Material for light-emitting layer, organic electroluminescent display device, and display panel

Abstract

At least one embodiment of the present disclosure provides a material for a light-emitting layer. The material for the light-emitting layer comprises: a carrier transport material, an energy transfer material, and a light-emitting material, wherein the light-emitting material comprises a platinum complex, and the energy transfer material comprises a rare earth complex. A trace amount of rare earth complex is added into the material for the light-emitting layer, and rare earth complex molecules can store excess carriers, so that the excess carriers can be transferred to the molecules of the light-emitting material by means of intermolecular hopping under the action of the continuously increased external electric field, and carriers around the molecules of the light-emitting material can be balanced, reducing the intensification of a triplet-triplet annihilation (TTA) process and a triplet-polaron quenching (TPQ) process, and reducing the internal Joule heat.

Description

Material for light-emitting layer, organic electroluminescent display device and display panel Technical Field

[0001] Embodiments of the present disclosure relate to a material for a light-emitting layer, an organic electroluminescent display device, and a display panel. Background Art

[0002] People's demand for organic light-emitting diode display panels in various life scenarios and their frequency of use are increasing, which requires organic light-emitting diode display panels to have high performance in terms of display efficiency, service life, color gamut and viewing angle.

[0003] According to spin quantum statistics theory, in an organic light-emitting diode (OLED) display panel, the excitons generated by the recombination of electrons injected from the cathode and holes injected from the anode consist of 25% singlet excitons and 75% triplet excitons. Typically, fluorescent materials can only utilize singlet excitons, resulting in a theoretical internal quantum efficiency (IQE) of 25% for the resulting OLED display panel. Phosphorescent materials containing heavy metals can simultaneously capture both singlet and triplet excitons, enabling OLED display panels to achieve a theoretical IQE of 100% while also achieving low voltage and spectral stability. However, in blue phosphorescent devices, the high energy of triplet excitons can easily lead to decomposition of the phosphorescent material, and the long, microsecond-scale lifetime of triplet excitons can easily lead to triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA), resulting in a short lifetime and severe efficiency roll-off for the OLED display panel. Therefore, the performance of blue PhOLEDs is in urgent need of improvement.

[0004] Summary of the Invention

[0005] At least one embodiment of the present disclosure provides a light-emitting layer material, an organic electroluminescent display device, and a display panel. The embodiments of the present disclosure introduce a trace amount of rare earth complexes, such as thulium (III) complexes, dysprosium (III) complexes, or cerium (III) complexes, into the light-emitting layer of a blue phosphorescent organic light-emitting diode to regulate the carrier distribution and energy transfer rate of the light-emitting layer, thereby improving the operating efficiency and service life of the blue phosphorescent organic light-emitting diode display device, thereby solving the technical problems of short service life and severe efficiency roll-off at high brightness of blue phosphorescent organic light-emitting diode display devices.

[0006] At least one embodiment of the present disclosure provides a material for a light-emitting layer, which includes: a carrier transport material, an energy transfer material, and a light-emitting material, wherein the light-emitting material includes a platinum complex, and the energy transfer material includes a rare earth complex.

[0007] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the rare earth complex includes at least one of a thulium complex, a dysprosium complex, and a cerium complex.

[0008] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the general structural formula of the rare earth complex includes At least one of, R1 to R4 are each independently selected from hydrogen, deuterium, F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 Heteroarylthio group, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, substituted or unsubstituted C5-C 60 Carbocyclic group, substituted or unsubstituted C1-C 60 heterocyclic group, -Si(Q')(Q") (Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q") and -P(=S)(Q')(Q"), wherein Q', Q", Q'' and ''' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 At least one of a heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0009] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the structural formula of the rare earth complex includes: At least one of .

[0010] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the general structural formula of the rare earth complex includes: X is selected from I -1 Br -1 、Cl -1 、NO3 -1 、CH3COO -1 、CCl3COO -1 CF3COO -1 、ClO4 -1 、BF4 -1 , BPh4 -1 、N3 -1 , substituted or unsubstituted pyrazole anion, p-toluenesulfonate, p-toluenesulfonate, o-nitrophenoloxy, p-nitrophenoloxy, m-nitrophenoloxy, 2,4-dinitrophenoloxy, 3,5-nitrophenoloxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy anion, trifluoromethanesulfonate, tetrafluoroborate and hexafluorophosphate; R5, R6, R7 and R8 are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"), wherein Q', Q", Q'', and Q'' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0011] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the structural formula of the rare earth complex includes: At least one of .

[0012] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the general structural formula of the platinum complex includes A1 to A4 are each independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 A heterocyclic group, and at least one of A1 to A4 contains a carbene group directly connected to Pt; X1 to X 10 are each independently C or N; L1 to L3 are each independently selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-)- and -Ge(R')(R")-; R9 to R 12R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 a heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k1 to k4 are each independently selected from an integer from 0 to 10; Q', Q", Q"' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0013] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the structural formula of the platinum complex is At least one of .

[0014] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the carrier transport material includes a combination of a hole transport material and an electron transport material.

[0015] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the general structural formula of the hole transport material is: A5 to A8 are independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 Heterocyclic group; L4 is selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')- and -Ge(R')(R")-; R 13 to R 17 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k5 to k9 are each independently selected from an integer from 0 to 10; Q', Q", Q'' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0016] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the structural formula of the hole transport material includes: At least one of .

[0017] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the electron transport material has the general structural formula: A 10 To A 12 Independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 a heterocyclic group; Z1 to Z3 are each independently CH or N; L6 to L8 are each independently selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-, and -Ge(R')(R")-; R 18 to R 20R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 a heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); K7, K8, and K9 are each independently selected from an integer from 0 to 10; Q', Q", Q'', and are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0018] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the structural formula of the electron transport material includes: At least one of .

[0019] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the carrier transport material includes a bipolar material.

[0020] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the bipolar material includes an electron-donating part and an electron-withdrawing part, the electron-donating part includes carbazole, and the electron-withdrawing part includes at least one of phosphorus oxide, cyano, pyridine, carbazole, triazole and phenylimidazole.

[0021] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the structural formula of the bipolar material includes: At least one of .

[0022] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the energy of the lowest triplet excited state of the carrier transport material is greater than the energy of the lowest triplet excited state of the energy transfer material, and the energy of the lowest triplet excited state of the energy transfer material is greater than the energy of the lowest triplet excited state of the light-emitting material.

[0023] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the mass percentage of the carrier transport material is 80% to 95%, the mass percentage of the energy transfer material is 0.1% to 1%, and the mass percentage of the light-emitting material is 5% to 20%.

[0024] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the electroemission spectrum of the energy transfer material and the absorption spectrum of the light-emitting material have a spectral overlapping range, and after normalization, the area of ​​the spectral overlapping range is greater than or equal to 50% of the area of ​​the absorption spectrum of the light-emitting material.

[0025] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the energy of the highest triplet excited state of the energy transfer material is greater than the energy of the highest triplet excited state of the carrier transport material, and the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is less than or equal to 0.2 eV.

[0026] For example, in the material of the light-emitting layer provided in at least one embodiment of the present disclosure, the difference between the energy of the lowest triplet excited state of the carrier transport material and the energy of the lowest triplet excited state of the energy transfer material is greater than or equal to 0.3 eV.

[0027] At least one embodiment of the present disclosure also provides an organic electroluminescent display device, which includes a first electrode, a hole transport layer, a hole injection layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode stacked in sequence, wherein the light-emitting layer is formed using the material of any of the light-emitting layers described above.

[0028] For example, in the organic electroluminescent display device provided in at least one embodiment of the present disclosure, the material of the light-emitting layer is a blue phosphorescent material.

[0029] At least one embodiment of the present disclosure further provides a display panel, which includes any one of the organic electroluminescent display devices described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0031] FIG1 is a schematic cross-sectional view of an organic electroluminescent display device according to at least one embodiment of the present disclosure;

[0032] FIG2 is a schematic diagram showing different luminous intensities caused by different insertion positions of the intercalation device provided by an embodiment of the present disclosure;

[0033] FIG3 is a schematic diagram showing different current efficiencies resulting from different current densities of a top-emitting device provided by an embodiment of the present disclosure;

[0034] FIG4 is a block diagram of a display panel provided by at least one embodiment of the present disclosure;

[0035] FIG5 is a schematic diagram of a cross-sectional structure of a display panel provided by at least one embodiment of the present disclosure;

[0036] FIG6 is a schematic diagram of the circuit structure of a pixel driving circuit included in the display panel shown in FIG5 ;

[0037] FIG7 is a schematic diagram of white light color shift of a display panel provided by at least one embodiment of the present disclosure; and

[0038] FIG8 is a schematic diagram illustrating attenuation of white light brightness of a display panel provided by at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0040] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0041] Generally, the light-emitting layer of an organic light-emitting diode display device is composed of a host material and a guest light-emitting material. Under the action of an electric field, carriers are injected through the electrode and then transported to the light-emitting layer by the carrier transport layer. The host material captures the carriers and transmits them to the light-emitting layer through the host material. Energy transfer or Dexter energy transfer causes the guest luminescent material to emit light, or the guest luminescent material directly captures carriers to emit light. However, the different migration rates of carriers in each layer structure will cause some holes or electrons to remain in the recombination area, which will lead to the problem of relatively narrowing the exciton recombination zone and unbalanced carrier distribution, further causing the intensification of triplet-triplet annihilation (TTA) and triplet-polaron quenching (TPQ) processes, thereby increasing Joule heating inside the organic light-emitting diode display device and causing the display efficiency and life of the organic light-emitting diode display device to deteriorate. The inventors of the present disclosure have noticed that a trace amount of rare earth complex can be added to the material of the light-emitting layer of the organic light-emitting diode device, and the rare earth complex molecules can store excess carriers. The excess carriers can be transferred to the luminescent material molecules through intermolecular hopping under the action of an increasing external electric field, so that the carriers around the luminescent material molecules can be balanced. On the other hand, the appropriate triplet energy of the rare earth complex acts as an energy ladder, thereby promoting energy transfer from the host material to the guest luminescent material, which is beneficial to the exciton radiation attenuation. Furthermore, trace amounts of doping do not alter the overall exciton density or the location of the recombination zone in the light-emitting layer, nor do they degrade other performance characteristics of the organic light-emitting diode display device. Therefore, the embodiments disclosed herein, by adding a trace amount of a rare earth complex as a sensitizer to the light-emitting layer material and using this light-emitting layer material to form the light-emitting layer of an organic light-emitting diode, can produce a highly efficient and stable organic light-emitting diode, effectively mitigating the efficiency roll-off of the organic light-emitting diode at high brightness.

[0042] At least one embodiment of the present disclosure provides a material for a light-emitting layer, comprising: a carrier transport material, an energy transfer material, and a light-emitting material, wherein the light-emitting material comprises a platinum complex, and the energy transfer material comprises a rare earth complex. By adding a trace amount of the rare earth complex to the material of the light-emitting layer, and the rare earth complex molecules being capable of storing excess carriers, the excess carriers can be transferred to the molecules of the light-emitting material through intermolecular hopping under the action of an increasing external electric field, thereby balancing the carriers around the molecules of the light-emitting material, thereby reducing the exacerbation of triplet-triplet annihilation (TTA) and triplet-polaron quenching (TPQ) processes and reducing internal Joule heating. For example, the appropriate triplet energy of the rare earth complex can act as an energy ladder, thereby facilitating exciton radiative decay.

[0043] For example, when a trace amount of a rare earth complex is used as a sensitizer as part of the material of the light-emitting layer, and this light-emitting layer material is used to form the light-emitting layer and used in a blue light-emitting organic light-emitting diode, a highly efficient and stable blue light-emitting organic light-emitting diode can be obtained. When this blue light-emitting organic light-emitting diode is used in a display panel, it can effectively alleviate the problem of display efficiency roll-off of the display panel at high brightness.

[0044] For example, in one embodiment of the present disclosure, the rare earth complex included in the energy transfer material may be a thulium (III) complex and a dysprosium (III) complex whose electronic transition is ff transition, and a cerium (III) complex whose electronic transition is df transition.

[0045] For example, in one example, introducing a trace amount of thulium (III) complex, or dysprosium (III) complex, or cerium (III) complex into the light-emitting layer of a blue phosphorescent organic light-emitting diode can regulate the carrier distribution and energy transfer rate of the light-emitting layer, thereby improving the display efficiency and service life of the final display device, thereby solving the technical problems of short life and severe efficiency roll-off at high brightness of blue light-emitting organic light-emitting diode display devices.

[0046] For example, the carrier transport material of an organic light-emitting diode that emits blue light needs to meet the following conditions: the energy of the carrier transport material is higher than that of the triplet excited state of the light-emitting material to prevent energy backflow. T ≈2.8eV. The carrier transport material matches the HOMO and LUMO energy levels of the carrier transport layer / blocking layer and the light-emitting layer, reducing the carrier injection barrier and the resulting display panel's lighting and operating voltages. The carrier transport material's excellent carrier transport capability balances the hole and electron densities in the light-emitting layer and broadens the carrier recombination zone, resulting in excellent thermal stability.

[0047] For example, in one example, the structural formula of the rare earth complex includes At least one of the above general structural formulas are respectively the general structural formulas of thulium (III) complex, dysprosium (III) complex and cerium (III) complex. For specific structures, please refer to the relevant description below.

[0048] For example, in one example, the structural formula of the rare earth complex includes At least one of, R1 to R4 are each independently selected from hydrogen, deuterium, F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 Heteroarylthio group, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, substituted or unsubstituted C5-C 60 Carbocyclic group, substituted or unsubstituted C1-C 60 heterocyclic group, -Si(Q')(Q") (Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q") and -P(=S)(Q')(Q"), wherein Q', Q", Q'' and ''' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 At least one of a heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0049] For example, in one example, the structural formula of the rare earth complex includes: At least one of the above-mentioned structures, using the thulium (III) complex and the dysprosium (III) complex as the energy transfer material can make the display effect of the finally formed display panel good.

[0050] For example, in one example, the general structural formula of the rare earth complex includes: X is selected from I -1 Br -1 、Cl -1 、NO3-1 、CH3COO -1 、CCl3COO -1 CF3COO -1 、ClO4 -1 、BF4 -1 , BPh4 -1 、N3 -1 , substituted or unsubstituted pyrazole anion, p-toluenesulfonate, p-toluenesulfonate, o-nitrophenoloxy, p-nitrophenoloxy, m-nitrophenoloxy, 2,4-dinitrophenoloxy, 3,5-nitrophenoloxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy anion, trifluoromethanesulfonate, tetrafluoroborate and hexafluorophosphate; R5, R6, R7 and R8 are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"), wherein Q', Q", Q'', and Q'' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0051] For example, in one example, the structural formula of the rare earth complex includes:

[0052] At least one of .

[0053] For example, in one example, the structural formula of the platinum complex includes A1 to A4 are each independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 A heterocyclic group, and at least one of A1 to A4 contains a carbene group directly connected to Pt; X1 to X 10 are each independently C or N; L1 to L3 are each independently selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-)- and -Ge(R')(R")-; R9 to R 12 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k1 to k4 are each independently selected from an integer from 0 to 10; Q', Q", Q"' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0054] For example, in one embodiment of the present disclosure, the structural formula of the platinum complex is At least one of the above, it should be noted that the structural formula of the platinum complex provided in the embodiments of the present disclosure is not limited thereto, and can also be any other platinum complex that meets the requirements, and the embodiments of the present disclosure are not limited thereto.

[0055] For example, in one example, the carrier transport material includes a combination of a hole transport material and an electron transport material. Electrons and holes exist in the carrier transport material, so that there are enough electrons and holes to recombine and emit light.

[0056] For example, in one example, the structural formula of the hole transport material is:

[0057] A5 to A8 are independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C60 Heterocyclic group; L4 is selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')- and -Ge(R')(R")-; R 13 to R 17 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k5 to k9 are each independently selected from an integer from 0 to 10; Q', Q", Q'' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 Heteroaryl, monovalent non-aromatic fused polycyclic group, monovalent non-aromatic fused heteropolycyclic group, biphenyl group and terphenyl group. Of course, the embodiments of the present disclosure are not limited thereto, and the structural formula of the hole transport material can also be other structural formulas.

[0058] For example, in one example, the structural formula of the hole transport material includes:

[0059] At least one of .

[0060] For example, in one embodiment of the present disclosure, the electron transport material has the general structural formula: A 10 To A 12 Independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 a heterocyclic group; Z1 to Z3 are each independently CH or N; L6 to L8 are each independently selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-, and -Ge(R')(R")-; R 18 to R 20 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); K7, K8, and K9 are each independently selected from an integer from 0 to 10; Q', Q", Q"' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0061] For example, in one embodiment, the structural formula of the electron transport material includes:

[0062] At least one of .

[0063] For example, in one embodiment, the carrier transport material includes a bipolar material. A bipolar material is a semiconductor material that has both n-type and p-type conductivity properties. Electrons or holes can move freely in the bipolar material. The bipolar material can better meet the requirements of semiconductor devices for different conductivity properties, thereby improving the display quality of the display panel.

[0064] For example, in one example, the bipolar material includes an electron-donating portion and an electron-withdrawing portion, the electron-donating portion includes carbazole, and the electron-withdrawing portion includes at least one of phosphorus oxygen, cyano, pyridine, carbidine, triazole and phenylimidazole. The electron-donating portion of the bipolar material can be combined with the group with electron-withdrawing properties in the mixed material, and the electron-withdrawing portion of the bipolar material can be combined with the group with electron-donating properties in the mixed material.

[0065] For example, in one embodiment, the structural formula of the bipolar material includes:

[0066] At least one of .

[0067] For example, in one example, the energy of the lowest triplet excited state of the carrier transport material is greater than the energy of the lowest triplet excited state of the energy transfer material, and the energy of the lowest triplet excited state of the energy transfer material is greater than the energy of the lowest triplet excited state of the luminescent material, that is, the energy of the lowest triplet excited state of the carrier transport material, the energy of the lowest triplet excited state of the energy transfer material, and the energy of the lowest triplet excited state of the luminescent material decrease in sequence, which can form a gradual trend to make the emitted light more uniform.

[0068] For example, among the materials of the light-emitting layer, the mass percentage of the carrier transport material is 80% to 95%, the mass percentage of the energy transfer material is 0.1% to 1%, and the mass percentage of the light-emitting material is 5% to 20%. The materials of the light-emitting layer in the above combination range can make the display effect of the display panel good when used in the display panel, and make the manufacturing cost of the material of the light-emitting layer relatively low.

[0069] For example, in another example, the mass percentage of the carrier transport material is 85% to 90%, the mass percentage of the energy transfer material is 0.3% to 0.7%, and the mass percentage of the light emitting material is 10% to 15%.

[0070] For example, in yet another example, the mass percentage of the carrier transport material is 87%, the mass percentage of the energy transfer material is 0.5%, and the mass percentage of the light emitting material is 12.5%.

[0071] For example, in yet another example, the mass percentage of the carrier transport material is 88%, the mass percentage of the energy transfer material is 0.5%, and the mass percentage of the light emitting material is 11.5%.

[0072] For example, when an organic light emitting diode display device is formed using the material of the light emitting layer provided by the embodiments of the present disclosure, the thickness of the light emitting layer is 10 to 100 nm.

[0073] For example, in one example, the electroemission spectrum of the energy transfer material and the absorption spectrum of the luminescent material have a spectral overlap range, and after normalization, the area of ​​the spectral overlap range is greater than or equal to 50% of the area of ​​the absorption spectrum of the luminescent material, which can make the emitted light more pure.

[0074] For example, in one example, the energy of the highest triplet excited state of the energy transfer material is greater than the energy of the highest triplet excited state of the carrier transport material, and the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is less than or equal to 0.2 eV. Setting the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material to less than or equal to 0.2 eV can make the luminescence efficiency of the finally formed device higher.

[0075] For example, when the difference between the energy of the highest triplet excited state of the carrier transport material and the energy of the highest triplet excited state of the energy transfer material is greater than 0.2 eV, the energy transfer efficiency will be reduced, thereby affecting the luminous efficiency of the final light-emitting device.

[0076] For example, in one example, the difference between the energy of the lowest triplet excited state of the carrier transport material and the energy of the lowest triplet excited state of the energy transfer material is greater than or equal to 0.3 eV. For example, in one example, the energy of the lowest triplet excited state of the carrier transport material is 0.8 eV, and the energy of the lowest triplet excited state of the energy transfer material is 0.5 eV. In another example, the energy of the lowest triplet excited state of the carrier transport material is 1.2 eV, and the energy of the lowest triplet excited state of the energy transfer material is 0.8 eV. In yet another example, the energy of the lowest triplet excited state of the carrier transport material is 1.8 eV, and the energy of the lowest triplet excited state of the energy transfer material is 1.2 eV.

[0077] At least one embodiment of the present disclosure further provides an organic electroluminescent display device. For example, FIG1 is a schematic diagram of the cross-sectional structure of an organic electroluminescent display device provided by at least one embodiment of the present disclosure. As shown in FIG1 , the organic electroluminescent display device 100 includes a first electrode 101, a hole transport layer 102, a hole injection layer 103, an electron blocking layer 104, a light-emitting layer 105, a hole blocking layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode 109, which are stacked in sequence. The light-emitting layer 105 is formed using the material of the light-emitting layer in any of the above-mentioned embodiments, that is, the material of the light-emitting layer includes a carrier transport material, an energy transfer material, and a light-emitting material, and the light-emitting material includes a platinum complex, and the energy transfer material includes a rare earth complex. When the organic electroluminescent display device is used in a display panel, the display efficiency and service life of the display panel can be improved.

[0078] For example, in one example, the material of the light-emitting layer in the organic electroluminescent display device is a blue phosphorescent material, that is, the organic electroluminescent display device is a blue phosphorescent device.

[0079] For example, in the structure shown in FIG1 , the first electrode 101 is formed of an electrode material with a high work function, and the first electrode 101 can serve as the anode of an organic electroluminescent display device. The material of the first electrode 101 in a bottom-emitting device can be indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), or zinc oxide (ZnO), and the thickness of the first electrode 101 is 80 to 200 nm. The material of the second electrode 109 in a top-emitting device can be Ag / ITO, Ag / IZO, Ag / SnO2, Ag / ZnO, Al / ITO, or Al / IZO, that is, the second electrode 109 is a double-layer stacked structure formed by a metal layer and a metal oxide layer, wherein the thickness of the metal layer is 10 to 100 nm and the thickness of the oxide layer is 5 to 20 nm.

[0080] For example, the hole injection layer 102 can be made of a hole injection material such as MnO3 and CuPc. Alternatively, the hole transport material can be p-type doped to obtain a hole injection material. For example, the hole injection layer can be made of NPB:F4TCNQ, TAPC:MnO3, etc., with a p-type doping concentration of 0.5% to 10% by mass. The thickness of the hole injection layer 102 can be 5 nm to 20 nm.

[0081] For example, the primary function of the hole transport layer 103 is to transport holes. The material for the hole transport layer 103 can be a carbazole material with high hole mobility. The hole transport layer 103 can be formed by evaporation. For example, in one embodiment of the present disclosure, the thickness of the hole transport layer 103 is 80 to 140 nm.

[0082] For example, the energy of the lowest triplet excited state (T1) of the material of the electron blocking layer 104 is greater than the energy of the lowest triplet excited state (T1) of the transition metal complex material in the light-emitting layer 105, and the difference is greater than or equal to 0.2 eV. The HOMO energy level of the material of the electron blocking layer 104 is deeper than the HOMO energy level of the host material in the light-emitting layer 105, and the difference is less than or equal to 0.2 eV. For example, in one embodiment of the present disclosure, the thickness of the electron blocking layer 104 is 1 to 100 nm.

[0083] For example, the energy of the lowest triplet excited state (T1) of the hole blocking layer 106 is greater than the energy of the lowest triplet excited state (T1) of the material of the transition metal complex in the light-emitting layer 105, and the difference between the energy of the lowest triplet excited state (T1) of the hole blocking layer 106 and the energy of the lowest triplet excited state (T1) of the material of the transition metal complex in the light-emitting layer 105 is less than or equal to 0.2 eV. The LUMO energy level of the material of the hole blocking layer 106 is shallower than the LUMO energy level of the carrier transport material in the light-emitting layer 105, and the difference between the LUMO energy level of the material of the hole blocking layer 106 and the LUMO energy level of the carrier transport material in the light-emitting layer 105 is less than or equal to 0.2 eV. For example, in one embodiment of the present disclosure, the thickness of the hole blocking layer 106 is 1 to 30 nm.

[0084] For example, the material of the electron transport layer 107 is Liq doped into a material with strong electron transport capability. The doping ratio of Liq is 10:1 to 1:1 in terms of mass percentage, and the thickness of the electron transport layer 107 is 10 to 70 nm.

[0085] For example, the material of the electron injection layer 108 may include Yb, Li, LiF, NaCl, CsF, Li2O, BaO, Liq, etc., or a combination of these materials. For example, the thickness of the electron injection layer 108 is 0.5-2 nm.

[0086] For example, in the structure shown in FIG1 , the second electrode 109 can serve as the cathode of the organic electroluminescent display device. For example, the material of the second electrode 109 is an electrode material with a low work function. For example, such low work function electrode materials include Mg, Ag, Al, Al / Li, Ca, Mg / In, and Mg / Ag. When the organic electroluminescent display device is a bottom-emitting device, the thickness of the second electrode 109 is 80 to 100 nm. When the organic electroluminescent display device is a top-emitting device, the thickness of the second electrode 109 is 10 to 20 nm. When the material of the second electrode 109 is an alloy formed by Mg and Ag, the molar ratio of the metal Mg to Ag is 3:7 to 1:9.

[0087] For example, in another example, when the organic electroluminescent display device further includes a light extraction layer disposed between the light-emitting layer 105 and the second electrode 109, the light extraction layer has a refractive index greater than 1.8 and a thickness of 50 to 100 nm. The second electrode 109 may cover the light extraction layer.

[0088] For example, before preparing an organic electroluminescent display device, the glass substrate is washed several times and then placed in oxygen plasma. Then, the sample is transferred to a vacuum evaporation system, and each layer structure formed by the organic material is prepared by vacuum evaporation deposition. During the entire preparation process of the organic electroluminescent display device, the organic material is placed in an oxygen plasma at a temperature of 5×10 -6 Torr high vacuum environment The electrode layer is also formed by thermal deposition. For example, in one example, when the electron injection layer 108 is formed of Yb metal and the second electrode 109 is formed of Mg metal, the thermal deposition rates of the electron injection layer 108 and the second electrode 109 are both When the second electrode 109 is formed of Ag metal, the thermal deposition rate of the second electrode 109 is

[0089] For example, in one example, the structure of the intercalation device 1 is: ITO / HIL (10 nm) / HTL (100 nm) / EBL (5 nm) / EML (46% P-4: 46% N-4: 8% Pt-1, x nm) / IL (TBRB, 0.6 nm) / EML (46% P-4: 46% N-4: 8% Pt-1, L x nm) / HBL (5 nm) / ETL (35 nm) / EIL (1 nm) / Mg:Ag (100 nm), wherein ITO represents the first electrode 101, HIL (10 nm) represents a hole injection layer with a thickness of 10 nm, HTL (100 nm) represents a hole transport layer with a thickness of 100 nm, EBL (5 nm) represents an electron blocking layer with a thickness of 5 nm, EML (46% P-4: 46% N-4: 8% Pt-1, x nm) nm) represents a first light-emitting layer with a thickness of x nm, which is formed by materials of a light-emitting layer formed by a combination of a platinum complex with a mass percentage of 8% and a carrier transport material with a mass percentage of 92%. IL (TBRB, 0.6 nm) represents an insertion layer with a thickness of 0.6 nm. EML (46% P-4:46% N-4:8% Pt-1, Lx nm) represents a second light-emitting layer with a thickness of Lx nm, which is formed by materials of a light-emitting layer formed by a combination of a platinum complex with a mass percentage of 8%, a rare earth complex with a mass percentage of 46%, and a carrier transport material with a mass percentage of 46%. L is the total length of the second light-emitting layer. HBL (5 nm) represents a hole blocking layer with a thickness of 5 nm. ETL (35 nm) represents an electron transport layer with a thickness of 35 nm. EIL (1 nm) represents an electron injection layer with a thickness of 1 nm. Mg:Ag (100 nm) represents a second electrode 109 with a thickness of 100 nm.

[0090] For example, in one example, the structure of the intercalation device 2 is: ITO / HIL (10 nm) / HTL (100 nm) / EBL (5 nm) / EML (46% P-4: 46% N-4: 0.5% Tm-1: 7.5% Pt-1, x nm) / IL (TBRB, 0.6 nm) / EML (46% P-4: 46% N-4: 0.5% Tm-1: 7.5% Pt-1, Lx nm) / HBL(5nm) / ETL(35nm) / EIL(1nm) / Mg:Ag(100nm), wherein ITO represents the first electrode 101, HIL(10nm) represents a hole injection layer with a thickness of 10nm, HTL(100nm) represents a hole transport layer with a thickness of 100nm, EBL(5nm) represents an electron blocking layer with a thickness of 5nm, and EML(46%P-4:46%N-4:0.5%Tm-1:7.5%Pt-1,x nm) represents a light-emitting layer formed by a combination of a platinum complex with a mass percentage of 7.5%, a thulium complex with a mass percentage of 0.5%, and a carrier transport material with a mass percentage of 92%, with a thickness of x. nm, IL (TBRB, 0.6 nm) represents the thickness of the insertion layer is 0.6 nm, EML (46% P-4: 46% N-4: 0.5% Tm-1: 7.5% Pt-1, Lx nm) represents the second light-emitting layer with a thickness of L-x nm formed by the material of the light-emitting layer formed by a combination of a platinum complex with a mass percentage of 7.5%, a thulium complex with a mass percentage of 0.5%, a rare earth complex with a mass percentage of 46%, and a carrier transport material with a mass percentage of 46%, and L is the total length of the second light-emitting layer, HBL (5 nm) represents a hole blocking layer with a thickness of 5 nm, ETL (35 nm) represents an electron transport layer with a thickness of 35 nm, EIL (1 nm) represents an electron injection layer with a thickness of 1 nm, and Mg:Ag (100 nm) represents a second electrode 109 with a thickness of 100 nm.

[0091] For example, in one example, the structure of the intercalation device 3 is: ITO / HIL (10 nm) / HTL (100 nm) / EBL (5 nm) / EML (46% P-4: 46% N-4: 0.5% Dy-1: 8% Pt-1, x nm) / IL (TBRB, 0.6 nm) / EML (46% P-4: 46% N-4: 0.5% Dy-1: 7.5% Pt-1, Lx nm) / HBL(5nm) / ETL(35nm) / EIL(1nm) / Mg:Ag(100nm), wherein ITO represents the first electrode 101, HIL(10nm) represents a hole injection layer with a thickness of 10nm, HTL(100nm) represents a hole transport layer with a thickness of 100nm, EBL(5nm) represents an electron blocking layer with a thickness of 5nm, and EML(46%P-4:46%N-4:0.5%Dy-1:7.5%Pt-1,x nm) represents a light-emitting layer formed by a combination of a platinum complex with a mass percentage of 7.5%, a dysprosium complex with a mass percentage of 0.5%, and a carrier transport material with a mass percentage of 92%, with a thickness of x. nm, IL (TBRB, 0.6 nm) represents the thickness of the insertion layer is 0.6 nm, EML (46% P-4: 46% N-4: 0.5% Dy-1: 7.5% Pt-1, Lx nm) represents the second light-emitting layer with a thickness of L-x nm formed by the material of the light-emitting layer formed by a combination of a platinum complex with a mass percentage of 7.5%, a dysprosium complex with a mass percentage of 0.5%, a rare earth complex with a mass percentage of 46%, and a carrier transport material with a mass percentage of 46%, and L is the total length of the second light-emitting layer, HBL (5 nm) represents a hole blocking layer with a thickness of 5 nm, ETL (35 nm) represents an electron transport layer with a thickness of 35 nm, EIL (1 nm) represents an electron injection layer with a thickness of 1 nm, and Mg:Ag (100 nm) represents a second electrode 109 with a thickness of 100 nm.

[0092] For example, in one example, the structure of the intercalation device 4 is: ITO / HIL (10 nm) / HTL (100 nm) / EBL (5 nm) / EML (46% P-4: 46% N-4: 0.5% Ce-1: 7.5% Pt-1, x nm) / IL (TBRB, 0.6 nm) / EML (46% P-4: 46% N-4: 0.5% Ce-1: 7.5% Pt-1, Lx nm) / HBL (5 nm) / ETL (35 nm) / EIL (1 nm) / Mg:Ag (100 nm), wherein ITO represents the first electrode 101, HIL (10 nm) represents a hole injection layer with a thickness of 10 nm, HTL (100 nm) represents a hole transport layer with a thickness of 100 nm, EBL (5 nm) represents an electron blocking layer with a thickness of 5 nm, and EML (46% P-4:46% N-4:0.5% Ce-1:7.5% Pt-1, x nm) represents a light-emitting layer formed by a combination of a platinum complex with a mass percentage of 7.5%, a cerium complex with a mass percentage of 0.5%, and a carrier transport material with a mass percentage of 92%, with a thickness of x. nm, IL (TBRB, 0.6 nm) represents the thickness of the insertion layer is 0.6 nm, EML (46% P-4: 46% N-4: 0.5% Ce-1: 7.5% Pt-1, Lx nm) represents the second light-emitting layer with a thickness of Lx nm formed by the material of the light-emitting layer formed by a combination of a platinum complex with a mass percentage of 7.5%, a cerium complex with a mass percentage of 0.5%, and a carrier transport material with a mass percentage of 92%, and L is the total length of the second light-emitting layer, HBL (5 nm) represents a hole blocking layer with a thickness of 5 nm, ETL (35 nm) represents an electron transport layer with a thickness of 35 nm, EIL (1 nm) represents an electron injection layer with a thickness of 1 nm, and Mg:Ag (100 nm) represents a second electrode 109 with a thickness of 100 nm.

[0093] Wherein, the above x is respectively 0.06L, 0.33L, 0.6L, and 0.86L. The main function of the above insertion layer IL is to study the position of the luminescence center in the luminescent layer.

[0094] For example, Figure 2 is a schematic diagram illustrating the different luminous intensities resulting from different insertion positions of the intercalation device provided by an embodiment of the present disclosure. As shown in Figure 2, the abscissa represents the insertion position of the intercalation layer, and the ordinate represents the luminous intensities of different intercalation devices. For example, starting from the side close to the electron blocking layer, 0.06L represents a distance from the electron blocking layer of 0.06 times L, where L is the total length of the light-emitting layer.

[0095] For example, as shown in Figure 2, the exciton distribution in the light-emitting layer of intercalation device 1 is significantly uneven, primarily concentrated on one side of the hole blocking layer. This results in lower luminous efficiency and a shorter service life for intercalation device 1. The exciton distribution in the light-emitting layer of intercalation device 2 is more balanced, which is beneficial for improving the luminous efficiency and extending the service life of intercalation device 2. The exciton distribution in the light-emitting layer of intercalation device 3 is more balanced, which is beneficial for improving the luminous efficiency and extending the service life of intercalation device 3. The exciton distribution in the light-emitting layer of intercalation device 4 is more balanced, which is beneficial for improving the luminous efficiency and extending the service life of intercalation device 4.

[0096] For example, in one example, the structure of the top emission device 1 is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4:46% N-4:8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 100nm. ) represents an electron blocking layer with a thickness of 5 nm, EML (46% P-4:46% N-4:8% Pt-1, 30 nm) represents a first light-emitting layer with a thickness of 30 nm formed by a light-emitting layer composed of a platinum complex with a mass percentage of 8% and a carrier transport material with a mass percentage of 92%, HBL (5 nm) represents a hole blocking layer with a thickness of 5 nm, ETL (35 nm) represents an electron transport layer with a thickness of 35 nm, EIL (1 nm) represents an electron injection layer with a thickness of 1 nm, Mg: Ag (15 nm) represents a second electrode 109 with a thickness of 15 nm, and CPL (65 nm) represents a light extraction layer with a thickness of 65 nm.

[0097] For example, in one example, the structure of the top-emitting device 2 is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 0.5% Tm-1: 8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. electron blocking layer, EML (46% P-4: 46% N-4: 0.5% Tm-1: 7.5% Pt-1, 30nm) represents a light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a platinum complex with a mass percentage of 7.5%, a thulium complex with a mass percentage of 0.5%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0098] For example, in one example, the structure of the top-emitting device 3 is: ITO / Ag / ITO / HIL (10 nm) / HTL (100 nm) / EBL (5 nm) / EML (46% P-4: 46% N-4: 0.5% Dy-1: 8% Pt-1, 30 nm) / HBL (5 nm) / ETL (35 nm) / EIL (1 nm) / Mg: Ag (15 nm) / CPL (65 nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10 nm) represents a hole injection layer with a thickness of 10 nm, and HTL (100 nm) represents a hole transport layer with a thickness of 100 nm. EBL (5nm) represents an electron blocking layer with a thickness of 5nm, EML (46% P-4:46% N-4:0.5% Tm-1:7.5% Pt-1, 30nm) represents a light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a platinum complex with a mass percentage of 7.5%, a thulium complex with a mass percentage of 0.5%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0099] For example, in one example, the structure of the top emission device 4 is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 0.5% Dy-1: 8% Ce-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg: Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. electron blocking layer, EML (46% P-4: 46% N-4: 0.5% Dy-1: 7.5% Ce-1, 30nm) represents a light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a cerium complex with a mass percentage of 7.5%, a dysprosium complex with a mass percentage, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0100] For example, FIG3 is a schematic diagram showing different current efficiencies caused by different current densities of a top-emitting device provided by an embodiment of the present disclosure. The following Table 1 is obtained in combination with FIG3 .

[0101] Table 1: Performance test parameters of top-emitting devices 1 to 4 provided in the embodiments of the present disclosure

[0102] For example, in Table 1, J refers to current density, λ EL Refers to the peak, FWHM refers to the full width at half maximum, V on Refers to the device brightness of 1 cd m -2 Voltage at LT 95 Refers to 15mA cm -2 The lifetime of the device when the brightness decays from the initial value to 95% under certain conditions.

[0103] Combining FIG3 and Table 1, it can be seen that the addition of a trace amount of rare earth complexes can significantly improve the photoelectric performance of blue phosphorescent organic light-emitting diode devices.

[0104] For example, when the carrier transport material of the above-mentioned top-emitting device is changed, the following top-emitting device is obtained.

[0105] For example, in one example, the stacked structure of the top-emitting device 5 is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-6:46% N-6:0.5% Ce-1:8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. m electron blocking layer, EML (46% P-6:46% N-6:0.5% Ce-1:7.5% Pt-1, 30nm) represents a light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a cerium complex with a mass percentage of 0.5%, a platinum complex with a mass percentage of 7.5%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0106] For example, in one example, the stacked structure of the top-emitting device 6 is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-1:46% N-1:0.5% Ce-1:8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. m electron blocking layer, EML (46% P-6:46% N-6:0.5% Ce-1:7.5% Pt-1, 30nm) represents a light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a cerium complex with a mass percentage of 0.5%, a platinum complex with a mass percentage of 7.5%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0107] For example, in one example, the stacked structure of the top-emitting device 7 is: ITO / Ag / ITO / HIL (10 nm) / HTL (100 nm) / EBL (5 nm) / EML (92% BP-1:0.5% Ce-1:7.5% Pt-1, 30 nm) / HBL (5 nm) / ETL (35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (65 nm), wherein ITO / Ag / ITO represents the first electrode 101 having a three-layer stacked structure, HIL (10 nm) represents a hole injection layer with a thickness of 10 nm, HTL (100 nm) represents a hole transport layer with a thickness of 100 nm, EBL (5 nm) represents an electron blocking layer with a thickness of 5 nm, and EML (92% BP-1 :0.5% Ce-1:7.5% Pt-1, 30nm) represents a light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a cerium complex with a mass percentage of 0.5%, a platinum complex with a mass percentage of 7.5%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0108] By comparing top-emitting devices 5-7, the following Table 2 can be obtained.

[0109] Table 2: Performance test parameters of top-emitting devices 5 to 7 provided by the embodiments of the present disclosure

[0110] For example, taking a top-emitting device as an example, when the mass percentage of the energy transfer material in the light-emitting layer is greater than 1% or less than 0.1%, problems such as poor display effect and short lifespan will occur.

[0111] For example, in Comparative Example 1, the structure of the top-emitting device is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 0.05% Tm-1: 8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents a first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. electron blocking layer, EML (46% P-4: 46% N-4: 0.05% Tm-1: 8% Pt-1, 30nm) represents a first light-emitting layer with a thickness of 30nm, which is composed of a light-emitting layer composed of a thulium complex with a mass percentage of 0.05%, a platinum complex with a mass percentage of 8%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0112] For example, in Comparative Example 2, the structure of the top-emitting device is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 0.05% Dy-1: 8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg: Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents a first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. electron blocking layer, EML (46% P-4: 46% N-4: 0.05% Dy-1: 8% Pt-1, 30nm) represents a first light-emitting layer with a thickness of 30nm, which is composed of a light-emitting layer composed of a dysprosium complex with a mass percentage of 0.05%, a platinum complex with a mass percentage of 8%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0113] For example, in Comparative Example 3, the structure of the top-emitting device is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 0.05% Ce-1: 8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents a first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. electron blocking layer, EML (46% P-4: 46% N-4: 0.05% Ce-1: 8% Pt-1, 30nm) represents a first light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a combination of a cerium complex with a mass percentage of 0.05%, a platinum complex with a mass percentage of 8%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0114] For example, in Comparative Example 4, the structure of the top-emitting device is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4:46% N-4:2% Tm-1:8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents a first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. m electron blocking layer, EML (46% P-4:46% N-4:2% Tm-1:8% Pt-1, 30nm) represents a first light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a combination of 2% by mass of a thulium complex, 8% by mass of a platinum complex, and 92% by mass of a carrier transport material, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0115] For example, in Comparative Example 5, the structure of the top-emitting device is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 2% Dy-1: 8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents a first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. m electron blocking layer, EML (46% P-4:46% N-4:2% Dy-1:8% Pt-1, 30nm) represents a first light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a combination of a dysprosium complex with a mass percentage of 2%, a platinum complex with a mass percentage of 8%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0116] For example, in Comparative Example 6, the structure of the top-emitting device is: ITO / Ag / ITO / HIL (10nm) / HTL (100nm) / EBL (5nm) / EML (46% P-4: 46% N-4: 2% Ce-1: 8% Pt-1, 30nm) / HBL (5nm) / ETL (35nm) / EIL (1nm) / Mg:Ag (15nm) / CPL (65nm), wherein ITO / Ag / ITO represents a first electrode 101 having a three-layer stacked structure, HIL (10nm) represents a hole injection layer with a thickness of 10nm, HTL (100nm) represents a hole transport layer with a thickness of 100nm, and EBL (5nm) represents a hole transport layer with a thickness of 5nm. m electron blocking layer, EML (46% P-4:46% N-4:2% Ce-1:8% Pt-1, 30nm) represents a first light-emitting layer with a thickness of 30nm formed by a light-emitting layer composed of a combination of a cerium complex with a mass percentage of 2%, a platinum complex with a mass percentage of 8%, and a carrier transport material with a mass percentage of 92%, HBL (5nm) represents a hole blocking layer with a thickness of 5nm, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0117] For example, the top-emitting devices in Comparative Examples 1 to 6 are tested to obtain the following Table 3.

[0118] Table 3: Performance test parameters of top-emitting devices in Comparative Examples 1 to 6

[0119] For example, by comparing Table 1 and Table 3, it can be concluded that when the mass percentage of the energy transfer material added to the material of the light-emitting layer is less than 0.1%, or greater than 1%, the service life of the blue phosphorescent organic light-emitting diode device will be shortened, and the on-state voltage of the blue light-emitting device will be increased, thereby reducing the photoelectric performance of the blue phosphorescent organic light-emitting diode device. Therefore, the mass percentage of the energy transfer material in the material of the light-emitting layer needs to be limited to 0.1% to 1%.

[0120] For example, in one example, a blue phosphorescent tandem device is more conducive to increasing device stability and improving EQE. When used in display panels, it can reduce the relative area of ​​blue light pixels while meeting optoelectronic performance indicators and increasing PPI. Tandem blue OLEDs further include a charge generation layer located between the first and second light-emitting layers.

[0121] For example, in one example, a blue OLED with a tandem structure is as follows: ITO / Ag / ITO / HIL (10 nm) / HTL1 (30 nm) / EBL1 (5 nm) / EML1 (20 nm) / HBL1 (5 nm) / NCGL (15 nm) / PCGL (10 nm) / HTL2 (30 nm) / EBL2 (5 nm)EML2 (20 nm) / HBL2 (5 nm) / ETL (35 nm) / EIL (1 nm) / Mg:Ag (15 nm) / CPL (65 nm), wherein ITO / Ag / ITO represents a first electrode 101 with a three-layer stacked structure, HIL (10 nm) represents a hole injection layer with a thickness of 10 nm, HTL1 (30 nm) represents a hole transport layer with a thickness of 30 nm, and EBL1 (5 nm) represents an electrode with a thickness of 5 nm. sub-blocking layer, EML1 (20nm) represents the first light-emitting layer with a thickness of 20nm, HBL1 (5nm) represents a hole blocking layer with a thickness of 5nm, NCGL (15nm) represents a 15nm N-type charge generation layer, PCGL (10nm) represents a 10nm P-type charge generation layer, HTL2 (30nm) represents a 30nm hole transport layer, EBL2 (5nm) represents a 5nm electron blocking layer, EML2 (20nm) represents a 20nm light-emitting layer, HBL2 (5nm) represents a 5nm hole blocking layer, ETL (35nm) represents an electron transport layer with a thickness of 35nm, EIL (1nm) represents an electron injection layer with a thickness of 1nm, Mg:Ag (15nm) represents a second electrode 109 with a thickness of 15nm, and CPL (65nm) represents a light extraction layer with a thickness of 65nm.

[0122] EML1 and EML2: 40% P-4: 60% N-4: 0.5% Ce-1: 8% Pt-1.

[0123] The following Table 4 was obtained by testing the tandem structured blue OLEDs.

[0124] Table 4: Performance test parameters of tandem blue OLEDs

[0125] For example, in addition to combinations of hole-transport and electron-transport materials, carrier transport materials can also be bipolar host materials. The electron-donating portion of bipolar host materials is primarily based on carbazole, while the electron-withdrawing portion is primarily based on phosphorus-oxy, cyano, pyridine, carboline, triazole, phenylimidazole, and the like. Specific examples of bipolar materials can be found in the relevant descriptions above.

[0126] For example, in an embodiment of the present disclosure, the energy of the highest triplet excited state of the energy transfer material is greater than the energy of the highest triplet excited state of the carrier transport material, and the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is less than or equal to 0.2 eV. For example, in the embodiments shown in top-emitting devices 1 to top-emitting devices 4 shown in Table 1, the energy of the highest triplet excited state of the energy transfer material is 2.5 eV, and the energy of the highest triplet excited state of the carrier transport material is 2.6 eV, that is, the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is equal to 0.1 eV.

[0127] For example, in the following comparative examples 7 to 9, the energy of the highest triplet excited state of the energy transfer material is 2.3 eV, and the energy of the highest triplet excited state of the carrier transport material is 2.6 eV, that is, the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is equal to 0.3 eV, so that the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is greater than 0.2 eV. The top-emitting devices shown in comparative examples 7 to 9 will cause the efficiency of energy transfer to be reduced.

[0128] For example, the top-emitting devices in Comparative Examples 7 to 9 were tested to obtain the following Table 5.

[0129] Table 5: Performance test parameters of top-emitting devices in Comparative Examples 7 to 9

[0130] For example, by comparing Table 1 and Table 5, it can be concluded that when the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is greater than 0.2 eV, the service life of the blue phosphorescent organic light-emitting diode device will be shortened and the on-state voltage of the blue light-emitting device will increase, thereby reducing the photoelectric performance of the blue phosphorescent organic light-emitting diode device. Therefore, it is necessary to set the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material to be less than or equal to 0.2 eV.

[0131] At least one embodiment of the present disclosure further provides a display panel. For example, FIG4 is a block diagram of a display panel provided by at least one embodiment of the present disclosure. As shown in FIG4 , the display panel includes any of the organic electroluminescent display devices described above. For example, using a blue organic light-emitting diode device in a display panel can reduce power consumption of the display panel and achieve higher color saturation when the brightness of the display panel is high.

[0132] In another aspect, the display panel includes the organic electroluminescent display device provided by any one of the above embodiments and a pixel driving circuit, wherein the pixel driving circuit is configured to drive the organic electroluminescent display device to emit light.

[0133] For example, FIG5 is a schematic cross-sectional view of a display panel according to at least one embodiment of the present disclosure. As shown in FIG5 , the display panel includes a base substrate BS; multiple thin-film transistors (TFTs) on the base substrate BS, each of which includes an active layer ACT; and a gate insulating layer GI located on the side of the active layer ACT away from the base substrate BS. A gate electrode G and a first capacitor electrode Ce1 (both part of the first gate metal layer) are located on the side of the gate insulating layer GI away from the base substrate BS. An insulating layer IN is located on the side of the gate G and the first capacitor electrode Ce1 away from the gate insulating layer GI. A second capacitor electrode Ce2 (part of the second gate metal layer) is located on the side of the insulating layer IN away from the gate insulating layer GI. An interlayer dielectric layer ILD is located on the side of the second capacitor electrode Ce2 away from the gate insulating layer GI. A source electrode S and a drain electrode D (part of the first source / drain metal layer) are located on the side of the interlayer dielectric layer ILD away from the gate insulating layer GI. A passivation layer PVX is located on the side of the source electrode S and the drain electrode D away from the interlayer dielectric layer ILD. The first planarization layer PLN1 is located on the side of the passivation layer PVX away from the interlayer dielectric layer ILD. The relay electrode RE (part of the second SD metal layer) is located on the side of the first planarization layer PLN1 away from the passivation layer PVX. The second planarization layer PLN2 is located on the side of the relay electrode RE (part of the second SD metal layer) away from the first planarization layer PLN1. The pixel definition layer PDL is used to define the sub-pixel openings and is located on the side of the second planarization layer PLN2 away from the base substrate BS. An organic electroluminescent display device LE is provided in each opening corresponding to the sub-pixel. The organic electroluminescent display device LE includes an anode AD located on a base substrate BS, a hole injection layer HIL located on a side of the anode AD away from the base substrate BS; a hole transport layer HTL located on a side of the hole injection layer HIL away from the base substrate BS; a light-emitting layer EL located on a side of the hole transport layer HTL away from the base substrate BS; an electron transport layer ETL located on a side of the light-emitting layer EL away from the base substrate BS; an electron injection layer EIL located on a side of the electron transport layer ETL away from the base substrate BS; and a cathode CD located on a side of the electron injection layer EIL away from the base substrate BS.

[0134] For example, as shown in FIG5 , an encapsulation layer EN is further provided in the display area of ​​the display panel. This encapsulation layer EN is used to encapsulate the light-emitting element LE, and is located on a side of the cathode layer CD away from the base substrate BS. In some embodiments, the encapsulation layer EN includes a first inorganic encapsulation sublayer CVD1 located on a side of the cathode layer CD away from the base substrate BS, an organic encapsulation sublayer IJP located on a side of the first inorganic encapsulation sublayer CVD1 away from the base substrate BS, and a second inorganic encapsulation sublayer CVD2 located on a side of the organic encapsulation sublayer IJP away from the base substrate BS.

[0135] For example, in some embodiments, the display panel further includes a touch structure TS. In some embodiments, the touch structure TS includes a buffer layer BUF, a first touch electrode layer TE1, a touch insulating layer TI, a second touch electrode layer TE2, and an overcoat layer OC. The buffer layer BUF is located on a side of the encapsulation layer EN away from the base substrate BS. The first touch electrode layer TE1 is located on a side of the buffer layer BUF away from the encapsulation layer EN. The touch insulating layer TI is located on a side of the first touch electrode layer TE1 away from the buffer layer BUF. The second touch electrode layer TE2 is located on a side of the touch insulating layer TI away from the buffer layer BUF. The overcoat layer OC is located on a side of the second touch electrode layer TE2 away from the touch insulating layer TI.

[0136] For example, FIG6 is a schematic diagram of the circuit structure of the pixel driving circuit included in the display panel shown in FIG5 . As shown in FIG6 , in some embodiments, each pixel driving circuit includes: a driving transistor Td; a storage capacitor Cst, which includes a first capacitor electrode Ce1 and a second capacitor electrode Ce2. The first transistor T1 has a gate connected to a corresponding reset control signal line rstN in a current stage (or current row) among a plurality of reset control signal lines, a first electrode connected to a corresponding first reset signal line Vint1N in a current stage (or current row) among a plurality of first reset signal lines, and a second electrode connected to the first capacitor electrode Ce1 of the storage capacitor Cst and the gate of the driving transistor Td. The second transistor T2 has a gate connected to a corresponding gate line GL among a plurality of gate lines, a first electrode connected to a corresponding data line DL among a plurality of data lines, and a second electrode connected to the first electrode of the driving transistor Td. The third transistor T3 has a gate connected to a corresponding gate line, a first electrode connected to the first capacitor electrode Ce1 of the storage capacitor Cst and the gate of the driving transistor Td, and a second electrode connected to the second electrode of the driving transistor Td. The fourth transistor T4 has a gate connected to a corresponding light-emission control signal line among the plurality of light-emission control signal lines em, a first electrode connected to a corresponding voltage supply line among the plurality of voltage supply lines Vdd, and a second electrode connected to the first electrode of the driving transistor Td and the second electrode of the second transistor T2. The fifth transistor T5 has a gate connected to the corresponding light-emission control signal line, a first electrode connected to the second electrodes of the driving transistor Td and the third transistor T3, and a second electrode connected to the anode of the light-emitting element LE. The sixth transistor T6 has a gate connected to a corresponding reset control signal line rst(N+1) in the next adjacent stage (or the next adjacent row) among the plurality of reset control signal lines, a first electrode connected to a corresponding second reset signal line Vint2N in the current stage (or the current row) among the plurality of second reset signal lines, and a second electrode connected to the second electrode of the fifth transistor and the anode of the light-emitting element LE. The second capacitor electrode Ce2 is connected to the corresponding voltage supply line and the first electrode of the fourth transistor T4.

[0137] For example, the performance test method of the display panel of the embodiment of the present disclosure is: setting the final brightness of the display panel to 800 cd m -2 The number of sub-pixels in the display panel is: 1,370,250 for red, 2,740,500 for green, and 1,370,250 for blue; the opening area is 190.00 μm for red. 2 , green is 242.50μm 2 , blue is 212.50μm 2The reference color coordinates of the display panel are set as follows: red (0.679, 0.321), green (0.260, 0.706), and blue (0.130, 0.041), resulting in the following performance (Table 6).

[0138] Table 6: Test data of the performance of the display panel of the embodiment of the present disclosure

[0139] From Table 6 above, it can be seen that the display panel has excellent optoelectronic performance and low power consumption.

[0140] Figure 7 is a schematic diagram illustrating the color shift of white light from a display panel according to at least one embodiment of the present disclosure, and Figure 8 is a schematic diagram illustrating the attenuation of white light brightness from a display panel according to at least one embodiment of the present disclosure. The horizontal axes of Figures 7 and 8 represent angles. For example, 0° is perpendicular to the light-emitting surface of the display panel, and 30° represents a 30° angle between the light-emitting angle of the display panel and the plane of the display panel.

[0141] At least one embodiment of the present disclosure provides a material for a light-emitting layer, an organic electroluminescent display device, and a display panel. The embodiments of the present disclosure introduce a trace amount of thulium (III) complex, or dysprosium (III) complex, or cerium (III) complex into the light-emitting layer of a blue phosphorescent organic light-emitting diode, which can regulate the carrier distribution and energy transfer rate of the light-emitting layer, thereby improving the display efficiency and service life of the display panel, thereby solving the problems of short service life and severe efficiency roll-off at high brightness of organic light-emitting diode display devices.

[0142] There are a few points to note:

[0143] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to conventional designs.

[0144] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale.

[0145] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to form new embodiments.

[0146] The above description is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. The protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A material for a light-emitting layer, comprising: Carrier transport material, energy transfer material and luminescent material, wherein the luminescent material comprises a platinum complex and the energy transfer material comprises a rare earth complex.

2. The material for the light-emitting layer according to claim 1, wherein The rare earth complex includes at least one of a thulium complex, a dysprosium complex and a cerium complex.

3. The material for the light-emitting layer according to claim 2, wherein The general structural formula of the rare earth complex includes At least one of, R1 to R4 are each independently selected from hydrogen, deuterium, F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 Heteroarylthio group, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, substituted or unsubstituted C5-C 60 Carbocyclic group, substituted or unsubstituted C1-C 60 heterocyclic group, -Si(Q')(Q") (Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q") and -P(=S)(Q')(Q"), wherein Q', Q", Q'' and ''' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 At least one of a heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

4. The material for the light-emitting layer according to claim 3, wherein The structural formula of the rare earth complex includes: At least one of .

5. The material for the light-emitting layer according to claim 2, wherein The general structural formula of the rare earth complex includes: X is selected from I -1 Br -1 、Cl -1 、NO3 -1 、CH3COO -1 、CCl3COO -1 CF3COO -1 、ClO4 -1 、BF4 -1 , BPh4 -1 、N3 -1 , at least one of a substituted or unsubstituted pyrazole anion, p-toluate, p-toluenesulfonate, o-nitrophenoloxy, p-nitrophenoloxy, m-nitrophenoloxy, 2,4-dinitrophenoloxy, 3,5-nitrophenoloxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy anion, trifluoromethanesulfonate, tetrafluoroborate and hexafluorophosphate; R5, R6, R7 and R8 are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q"), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"), wherein Q', Q", Q'', and Q'' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

6. The material for the light-emitting layer according to claim 5, wherein The structural formula of the rare earth complex includes: At least one of .

7. The material for the light-emitting layer according to any one of claims 1 to 6, wherein The general structural formula of the platinum complex includes A1 to A4 are each independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 A heterocyclic group, and at least one of A1 to A4 contains a carbene group directly connected to Pt; X1 to X 10 are each independently C or N; L1 to L3 are each independently selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-)-, and -Ge(R')(R")-; R9 to R 12 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q")'), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k1 to k4 are each independently selected from an integer from 0 to 10; Q', Q", Q"' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

8. The material for the light-emitting layer according to claim 7, wherein The structural formula of the platinum complex is At least one of .

9. The material for the light-emitting layer according to any one of claims 1 to 8, wherein The carrier transport material includes a combination of a hole transport material and an electron transport material.

10. The material for the light-emitting layer according to claim 9, wherein The general structural formula of the hole transport material is: A5 to A8 are independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 heterocyclic groups; L4 is selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-, and -Ge(R')(R")-; R 13 to R 17 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q")'), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k5 to k9 are each independently selected from an integer from 0 to 10; Q', Q", Q"' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocycloalkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

11. The material for the light-emitting layer according to claim 10, wherein The structural formula of the hole transport material includes: At least one of .

12. The material for the light-emitting layer according to any one of claims 9 to 11, wherein The general structural formula of the electron transport material is: A 10 To A 12 Independently selected from substituted or unsubstituted C5-C 60 Carbocyclic groups and substituted or unsubstituted C1-C 60 heterocyclic groups; Z1 to Z3 are each independently CH or N; L6 to L8 are each independently selected from a single bond, -O-, -S-, -C(R')(R")-, -C(R')=, =C(R')-, -C(R')=C(R")-, -C(=O)-, -C(=S)-, -C≡C-, -B(R')-, -N(R')-, -P(R')-, -Si(R')(R")-, -P(=O)(R')-, and -Ge(R')(R")-; R 18 to R 20 R', R" are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amidino, hydrazine, hydrazone, substituted or unsubstituted C1-C 60 Alkyl, substituted or unsubstituted C2-C 60 Alkenyl, substituted or unsubstituted C2-C 60 Alkynyl, substituted or unsubstituted C1-C 60 Alkoxy, substituted or unsubstituted C3-C 10 Cycloalkyl, substituted or unsubstituted C1-C 10 Heterocycloalkyl, substituted or unsubstituted C3-C 10 Cycloalkenyl, substituted or unsubstituted C1-C 10 Heterocycloalkenyl, substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C6-C 60 Aryloxy, substituted or unsubstituted C6-C 60 Arylthio, substituted or unsubstituted C1-C 60 Heteroaryl, substituted or unsubstituted C1-C 60 Heteroaryloxy, substituted or unsubstituted C1-C 60 heteroarylthio, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, -Si(Q')(Q")(Q")'), -B(Q')(Q"), -N(Q')(Q"), -P(Q')(Q"), -C(=O)(Q'), -S(=O)(Q'), -S(=O)2(Q'), -P(=O)(Q')(Q"), and -P(=S)(Q')(Q"); k 10 to k 12 are each independently selected from an integer from 0 to 10; Q', Q", Q"' are each independently selected from hydrogen, deuterium, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, C1-C 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 10 Cycloalkyl, C1-C 10 Heterocycloalkyl, C3-C 10 Cycloalkenyl, C1-C 10 Heterocyclic Alkenyl, C6-C 60 Aryl, C1-C 60 heteroaryl group, a monovalent non-aromatic fused polycyclic group, a monovalent non-aromatic fused heteropolycyclic group, a biphenyl group, and a terphenyl group.

13. The material for the light-emitting layer according to claim 12, wherein The structural formula of the electron transport material includes: At least one of .

14. The material for the light-emitting layer according to any one of claims 1 to 8, wherein The carrier transport material includes a bipolar material.

15. The material for the light-emitting layer according to claim 14, wherein The bipolar material includes an electron donating portion and an electron withdrawing portion, wherein the electron donating portion includes carbazole, and the electron withdrawing portion includes at least one of a phosphorus oxygen group, a cyano group, a pyridine group, a carboline group, a triazole group, and a phenylimidazole group.

16. The material for the light-emitting layer according to claim 14, wherein The structural formula of the bipolar material includes: At least one of .

17. The material for the light-emitting layer according to any one of claims 1 to 16, wherein The energy of the lowest triplet excited state of the carrier transport material is greater than the energy of the lowest triplet excited state of the energy transfer material, and the energy of the lowest triplet excited state of the energy transfer material is greater than the energy of the lowest triplet excited state of the light emitting material.

18. The material for the light-emitting layer according to claim 17, wherein The mass percentage of the carrier transport material is 80% to 95%, the mass percentage of the energy transfer material is 0.1% to 1%, and the mass percentage of the luminescent material is 5% to 20%.

19. The material for the light-emitting layer according to claim 17, wherein The electroemission spectrum of the energy transfer material and the absorption spectrum of the luminescent material have a spectral overlap range, and after normalization, the area of ​​the spectral overlap range is greater than or equal to 50% of the area of ​​the absorption spectrum of the luminescent material.

20. The material for the light-emitting layer according to any one of claims 17 to 19, wherein The energy of the highest triplet excited state of the energy transfer material is greater than the energy of the highest triplet excited state of the carrier transport material, and the difference between the energy of the highest triplet excited state of the energy transfer material and the energy of the highest triplet excited state of the carrier transport material is less than or equal to 0.2 eV.

21. The material for the light-emitting layer according to claim 20, wherein The difference between the energy of the lowest triplet excited state of the carrier transport material and the energy of the lowest triplet excited state of the energy transfer material is greater than or equal to 0.3 eV.

22. An organic electroluminescent display device comprising a first electrode, a hole transport layer, a hole injection layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode stacked in sequence, wherein: The light-emitting layer is formed using the material of any one of claims 1 to 21.

23. The organic electroluminescent display device according to claim 22, wherein: The material of the light-emitting layer is a blue phosphorescent material.

24. A display panel comprising the organic electroluminescent display device according to claim 22 or 23.

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