layer 700 can be used for transporting holes. The material of the hole transport layer 700 can include a carbazole-based material, for example.

[0136] It should be noted that for the top emitting device, the color coordinates of the blue light emitting layer 201 can be adjusted by adjusting the thickness of the hole transport layer 700 according to the micro resonant cavity principle.

[0137] The hole injection layer 600 in the organic light emitting device 000 can be located on the side of the hole transport layer 700 facing away from the hole blocking layer 300. The hole injection layer 600 can be used for improving the efficiency of hole injection. The material of the hole injection layer 600 can include copper phthalocyanine, manganese trioxide, etc.

[0138] The first anode 501 in the organic light emitting device 000 can be arranged corresponding to the first light emitting layer 100, and can be located on the side of the hole injection layer 600 facing away from the first light emitting layer 100. The second anode 502 can be arranged corresponding to the second light emitting layer 200, and can be located on the side of the hole injection layer 600 facing away from the second light emitting layer 200. In a possible implementation, the material of the first anode 501 and the second anode 502 can be a high work function electrode material. In another possible implementation, the first anode 501 and the second anode 502 can be a composite electrode formed by a metal and an oxide, for example, silver / indium tin oxide, aluminum / indium tin oxide, silver / indium zinc oxide, aluminum / indium zinc oxide, etc., and the thickness of the metal layer in the composite electrode is in the range of 50 nanometers to 200 nanometers, and the thickness of the oxide layer is in the range of 5 nanometers to 20 nanometers. Optionally, when the organic light emitting device is a top emitting device, the composite anode can be a full reflection anode, and the reflectivity of the composite anode for a 550 nanometer wavelength needs to be greater than 80%.

[0139] The optical cover layer 1200 in the organic light emitting device 000 can be located on the side of the cathode layer 1100 facing away from the electron injection layer 1000. Here, the optical cover layer 1200 can be used for improving the optical output of the organic light emitting device 000. The material of the optical cover layer 1200 can include an organic small molecule material with a refractive index greater than 1.8, for example. The thickness of the optical cover layer 1200 is in the range of 50 nanometers to 100 nanometers.

[0140] In the embodiments of the present application, please refer to Figure 4 , Figure 4is a schematic diagram of a film layer structure of still another organic light emitting device provided in the present application. The organic light emitting device 000 in the above embodiments can be a tandem organic light emitting device with a periodic structure. For example, the periodic structure of the organic light emitting device 000 can be greater than or equal to 2. Here, the tandem organic light emitting device can further include a substrate 00a, a first charge generation layer 00b, and a second charge generation layer 00c.

[0141] The substrate 00a can be located on a side of the first anode 501 and the second anode 502 facing away from the hole injection layer 600. Here, the substrate 00a can be used to support the tandem organic light emitting device.

[0142] The first charge generation layer 00b in the tandem organic light emitting device can be located on a side of the electron transport layer 400 facing away from the hole blocking layer 300, and the second charge generation layer 00c can be located on a side of the first charge generation layer 00b facing away from the hole blocking layer 300. Here, the first charge generation layer 00b can be used to generate hole-type charges, and the second charge generation layer 00c can be used to generate electron-type charges.

[0143] In a possible implementation manner, the electron transport layer 400 can not be arranged on a side closest to the first anode 501 and the second anode 502.

[0144] It should be noted that since the first guest material in the first light emitting layer 100 and the second guest material in the second light emitting layer 200 in the present application can both include boron elements, when a 500-nanometer light is used to irradiate a display surface of a display panel prepared by using the organic light emitting device 000, the organic light emitting device 000 can emit light with a spectral peak wavelength in a range of 515 nanometers to 540 nanometers. When a 600-nanometer light is used to irradiate a display surface of a display panel prepared by using the organic light emitting device 000, the organic light emitting device 000 can emit light with a spectral peak wavelength in a range of 615 nanometers to 640 nanometers.

[0145] The performance of the organic light emitting device provided in the embodiments of the present application is tested and compared as follows. Figure 1 The organic light emitting device shown in the above embodiments is prepared according to the following conditions.

[0146] Embodiment 1

[0147] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / first microcavity adjustment layer (R-HTL) / first electron blocking layer (R-EBL) / red hole-type host material (TRM) : red thermally activated delayed fluorescence material (TRH) : red guest material (RD) (25 nm, 70%: 29%: 1%) / hole blocking layer (HB-1) / electron transport layer: lithium quinolate (ET-1: LIQ) (1:1, 35 nm) / electron injection layer (EIL) (1 nm) / magnesium: silver (Mg:Ag) (15 nm) / optical capping layer (CPL) (60 nm).

[0148] Green organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjustment layer (G-HTL) / first electron blocking layer (G-EBL) / green hole-type host material (TGM) : green thermally activated delayed fluorescence material (TGH) : green guest material (GD) (30 nm, 60%: 39%: 1%) / HB-1 / ET-1: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0149] Blue organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole-type host material (BH) : blue guest material (BD) (20 nm, 3%) / HB-1 / ET-1: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0150] Example 2

[0151] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / TRM: TRH: RD (25 nm, 70%: 29%: 1%) / hole blocking layer (HB-2) / ET-1: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0152] Green organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjustment layer (G-HTL) / first electron blocking layer (G-EBL) / TGM: TGH: GD (30 nm, 60%: 39%: 1%) / HB-2 / ET-1: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0153] Blue organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole type host material (BH) : blue guest material (BD) (20 nm, 3%) / HB-2 / ET-1 : LIQ (1 : 1, 35 nm) / EIL (1 nm) / Mg : Ag (15 nm) / CPL (60 nm).

[0154] Example 3

[0155] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / red hole type host material (PRH) : red electron type host material (TRH) : red phosphor guest material (PRD) (40 nm, 40% : 57% : 3%) / HB-2 / ET-1 : LIQ (1 : 1, 35 nm) / EIL (1 nm) / Mg : Ag (15 nm) / CPL (60 nm).

[0156] Green organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjusting layer (G-HTL) / first electron blocking layer (G-EBL) / TGM : TGH : GD (30 nm, 60% : 39% : 1%) / HB-2 / ET-1 : LIQ (1 : 1, 35 nm) / EIL (1 nm) / Mg : Ag (15 nm) / CPL (60 nm).

[0157] Blue organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole type host material (BH) : blue guest material (BD) (20 nm, 3%) / HB-2 / ET-1 : LIQ (1 : 1, 35 nm) / EIL (1 nm) / Mg : Ag (15 nm) / CPL (60 nm).

[0158] Example 4

[0159] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / PRH : TRH : PRD (40 nm, 40% : 57% : 3%) / HB-2 / ET-2 : LIQ (1 : 1, 35 nm) / EIL (1 nm) / Mg : Ag (15 nm) / CPL (60 nm).

[0160] Green organic light-emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjustment layer (G-HTL) / first electron blocking layer (G-EBL) / TGM:TGH:GD (30 nm, 60%:39%:1%) / HB-2 / ET-2:LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0161] Blue organic light-emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole-type host material (BH): blue guest material (BD) (20 nm, 3%) / HB-2 / ET-2:LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0162] Example 5

[0163] Red organic light-emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / PRH:TRH:PRD (40 nm, 40%:57%:3%) / HB-1 / ET-2:LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0164] Green organic light-emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjustment layer (G-HTL) / first electron blocking layer (G-EBL) / TGM:TGH:GD (30 nm, 60%:39%:1%) / HB-1 / ET-2:LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0165] Blue organic light-emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole-type host material (BH): blue guest material (BD) (20 nm, 3%) / HB-1 / ET-2:LIQ (1:1, 35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (60 nm).

[0166] Example 6

[0167] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / PRH: TRH: PRD (40 nm, 40%: 57%: 3%) / HB-3 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0168] Green organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjusting layer (G-HTL) / first electron blocking layer (G-EBL) / TGM: TGH: GD (30 nm, 60%: 39%: 1%) / HB-3 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0169] Blue organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole type host material (BH): blue guest material (BD) (20 nm, 3%) / HB-3 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0170] Example 7

[0171] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / PRH: TRH: PRD (40 nm, 40%: 57%: 3%) / HB-2 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0172] Green organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjusting layer (G-HTL) / first electron blocking layer (G-EBL) / green hole type host material (PGH): green electron type host material (NGH): metal complex type material (PGD): GD (35 nm, 51%: 40%: 8%: 1%) / HB-2 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0173] Blue organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole type host material (BH) : blue guest material (BD) (20 nm, 3%) / HB-2 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0174] Example 8

[0175] Red organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / R-HTL / R-EBL / PRH: TRH: PRD (40 nm, 40%: 57%: 3%) / HB-1 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0176] Green organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second microcavity adjustment layer (G-HTL) / first electron blocking layer (G-EBL) / green hole type host material (PGH) : green electron type host material (NGH) : metal complex material (PGD) : GD (35 nm, 51%: 40%: 8%: 1%) / HB-1 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0177] Blue organic light emitting device: Ag (100 nm) / ITO (8 nm) / HIL / HTL / second electron blocking layer (B-EBL) / blue hole type host material (BH) : blue guest material (BD) (20 nm, 3%) / HB-1 / ET-2: LIQ (1:1, 35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (60 nm).

[0178] Wherein, HB-1, HB-2 and HB-3 are three different hole blocking layer materials, and ET-1 and ET-2 are two different electron transport layer materials.

[0179] In the embodiments of the present application, the physical property parameters of the above-mentioned materials can be referred to the following table:

[0180] Table 1 Material molecular energy orbit and excited state

[0181]

[0182]

[0183] Here, the highest occupied molecular orbital energy level (HOMO) of each material, the lowest unoccupied molecular orbital energy level (LUMO) of each material can be obtained by photoelectron spectroscopy combined with ultraviolet-visible absorption spectrum. The triplet first excited state energy (T1) of the material, the singlet first excited state energy (S1) of the material can be measured by 77K low temperature photoluminescence method in dilute solution, and the above data can be obtained by tangent method at the rising critical point of the spectrum.

[0184] In the embodiment of the present application, a red single-carrier device can be prepared corresponding to the red light-emitting layer 101, a green single-carrier device can be prepared corresponding to the green light-emitting layer 102, and a blue single-carrier device can be prepared corresponding to the blue light-emitting layer 201. Here, the single-carrier device can include a single-hole device (Hole Only Device, referred to as HOD) and a single-electron device (Electron Only Device, referred to as EOD).

[0185] Please refer to Figure 5 , Figure 5 is a voltage and current density characteristic curve of a red single-carrier device provided by the embodiment of the present application. In the figure, the black line represents the change curve of the current density of the single-electron device prepared by using the red light-emitting layer 101 with the voltage, and the gray line represents the change curve of the current density of the single-hole device prepared by using the red light-emitting layer 101 with the voltage. As shown in Figure 5 , the current density of the single-hole device prepared by using the red light-emitting layer 101 gradually increases with the increase of the voltage, and the current density of the red single-hole device is greater than that of the red single-electron device, so the hole conduction is more dominant in the red light-emitting layer 101.

[0186] In the present application, please refer to Figure 6 , Figure 6 is a voltage and current density characteristic curve of a green single-carrier device provided by the embodiment of the present application. In the figure, the black line represents the change curve of the current density of the single-electron device prepared by using the green light-emitting layer 102 with the voltage, and the gray line represents the change curve of the current density of the single-hole device prepared by using the green light-emitting layer 102 with the voltage. As shown in Figure 5 , the current density of the single-hole device prepared by using the green light-emitting layer 102 gradually increases with the increase of the voltage, and the current density of the green single-hole device is greater than that of the green single-electron device, so the hole conduction is more dominant in the green light-emitting layer 102.

[0187] In the embodiment of the present application, please refer to Figure 7 , Figure 7is a voltage and current density characteristic curve of a blue single-carrier device provided by an embodiment of the present application. In the figure, the black line represents the current density-voltage curve of the single-electron device prepared by using the blue light-emitting layer 201, and the gray line represents the current density-voltage curve of the single-hole device prepared by using the blue light-emitting layer 201. As shown in Figure 6 , the current density of the single-electron device prepared by using the blue light-emitting layer 201 gradually increases with the increase of the voltage, and the current density of the single-electron device is greater than that of the single-hole device, so that the electron conduction is more dominant in the blue light-emitting layer 201.

[0188] In the embodiment of the present application, the performance of the organic light-emitting device provided by the above-mentioned embodiments 1, 2, 3, 4, 5, 6, 7 and 8 is tested, and the test results can be seen in the following tables:

[0189] Table 2: Summary of device characteristics

[0190]

[0191] In the present application, please refer to Table 1, Table 2 and Figure 8 , Figure 8 is a comparison chart of the physical parameters of the materials of the organic light-emitting device provided by an embodiment of the present application. The hole blocking layer 300 in the embodiment 1 uses the HB-1 material, and the electron transport layer 400 uses the ET-1 material. Here, the electron transport layer 400 has a deeper lowest unoccupied molecular orbital energy level relative to the hole blocking layer 300, and a shallower lowest unoccupied molecular orbital energy level relative to the red electron-type host material TRH and the green electron-type host material TGH. In this way, the carrier balance in the light-emitting layer of the organic light-emitting device 000 can be optimized, so as to ensure that the efficiency and the lifetime of the organic light-emitting device 000 prepared by using different light-emitting layers are both high.

[0192] In the embodiment of the present application, please refer to Table 1, Table 2 and Figure 9 , Figure 9This is a comparison chart of the physical properties of another material of an organic light-emitting device provided in an embodiment of the present application. The hole blocking layer 300 in Example 2 uses HB-2 material with a shallower lowest unoccupied molecular orbital energy level. In this way, the potential barrier between the hole blocking layer 300 and the electron transport layer 400 will increase, thereby slowing down the transmission speed of electrons from the electron transport layer 400 to the hole blocking layer 300. It should be noted that since hole conduction is more dominant in the red light-emitting layer 101 and the green light-emitting layer 102, the number of holes in the red light-emitting layer 101 and the green light-emitting layer 102 will be greater. In addition, since electron conduction is more dominant in the blue light-emitting layer 201, the number of electrons in the blue light-emitting layer 201 will be greater. In this case, since the transmission speed of electrons from the electron transport layer 400 to the hole blocking layer 300 will slow down, the number of electrons in the red organic light-emitting device and the green organic light-emitting device will decrease, thereby reducing the efficiency and life of the red organic light-emitting device and the green organic light-emitting device. However, since the transmission speed of electrons from the electron transport layer 400 to the hole blocking layer 300 becomes slower, the blue light-emitting layer 201 is less likely to be in an electron excess state, and thus the efficiency and life of the blue organic light-emitting device are improved.

[0193] In the examples of the present application, referring to Tables 1 and 2, Example 3 replaces the materials in the red light-emitting layer with a red hole-type host material PRH, a red electron-type host material TRH, and a red phosphorescent guest material PRD, relative to Example 2. In this case, due to the better properties of the red hole-type host material PRH, the red electron-type host material TRH, and the red phosphorescent guest material PRD, the efficiency and lifespan of the red organic light-emitting device are significantly improved.

[0194] In this application, please refer to Table 1, Table 2 and Figure 10 , Figure 10 This is a comparison chart of the physical parameters of the materials of another organic light-emitting device provided in the embodiments of the present application. Compared with Example 3, the electron transport layer 400 in Example 4 adopts the ET-2 material with a shallower lowest unoccupied molecular orbital energy level. In this case, the potential barrier between the hole blocking layer 300 and the electron transport layer 400 can be effectively reduced, thereby increasing the transmission speed of electrons from the electron transport layer 400 to the hole blocking layer 300. In this way, the number of electrons in the green organic light-emitting device will increase, thereby improving the efficiency and life of the green organic light-emitting device. At the same time, since there is still a potential barrier for electrons to be transmitted from the hole blocking layer 300 to the electron transport layer 400, the blue light-emitting layer 201 is still not easy to be in a state of excess electrons. For this reason, the efficiency and life of the blue organic light-emitting device can be guaranteed to be good.

[0195] Please note that, please refer toFigure 11 , Figure 11 is a curve of the mobility of the electron transport layer material provided in the embodiment of the present application changing with voltage. In the figure, the black line represents the curve of the mobility of the ET-2 material changing with voltage, and the gray line represents the curve of the mobility of the ET-1 material changing with voltage. Here, it can be known from the mobility test of the materials that the electron transport characteristics of the ET-1 material and the ET-2 material are very close, and thus the characteristic change of the organic light emitting device 000 can be ensured to be mainly caused by the energy level difference.

[0196] In the embodiment of the present application, please refer to Table 1, Table 2 and Figure 12 , Figure 12 is a comparison figure of physical property parameters of materials of another organic light emitting device provided in the embodiment of the present application. In comparison with Embodiment 5, the hole blocking layer 300 in Embodiment 6 adopts the HB-3 material with the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level close to the HB-2 material, and the first excited triplet state energy lower than the green electron-type host material TGH. In this case, the hole blocking layer 300 cannot block the excitons generated in the green light emitting layer 102 from leaking along the side toward the electron transport layer 400, and thus the light emitting efficiency of the green organic light emitting device is relatively low.

[0197] In the embodiment of the present application, please refer to Table 1, Table 2 and Figure 13 , Figure 13 is a comparison figure of physical property parameters of materials of another organic light emitting device provided in the embodiment of the present application. In comparison with Embodiment 5, the hole blocking layer 300 in Embodiment 6 adopts the HB-3 material with the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level close to the HB-2 material, and the first excited triplet state energy lower than the green electron-type host material TGH. In this case, the hole blocking layer 300 cannot block the excitons generated in the green light emitting layer 102 from leaking along the side toward the electron transport layer 400, and thus the light emitting efficiency of the green organic light emitting device is relatively low.

[0198] In the present application, please refer to Table 1 and Table 2, in comparison with Embodiment 4, the green light emitting layer 102 in Embodiment 7 adopts the green hole-type host material PGH, the green electron-type host material NGH, the metal complex material PGD and the green guest material GD. In this case, the efficiency and the life of the red organic light emitting device, the green organic light emitting device and the blue organic light emitting device are all relatively high.

[0199] In the embodiments of the present application, referring to Tables 1 and 2, compared to Example 7, Example 8 uses the HB-1 material with a deeper lowest unoccupied molecular orbital energy level for the hole blocking layer 300. In this case, the blue light-emitting layer 201 is prone to an excess of electrons, which results in a reduced lifespan of the blue organic light-emitting device.

[0200] In the present application, in general, the efficiency and lifespan of the red organic light-emitting device, the green organic light-emitting device and the blue organic light-emitting device in Example 4 are all good.

[0201] Here, the energy level relationship of different film structures in the organic light-emitting devices provided in Examples 1, 2, 3, 4, 5, 6, 7 and 8 is analyzed, and the results can be seen in the following table:

[0202] Table 3 Energy level relationships of different film structures in organic light-emitting devices

[0203]

[0204] Wherein, LUMO(P) represents the lowest unoccupied molecular orbital energy level of the material of the hole blocking layer 300, LUMO(S) represents the lowest unoccupied molecular orbital energy level of the material of the electron transport layer 400, and LUMO(H) represents the lowest unoccupied molecular orbital energy level of the first electron-type host material.

[0205] In the embodiments of the present application, as shown in Table 3, except for the organic light-emitting device 000 in Example 6, all organic light-emitting devices 000 that meet the above formula exhibit good performance. It should be noted that because the hole blocking layer 300 in Example 6 uses the HB-3 material, whose triplet first excited state energy is lower than that of the green electron-type host material TGH, even though the organic light-emitting device 000 in Example 6 meets the above formula, its performance is not good.

[0206] In summary, an organic light-emitting device provided in an embodiment of the present application includes: a first light-emitting layer, a second light-emitting layer, a hole blocking layer, and an electron transport layer. Since the electron transport layer in the organic light-emitting device can have a lowest unoccupied molecular orbital energy level that is deeper than the hole blocking layer and shallower than the first electronic-type host material. Therefore, it is possible to achieve a better carrier balance in both the first light-emitting layer and the second light-emitting layer. And by specifying the material selection of the electron transport layer, the organic light-emitting device can realize the sharing of the first light-emitting layer and the second light-emitting layer, thereby ensuring that the efficiency and life of the organic light-emitting device prepared with different light-emitting layers are high, and thus ensuring a better display effect of the display panel.

[0207] The embodiment of the present application also provides a display panel.Figure 14 as shown, Figure 14 is a schematic diagram of a film layer structure of a display panel provided in an embodiment of the present application. The display panel can include a driving backplate 001 and a plurality of organic light emitting devices 000 located on one side of the driving backplate 001. Here, the organic light emitting devices 000 can be red organic light emitting devices in the above embodiment.

[0208] In the present application, the display panel can further include a pixel definition layer 002 located on one side of the driving backplate 001. The pixel definition layer 002 can have a plurality of pixel openings V1, which can correspond to the plurality of organic light emitting devices 000 one by one. Here, the first anode 501 in the organic light emitting device 000 can be located on the side of the pixel definition layer 002 facing the driving backplate 001, and the orthographic projection of each pixel opening V1 in the pixel definition layer 002 on the driving backplate 001 can be located within the orthographic projection of the first anode 501 in the corresponding organic light emitting device 000 on the driving backplate 001. At least part of the organic functional layer and at least part of the cathode layer 1100 in each organic light emitting device 000 can be located within the corresponding pixel opening V1.

[0209] In an embodiment of the present application, the driving backplate 001 can include a substrate 001a and a plurality of pixel driving circuits 001b located on one side of the substrate 001a. The plurality of organic light emitting devices 000 in the display panel can be located on the side of the plurality of pixel driving circuits 001b away from the substrate 001a. Here, the plurality of pixel driving circuits 001b in the driving backplate 001 can correspond to the plurality of organic light emitting devices 000 one by one, and each pixel driving circuit 001b can be electrically connected to the first anode 501 in the corresponding organic light emitting device 000. Each pixel driving circuit 001b can apply a driving signal to the corresponding first anode 501, so that the red light emitting layer 101 within the pixel opening V1 corresponding to this first anode 501 can emit light outward.

[0210] Optionally, the driving backplate 001 in the display panel can further include a planar layer 001c located on the side of the plurality of pixel driving circuits 001b away from the substrate 001a. The plurality of organic light emitting devices 000 in the display panel can be located on the side of the planar layer 001c away from the substrate 001a. Here, the planar layer 001c can have a plurality of connection vias V2, which can correspond to the plurality of organic light emitting devices 000 one by one and can correspond to the plurality of pixel driving circuits 001b one by one. Each pixel driving circuit 001b can be electrically connected to the first anode 501 in the corresponding organic light emitting device 000 through the corresponding connection via V2.

[0211] In an embodiment of the present application, please refer to Figure 15 ,Figure 15 is another schematic view of a film layer structure of a display panel provided by an embodiment of the present application. The display panel can further include an encapsulation layer 004 located on a side of the plurality of organic light emitting devices 000 away from the substrate 001a. Here, the encapsulation layer 004 is configured to encapsulate the organic light emitting devices 000 to prevent water and oxygen in the external environment from corroding the red light emitting layer 101 in the organic light emitting devices 000, so that the service life of the organic light emitting devices 000 is relatively high.

[0212] An embodiment of the present application further provides a display device, which can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, etc. The display device can include a driving assembly and a display panel electrically connected to the driving assembly. The display panel can be the display panel in the above embodiments.

[0213] It should be noted that in the drawings, the dimensions of layers and regions can be exaggerated for clarity. It will be further understood that when a layer or element is referred to as being "on" another layer or element, it can be directly on the other element or intervening layers can also be present. In addition, it will be understood that when a layer or element is referred to as being "beneath" another layer or element, it can be directly beneath the other element, or intervening layers or elements can also be present. In addition, it will be understood that when a layer or element is referred to as being "between" two layers or elements, it can be the only layer or element between the two layers or elements or one or more intervening layers or elements can also be present. Similar reference numerals can be used throughout the specification for like elements.

[0214] In the present application, the terms "first" and "second" are used only for descriptive purposes, and should not be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless otherwise explicitly limited.

[0215] The above description is only some optional embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An organic light-emitting device, characterized in that: include: A first light-emitting layer (100), a second light-emitting layer (200), a hole blocking layer (300) and an electron transport layer (400); The first light-emitting layer (100) and the second light-emitting layer (200) are arranged side by side, the hole blocking layer (300) is located on the same side of the first light-emitting layer (100) and the second light-emitting layer (200), and the electron transport layer (400) is located on a side of the hole blocking layer (300) away from the first light-emitting layer (100) and the second light-emitting layer (200); The first light-emitting layer (100) comprises: a hole-type host material, a first electron-type host material and a first guest material; the first electron-type host material comprises a metal complex material; the first guest material comprises a fluorescent guest material and a third electron-type host material; the second light-emitting layer (200) comprises: a second electron-type host material and a second guest material; The hole blocking layer (300) has: a higher triplet first excited state energy than the first electronic type host material and the second electronic type host material; a deeper highest occupied molecular orbital energy level than the first electronic type host material and the second electronic type host material; and a shallower lowest unoccupied molecular orbital energy level than the first electronic type host material and the second electronic type host material; The electron transport layer (400) has a lowest unoccupied molecular orbital energy level that is deeper than that of the hole blocking layer (300) and shallower than that of the first electronic type host material, and also has a lowest unoccupied molecular orbital energy level that is shallower than that of the third electronic type host material.

2. The organic light-emitting device according to claim 1, wherein The first light-emitting layer includes a red light-emitting layer and a green light-emitting layer arranged side by side, and the second light-emitting layer includes a blue light-emitting layer.

3. The organic light-emitting device according to claim 2, wherein: The red light-emitting layer comprises: a red hole-type host material, a red electron-type host material and a red guest material; The electron transport layer (400) satisfies: 2 × LUMO (P) - LUMO (S) - LUMO (B) ≧0.6eV; Wherein, LUMO (P) represents the lowest unoccupied molecular orbital energy level of the material of the hole blocking layer (300), LUMO (S) represents the lowest unoccupied molecular orbital energy level of the material of the electron transport layer (400), and LUMO (B) represents the lowest unoccupied molecular orbital energy level of the red electron-type host material.

4. The organic light-emitting device according to claim 3, characterized in that The red light-emitting layer satisfies: △Est = S1 (B) - T1 (B) < 0.3eV; T1(A)>T1(B)>T1(C); Among them, S1 (B) represents the singlet first excited state energy of the red electronic host material, T1 (A) represents the triplet first excited state energy of the red hole type host material, T1 (B) represents the triplet first excited state energy of the red electronic host material, and T1 (C) represents the triplet first excited state energy of the red guest material.

5. The organic light-emitting device according to claim 2, wherein: The green light-emitting layer comprises: a green hole-type host material, a green electron-type host material and a green guest material; The electron transport layer (400) satisfies: 2 × LUMO (P) - LUMO (S) - LUMO (H) ≧0.6eV; Wherein, LUMO (P) represents the lowest unoccupied molecular orbital energy level of the material of the hole blocking layer (300), LUMO (S) represents the lowest unoccupied molecular orbital energy level of the material of the electron transport layer (400), and LUMO (H) represents the lowest unoccupied molecular orbital energy level of the green electron-type host material.

6. The organic light-emitting device according to claim 5, characterized in that The green light-emitting layer satisfies: △Est = S1 (H) - T1 (H) < 0.3eV; T1(G)>T1(H)>T1(J); Among them, S1 (H) represents the singlet first excited state energy of the green electron-type host material, T1 (G) represents the triplet first excited state energy of the green hole-type host material, T1 (H) represents the triplet first excited state energy of the green electron-type host material, and T1 (J) represents the triplet first excited state energy of the green guest material.

7. The organic light-emitting device according to any one of claims 2 to 6, characterized in that: The red light-emitting layer comprises: a red hole-type host material, a red electron-type host material and a red guest material; the green light-emitting layer comprises: a green hole-type host material, a green electron-type host material and a green guest material; the blue light-emitting layer comprises: a blue electron-type host material and a blue guest material; the hole blocking layer (300) satisfies: T1(P)-T1(B)≧ 0.1eV; T1(P)-T1(H)≧ 0.1eV; T1(P)-T1(R)≧ 0.1eV; Wherein, T1(P) represents the triplet first excited state energy of the material of the hole blocking layer (300), T1(B) represents the triplet first excited state energy of the red electronic type main material, T1(H) represents the triplet first excited state energy of the green electronic type main material, and T1(R) represents the triplet first excited state energy of the blue electronic type main material.

8. The organic light-emitting device according to claim 7, characterized in that: The hole blocking layer (300) satisfies: HOMO (B) - HOMO (P) ≧ 0.2eV; HOMO (H) - HOMO (P) ≧ 0.2eV; HOMO (R) - HOMO (P) ≧ 0.2eV; Wherein, HOMO (P) represents the highest occupied molecular orbital energy level of the material of the hole blocking layer (300), HOMO (B) represents the highest occupied molecular orbital energy level of the red electronic type main material, HOMO (H) represents the highest occupied molecular orbital energy level of the green electronic type main material, and HOMO (R) represents the highest occupied molecular orbital energy level of the blue electronic type main material.

9. The organic light-emitting device according to claim 7, wherein: The hole blocking layer (300) satisfies: LUMO (P) - LUMO (B) ≧ 0.2eV; LUMO (P) - LUMO (H) ≧ 0.2eV; LUMO (P) - LUMO (R) ≧ 0.2eV; Wherein, LUMO (P) represents the lowest unoccupied molecular orbital energy level of the material of the hole blocking layer (300), LUMO (B) represents the lowest unoccupied molecular orbital energy level of the red electronic type main material, LUMO (H) represents the lowest unoccupied molecular orbital energy level of the green electronic type main material, and LUMO (R) represents the lowest unoccupied molecular orbital energy level of the blue electronic type main material.

10. The organic light-emitting device according to any one of claims 1 to 6, 8 to 9, characterized in that: The first guest material and the second guest material both include boron.

11. A display panel, characterized in that: include: A driving backplane, and a plurality of organic light-emitting devices located on one side of the driving backplane, wherein the organic light-emitting devices are the organic light-emitting devices according to any one of claims 1 to 10.

12. The display panel according to claim 11, wherein: When 500-nanometer light is used to illuminate the display surface of the display panel, the organic light-emitting device can emit light with a spectral peak wavelength in the range of 515 nanometers to 540 nanometers; when 600-nanometer light is used to illuminate the display surface of the display panel, the organic light-emitting device can emit light with a spectral peak wavelength in the range of 615 nanometers to 640 nanometers.

13. A display device, characterized in that: include: A driving component, and a display panel electrically connected to the driving component, wherein the display panel is the display panel according to claim 11 or 12.

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