Compound, light-emitting device, display substrate and display apparatus

Abstract

Provided in the present disclosure are a compound, a light-emitting device, a display substrate and a display apparatus. The structural formula of the compound is as represented by general formula (1): wherein the structural formula of G is as represented by general formula (2), where two wavy lines respectively represent positions at which G is attached to a triazine structure and L in general formula (1), respectively; the proportion of an electron cloud of the LUMO energy level of the compound on G is 3-60%; X is O, S, C(R1)(R2) or N(R3); A is phenyl or naphthyl; and Het is a substituted or unsubstituted dibenzofuran at least containing one N atom, a substituted or unsubstituted dibenzothiophene at least containing one N atom, a substituted or unsubstituted benzodibenzofuran at least containing one N atom, or a substituted or unsubstituted benzodibenzothiophene at least containing one N atom.

Description

Compound, light-emitting device, display substrate and display device TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of display, and particularly relates to a compound, a light-emitting device, a display substrate and a display device. BACKGROUND

[0002] Organic electroluminescence display (OLED) has the advantages of lightness, thinness, self-luminescence, low power consumption, no backlight source, wide viewing angle, fast response, etc., has gradually replaced liquid crystal display panel to become a new generation of flat panel display, and has great potential in flexible display. At present, OLED has been gradually applied to mobile phones, wearable devices, vehicles and computers in high-end display fields, and many enterprises are also developing foldable and rollable OLED screens to meet people's requirements for large-screen experience and product portability. The organic electron transport material in the OLED device has a significant impact on its performance, and the currently disclosed electron transport materials need to be improved in efficiency and service life. Therefore, it is of great practical application value to develop stable and efficient electron transport materials, improve device efficiency and prolong device service life. SUMMARY

[0003] In a first aspect, the present disclosure provides a compound, wherein the compound has a structural formula as shown in general formula (1):

[0004] wherein the structural formula of G is shown in general formula (2), wherein the two wavy lines respectively represent the positions of G and L connected to the triazine structure in general formula (1); the electron cloud of the LUMO energy level of the compound accounts for 3% to 60% on G;

[0005] X is O, S, C(R1)(R2), N(R3); A is phenyl or naphthyl;

[0006] R1, R2, R3, are the same or different from each other, and each is independently selected from any one of hydrogen, deuterium, a halogen atom, a cyano group, a nitro group, a hydroxyl group, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C2-C18 alkynyl group, a substituted or unsubstituted C3-C18 cycloalkyl group, a substituted or unsubstituted C1-C18 alkoxy group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted 5-60 membered heteroaryl group, and a substituted or unsubstituted 5-18 membered heterocyclyl group;

[0007] Ar1, Ar2 represent a substituted or unsubstituted C6-C60 aryl group, or a substituted or unsubstituted 6- to 60-membered heteroaryl group;

[0008] L is a direct bond, alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl and heteroaryl can be further substituted independently by one or more groups selected from the group consisting of deuterium, (C1-C30)alkyl, halo(C1-C30)alkyl, halogen, cyano, (C3-C30)cycloalkyl, 5- to 7-membered heterocycloalkyl, (C2-C30)alkenyl, (C2-C30)alkynyl, (C6-C30)aryl, (C1-C30)alkoxy, (C6-C30)aryloxy, (C2-C30)heteroaryl, (C6-C30)aryl-substituted (C2-C30)heteroaryl, (C6-C30)aryl(C1-C30)alkyl, (C1-C30)alkyl(C6-C30)aryl, (C6-C30)arylthio, mono- or di(C1-C30)alkylamino, mono- or di(C6-C30)arylamino, (C1-C30)alkyl(C6-C30)arylamino, di(C6-C30)arylboronyl, di(C1-C30)alkylboronyl, (C1-C30)alkyl(C6-C30)arylboronyl, tri(C1-C30)alkylsilyl, di(C1-C30)alkyl(C6-C30)arylsilyl, (C1-C30)alkyldi(C6-C30)arylsilyl, tri(C6-C30)arylsilyl, N-carbazolyl, carboxyl, nitro and hydroxyl;

[0009] Het has a structural formula of one of the following general formula (2-1), general formula (2-2), general formula (2-3), general formula (2-4):

[0010] X1, X2, X3, X4 represent S or O, C, N, A1 to A10 each independently represent CH, C(Ra) or N, B1 to B10 each independently represent CH, C(Rb) or N, E1 to E10 each independently represent CH, C(Rc) or N, Y1 to Y8 each independently represent CH, C(Rc) or N;

[0011] At least one of A1 to A10 of general formula (2-1), at least one of B1 to B10 of general formula (2-2), at least one of E1 to E10 of general formula (2-3), and at least one of Y1 to Y8 of general formula (2-4) is N;

[0012] Ra, Rb, Rc, each independently, are the same or different, selected from a group consisting of hydrogen, deuterium, a halogen atom, a hydroxyl group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group having a carbon number of 1-20, a substituted or unsubstituted alkoxy group having a carbon number of 1-20, a substituted or unsubstituted aroxy group having a ring-forming carbon number of 6-30, a substituted or unsubstituted arylthio group having a ring-forming carbon number of 6-30, a substituted or unsubstituted aryl group having a ring-forming carbon number of 6-30, and a substituted or unsubstituted heterocyclic group having a ring-forming atom number of 5-30.

[0013] In some embodiments, in the presence of multiple Ra, multiple Rb, and multiple Rc, each of adjacent Ra, adjacent Rb, and adjacent Rc is independently bonded to each other to form a ring structure.

[0014] In some embodiments, the structure represented by the general formula (1) is selected from any one of the following structural formulae:

[0015] In some embodiments, the LUMO energy level of the compound is between 1.8 eV and 2.3 eV.

[0016] In some embodiments, the reorganization energy of the compound is less than or equal to 0.4 eV.

[0017] In some embodiments, the triplet energy level of the compound is between 2.0 eV and 2.6 eV.

[0018] In a second aspect, the present disclosure also provides a light-emitting device, comprising a first electrode, a light-emitting layer, and a second electrode which are sequentially stacked, wherein the light-emitting layer comprises a first material, and the first material comprises the compound described above.

[0019] In some embodiments, the light-emitting layer comprises a host material and a guest material, the host material comprises an electron-type host material and a hole-type host material, the electron-type host material comprises the first material, and the hole-type host material has the following structural formula:

[0020] The electron-type host material and the hole-type host material form an exciplex.

[0021] In some embodiments, the HOMO energy level of the hole-type host material is between 5.0 eV and 5.4 eV.

[0022] In some embodiments, the weight ratio of the hole-type host material to the electron-type host material is between 1:9 and 9:1.

[0023] In some embodiments, the weight percentage of the guest material in the light-emitting layer is between 1 wt% and 3 wt%.

[0024] In some embodiments, the light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along a direction close to the light-emitting layer, wherein the absolute value of the difference between the HOMO energy level of the electron blocking layer and the HOMO energy level of the hole-type host material is less than or equal to 0.3 eV.

[0025] In some embodiments, the light-emitting device further includes: an electron injection layer, an electron transport layer, and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along a direction close to the light-emitting layer, wherein the absolute value of the difference between the LUMO energy level of the hole blocking layer and the LUMO energy level of the electron-type host material is less than or equal to 0.3 eV.

[0026] In some embodiments, the light-emitting device further includes: an electron injection layer, an electron transport layer, and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along a direction close to the light-emitting layer, wherein the HOMO energy level of the hole blocking layer is greater than the HOMO energy level of the electron-type host material, and the difference between the two is greater than or equal to 0.3 eV;

[0027] The light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer, wherein the LUMO energy level of the electron blocking layer is greater than the LUMO energy level of the hole-type host material, and the difference between the two is greater than or equal to 0.3 eV.

[0028] In some embodiments, the absolute value of the difference between the molecular weight of the hole-type host material and the molecular weight of the electron-type host material is less than or equal to 300.

[0029] In some embodiments, the molecular weight of both the hole-type host material and the electron-type host material is greater than or equal to 600, and the molecular weight of the guest material is between 700 and 1500.

[0030] In some embodiments, the distance between the electron cloud of the HOMO level of the hole-type host material and the electron cloud of the LUMO level of the electron-type host material is between 3 and 5 angstroms.

[0031] In some embodiments, the emission wavelength λ of the cavitation host material is... P The emission wavelength λ of the electronic host material is between 380 nm and 430 nm. N The excimer complex emits light at a wavelength between 420 nm and 480 nm, where λe-λ P ≥20nm, λe-λ N ≥20nm.

[0032] In some embodiments, the light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer; the electron blocking layer includes a first sub-blocking layer and a second sub-blocking layer disposed sequentially along the direction close to the light-emitting layer; the thickness of the first sub-blocking layer is greater than the thickness of the second sub-blocking layer; and the mobility of the first sub-blocking layer is greater than the mobility of the second sub-blocking layer.

[0033] In some embodiments, the light-emitting device further includes: a hole injection layer, a hole transport layer and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer; and an electron injection layer, an electron transport layer and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along the direction close to the light-emitting layer.

[0034] The mobility of the hole-blocking layer is 10 -7 ~10 -9 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between,

[0035] The mobility of the electron transport layer is 10. -5 ~10 -7 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between,

[0036] The mobility of the hole transport layer is 10. -4 ~10 -6 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between,

[0037] The electron blocking layer has a mobility of 10. -4 ~10 -7 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between.

[0038] In some embodiments, the light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer; and an electron injection layer, an electron transport layer, and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along the direction close to the light-emitting layer; the electron blocking layer includes a first sub-blocking layer and a second sub-blocking layer disposed sequentially along the direction close to the light-emitting layer.

[0039] The triplet energy level of the luminescent layer is lower than the triplet energy level of either the second sub-blocking layer or the hole blocking layer.

[0040] In some embodiments, the light-emitting layer is used to emit red light;

[0041] The light-emitting layer further includes a dopant, which is used to emit light with a wavelength between 600 and 650 nm; the emission peak of the light-emitting layer is between 600 and 650 nm.

[0042] Thirdly, this disclosure also provides a display substrate including the above-mentioned light-emitting device.

[0043] Fourthly, this disclosure also provides a display device including the aforementioned display substrate. Attached Figure Description

[0044] Figure 1 shows the spectral curves of different materials provided in some embodiments.

[0045] Figure 2 is a schematic diagram of the structure of the light-emitting device provided in some embodiments of this disclosure.

[0046] Figures 3 to 6 are schematic diagrams of LUMO electron cloud distributions with different structures provided in some embodiments of this disclosure.

[0047] Figure 7 is a schematic diagram of a display substrate provided in some embodiments of this disclosure. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this disclosure do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this disclosure are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to such processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this disclosure are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” in this disclosure refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can indicate: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," "third," etc., used in this disclosure are merely to distinguish similar objects and do not represent a specific ordering of objects. "Above," "below," "left," "right," etc., are only used to indicate relative positional relationships; when the absolute position of the described objects changes, the relative positional relationship may also change accordingly.

[0050] An OLED device comprises, sequentially deposited on a substrate, an anode, a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an emissive layer (EML), another hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL), and a cathode. During operation, a voltage is applied to the anode and cathode. Holes injected from the anode move to the emissive layer via hole transport, and electrons injected from the cathode move to the emissive layer via the electron transport layer. Holes and electrons recombine in the emissive layer to generate excitons, which emit light when they transition from the excited state to the ground state. The injection and flow of holes and electrons must be balanced for the OLED device with this structure to function properly.

[0051] In OLED devices, excitons formed by the recombination of electrons and holes are not restricted by spin rules. According to published statistics, the ratio of excited singlet states to excited triplet states is 1:3. Fluorescent electroluminescence only utilizes the excited singlet state, that is, only about 25% of the input energy, while the energy of the excited triplet state, which accounts for 75% of the input energy, is wasted. Phosphorescence organic light-emitting diode (PHOLED) devices can utilize both excited singlet and excited triplet states simultaneously. Through spin-orbit coupling, the 75% of triplet excitons that would otherwise be unusable can transition to the ground state, breaking the limitation of OLED devices having an internal quantum efficiency of no more than 25%. In principle, the internal quantum efficiency of PHOLEDs can reach 100%. Therefore, phosphorescence organic light-emitting diode is considered an effective way to improve device efficiency.

[0052] Therefore, the choice of emissive layer material directly affects the efficiency of exciton formation, and thus the performance of the device. Currently, in existing red OLED devices, the emissive layer consists of a host material and a phosphorescent guest material. The host material can be a single-component material or a multi-component material. When the emissive layer includes multi-component materials, namely hole-type host (RH-P) materials and electron-type host (RH-N) materials, the RH-P and RH-N materials can form exciton complexes. Under electro-excitation, electrons and holes recombine on the host to form excitons. The excitons are transferred from the host to the phosphorescent guest through energy transfer, and then emit light through radiative transitions in the phosphorescent guest.

[0053] However, due to the non-radiative transition processes such as triplet-tripter annihilation and triplet-polaron annihilation, phosphorescent materials have very low luminescence efficiency when formed on their own. Only by doping them into the host material can they emit light efficiently. Therefore, the development of the host material is particularly important.

[0054] Specifically, the host material used in organic electroluminescent phosphorescent devices should possess the following properties:

[0055] (1) Possessing good charge transport characteristics: The host material must have certain transport characteristics (holes and electrons). The transport characteristics of holes and electrons, in other words, the balance of holes and electrons, determine the position of the exciton recombination region in the EML layer. The position of the exciton recombination region affects the device lifetime and efficiency. Too many or too few holes will lead to a decrease in device efficiency. If the exciton recombination region is far from the center of the EML and close to an adjacent layer, it will affect the electron and hole resistance of the layer material, thereby degrading the layer material and thus leading to a decrease in device lifetime. Specifically: RH-P has a higher hole mobility, and RH-N has a higher electron mobility.

[0056] (2) Good energy level matching between host and guest: Generally, the host gap is required to be larger than the guest gap so that the exciton energy can be effectively transferred to the guest molecule to emit phosphorescence, or the charge can be trapped directly on the guest to form exciton radiation decay to emit phosphorescence. RH-P has a suitable HOMO, and RH-N has a suitable LUMO.

[0057] (3) Suitable singlet level (S1 level) and triplet level (T1 level): The energy level of the host material is higher than the T1 level of the guest material (RD), which ensures that the excitons formed on the host material can be transferred to the phosphorescent guest through energy transfer, causing it to emit red light. Figure 1 shows the spectral curves of different materials provided in some embodiments. Figure 1 shows the spectral curves of the guest material, the hole-type host material, the electron-type host material, and the excitocomplex. The horizontal axis in Figure 1 represents the wavelength, the vertical axis represents the normalized intensity, and the shaded area represents the overlapping area between the absorption spectrum of the excitocomplex and the spectrum of the guest material. That is, the energy of the host material can be transferred to the guest material through energy transfer.

[0058] (4) Typically, it must possess certain phosphorescence properties. At low temperatures, its phosphorescence peak wavelength must be shorter than that of the guest phosphorescent material. This means that the T1 energy level of the host material must be greater than that of the guest material, and it must have a longer phosphorescence lifetime. Among these, the energy level structure matching between the host and guest materials is a key factor restricting the luminous efficiency of the device.

[0059] (5) The main material has good film-forming properties, ensuring that the material can form a good amorphous film.

[0060] (6) Thermal stability: The main material needs to have excellent thermal stability to prevent the device performance from deteriorating (such as material cracking during the vapor deposition process, which leads to a decrease in device life).

[0061] This disclosure provides a compound that can be used as a host material, mixed with phosphorescent materials, for application in light-emitting devices, thereby improving the efficiency and lifespan of the light-emitting devices and reducing their voltage. Figure 2 is a schematic diagram of the structure of a light-emitting device provided in some embodiments of this disclosure. As shown in Figure 2, the light-emitting device includes a first electrode 11, a light-emitting layer, and a second electrode 19 sequentially stacked on a substrate 10. The material of the first electrode 11 includes, for example, indium tin oxide (ITO), and the material of the second electrode 19 includes a metal, such as a magnesium-silver (Mg / Ag) alloy.

[0062] In one specific example, the light-emitting device includes, in a direction away from the substrate, the following layers arranged sequentially: a first electrode 11, a hole injection layer 12, a hole transport layer 13, an electron blocking layer 14, a light-emitting layer 15, a hole blocking layer 16, an electron transport layer 17, an electron injection layer 18, and a second electrode 19. The compound in the embodiments of this disclosure is applied to the light-emitting layer.

[0063] The structural formula of the compound provided in the embodiments of this disclosure is shown in the following general formula (1):

[0064] Wherein, the structural formula of G is shown in general formula (2), where the two wavy lines represent the positions where G connects to the triazine structure and L in general formula (1), respectively; specifically, the structural formula of the compound in the embodiments of this disclosure can be shown as follows:

[0065] In this compound, the electron cloud of the LUMO level accounts for 3% to 60% of G; X is O, S, C(R1)(R2), N(R3); and A is phenyl or naphthyl.

[0066] R1, R2, and R3 may be the same as or different from each other, and each is independently selected from any one of hydrogen, deuterium, halogen atom, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C2-C18 alkynyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C1-C18 alkoxy, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted 5-60-membered heteroaryl, and substituted or unsubstituted 5-18-membered heterocyclic group.

[0067] Ar1 and Ar2 represent substituted or unsubstituted C6-C60 aryl groups, or substituted or unsubstituted 6- to 60 heteroaryl groups.

[0068] L represents a direct bond, alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, and heteroaryl group that may be independently further substituted by one or more groups selected from the group consisting of: deuterium, (C1-C30)alkyl, halo(C1-C30)alkyl, halogen, cyano, (C3-C30)cycloalkyl, 5- to 7-membered heterocycloalkyl, (C2-C30)alkenyl, (C2-C30)alkynyl, (C6-C30)aryl, (C1-C30)alkoxy, (C6-C30)aryloxy, (C2-C30)heteroaryl, (C6-C30)aryl-substituted (C2-C30)heteroaryl, (C6-C30)aryl(C1-C30)alkyl, (C1-C30) Alkyl (C6-C30)aryl, (C6-C30)arylthio, mono- or di(C1-C30)alkylamino, mono- or di(C6-C30)arylamino, (C1-C30)alkyl(C6-C30)arylamino, di(C6-C30)arylboryl, di(C1-C30)alkylboryl, (C1-C30)alkyl(C6-C30)arylboryl, tri(C1-C30)alkylsilyl, di(C1-C30)alkyl(C6-C30)arylsilyl, (C1-C30)alkyldi(C6-C30)arylsilyl, tri(C6-C30)arylsilyl, N-carbazole, carboxyl, nitro and hydroxyl.

[0069] In some embodiments, the structural formula of Het is one of the following general formulas (2-1), (2-2), (2-3), and (2-4):

[0070] X1, X2, X3, X4 represent S or O, C, N; A1 to A10 each independently represent CH, C(Ra) or nitrogen atom N; B1 to B10 each independently represent CH, C(Rb) or nitrogen atom N; E1 to E10 each independently represent CH, C(Rc) or nitrogen atom N; Y1 to Y8 each independently represent CH, C(Rc) or nitrogen atom N.

[0071] In general formula (2-1), at least one of A1 to A10 is N; in general formula (2-2), at least one of B1 to B10 is N; in general formula (2-3), at least one of E1 to E10 is N; and in general formula (2-4), at least one of Y1 to Y8 is N.

[0072] Ra, Rb, and Rc may be the same as or different from each other, and are respectively selected from hydrogen, D, halogen atom, hydroxyl, cyano, substituted or unsubstituted amino, substituted or unsubstituted alkyl with 1 to 20 carbon atoms, substituted or unsubstituted alkoxy with 1 to 20 carbon atoms, substituted or unsubstituted aryloxy with 6 to 30 carbon atoms forming the ring, substituted or unsubstituted aryl with 6 to 30 carbon atoms forming the ring, substituted or unsubstituted aryl with 6 to 30 carbon atoms forming the ring, and substituted or unsubstituted heterocyclic group with 5 to 30 atoms forming the ring.

[0073] In some embodiments, when there are multiple Ra, multiple Rb, and multiple Rc, the multiple Ra may be the same or different from each other, the multiple Rb may be the same or different from each other, and the multiple Rc may be the same or different from each other. When there are multiple R2, the multiple R2 may be the same or different from each other; adjacent Ra, adjacent Rb, and adjacent Rc are independently bonded to each other to form a ring structure.

[0074] The LUMO electron cloud of the compounds disclosed herein accounts for 3% to 60% of the electron cloud in G. The position of the triazine connected to the benzene ring in the G structure has a significant impact on the proportion of the LUMO electron cloud in the G structure. The substituent at the Het position also has a significant impact on the proportion of the LUMO electron cloud in the G structure.

[0075] The compounds disclosed herein, by adjusting the connection positions of triazine and benzene in the G structure, the connection positions of N heterogroup and G structure, and the position of N hetero, can be made to have suitable LUMO energy levels, which can be used as N-type materials for RH, and can form excitocomplexes with appropriate P-type materials, serving as host materials for red light devices, and can be combined with guest materials to achieve red light emission.

[0076] Furthermore, the compounds disclosed herein contain groups of the general formula Het. By changing the substitution positions and the positions of N-type heteroatoms, the compounds, as N-type materials for red light, possess appropriate HOMO energy levels, which act as electron blockers, thereby achieving optimal matching with adjacent functional layers. In addition, the compounds disclosed herein have a rigid structure, and the molecular structure has a relatively stable geometric configuration, making the molecules less prone to deformation under an applied electric field and resulting in lower recombination energy. At the same time, the more rigid structure gives the compounds a higher glass transition temperature, improving the film-forming properties and thermal stability of the compounds, further enhancing the luminescence lifetime and operational stability of the devices. Moreover, the G structure in general formula (1) and the triazine group can form better conjugation, resulting in better molecular planarity, which can improve the carrier mobility of the host material and increase the exciton recombination rate, thereby reducing the operating voltage of the device and making it more valuable for applications.

[0077] The compounds provided in this disclosure contain groups with the general formula Het, which increases the spatial configuration of the molecules, reduces intermolecular interactions, and avoids redshift of the spectrum of the host material under thin film conditions. This prevents excitons formed on the host material from being effectively transferred to the guest, thus avoiding the problem of reduced guest luminescence efficiency and ensuring the efficiency of the device.

[0078] In this embodiment, hydrogen atoms comprise isotopes with different numbers of neutrons, namely protium, deuterium, and tritium. H atoms are common elements in the film layers of OLED devices. Deuterium is an isotope of hydrogen, and the carbon-deuterium bond has a shorter bond length, higher bond energy, and lower vibrational energy compared to the carbon-hydrogen bond. Therefore, replacing hydrogen atoms in organic molecules with deuterium atoms is an effective means of regulating the physicochemical properties of molecules. Introducing deuterium into the small organic molecules of OLED devices can suppress molecular vibrations, narrow the spectrum (dopant materials), reduce bond lengths, increase bond energy, and improve molecular stability, thereby helping to extend the lifespan of the device. Deuteration has the following advantages:

[0079] First, when hydrogen is replaced by deuterium, the chemical properties of the compound remain almost unchanged. Second, since the atomic weight of deuterium is twice that of hydrogen, the physical properties of deuterated compounds may change. The vibrational energy levels of deuterated compounds decrease, which can prevent the reduction in quantum efficiency caused by collisions due to van der Waals forces or intermolecular vibrations. Third, CD bonds can improve the stability of the compound, thus improving device efficiency and lifetime. Fourth, the more deuterated atoms there are, the more energy is required for side reactions, making side reactions less likely to occur, and significantly increasing the stability of the compound.

[0080] In some embodiments, the structure shown in general formula (1) is selected from any of the following structural formulas:

[0081] In some embodiments, Het can be represented by any of the groups shown in the following structural formulas:

[0082] In some embodiments, L is represented by a group shown in any of the following structural formulas:

[0083] In this context, * represents a chemical bond connection site.

[0084] In some embodiments, Ar1 and Ar2 may be independently selected from groups represented by the following structural formulas:

[0085] In some embodiments, the structure represented by general formula (1) is selected from any of the following structural formulas:

[0086] In some embodiments, the LOMO energy level of the compound is between 1.8 eV and 2.3 eV, for example, between 1.8 eV and 1.9 eV; or between 1.9 eV and 2.0 eV; or between 2.0 eV and 2.2 eV; or between 2.2 eV and 2.3 eV.

[0087] In some embodiments, the triplet energy level T1 of the compound satisfies: 2.0 eV ≤ T1 ≤ 2.6 eV. For example, 2.1 eV ≤ T1 ≤ 2.2 eV; or 2.2 eV ≤ T1 ≤ 2.3 eV; or 2.3 eV ≤ T1 ≤ 2.4 eV; or 2.4 eV ≤ T1 ≤ 2.6 eV.

[0088] In some embodiments, the recombination energy λ of the compound satisfies: λ ≤ 0.4 eV. For example, 0.15 eV ≤ λ ≤ 0.2 eV; or 0.2 eV ≤ λ ≤ 0.25 eV; or 0.25 eV ≤ λ ≤ 0.3 eV; or 0.3 eV ≤ λ ≤ 0.32 eV; or 0.32 eV ≤ λ ≤ 0.35 eV; or 0.35 eV ≤ λ ≤ 0.4 eV.

[0089] By controlling the T1, λ, and LUMO of the compound within the above ranges, the device can have better performance.

[0090] The following examples illustrate a method for synthesizing a compound, wherein, if expressed by a general formula, it means that all substances represented by that general formula are applicable to this reaction process.

[0091] The compounds shown in the above formulas can be synthesized using known methods. For example, cross-coupling reactions of transition metals such as nickel and palladium can be used. Other synthetic methods utilize CC,CN coupling reactions of transition metals such as magnesium or zinc. Among the above reactions, the Suzuki and Miyaura reactions are preferred due to their mild reaction conditions and superior selectivity for various functional groups.

[0092] The following are some exemplary methods for synthesizing compounds:

[0093] (1) Synthesis of compound RH-1:

[0094] Specifically, in a three-necked flask, 1-1a (25 mmol), 1-1b (20 mmol), potassium carbonate (40 mmol), THF (200 mL), and bis(tri-tert-butylphosphine)palladium (5 mmol) were added and refluxed at 80 °C for 3 hours under nitrogen protection. The mixture was then cooled to room temperature, and the resulting solid was filtered. After filtration, the solid was washed with 100 mL of tetrahydrofuran, 500 mL of ethyl acetate, 500 mL of water, and 300 mL of ethanol. The solution was dried to give intermediate 1-1c in 94% yield. Then, under nitrogen atmosphere, 1-1c (50 mmol) and 1-1d were added to 300 mL of dioxane in a 1:1.1 ratio, and the resulting mixture was stirred and refluxed. Subsequently, potassium acetate (165 mmol) was introduced into the mixture, and the mixture was stirred thoroughly. Then, tetra(triphenyl-phosphine)palladium (1.67 mmol) was introduced. After reacting for 12 hours, the product was cooled to room temperature, and the resulting solid was filtered. After filtration, the solid was washed with 100 ml tetrahydrofuran, 500 ml ethyl acetate, 500 ml water, and 300 ml ethanol. The product was dried to prepare intermediate 11e (95.2%).

[0095] In a three-necked flask, 1-1a (25 mmol), 1-1b (20 mmol), potassium carbonate (40 mmol), THF (180 mL), and bis(tri-tert-butylphosphine)palladium (5 mmol) were added. The mixture was heated to reflux at 90 °C for 3 hours under nitrogen protection, cooled to room temperature, and the resulting solid was filtered. After filtration, the solid was washed with 100 mL of tetrahydrofuran, 500 mL of ethyl acetate, 500 mL of water, and 300 mL of ethanol. The solution was dried to give compound RH-1 in 85.2% yield.

[0096] (2) Synthesis of compound RH-2:

[0097] The synthesis of compound RH-2 can be referenced from the synthesis of RH-1, with a yield of 83.6%.

[0098] (3) Synthesis of compound RH-3:

[0099] The synthesis of compound RH-3 can be referenced from the synthesis of RH-1, with a yield of 69.4%.

[0100] (4) Synthesis of compound RH-4:

[0101] The synthesis of compound RH-4 can be referenced from the synthesis of RH-1, with a yield of 87.6%.

[0102] (5) Synthesis of compound RH-5:

[0103] The synthesis of compound RH-5 can be referenced from the synthesis of RH-1, with a yield of 89.8%.

[0104] (6) Synthesis of compound RH-6:

[0105] The synthesis of compound RH-6 can be referenced from the synthesis of RH-1, with a yield of 90.6%.

[0106] (7) Synthesis of compound RH-7:

[0107] The synthesis of compound RH-7 can be referenced from the synthesis of RH-1, with a yield of 87.3%.

[0108] (8) Synthesis of compound RH-8:

[0109] The synthesis of compound RH-8 can be referenced from the synthesis of RH-1, with a yield of 82.4%.

[0110] (9) Synthesis of compound RH-9:

[0111] The synthesis of compound RH-9 can be referenced from the synthesis of RH-1, with a yield of 85.7%.

[0112] (10) Synthesis of compound RH-10:

[0113] The synthesis of compound RH-10 can be referenced from the synthesis of RH-1, with a yield of 84.2%.

[0114] Similarly, synthesize the compounds listed in Tables 1 to 4 below:

[0115] Table 1

[0116] Table 2

[0117] Table 3

[0118] Table 4

[0119] In Tables 1 to 4, intermediate 1 in the synthesis examples of compounds RH-11 to RH-30 is referred to as intermediate 1-11 to intermediate 1-30, and its structural formula is as follows:

[0120] The structural formulas of products 11 to 30 in Tables 1 to 4 (that is, the structural formulas of compounds RH-11 to RH-30) are as follows:

[0121] It should be noted that some of the compounds are listed in Tables 1 to 4. The preparation processes of the compounds not listed are similar to those of the compounds listed above, and will not be described in detail here.

[0122] Tables 5 and 6 show the distribution of LUMO electron clouds in molecules of some structures and the proportion of LUMO electron clouds on G.

[0123] Table 5

[0124] Table 6

[0125] The structural formulas of structures 1 to 14 are shown in the following structural formulas (7-1) to (7-14).

[0126] The LUMO electron cloud distributions in molecules of structures 1 to 4 are shown in Figure 3; the LUMO electron cloud distributions in molecules of structures 5 to 7 are shown in Figure 4; the LUMO electron cloud distributions in molecules of structures 8 to 11 are shown in Figure 5; and the LUMO electron cloud distributions in molecules of structures 12 to 14 are shown in Figure 6.

[0127] For the compounds of the present invention, some performance parameters were determined: HOMO, LUMO, S1, T1 of the above compounds were obtained by simulation calculation, and the mobility (EOD:ITO / ET10nm / ET:LiQ(1:150%)15nm / RH 110nm / ET:LiQ(1:150%)15nm / Yb 1nm / Mg:Ag(8:2)80nm) was obtained by SCLC test. The test results are shown in Tables 7 and 8.

[0128] Table 7

[0129] Table 8

[0130] As shown in the table above, the compounds provided in this disclosure possess suitable T1, HOMO, and LUMO energy levels, recombination energies, and mobilities for red light emission. Simulation results also demonstrate that the compounds provided in this disclosure, by adjusting the connection positions of the triazine and benzene in the G structure, the N-heterogroup and G, and the N-heterogroup itself, can achieve suitable LUMO energy levels. These compounds can be used as electronic host materials and can form excitocomposites with suitable hole-type host materials. As host materials for red light devices, they can be combined with guest materials to achieve red light emission.

[0131] The disclosed compound contains a group of the general formula Het. By changing the substitution position and the position of N-hexane, the compound, as the electronic host material of the red light emitting layer, has an appropriate HOMO energy level, which acts as a blocking electron, thereby achieving optimal matching with the adjacent functional layers.

[0132] Meanwhile, the compound disclosed herein possesses a rigid structure with a relatively stable molecular geometry, making the molecule less prone to deformation under an applied electric field and resulting in lower recombination energy. Furthermore, the more rigid structure gives the compound a higher glass transition temperature, improving its film-forming properties and thermal stability, further enhancing the device's luminescence lifetime and operational stability. In addition, the G structure and the triazine group can form good conjugation, improving the molecular planarity, increasing carrier mobility and exciton recombination rate in the host material, thereby reducing the device's operating voltage and enhancing its application value. The more rigid structure also gives the compound a higher glass transition temperature, improving its film-forming properties and thermal stability, further enhancing the device's luminescence lifetime and operational stability. Moreover, the electron cloud at T1 in the material mainly depends on the groups at low T1; in the compound disclosed herein, the T1 electron cloud is entirely distributed on G, a characteristic that better matches red light emission.

[0133] The compounds provided in this disclosure contain groups with the general formula Het, which increases the spatial configuration of the molecules, reduces intermolecular interactions, and prevents the host material from experiencing a redshift in the spectrum under thin film conditions. This avoids the problem that excitons formed on the host material cannot be effectively transferred to the guest material, thereby preventing a decrease in the luminescence efficiency of the guest material and ensuring the efficiency of the device.

[0134] The light-emitting device in the embodiments of this disclosure is described below. In a specific example, the light-emitting device includes, in sequence along a direction away from the substrate, a first electrode 11, a hole injection layer 12, a hole transport layer 13, an electron blocking layer 14, a light-emitting layer 15, a hole blocking layer 16, an electron transport layer 17, an electron injection layer 18, and a second electrode 19.

[0135] The substrate material can be any transparent rigid or flexible material, such as glass or polyimide.

[0136] The material of the first electrode 11 is a high work function electrode material, such as transparent oxide ITO or IZO; or, the first electrode 11 may also be a composite electrode formed by ITO / Ag / ITO, Ag / IZO, CNT / ITO, CNT / IZO, GO / ITO, GO / IZO, etc.

[0137] The hole injection layer 12 can be made of inorganic oxides, such as molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, manganese oxide, etc., or it can be a dopant of a strong electron-withdrawing system, such as F4TCNQ, HATCN, etc. P-type doping can also be performed on the hole transport material. The thickness of the hole injection layer 12 can be 5–20 nm, and the hole injection layer 12 is formed by co-evaporation.

[0138] The hole transport layer 13 is made of a material with good hole transport properties, such as aromatic amines or carbazoles, such as NPB, TPD, BAFLP, DFLDPBi, etc. The thickness of the hole transport layer 13 can be 100–2000 nm.

[0139] The electron blocking layer 14 also has good hole transport characteristics. The light-emitting auxiliary layer can be a red light-emitting auxiliary layer, a green light-emitting auxiliary layer, or a blue light-emitting auxiliary layer. The specific material can be an aromatic amine or carbazole material, such as CBP, PCzPA, etc. In one example, the electron blocking layer 14 may include a first sub-blocking layer 141 and a second sub-blocking layer 142 arranged sequentially along the direction close to the light-emitting layer 15.

[0140] The light-emitting layer 15 includes a first material, which includes the compound provided in the above embodiments. The light-emitting layer 15 is used to emit red light, and its thickness is between 10 and 100 nm.

[0141] In some embodiments, the light-emitting layer 15 includes a host material and a guest material. The host material includes an electronic host material and a hole host material. The electronic host material includes the aforementioned compound. The electronic host material and the hole host material form an excitocomplex.

[0142] In some embodiments, the structural formula of the cavitation-type body material is as follows:

[0143] In some embodiments, the HOMO energy level of the cavitation host material is between 5.0 eV and 5.4 eV.

[0144] In some embodiments, the weight ratio of the hole-type host material to the electron-type host material is between 1:9 and 9:1. For example, the weight ratio is 1:1, 4:6, or 6:4.

[0145] In some embodiments, the weight percentage of the guest material in the light-emitting layer 15 is between 1 wt% and 3 wt% to ensure the light-emitting effect of the light-emitting layer 15. For example, the weight percentage of the guest material in the light-emitting layer 15 is 1 wt%, 2 wt%, or 3 wt%.

[0146] The hole-blocking layer 16 and the electron transport layer 17 can be aromatic heterocyclic compounds, such as imidazole derivatives, imidazopyridine derivatives, benzimidazole-phenanthridine derivatives, and other imidazole derivatives; pyrimidine derivatives, triazine derivatives, and other azine derivatives; quinoline derivatives, isoquinoline derivatives, phenanthreneroline derivatives, and other compounds containing a nitrogen-containing six-membered ring structure (including compounds with phosphine oxide substituents on the heterocycle, such as OXD-7, TAZ, p-EtTAZ), BPhen, BCP, etc. The thickness of the hole-blocking layer 16 is between 5 and 100 nm, and the thickness of the electron transport layer 17 is between 20 and 100 nm.

[0147] The electron injection layer 18 is made of materials such as LiF, Yb, Mg, Ca or their compounds, and its thickness is between 1 and 10 nm.

[0148] In this context, the HOMO level of electron blocking layer 14 is denoted as HOMO(EBL), the HOMO level of hole blocking layer 16 is denoted as HOMO(HBL), the HOMO level of hole-type host material is denoted as HOMO(Host-P), and the HOMO level of electron-type host material is denoted as HOMO(Host-N); the LUMO level of electron blocking layer 14 is denoted as LUMO(EBL), the LUMO level of hole blocking layer 16 is denoted as LUMO(HBL), the LUMO level of hole-type host material is denoted as LUMO(Host-P), and the LUMO level of electron-type host material is denoted as LUMO(Host-N).

[0149] In some embodiments, |HOMO(Host-P)-HOMO(EBL)| ≤ 0.3 eV, thereby reducing the energy level gap between the electron blocking layer 14 and the hole-type host material, which is beneficial for hole transport. For example, |HOMO(Host-P)-HOMO(EBL)| = 0; or 0 < |HOMO(Host-P)-HOMO(EBL)| ≤ 0.1 eV; or 0.1 < |HOMO(Host-P)-HOMO(EBL)| ≤ 0.2 eV; or 0.2 < |HOMO(Host-P)-HOMO(EBL)| ≤ 0.3 eV.

[0150] In some embodiments, |LUMO(HBL)-LUMO(Hos-N)| ≤ 0.3 eV, thereby reducing the energy level gap between the hole blocking layer 16 and the electron-type host material, which is beneficial for electron transport. For example, |LUMO(HBL)-LUMO(Hos-N)| = 0, or 0 < |LUMO(HBL)-LUMO(Hos-N)| ≤ 0.1 eV, or 0.1 < |LUMO(HBL)-LUMO(Hos-N)| ≤ 0.2 eV, or 0.2 < |LUMO(HBL)-LUMO(Hos-N)| ≤ 0.3 eV.

[0151] In some embodiments, HOMO(HBL)-HOMO(Host-N)≥0.3eV, thereby facilitating the hole blocking layer 16's ability to block holes. LUMO(EBL)-LUMO(Host)≥0.3eV.

[0152] In some embodiments, the absolute value of the difference between the molecular weight of the hole-type host material and the molecular weight of the electron-type host material is less than or equal to 300, thereby ensuring that the evaporation temperatures of the hole-type host material and the electron-type host material are relatively similar, and preventing phase separation during the evaporation process of the light-emitting layer 15.

[0153] In one example, the molecular weights of both the hole-type host material and the electron-type host material are greater than or equal to 600, while the molecular weights of the guest material are between 700 and 1500.

[0154] In some embodiments, the emission wavelength λ of the cavitation host material is... P The emission wavelength λ of the electronic host material is between 380 nm and 430 nm. N Between 420 nm and 480 nm, the emission wavelength of the exolytic complex is λe, where λe-λ P ≥20nm, λe-λ N ≥20nm.

[0155] In some embodiments, the thickness of the first sub-blocking layer 141 is greater than the thickness of the second sub-blocking layer 142, and the mobility of the first sub-blocking layer is greater than the mobility of the second sub-blocking layer 142, thereby facilitating a reduction in the voltage of the light-emitting device. For example, the thickness of the first sub-blocking layer 141 is between 100 angstroms and 150 angstroms, and the thickness of the second sub-blocking layer 142 is between 20 angstroms and 100 angstroms.

[0156] In some embodiments, the mobility of the hole blocking layer 16 is 10 -7 ~10 -9 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 Between these values, the mobility of electron transport layer 17 is between 10 and 10. -5 ~10 -7 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 Between, the mobility of hole transport layer 13 is 10 -4 ~10 -6 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 Between, the mobility of electron blocking layer 14 is 10 -4 ~10 -7 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 This allows for a better match in the mobility of each film layer, which in turn helps to adjust the exciton recombination region in the luminescent layer 15, thereby improving the luminescence effect.

[0157] In some embodiments, the triplet energy level of the light-emitting layer 16 is lower than the triplet energy level of either the second sub-blocking layer 142 or the hole blocking layer 16, to prevent exciton leakage from the light-emitting layer 16.

[0158] In some embodiments, the light-emitting layer 15 includes a host material and a guest material, as well as a dopant, wherein the dopant is capable of emitting light with a wavelength between 600 and 650 nm to improve the quantum yield of the light-emitting layer 15; the emission peak of the light-emitting layer 15 is between 600 and 650 nm to ensure that the light emitted by the light-emitting layer 15 has maximum brightness.

[0159] The fabrication process of the light-emitting device is as follows:

[0160] S1. A first electrode 11 is formed on a substrate, the material of which is, for example, indium tin oxide (ITO). The substrate with the first electrode 11 formed is then ultrasonically treated in a cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone-ethanol mixed solvent, and baked in a clean environment until all moisture is removed. The material of the first electrode 11 is ITO.

[0161] S2. Place the substrate on which the first electrode 11 is formed in a vacuum chamber and evacuate it to 1×10-5 to 1×10-6. Vacuum deposit a hole injection layer 12 with a thickness of 10 nm on the first electrode 11.

[0162] S3. A hole transport layer 13 with a thickness of 100 nm is deposited on the hole injection layer 12.

[0163] S4. An electron blocking layer 14 is vacuum-deposited on the hole transport layer 13. The electron blocking layer 14 includes, for example, a first sub-blocking layer 141 and a second sub-blocking layer 142. The thickness of the first sub-blocking layer 141 is 42 nm and the thickness of the second sub-blocking layer 142 is 43 nm.

[0164] S5. A light-emitting layer 15 is vacuum-deposited on the electron blocking layer 14. The light-emitting layer 15 includes a host material and a guest material. During the deposition, a multi-source co-evaporation method can be used, and the weight ratio of the host material to the guest material is 98:2. The thickness of the light-emitting layer 15 is 45 nm.

[0165] S6. A hole blocking layer 16 with a thickness of 5nm is vacuum-deposited on the light-emitting layer 15.

[0166] S7. An electron transport layer 17 with a thickness of 30 nm is vacuum-deposited on top of the hole blocking layer 16.

[0167] S8. A 1nm thick Yb layer is vacuum-deposited on the electron transport layer 17 as an electron injection layer 18.

[0168] S9. A second electrode 19 is deposited on the electron injection layer 18. The second electrode 19 can be a Mg / Ag alloy layer with a Mg to Ag content ratio of, for example, 1:9, and the thickness of the second electrode 19 is 100 nm.

[0169] Performance tests were performed on the light-emitting devices of different examples below. The tested examples include Examples 1-30 and Comparative Examples 1-14. Tables 9 and 10 show the compounds used in the film layers of each example. In each example, the first electrode 11 is made of indium tin oxide, the second electrode 19 is made of Mg / Ag alloy, and the hole injection layer 12 is made of HT-1 and PD (structural formulas below). The hole transport layer 13 uses compound HT-1 (structural formula below), the hole blocking layer 16 uses compound HBL-1, the electron transport layer 17 uses compound ET-1, and the electron injection layer 18 uses Yb. The materials of the remaining film layers are detailed in the tables. In Examples 1-30, the electron host material in the light-emitting layer uses compounds provided in this disclosure; in Comparative Examples 1-14, the electron host material in the light-emitting layer is selected from compounds RH-N1 to RH-N12; the hole host material in the light-emitting layer of each example includes compound RH-P; and the guest material in the light-emitting layer of each example includes compound RD.

[0170] Table 9

[0171] Table 10

[0172] The driving voltage and luminous efficiency of the light-emitting devices in each example were measured at a fixed current density. The data results of driving voltage, luminous efficiency, and lifetime for each example are shown in Table 11.

[0173] Table 11

[0174] Comparisons show that the compounds disclosed in this paper have better rigidity, fewer splitting energy levels, and fewer nonradiative transitions, thereby improving the efficiency of the device.

[0175] Comparison shows that the compound disclosed in this paper has a better rigid structure. The more rigid structure gives the compound a higher glass transition temperature, improves the film-forming properties and thermal stability of the compound, and further improves the luminescence lifetime and operational stability of the device.

[0176] By comparison, it can be seen that the compounds disclosed herein introduce heteroatoms (O, S, N) into their molecules. The presence of heteroatoms in the molecules gives the material greater polarity, which improves the interface energy level between the material and adjacent functional layers, thereby improving the injection characteristics of the material, further strengthening the interaction with adjacent functional layers, and reducing the operating voltage of the device.

[0177] The nitrogen-containing compounds disclosed herein include triazine, G, and Het structures. By adjusting the connection positions between these three structures, the electron clouds of different compounds can vary, thereby appropriately controlling the energy levels and mobility of the materials to meet the needs of different devices.

[0178] When the compound disclosed herein is combined with a hole-type material to form an excimer complex and used as the host material of the light-emitting layer 15, the target compound has a high electron mobility, which helps to achieve a balance between electrons and holes in the light-emitting layer 15, widens the recombination region of electrons and holes in the light-emitting layer 15, improves the luminous efficiency of electroluminescence, reduces the driving voltage of organic electroluminescence, and improves the lifetime of the device.

[0179] The compounds disclosed herein are more suitable as electronic host materials in the hybrid host of organic electroluminescent devices, especially as electronic host materials for red light-emitting devices. When the nitrogen-containing compounds of this disclosure are used in the emitting layer 15 material of organic electroluminescent devices, the electron transport performance of the device will be effectively improved, and the luminous efficiency and lifespan of the device will be enhanced.

[0180] This disclosure also provides a display substrate including the light-emitting devices described in the above embodiments. In one example, the display substrate includes multiple light-emitting devices, such as red, green, and blue light-emitting devices.

[0181] In red light-emitting devices, the light-emitting layer may include a phosphorescent host and a red phosphorescent dopant; in green light-emitting devices, the light-emitting layer may include a phosphorescent host and a green phosphorescent dopant; or it may include a fluorescent host and a fluorescent dopant; the blue light-emitting layer may use a blue phosphorescent host material and a blue phosphorescent dopant, or it may use a blue fluorescent host material and a blue fluorescent dopant. Each host material (such as a red phosphorescent host material or a green fluorescent host material) may contain one material or a mixture of two or more materials.

[0182] For example, the host material of the blue luminescent layer can be selected from anthracene derivatives such as ADN and MADN; the guest material can be pyrene derivatives, fluorene derivatives, perylene derivatives, styrene-amine derivatives, metal complexes, etc., such as TBPe, BDAVBi, DPAVBi, FIrpic, etc. The host material of the green luminescent layer can be selected from coumarin dyes, quinacrine copper derivatives, polycyclic aromatic hydrocarbons, diamine anthracene derivatives, carbazole derivatives, such as DMQA, BA-NPB, Alq3, etc., and the guest material can be metal complexes, such as Ir(ppy)3, Ir(ppy)2(acac), etc. The host material of the red luminescent layer is as described above, and the guest material can be metal complexes, such as Ir(piq)2(acac), PtOEP, Ir(btp)2(acac), etc.

[0183] Figure 7 is a schematic diagram of a display substrate provided in some embodiments of this disclosure. As shown in Figure 7, the display substrate includes a driving circuit layer 20 disposed on a substrate 10, a light-emitting structure layer 30 disposed on the driving circuit layer 20, and an encapsulation layer 40 disposed on the light-emitting structure layer 30. In some possible implementations, the display substrate may include other film layers, which are not limited herein.

[0184] The driving circuit layer 20 may include transistors and storage capacitors constituting pixel circuits. Figure 7 shows only one transistor and one storage capacitor in each pixel circuit. The transistor includes an active layer 202, a gate electrode 201, a source electrode 203, and a drain electrode 204. In some possible implementations, the driving circuit layer 20 of each sub-pixel may include: a buffer layer BFL disposed on the substrate 10, an active layer 202 disposed on the buffer layer BFL, a first gate insulating layer GI1 covering the active layer 202, a gate electrode 201 and a first capacitor electrode 205 disposed on the first gate insulating layer GI1, a second gate insulating layer GI2 covering the gate electrode 201 and the first capacitor electrode 205, a second capacitor electrode 206 disposed on the second gate insulating layer GI2, and an interlayer insulating layer ILD covering the second capacitor electrode 206. A via is formed in the interlayer insulating layer ILD, and the via exposes the active layer 202. Source electrode 203 and drain electrode 204 are disposed on the interlayer insulating layer (ILD), and are connected to the active layer 202 via vias. A planarization layer (PLN) is located on the side of the source electrode 203 and drain electrode 204 away from the substrate 10. A first capacitor electrode 205 and a second capacitor electrode 206 constitute a storage capacitor. In some possible implementations, the buffer layer (BFL), the first gate insulating layer (GI1), the second gate insulating layer (GI2), and the interlayer insulating layer (ILD) can be any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), and can be a single layer, multiple layers, or a composite layer. The gate electrode 201, source electrode 203, drain electrode 204, first capacitor electrode 205, and second capacitor electrode 206 can be made of metallic materials, such as any one or more of silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo), or alloys of the above metals, such as aluminum-neodymium alloy (AlNd) or molybdenum-niobium alloy (MoNb). They can be single-layer structures or multi-layer composite structures, such as Ti / Al / Ti. The active layer 202 can be made of amorphous indium gallium zinc oxide (a-IGZO), zinc oxynitride (ZnON), indium zinc tin oxide (IZTO), amorphous silicon (a-Si), polycrystalline silicon (p-Si), hexathiophene, or polythiophene, etc. Therefore, this disclosure applies to transistors manufactured based on oxide technology, silicon technology, or organic technology. The active layer 202 based on oxide technology can be made of oxides containing indium and tin, oxides containing tungsten and indium, oxides containing tungsten, indium and zinc, oxides containing titanium and indium, oxides containing titanium, indium and tin, oxides containing indium and zinc, oxides containing silicon, indium and tin, oxides containing indium, gallium and zinc, etc.

[0185] The light-emitting structure layer 30 includes a pixel defining layer (PDL) and multiple light-emitting devices. The PDL has multiple pixel openings, and the light-emitting devices are located in the pixel openings. Figure 7 only schematically shows the first electrode 11, the light-emitting layer 15, and the second electrode 19 of the light-emitting devices.

[0186] In one example, a light extraction layer (not shown) may be disposed on the side of the second electrode 19 of the light-emitting device away from the substrate 10, with a thickness of 60-100 nm. The material of the light extraction layer includes aromatic heterocyclic organic compounds, such as triarylamines, cyclic ureas, acyl compounds, dibenzothiophenes, dibenzofurans, and carbazoles. By providing a light extraction layer, the light extraction efficiency of the light-emitting device can be improved.

[0187] The encapsulation layer 40 may include a first encapsulation layer 401, a second encapsulation layer 402 and a third encapsulation layer 403 stacked together. The first encapsulation layer 401 and the third encapsulation layer 403 may be made of inorganic materials, while the second encapsulation layer 402 may be made of organic materials. The second encapsulation layer 402 is disposed between the first encapsulation layer 401 and the third encapsulation layer 403, which can ensure that external moisture cannot enter the light-emitting structure layer 30.

[0188] This disclosure also provides a display device, including the display substrate described in the above embodiments.

[0189] Display devices can include any device or product with display functionality. For example, a display device can be a smartphone, mobile phone, e-book reader, desktop computer (PC), laptop PC, netbook PC, personal digital assistant (PDA), portable multimedia player (PMP), digital audio player, mobile medical device, camera, wearable device (e.g., head-mounted device, electronic clothing, electronic bracelet, electronic necklace, electronic accessory, electronic tattoo, or smartwatch), television set, etc.

[0190] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A compound, wherein, The structural formula of the compound is shown in general formula (1): The structural formula of G is shown in general formula (2), where the two wavy lines represent the positions of G and the triazine structure and L in general formula (1), respectively; the proportion of the electron cloud of the LUMO energy level of the compound on G is 3% to 60%. X represents O, S, C(R1)(R2), or N(R3); A represents phenyl or naphthyl. R1, R2, and R3 may be the same as or different from each other, and each is independently selected from any one of hydrogen, deuterium, halogen atom, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C2-C18 alkynyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C1-C18 alkoxy, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted 5-60-membered heteroaryl, and substituted or unsubstituted 5-18-membered heterocyclic group. Ar1 and Ar2 represent substituted or unsubstituted C6-C60 aryl groups, or substituted or unsubstituted 6- to 60 heteroaryl groups; L represents a direct bond, alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, and heteroaryl group that may be independently further substituted by one or more groups selected from the group consisting of: deuterium, (C1-C30)alkyl, halo(C1-C30)alkyl, halogen, cyano, (C3-C30)cycloalkyl, 5- to 7-membered heterocycloalkyl, (C2-C30)alkenyl, (C2-C30)alkynyl, (C6-C30)aryl, (C1-C30)alkoxy, (C6-C30)aryloxy, (C2-C30)heteroaryl, (C6-C30)aryl-substituted (C2-C30)heteroaryl, (C6-C30)aryl(C1-C30)alkyl, (C1-C30) Alkyl (C6-C30)aryl, (C6-C30)arylthio, mono- or di(C1-C30)alkylamino, mono- or di(C6-C30)arylamino, (C1-C30)alkyl(C6-C30)arylamino, di(C6-C30)arylboryl, di(C1-C30)alkylboryl, (C1-C30)alkyl(C6-C30)arylboryl, tri(C1-C30)alkylsilyl, di(C1-C30)alkyl(C6-C30)arylsilyl, (C1-C30)alkyldi(C6-C30)arylsilyl, tri(C6-C30)arylsilyl, N-carbazole, carboxyl, nitro and hydroxyl; The structural formula of Het is one of the following general formulas (2-1), (2-2), (2-3), and (2-4): X1, X2, X3, X4 represent S or O, C, N; A1 to A10 each independently represent CH, C(Ra) or N; B1 to B10 each independently represent CH, C(Rb) or N; E1 to E10 each independently represent CH, C(Rc) or N; Y1 to Y8 each independently represent CH, C(Rc) or N. In general formula (2-1), at least one of A1 to A10 is N; in general formula (2-2), at least one of B1 to B10 is N; in general formula (2-3), at least one of E1 to E10 is N; and in general formula (2-4), at least one of Y1 to Y8 is N. Ra, Rb, and Rc may be the same as or different from each other, and are respectively selected from hydrogen, deuterium, halogen atom, hydroxyl, cyano, substituted or unsubstituted amino, substituted or unsubstituted alkyl with 1 to 20 carbon atoms, substituted or unsubstituted alkoxy with 1 to 20 carbon atoms, substituted or unsubstituted aryloxy with 6 to 30 carbon atoms forming the ring, substituted or unsubstituted aryl with 6 to 30 carbon atoms forming the ring, and substituted or unsubstituted heterocyclic group with 5 to 30 carbon atoms forming the ring.

2. The compound according to claim 1, wherein, In the presence of multiple Ra, multiple Rb, and multiple Rc, adjacent Ra, adjacent Rb, and adjacent Rc independently bond to each other to form a ring structure.

3. The compound according to claim 1, wherein, The structure shown in general formula (1) is selected from any of the following structural formulas:

4. The compound according to any one of claims 1 to 3, wherein, The LUMO energy level of the compound is between 1.8 eV and 2.3 eV.

5. The compound according to any one of claims 1 to 3, wherein, The recombination energy of the compound is less than or equal to 0.4 eV.

6. The compound according to any one of claims 1 to 3, wherein, The triplet energy level of the compound is between 2.0 eV and 2.6 eV.

7. A light-emitting device, wherein, It includes a first electrode, a light-emitting layer, and a second electrode stacked sequentially, wherein the light-emitting layer comprises a first material, and the first material comprises a compound according to any one of claims 1 to 6.

8. The light-emitting device according to claim 7, wherein, The light-emitting layer comprises a host material and a guest material. The host material includes an electron-type host material and a hole-type host material. The electron-type host material includes the first material. The structural formula of the hole-type host material is as follows: The electron-type host material and the hole-type host material form an excitocomplex.

9. The light-emitting device according to claim 8, wherein, The HOMO energy level of the hole-type host material is between 5.0 eV and 5.4 eV.

10. The light-emitting device according to claim 8, wherein, The weight ratio of the hole-type host material to the electron-type host material is between 1:9 and 9:

1.

11. The light-emitting device according to claim 8, wherein, The weight percentage of the guest material in the light-emitting layer is between 1 wt% and 3 wt%.

12. The light-emitting device according to claim 8, wherein, The light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer, wherein the absolute value of the difference between the HOMO energy level of the electron blocking layer and the HOMO energy level of the hole-type host material is less than or equal to 0.3 eV.

13. The light-emitting device according to claim 8, wherein, The light-emitting device further includes: an electron injection layer, an electron transport layer, and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along the direction close to the light-emitting layer, wherein the absolute value of the difference between the LUMO energy level of the hole blocking layer and the LUMO energy level of the electron-type host material is less than or equal to 0.3 eV.

14. The light-emitting device according to claim 8, wherein, The light-emitting device further includes: an electron injection layer, an electron transport layer, and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along the direction close to the light-emitting layer, wherein the HOMO energy level of the hole blocking layer is greater than the HOMO energy level of the electron-type host material, and the difference between the two is greater than or equal to 0.3 eV. The light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer, wherein the LUMO energy level of the electron blocking layer is greater than the LUMO energy level of the hole-type host material, and the difference between the two is greater than or equal to 0.3 eV.

15. The light-emitting device according to claim 8, wherein, The absolute value of the difference between the molecular weight of the hole-type host material and the molecular weight of the electron-type host material is less than or equal to 300.

16. The light-emitting device according to claim 15, wherein, The molecular weight of both the hole-type host material and the electron-type host material is greater than or equal to 600, and the molecular weight of the guest material is between 700 and 1500.

17. The light-emitting device according to claim 8, wherein, The distance between the electron cloud of the HOMO level of the hole-type host material and the electron cloud of the LUMO level of the electron-type host material is between 3 and 5 angstroms.

18. The light-emitting device according to claim 8, wherein, The emission wavelength λ of the cavitation host material P The emission wavelength λ of the electronic host material is between 380 nm and 430 nm. N The excimer complex emits light at a wavelength between 420 nm and 480 nm, where λe-λ P ≥20nm, λe-λ N ≥20nm.

19. The light-emitting device according to claim 7, wherein, The light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer located between the first electrode and the light-emitting layer and arranged sequentially along the direction close to the light-emitting layer. The electron blocking layer includes a first sub-blocking layer and a second sub-blocking layer arranged sequentially along the direction close to the light-emitting layer. The thickness of the first sub-blocking layer is greater than the thickness of the second sub-blocking layer, and the mobility of the first sub-blocking layer is greater than the mobility of the second sub-blocking layer.

20. The light-emitting device according to claim 7, wherein, The light-emitting device further includes: a hole injection layer, a hole transport layer and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer; and an electron injection layer, an electron transport layer and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along the direction close to the light-emitting layer. The mobility of the hole-blocking layer is 10 -7 ~10 -9 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between, The mobility of the electron transport layer is 10. -5 ~10 -7 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between, The mobility of the hole transport layer is 10. -4 ~10 -6 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between, The electron blocking layer has a mobility of 10. -4 ~10 -7 cm 2 V -1 s -1 @5000V 1 / 2 / m 1 / 2 between.

21. The light-emitting device according to claim 7, wherein, The light-emitting device further includes: a hole injection layer, a hole transport layer, and an electron blocking layer disposed sequentially between the first electrode and the light-emitting layer and along the direction close to the light-emitting layer; and an electron injection layer, an electron transport layer, and a hole blocking layer disposed sequentially between the second electrode and the light-emitting layer and along the direction close to the light-emitting layer; the electron blocking layer includes a first sub-blocking layer and a second sub-blocking layer disposed sequentially along the direction close to the light-emitting layer. The triplet energy level of the luminescent layer is lower than the triplet energy level of either the second sub-blocking layer or the hole blocking layer.

22. The light-emitting device according to any one of claims 7 to 21, wherein, The light-emitting layer is used to emit red light; The light-emitting layer further includes a dopant, which is used to emit light with a wavelength between 600 and 650 nm; the emission peak of the light-emitting layer is between 600 and 650 nm.

23. A display substrate, wherein, The light-emitting device includes any one of claims 7 to 22.

24. A display device, wherein, Includes the display substrate as described in claim 23.

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