Luminescent material, luminescent device and display device

Abstract

The invention provides a light-emitting material, a light-emitting device and a display device, belongs to the technical field of display, and can solve the problems of low efficiency and service life of an existing light-emitting device. The luminescent material comprises a host material and a guest material, the host material is selected from molecules with a first general formula, a second general formula or a third general formula; the first general formula is # imgabs 0, the second general formula is # imgabs 1, the third general formula is # imgabs 2, R1 to R6 are electron donating groups and are selected from electron-rich arylamine groups containing at least one nitrogen atom; the guest material is selected from molecules having a fourth general formula; a fourth general formula: # imgabs3 # X1 is an electron donating group and is selected from electron-rich arylamine groups containing at least one nitrogen atom; x2 is an electron withdrawing group; and R11 and R21 are respectively and independently selected from at least one of hydrogen, deuterium, halogen group, alkyl group, cycloalkyl group, heteroalkyl group, aralkyl group, alkoxy group, aryloxy group, amino group and silyl group.

Description

Technical Field

[0001] The present disclosure belongs to the field of display technology, and specifically relates to a luminescent material, a luminescent device and a display apparatus. Background Art

[0002] Thermally activated delayed fluorescence (TADF) materials can achieve reverse intersystem crossing (RISC) conversion of triplet excitons into singlet excitons and obtain 100% internal quantum efficiency, and have become the most popular luminescent materials at present. Summary of the invention

[0003] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a light-emitting material, a light-emitting device and a display device.

[0004] In a first aspect, an embodiment of the present disclosure provides a luminescent material, the luminescent material comprising: a host material and a guest material;

[0005] The host material is selected from molecules having the first general formula, the second general formula or the third general formula;

[0006] The first general formula:

[0007] The second general formula:

[0008] The third general formula:

[0009] R1 to R6 are electron-donating groups selected from electron-rich aromatic amine groups containing at least one nitrogen atom;

[0010] The guest material is selected from molecules having the fourth general formula;

[0011] The fourth general formula:

[0012] X1 is an electron-donating group selected from electron-rich aromatic amine groups containing at least one nitrogen atom;

[0013] X2 is an electron-withdrawing group selected from at least one of cyano, trifluoromethyl, pyridine, pyrimidine, and triazine groups;

[0014] R11 and R21 are each independently selected from at least one of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, and phosphino;

[0015] Any adjacent substituents on the same ring are optionally joined or fused to form a ring.

[0016] In some embodiments, R1 to R6, X1 is selected from one of the following molecules;

[0017]

[0018]

[0019] In some embodiments, the host material is selected from one of the following molecules;

[0020]

[0021]

[0022] In some embodiments, the guest material is selected from one of the following molecules;

[0023]

[0024]

[0025] In some embodiments, the doping ratio of the guest material is 1% to 3%.

[0026] In a second aspect, an embodiment of the present disclosure provides a light-emitting device, the light-emitting device comprising: a substrate, a first electrode and a second electrode located on the substrate and arranged opposite to each other, and an organic light-emitting layer located between the first electrode and the second electrode;

[0027] The material of the organic light-emitting layer includes the light-emitting material provided in the first aspect.

[0028] In some embodiments, the light emitting device further comprises: a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer;

[0029] The hole injection layer, the hole transport layer and the electron blocking layer are sequentially stacked and arranged between the first electrode and the organic light-emitting layer in a direction away from the first electrode;

[0030] The hole blocking layer, the electron transport layer and the electron injection layer are sequentially stacked and arranged between the second electrode and the organic light emitting layer in a direction away from the second electrode.

[0031] In some embodiments, the light emitting device further comprises: a cover layer and an encapsulation layer;

[0032] The covering layer is located on a side of the second electrode facing away from the first electrode;

[0033] The encapsulation layer is located on a side of the cover layer away from the second electrode.

[0034] In some embodiments, the light emitting device is a red light emitting device.

[0035] In a third aspect, an embodiment of the present disclosure provides a display device, comprising a light-emitting device as provided in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a light-emitting device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The components of the embodiments of the present disclosure generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the present disclosure claimed for protection, but merely represents the selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present disclosure. In the absence of conflict, the various embodiments of the present disclosure and the various features in the embodiments can be combined with each other.

[0038] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantitative restrictions, but indicate that there is at least one. "Including" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0039] The "multiple or several" mentioned in this disclosure refers to two or more. "And / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0040] At present, the traditional design principles of most TADF materials can be simplified to donor (D)-acceptor (A) with one or more donors or acceptors, or D-π-A structure, or exciplex system. For the exciplex system, the acceptor and donor units are relatively independent, and the overlap integral of the highest occupied molecular orbital (HOMO) energy level and the lowest occupied molecular orbital (LUMO) energy level is extremely small, thereby obtaining an extremely small energy level difference ΔE between the singlet state and the triplet state. ST , promoting the RISC process.

[0041] There are relatively few molecular pairs of the currently known exciplex system, and multiple potential radiation channels cause spectral impurity and severe efficiency roll-off. In addition, the lifespan of light-emitting devices made from molecules of the exciplex system is relatively poor.

[0042] In order to solve at least one of the above-mentioned technical problems, the embodiments of the present disclosure provide a light-emitting material, a light-emitting device and a display device. The light-emitting material, the light-emitting device and the display device provided by the embodiments of the present disclosure will be further described in detail below in combination with the accompanying drawings and specific implementation methods.

[0043] Before formally introducing the resource management method provided by the embodiment of the present disclosure, special terms involved in the light-emitting materials, light-emitting devices and display devices provided by the embodiment of the present disclosure are explained to facilitate understanding of the embodiment of the present disclosure.

[0044] Exciplex: An aggregate of two molecules or atoms of different species, which interact strongly in the excited state, produce new energy levels, emit different spectra from those of individual species, and have no fine structure. In the ground state, the interaction is weak or nonexistent.

[0045] Intersystem Crossing (ISC) is a non-radiative transition process in which the electrons in an excited state of a molecule undergo spin reversal, causing the multiplicity of the molecule to change.

[0046] Reverse Intersystem Crossing (RISC): The process in which triplet excitons are converted into singlet excitons through spin-orbit coupling.

[0047] Singlet state: According to the Pauli exclusion principle, the spin directions of two electrons in the same orbit must be opposite to each other, that is, the electrons in the ground state molecule are spin-paired and the net spin is zero. This molecular electronic energy state in which all electrons are paired is called a singlet state.

[0048] Triplet state: A quantum state of a system with spin 1, such that there are three allowed spin components: -1, 0, and +1. A molecule is in an excited triplet state, i.e., it contains two electrons with unpaired spins.

[0049] Locally Excited (LE): After the electron transition in a molecule, only the excited state of local atoms or groups is involved. During the electron transition of this excited state, the position of the atomic nucleus and its environment inside the molecule remain almost unchanged. The transition mode is a vertical transition, which occurs at the point with the minimum nuclear kinetic energy, that is, the extreme position of vibration.

[0050] Intramolecular Charge Transfer (ICT): The electrons and holes in the molecule are localized in different molecular sites or different sites of the same molecule, and energy is transferred through charge transfer.

[0051] Electron donating group: refers to a group that can increase the electron cloud density on the benzene ring when the substituent replaces the hydrogen on the benzene ring. These groups increase the electron cloud density on the benzene ring through the combined effects of inductive effect, conjugation effect and hyperconjugation effect.

[0052] Electron-withdrawing group: refers to a group that reduces the electron cloud density on the benzene ring when the substituent replaces the hydrogen on the benzene ring. These groups usually show a positive electric field to the outside.

[0053] In a first aspect, the embodiments of the present disclosure provide a luminescent material, the luminescent material comprising: a host material and a guest material. The host material is selected from molecules having the first general formula, the second general formula or the third general formula.

[0054] The first general formula: The second general formula: The third general formula:

[0055] R1 to R6 are electron-donating groups selected from electron-rich aromatic amine groups containing at least one nitrogen atom.

[0056] The guest material is selected from molecules having the fourth general formula.

[0057] The fourth general formula:

[0058] X1 is an electron-donating group selected from electron-rich aromatic amine groups containing at least one nitrogen atom. X2 is an electron-withdrawing group selected from at least one of cyano, trifluoromethyl, pyridine, pyrimidine, and triazine groups. R11 and R21 are each independently selected from at least one of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silane, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfenyl, sulfinyl, sulfonyl, and phosphino. Any adjacent substituents on the same ring are optionally joined or fused to form a ring.

[0059] In the luminescent material provided by the embodiment of the present disclosure, the TADF material of the exciplex type based on triazine derivatives has the characteristics of fast ISC, and the singlet exciton can be quickly converted to triplet exciton. As an acceptor molecule, it matches the donor molecule to form an exciplex. As the main material in the luminescent material, it eliminates the competitive emission process such as fluorescence of the LE state. The emission channel is only the ICT state singlet emission generated after the RISC of the LE state triplet exciton. The favorable coupling between the LE state and the ICT state can increase the spin-orbit coupling effect, reduce the delayed fluorescence lifetime, and suppress the efficiency roll-off. The single emission channel can improve the color purity. In addition, the folded acceptor structure as the guest material forms a spatial charge transfer effect, increases the steric hindrance, and improves the efficiency and life of the light-emitting device.

[0060] In some embodiments, R1 to R6 and X1 are electron-donating groups selected from electron-rich aromatic amine groups containing at least one nitrogen atom, wherein the nitrogen atom is connected to the benzene ring between the electron-withdrawing groups, such as diphenylamine, carbazole, acridine, phenoxazine groups, etc. The specific chemical formula and substitution position are shown in the following molecular formula.

[0061]

[0062] In some embodiments, the host material is selected from one of the following molecules.

[0063]

[0064]

[0065]

[0066] It can be seen from the above molecular formulas that the TADF material of the exciplex type based on triazine derivatives has the characteristics of fast ISC. The singlet exciton can be quickly converted into triplet exciton, and it can be used as an acceptor molecule to form an exciplex with the donor molecule. As the main material in the luminescent material, it eliminates the competitive emission process such as LE state fluorescence. The emission channel is only the ICT state singlet emission generated after the RISC of the LE state triplet exciton. The favorable coupling between the LE state and the ICT state can increase the spin-orbit coupling effect, reduce the delayed fluorescence lifetime, and suppress the efficiency roll-off. The single emission channel can improve the color purity.

[0067] by For example, the synthesis process is as follows:

[0068] Intermediate 1. Intermediate 2.

[0069]

[0070] In some embodiments, the guest material is selected from one of the following molecules.

[0071]

[0072]

[0073] It can be seen from the above molecular formulas that the folded acceptor structure as a guest material forms a spatial charge transfer effect, increases spatial steric hindrance, and improves the efficiency and life of the light-emitting device.

[0074] by For example, the synthesis process is as follows:

[0075] Intermediate 3.

[0076]

[0077] In some embodiments, the doping ratio of the guest material is 1% to 3%.

[0078] In practical applications, the doping ratio of the guest material may be 1% to 3%, for example, 1%. Increasing the doping ratio of the guest material may cause the color of the manufactured light-emitting device to red shift, thereby improving the color control capability.

[0079] In a second aspect, the present disclosure provides a light emitting device. Figure 1 A schematic diagram of a light emitting device provided in an embodiment of the present disclosure is shown in FIG. Figure 1As shown, the light-emitting device includes: a base substrate 100, a first electrode 101 and a second electrode 102 located on the base substrate 100 and arranged opposite to each other, and an organic light-emitting layer 103 located between the first electrode 101 and the second electrode 102; the material of the organic light-emitting layer 103 includes the light-emitting material provided in any of the above embodiments.

[0080] The base substrate 100 can be made of a rigid material such as glass, which can improve the bearing capacity of the base substrate 100 for other film layers thereon. Of course, the base substrate 100 can also be made of a flexible material such as polyimide (PI), which can improve the overall bending and stretching resistance of the light-emitting device, and avoid the stress generated during bending, stretching, and twisting that causes the base substrate 100 to break and cause a short circuit. In practical applications, the material of the base substrate 100 can be reasonably selected according to actual needs to ensure that the light-emitting device has good performance.

[0081] The first electrode 101 may be a reflective electrode, and its structure may be a single layer or a multilayer structure, and its material may be selected from electrode materials with high work function, such as metals, metal compounds, and combinations of metals and metal compounds. Exemplarily, the material of the first electrode 101 may be selected from at least one of indium tin oxide (ITO), tin oxide (SnO2), titanium nitride (TiN), lithium oxide (Li2O), calcium oxide (CaO), indium zinc oxide (IZO), zinc oxide (ZnO), fluoride (LiF), magnesium fluoride (MgF2), silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), calcium and lithium fluoride alloy (Ca-LiF), aluminum and lithium fluoride alloy (AI-LiF), molybdenum (Mo), titanium (Ti), indium (In), tin (Sn), and zinc (Zn). The first electrode 101 may be a multilayer structure, and the multilayer structure may be silver / indium tin oxide (Ag / ITO) arranged in sequence in a direction away from the base substrate 100. Silver (Ag) has a high reflectivity, and indium tin oxide (ITO) has a high transmittance, and the combination of the two improves the light extraction efficiency. For another example, the multilayer structure may be silver / indium zinc oxide (Ag / IZO), silver / tin oxide (Ag / SnO2), silver / zinc oxide (Ag / ZnO), aluminum / indium tin oxide (Al / ITO), aluminum / indium zinc oxide (Al / IZO) or silver / indium tin oxide / silver (Ag / ITO / Ag), etc., arranged in sequence in a direction away from the base substrate 100. The thickness of the metal layer is 80 nanometers to 100 nanometers, and the thickness of the metal oxide layer is 5 nanometers to 20 nanometers. The reference value of the average reflectivity of the first electrode 101 in the visible light region is 85% to 95%.

[0082] The material of the second electrode 102 can be selected from electrode materials with low work function, such as metals, metal compounds and combinations of metals and metal compounds. Exemplarily, the material of the second electrode 102 can be selected from at least one of silver (Ag), magnesium (Mg), indium zinc oxide (IZO), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), calcium and lithium fluoride alloy (Ca-LiF), aluminum and lithium fluoride alloy (AI-LiF), molybdenum (Mo), titanium (Ti), indium (In), tin (Sn) and zinc (Zn). Specifically, the thickness of the second electrode 102 can be 10 nanometers to 20 nanometers, and magnesium-aluminum alloy (Mg-Al) can be used, and the adjustment ratio of magnesium to aluminum is 1:9. The organic light-emitting layer 103 is located between the first electrode 101 and the second electrode 102. The polarities of the first electrode 101 and the second electrode 102 are opposite. The first electrode 101 can be specifically an anode, and the second electrode 102 can be specifically a cathode. The anode can be connected to a high-level power signal terminal through a thin film transistor in a pixel circuit, and the cathode can be connected to a low-level power signal terminal. The organic light-emitting layer 103 can emit light under the drive of the electric field between the anode and the cathode. The material of the organic light-emitting layer 103 includes the light-emitting material provided in any of the above embodiments.

[0083] The organic light-emitting layer 103 of the light-emitting device provided in the embodiment of the present disclosure is made of a light-emitting material as provided in any of the above embodiments, wherein the TADF material of the exciplex type based on triazine derivatives has the characteristics of fast ISC, and the singlet exciton can be quickly converted to triplet excitons, and as an acceptor molecule, it is matched with a donor molecule to form an exciplex, which is used as a main material in the light-emitting material, eliminating the competitive emission process such as fluorescence of the LE state, and the emission channel is only the ICT state singlet emission generated after the RISC of the LE state triplet exciton. The favorable coupling between the LE state and the ICT state can increase the spin-orbit coupling effect, reduce the delayed fluorescence lifetime, and suppress the efficiency roll-off. The single emission channel can improve the color purity. In addition, the folded acceptor structure is used as a guest material to form a spatial charge transfer effect, increase the steric hindrance, and improve the efficiency and life of the light-emitting device.

[0084] In some implementations, such as Figure 1As shown, the light-emitting device also includes: a hole injection layer 104, a hole transport layer 105, an electron blocking layer 106, a hole blocking layer 107, an electron transport layer 108 and an electron injection layer 109; the hole injection layer 104, the hole transport layer 105 and the electron blocking layer 106 are sequentially stacked in a direction away from the first electrode 101 and arranged between the first electrode 101 and the organic light-emitting layer 103; the hole blocking layer 107, the electron transport layer 108 and the electron injection layer 109 are sequentially stacked in a direction away from the second electrode 102 and arranged between the second electrode 102 and the organic light-emitting layer 103.

[0085] The hole injection layer 104 is mainly used to reduce the hole injection barrier and improve the hole injection efficiency. The material of the hole injection layer 104 can be selected from 1,4,5,8,9,11-hexaazatriphenylhexanitrile (HATCN), manganese oxide (MnO 3 ), copper phthalocyanine (CuPc) and other hole injection materials, and p-type doping can also be performed in the above hole transport materials, such as NPB: F4TCNQ, TAPC: MnO 3 The thickness of the hole injection layer 104 is 5 nanometers to 20 nanometers, wherein the p-type doping concentration is 0.5% to 5%.

[0086] The main function of the hole transport layer 105 is to efficiently transport holes, which helps to improve the imbalance of carrier transport, avoid energy waste, and thus improve the luminous efficiency. The hole transport layer 105 can be selected from spirocyclic materials, triphenylamine materials, fluorene materials, carbazole materials, and phthalocyanine materials with high hole mobility and prepared by evaporation, and its thickness can be 10 nanometers to 100 nanometers.

[0087] The main function of the electron blocking layer 106 is to block electrons and prevent them from overflowing the light-emitting area when a high current density is injected, thereby reducing the light-emitting efficiency and light-emitting quality. The electron blocking layer 106 can be made of a semiconductor material with a wide bandgap, such as an oxide, a nitride, or a semiconductor material doped with a specific element. For example, the electron blocking layer 106 can be made of gallium trioxide (Ga 2 O 3 ), aluminum gallium nitride (AlGaN), etc. The thickness of the electron blocking layer 106 is 1 nanometer to 10 nanometers.

[0088] The main function of the hole blocking layer 107 is to block holes and prevent them from flowing out of the organic light-emitting layer 103, thereby ensuring that carriers recombine in the organic light-emitting layer 103 and improving the light-emitting efficiency. The hole blocking layer 107 can be selected from organic materials or inorganic materials with a lower HOMO energy level, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), o-phenanthroline (Bphen), 1,3,5-tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBi), etc. The thickness of the hole blocking layer 107 is 1 nanometer to 10 nanometers.

[0089] The main function of the electron transport layer 108 is to effectively transport electrons from the second electrode 102 to the organic light-emitting layer 103, which helps to improve the imbalance of carrier transport and avoid energy waste, thereby improving the light-emitting efficiency. The electron transport layer 108 can be selected from At least one of the above, wherein a material with strong electron transport capability may be doped, such as Liq, whose chemical formula is The doping ratio is 10:1 to 1:1. The thickness of the electron transport layer 108 is 10 nanometers to 50 nanometers.

[0090] The main function of the electron injection layer 109 is to promote the effective injection of electrons from the second electrode 102 to the electron transport layer 108. By optimizing the material and structure of the electron injection layer 109, the electron injection barrier can be reduced and the electron injection efficiency can be improved, thereby enhancing the performance of the device. The electron injection layer 109 can be selected from alkali metals, such as ytterbium (Yb), lithium (Li), lithium fluoride (LiF), sodium chloride (NaCl), cesium fluoride (CsF), lithium oxide (Li 2 The electron injection layer 109 may be at least one of: anode (C), cathode (A), cathode ray tube (B), cathode ray tube (C), cathode ray tube (D), cathode ray tube (E), and cathode ray tube (E). The electron injection layer 109 may have a thickness of 0.5 nm to 2 nm.

[0091] In some embodiments, Figure 1 As shown, the light emitting device further includes: a covering layer 110 and an encapsulation layer 111 ; the covering layer 110 is located on the side of the second electrode 102 away from the first electrode 101 ; and the encapsulation layer 111 is located on the side of the covering layer 110 away from the second electrode 102 .

[0092] The main function of the covering layer 110 is to guide the light emitted from the second electrode 102 to the front of the light-emitting device, while reducing the light loss reflected by the nearby electrodes during light emission, which can not only improve the optical efficiency, but also enhance the brightness and contrast of the picture. The covering layer 110 can be made of a high refractive index material, and its refractive index for light with a wavelength of 530 nanometers can be greater than 1.7, and its thickness can be 50 nanometers to 100 nanometers. The encapsulation layer 111 can be a single-layer structure or a multi-layer structure. When the encapsulation layer 111 is a multi-layer structure, the encapsulation layer 111 may include a first inorganic encapsulation layer (not shown in the figure), an organic encapsulation layer (not shown in the figure), and a second inorganic encapsulation layer (not shown in the figure) arranged in sequence, such as silicon nitride SiN+ink+silicon nitride SiN.

[0093] A glass substrate was used as the base substrate 100, and ITO was deposited on the glass substrate to form the first electrode 101. The glass substrate was cut into a size of 40 mm × 40 mm × 0.7 mm, and ultrasonically treated with isopropyl alcohol and pure water for 5 minutes each, and then cleaned by exposure to ultraviolet rays and ozone for 30 minutes. Then, the glass substrate and ITO were provided to a vacuum deposition device. Then, it was transferred to a vacuum evaporation system, and all organic materials were vacuum evaporated and deposited. In the entire light-emitting device preparation process, the organic materials were deposited at 5×10 -6 Torr's high vacuum environment The organic material layers are thermally deposited at a rate of 1.5 nm and 200 nm of aluminum (Al) are thermally deposited on the organic film at a rate of 1.5 nm and 200 nm, respectively. and The second electrode 102 is formed, and then the cover layer 110 and the encapsulation layer 111 are formed, and finally the light emitting device is formed.

[0094] In the embodiment of the present disclosure, due to the material properties of the organic light-emitting layer 103 of the light-emitting device, the light-emitting device is a red light-emitting device. The performance of the light-emitting device provided in the embodiment of the present disclosure will be further described in detail below in combination with specific materials.

[0095] The structures and materials of the base substrate 100, the first electrode 101, the second electrode 102, the hole injection layer 104, the hole transport layer 105, the electron blocking layer 106, the hole blocking layer 107, the electron transport layer 108, the electron injection layer 109, the covering layer 110 and the encapsulation layer 111 in each comparative example and embodiment are the same, the difference is that the material of the organic light-emitting layer 103 is different.

[0096] For example, the base substrate 100 is a glass substrate with a thickness of 100 nanometers, the material of the first electrode 101 is ITO / Al with a thickness of 100 nanometers, the material of the hole injection layer 104 is NPB:HATCN with a thickness of 10 nanometers and a doping ratio of 1.5%, the material of the hole transport layer 105 is TPBi with a thickness of 15 nanometers, the material of the electron blocking layer 106 is TCTA with a thickness of 5 nanometers, the material of the hole blocking layer 107 is Alq with a thickness of 20 nanometers, the material of the electron transport layer 108 is LiF with a thickness of 1 nanometer, the material of the second electrode 102 is Mg:Ag with a doping ratio of 1:9 and a thickness of 15 nanometers, and the thickness of the covering layer 110 is 55 nanometers.

[0097] Comparative Example 1: The material of the organic light-emitting layer 103 is an exciplex host + Ir phosphorescent guest, the thickness is 35 nanometers, and the chemical formula of the host material is: The chemical formula of the guest material is:

[0098] The doping ratio of the guest material is 1%.

[0099] Comparative Example 2: The material of the organic light-emitting layer 103 is single host + Ir phosphorescent guest, the thickness is 35 nanometers, and the chemical formula of the host material is: The chemical formula of the guest material is:

[0100] The doping ratio of the guest material is 1%.

[0101] Comparative Example 3: The material of the organic light-emitting layer 103 is single host + Pt phosphorescent guest, the thickness is 35 nanometers, and the chemical formula of the host material is: The chemical formula of the guest material is: The doping ratio of the guest material is 1%. Comparative Example 4: The material of the organic light-emitting layer 103 is an exciplex host + a non-twisted structure Pt phosphorescent guest, the thickness is 35 nanometers, and the chemical formula of the host material is: The chemical formula of the guest material is: The doping ratio of the guest material is 1%.

[0102] Comparative Example 5: The material of the organic light-emitting layer 103 is a triazine main body + a non-twisted structure Pt phosphorescent guest, the thickness is 35 nanometers, and the chemical formula of the main material is: The chemical formula of the guest material is: The doping ratio of the guest material is 1%.

[0103] Example 1: The material of the organic light-emitting layer 103 is an exciplex host + a Pt phosphorescent guest, with a thickness of 35 nanometers. The chemical formula of the host material is: The chemical formula of the guest material is: The doping ratio of the guest material is 1%.

[0104] Example 2: The material of the organic light-emitting layer 103 is an exciplex host + a Pt phosphorescent guest, with a thickness of 35 nanometers. The chemical formula of the host material is: The chemical formula of the guest material is: The doping ratio of the guest material is 3%.

[0105] Example 3: The material of the organic light-emitting layer 103 is an exciplex host + a Pt phosphorescent guest, with a thickness of 35 nanometers. The chemical formula of the host material is: The chemical formula of the guest material is: The doping ratio of the guest material is 1%.

[0106] The performance parameters of the light-emitting devices provided by the above-mentioned comparative examples and embodiments are shown in the following table:

[0107] Devices <![CDATA[Spectral wavelength λ EL / nm]]> Efficiency CE (cd / A) Lifespan (hours) Comparative Example 1 637 43 261 Comparative Example 2 640 41 280 Comparative Example 3 640 45 280 Comparative Example 4 623 45 397 Comparative Example 5 633 41 293 Example 1 640 48 436 Example 2 647 31 450 Example 3 632 46 420

[0108] Comparing Comparative Example 1 with Comparative Example 2, the excited complex as the main body does not improve the efficiency and lifespan of the Ir phosphorescent material. Compared with Example 3, Example 1 can see that the excited complex as the main body has a nearly doubled lifespan for the Pt phosphorescent material while the efficiency remains the same. Compared with Example 4, Example 1 can see that the torsion-containing acceptor group can undergo space charge transfer, and in addition to increasing the steric hindrance, the color can also be regulated to cause the color to red-shift. Compared with Example 3, Comparative Example 5 can see that the efficiency is slightly higher due to the greater steric hindrance, and the lifespan remains the same because there is no excited complex main body, which is a significant decrease compared with Example 1. Compared with Example 1, Example 2 can see that the color red-shifts when the doping rate is increased, which proves its ability to regulate color, but the efficiency has dropped significantly. Compared with Example 1, Example 3 can see that the efficiency and lifespan are almost the same, with only a slight decrease. It is estimated that the change in steric hindrance affects its performance.

[0109] In a third aspect, an embodiment of the present disclosure provides a display device, which includes a light-emitting device as provided in any of the above embodiments. Specifically, the display device can be a mobile phone, a laptop computer, a tablet computer, a smart TV, a car display screen, and other devices. Other essential components of the display device should be understood by ordinary technicians in the field, and will not be described in detail here, nor should they be used as limitations on the present disclosure. Its implementation principle and beneficial effects are similar to the implementation principle and beneficial effects of the light-emitting device provided in any of the above embodiments, and will not be described in detail here.

[0110] It should be noted that in the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It is also understood that when an element or layer is referred to as being "on" another element or layer, it may be directly on the other element, or there may be an intermediate layer. In addition, it is understood that when an element or layer is referred to as being "under" another element or layer, it may be directly under the other element, or there may be more than one intermediate layer or element. In addition, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it may be the only layer between the two layers or two elements, or there may also be more than one intermediate layer or element. Similar reference numerals throughout the text indicate similar elements.

[0111] In the several embodiments provided in the present disclosure, it should be understood that the disclosed organic materials, light-emitting devices and display devices can be implemented in other ways. For example, the organic materials, light-emitting devices and display device embodiments described above are only schematic, for example, the position of the components shown is only a logical functional position, and other positions may be arranged in actual implementation.

[0112] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A luminescent material, characterized in that: The luminescent material comprises: a host material and a guest material; the host material is selected from molecules having the first general formula, the second general formula or the third general formula; The first general formula: The second general formula: The third general formula: R1 to R6 are electron-donating groups selected from electron-rich aromatic amine groups containing at least one nitrogen atom; the guest material is selected from molecules having the fourth general formula; The fourth general formula: X1 is an electron-donating group selected from electron-rich aromatic amine groups containing at least one nitrogen atom; X2 is an electron-withdrawing group selected from at least one of cyano, trifluoromethyl, pyridine, pyrimidine, and triazine groups; R11 and R21 are each independently selected from at least one of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, and phosphino; Any adjacent substituents on the same ring are optionally joined or fused to form a ring.

2. The luminescent material according to claim 1, characterized in that R1 to R6, X1 is selected from one of the following molecules; 3. The luminescent material according to claim 1, characterized in that The host material is selected from one of the following molecules; 4. The luminescent material according to claim 1, characterized in that The guest material is selected from one of the following molecules; 5. The luminescent material according to claim 1, characterized in that The doping ratio of the guest material is 1% to 3%.

6. A light emitting device, characterized in that: The light emitting device comprises: a base substrate, a first electrode and a second electrode located on the base substrate and arranged opposite to each other, and an organic light emitting layer located between the first electrode and the second electrode; The material of the organic light-emitting layer includes the light-emitting material according to any one of claims 1 to 5.

7. The light emitting device according to claim 6, characterized in that: The light emitting device further comprises: a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and an electron injection layer; The hole injection layer, the hole transport layer and the electron blocking layer are sequentially stacked and arranged between the first electrode and the organic light-emitting layer in a direction away from the first electrode; The hole blocking layer, the electron transport layer and the electron injection layer are sequentially stacked and arranged between the second electrode and the organic light emitting layer in a direction away from the second electrode.

8. The light emitting device according to claim 7, characterized in that: The light emitting device further comprises: a covering layer and an encapsulation layer; The covering layer is located on a side of the second electrode facing away from the first electrode; The encapsulation layer is located on a side of the cover layer away from the second electrode.

9. The light emitting device according to claim 6, characterized in that: The light emitting device is a red light emitting device.

10. A display device, characterized in that: The display device comprises the light emitting device according to any one of claims 6 to 9.

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