Series organic light-emitting device

Abstract

The invention provides a combination of an organic compound and an alkali metal and a tandem organic electroluminescent device adopting the combination, the organic compound has a structure as shown in a formula (1), Z1-Z8 are respectively and independently N or CR0, R1 and R2 are respectively and independently selected from hydrogen or other substituent groups, X1-X4 are N or CR3, and at least one X is N. An organic electroluminescent device adopting a charge generation layer material composed of the compound and an alkali metal elementary substance shows excellent stability and relatively high efficiency.

Description

[0001] This invention relates to a series organic electroluminescent device, belonging to the field of organic optoelectronic display technology. Background Technology

[0002] In recent years, optoelectronic devices based on organic materials have become increasingly popular. The inherent flexibility of organic materials makes them ideal for fabrication on flexible substrates, allowing for the design and production of aesthetically pleasing and stylish optoelectronic products, offering unparalleled advantages over inorganic materials. Examples of such organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic field-effect transistors, organic photovoltaic cells, and organic sensors. OLEDs, in particular, have developed rapidly and have already achieved commercial success in the information display field. OLEDs can provide highly saturated red, green, and blue colors, and full-color displays made with them do not require an additional backlight, offering advantages such as vibrant colors, thinness, and flexibility.

[0003] The core of an OLED device is a thin-film structure containing various organic functional materials. Common functionalized organic materials include: hole injection materials, hole transport materials, hole blocking materials, electron injection materials, electron transport materials, electron blocking materials, as well as light-emitting host materials and light-emitting guest materials (dyes). When an electric current is applied, electrons and holes are injected and transported to the light-emitting region, where they recombine, thereby generating excitons and emitting light.

[0004] With the widespread use of OLEDs in small and medium-sized displays, new OLED screens are required to function normally even under strong light. Meanwhile, medium and large-sized OLED screens place even higher demands on brightness and lifespan. Therefore, a new OLED structure—the stacked OLED (also called a series OLED) structure—has emerged. The stacked OLED structure connects multiple light-emitting units in series through a charge generation layer (CGL). Compared to traditional single-emitting-unit devices, stacked OLEDs with multiple light-emitting units often have significantly higher current efficiency and brightness, while requiring a significantly lower current density for the same brightness. Simultaneously, multiple light-emitting central layers facilitate exciton separation, reducing the exciton density within the device's internal light-emitting layers and significantly extending the operating lifespan, effectively avoiding the trade-off between high brightness and long lifespan. Compared to single-layer OLED devices, dual-layer stacked structure devices can increase brightness by 2 times and extend lifespan by 4 times. If applied to smartphones, this could reduce power consumption by approximately 30%, meaning phones could accommodate smaller batteries and have thinner bodies. Currently, LCG has automotive products that use mass-produced stacked OLEDs. Apple and BOE are trying to apply this technology to the displays of mobile phones and other products. Stacked device technology is an important direction for the future development of high-brightness displays and white OLED devices.

[0005] As OLED products gradually enter the market, people have increasingly higher requirements for their performance. Current OLED materials and device structures cannot fully solve the problems related to efficiency, lifespan, and cost of OLED products. Through careful consideration and continuous experimentation, the researchers of this invention have discovered an ingenious combination scheme for charge generation layers, which is described in detail below. Surprisingly, the organic compounds and alkali metals disclosed in this invention are highly suitable for application in OLEDs and can effectively improve device performance. Summary of the Invention

[0006] Research has found that coordination of phenanthroline compounds with alkali metals can promote the process of metal losing electrons, effectively reduce the electron injection barrier, improve carrier balance in the device, and increase device efficiency, which has an important impact on the performance and application of tandem OLED devices.

[0007] The purpose of this invention is to provide a material solution for the charge generation layer in a series organic electroluminescent device, which can effectively improve the device performance of OLED.

[0008] To this end, the present invention adopts the following technical solution:

[0009] A series organic electroluminescent device includes the following structure: an anode, a cathode, at least two electroluminescent units disposed between the anode and the cathode, and a charge generation layer disposed between two adjacent electroluminescent units. The charge generation layer is formed by a host material and a dopant. The dopant is an alkali metal or a combination of two metals. Specifically, the dopant is selected from at least one of lithium, sodium, and potassium. Preferably, the dopant contains metallic lithium.

[0010] The main material has a structure as shown in formula (1):

[0011]

[0012] In formula (1), Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8 are each independently N or CR0, and R0 is independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 heterocyclic alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C1-C20 alkylsilyl, substituted or unsubstituted C1-C20 alkylamino, etc. The following are possible combinations of substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, substituted or unsubstituted C6-C60 arylamino, substituted or unsubstituted C3-C60 heteroarylamino, substituted or unsubstituted C6-C60 aryloxy, substituted or unsubstituted C6-C60 arylthio, and substituted or unsubstituted C6-C60 silylaryl, wherein two adjacent R0 groups are not connected or are connected by a single bond or -CR 1 R 2 -、-O-、-S-、-NR 3 - Connected into a loop; R 1 R 2 R 3 Each of the following is independently selected from hydrogen, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl;

[0013] The groups of the structure of formula (b) are fused together at the positions of Z2 and Z3 or Z3 and Z4 in formula (1) at the positions indicated by the dashed lines;

[0014] R1 and R2 are each independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 heterocycloalkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C6-C30 arylamino, and substituted or unsubstituted C1-C20 alkylsilyl.

[0015] a and b are independent integers from 1 to 7; when a is greater than or equal to 2, R1 are either identical or different, and any two adjacent R1 are either not connected or form a cycle; when b is greater than or equal to 2, R2 are either identical or different, and any two adjacent R2 are either not connected or form a cycle.

[0016] X1, X2, X3, and X4 are each independently N or CR3, and at least one of them is N. R3 is each independently any one of hydrogen, deuterium, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cyclic alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl.

[0017] The substitution of each substituted or unsubstituted group in Z1 to Z8, R1, R2, and X1 to X4 above refers to the independent substitution by a group selected from one or a combination of two of the following groups: deuterium, halogen, cyano, nitro, hydroxyl, amino, aldehyde, ester, C1-C10 chain alkyl, C2-C10 alkenyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C2-C10 heterocycloalkyl, C1-C10 alkylsilyl, C1-C10 alkylamino, C6-C60 aryloxy, C6-C60 arylamino, C6-C30 aryl, or C3-C30 heteroaryl.

[0018] Furthermore, in the charge generation layer, the mass ratio of the host material to the dopant is 1:(1%-30%), preferably 1:(1%-10%), and more preferably 1:(1%-5%).

[0019] Furthermore, the thickness of the charge generation layer is 1-30 nm, preferably 5-20 nm, and more preferably 8-15 nm.

[0020] More preferably, the main material is selected from the structure shown in formula (1-1) or formula (1-2):

[0021]

[0022] The definitions of X1, X2, X3, and X4 are the same as those in equation (1); the definitions of a and b are the same as those in equation (1).

[0023] In formula (1-1), Z1 and Z4 to Z8 are each independently selected from N or CRO, and R0 is each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) chain alkyl, substituted or unsubstituted C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) heterocycloalkyl, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkyl Oxyk-, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkylsilyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) arylamino, substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, etc.) Heteroarylamino groups (C6-C30, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), substituted or unsubstituted C6-C30 groups (C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), arylthioyl groups (C6-C30, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), silylaryl groups (C6-C30, C6, C9, C10, C12, C14, C15, C16, C18, etc.), substituted or unsubstituted C6-C30 groups (C6, C9, C10, C12, C14, C15, C16, C18, etc.). The following are possible interpretations of the following groups: aryl groups (C20, C22, C24, C26, C28, etc.); substituted or unsubstituted C6-C30 groups (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.); substituted or unsubstituted C3-C30 groups (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.); when Z4 to Z8 are selected from CR0, adjacent R0 groups are not connected or are connected by a single bond, -CR 1 R 2 -、-O-、-S-、-NR 3 - Connected into a loop (e.g., forming a ring) (e.g., dashed lines represent fusion sites of loops), R 1 R 2 R3 Each is independently selected from hydrogen, substituted or unsubstituted C1-C5 (e.g., C2, C3, C4, etc.) chain alkyl, substituted or unsubstituted C6-C15 (e.g., C6, C9, C10, C12, C14, etc.) aryl, and substituted or unsubstituted C3-C15 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, etc.) heteroaryl;

[0024] Preferably, when Z4 to Z8 are selected from CR0, at least one (e.g., 1, 2, 3, 4, 5) of the CR0s is not hydrogen; more preferably, when Z4 to Z8 are selected from CR0, at most three (e.g., 1, 2, 3) of the CR0s are not hydrogen.

[0025] Preferably, Z4 is selected from CR0, where R0 is not hydrogen, and Z5 to Z8 are selected from CH; or Z5 is selected from CR0, where R0 is not hydrogen, and Z4, Z6 to Z8 are selected from CH; or Z6 is selected from CR0, where R0 is not hydrogen, and Z4 to Z5, Z7 to Z8 are selected from CH; or Z7 is selected from CR0, where R0 is not hydrogen, and Z4 to Z6, Z8 are selected from CH.

[0026] Alternatively, preferably, Z5 and Z7 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected, and Z4, Z6, and Z8 are selected from CH; or Z5 and Z6 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or connected in a ring (preferably connected in a ring), and Z4, Z7-Z8 are selected from CH; or Z6 and Z7 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or connected in a ring (preferably connected in a ring), and Z4-Z5 and Z8 are selected from CH; or Z7-Z8 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or connected in a ring (preferably connected in a ring), and Z4-Z6 are selected from CH;

[0027] Alternatively, preferably, Z4, Z6, and Z7 are selected from CRO, all three R0s are not hydrogen, and the R0s in Z6 and Z7 are either not connected or connected in a ring (preferably connected in a ring), and Z5 and Z8 are selected from CH; or Z5, Z6, and Z7 are selected from CRO, all three R0s are not hydrogen, and the R0s in Z5 and Z6 are either not connected or connected in a ring, and the R0s in Z6 and Z7 are either not connected or connected in a ring (preferably, one pair of adjacent R0s in Z5, Z6, and Z7 are connected in a ring), and Z4 and Z8 are selected from CH; or Z5, Z7, and Z8 are selected from CR0, and none of the three R0s are hydrogen. The R0s in Z7 and Z8 are not connected or are connected to form a ring (preferably connected to form a ring). Z4 and Z6 are selected from CH; or Z6, Z7, and Z8 are selected from CR0, and none of the three R0s are hydrogen. The R0s in Z6 and Z7 are not connected or are connected to form a ring. The R0s in Z7 and Z8 are not connected or are connected to form a ring (preferably, one pair of adjacent R0s in Z6, Z7, and Z8 are connected to form a ring). Z4 to Z5 are selected from CH.

[0028] R1 and R2 are each independently selected from hydrogen, deuterium, cyano, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) chain alkyl, or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, substituted or unsubstituted C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) heterocyclic alkyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, or substituted or unsubstituted C6-C30 (e.g., C6, C9, C9, C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, or substituted or unsubstituted C6-C30 (e.g., C6, C9, C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl. Arylamino groups (C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), heteroaryl groups (C3-C30, etc.), substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.), alkylsilyl groups (C1-C10, C3, C4, C5, C6, C7, C8, C9, etc.).

[0029] Preferably, R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) aryl, substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) heteroaryl;

[0030] In formula (1-2), Z1, Z2, and Z5-Z8 are each independently selected from N or CR0, and R0 is each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) chain alkyl, substituted or unsubstituted C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) heterocycloalkyl, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) Alkoxy, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkylsilyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) arylamino, substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, etc.) Heteroarylamino groups (C6-C30, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), substituted or unsubstituted C6-C30 groups (C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), arylthioyl groups (C6-C30, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), silylaryl groups (C6-C30, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), substituted or unsubstituted C6-C30 groups (C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), silylaryl groups (C6-C30, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.). 20, C22, C24, C26, C28, etc.) aryl, substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) aryloxy, substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) heteroaryl; when Z2, Z5-Z8 are selected from CR0, two adjacent R0s are not connected or are connected by a single bond, -CR 1 R 2 -、-O-、-S-、-NR 3 - Connected into a loop (e.g., forming a ring) (e.g., dashed lines represent fusion sites of loops), R 1 R2 R 3 Each is independently selected from hydrogen, substituted or unsubstituted C1-C5 (e.g., C2, C3, C4, etc.) chain alkyl, substituted or unsubstituted C6-C15 (e.g., C6, C9, C10, C12, C14, etc.) aryl, and substituted or unsubstituted C3-C15 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, etc.) heteroaryl;

[0031] Preferably, when Z2, Z5 to Z8 are selected from CR0, at least one (e.g., 1, 2, 3, 4, 5) of the CR0s is not hydrogen; more preferably, when Z2, Z5 to Z8 are selected from CR0, at most three (e.g., 1, 2, 3) of the CR0s are not hydrogen.

[0032] Preferably, Z2 is selected from CR0, where R0 is not hydrogen, and Z5 to Z8 are selected from CH; or Z8 is selected from CR0, where R0 is not hydrogen, and Z2, Z5 to Z7 are selected from CH; or Z7 is selected from CR0, where R0 is not hydrogen, and Z2, Z5 to Z6, and Z8 are selected from CH; or Z6 is selected from CR0, where R0 is not hydrogen, and Z2, Z5, Z7 to Z8 are selected from CH.

[0033] Alternatively, preferably, Z6 and Z8 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected, and Z2, Z5, and Z7 are selected from CH; or Z7 and Z8 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or connected in a ring (preferably connected in a ring), and Z2, Z5 to Z6 are selected from CH; or Z6 and Z7 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or connected in a ring (preferably connected in a ring), and Z2, Z5, and Z8 are selected from CH; or Z5 to Z6 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or connected in a ring (preferably connected in a ring), and Z2, Z7 to Z8 are selected from CH;

[0034] Alternatively, preferably, Z2, Z6, and Z7 are selected from CRO, all three R0s are not hydrogen, and the R0s in Z6 and Z7 are either not connected or connected in a ring (preferably connected in a ring), and Z5 and Z8 are selected from CH; or Z6, Z7, and Z8 are selected from CRO, all three R0s are not hydrogen, the R0s in Z6 and Z7 are either not connected or connected in a ring, and the R0s in Z7 and Z8 are either not connected or connected in a ring (preferably, one pair of adjacent R0s in Z6, Z7, and Z8 are connected in a ring), and Z2 and Z5 are selected from CH; or Z5, Z6, and Z8 are selected from CR0, and none of the three R0s are hydrogen. The R0s in Z5 and Z6 are not connected or are connected to form a ring (preferably connected to form a ring), and Z2 and Z7 are selected from CH; or Z5, Z6, and Z7 are selected from CR0, and none of the three R0s are hydrogen. The R0s in Z5 and Z6 are not connected or are connected to form a ring, and the R0s in Z6 and Z7 are not connected or are connected to form a ring (preferably, one pair of adjacent R0s in Z5, Z6, and Z7 are connected to form a ring), and Z2 and Z8 are selected from CH;

[0035] R1 and R2 are each independently selected from hydrogen, deuterium, cyano, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) chain alkyl, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, substituted or unsubstituted C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) heterocyclic alkyl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, substituted or unsubstituted C6-C30 (e.g., C6, C4, C5, C6, C7, C8, C9, etc.) alkenyl, and substituted or unsubstituted C6-C30 (e.g., C6, C4, C5, C6, C7, C8, C9, etc.) alkenyl. 9. Any one of the following: arylamino groups (C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.); substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.); substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.); heteroaryl groups (substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.); alkylsilyl groups (C10, C12, C14, C5, C6, C7, C8, C9, etc.);

[0036] Preferably, R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C6-C30 (e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) aryl, substituted or unsubstituted C3-C30 (e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.) heteroaryl;

[0037] The substitution of the aforementioned substituted or unsubstituted groups refers to the independent substitution by a group selected from deuterium, halogen, cyano, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) chain alkyl, C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) alkoxy, C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) alkyl ... One of the following substitutions: cycloalkyl (C6, C7, C8, C9, etc.), alkylsilyl (C1-C10, e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.), aryl (C6-C20, e.g., C6, C9, C10, C12, C14, C15, C16, C18, etc.), or heteroaryl (C3-C20, e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, etc.).

[0038] More preferably, in formula (1-1), at most one of Z1, Z4 to Z8 is N; in formula (1-2), at most one of Z1, Z2, Z5 to Z8 is N; even more preferably, at most one of Z1, Z5 to Z8 (0 or 1) is N; even more preferably, in formula (1-1), at most one of Z1, Z5, Z7 (0 or 1) is N; in formula (1-2), at most one of Z1, Z6, Z8 (0 or 1) is N;

[0039] More preferably, in formulas (1-1) and (1-2), Z1, Z2, and Z4 to Z8 are each independently selected from CR0, and R0 is each independently selected from hydrogen, halogen, cyano, or any of the following substituted or unsubstituted groups, wherein "*" represents a linking site:

[0040]

[0041]

[0042] The substitution of each of the above-mentioned substituted or unsubstituted groups refers to the independent substitution by one of the following groups: deuterium, halogen, cyano, C1-C5 chain alkyl, C3-C5 cycloalkyl, C6-C20 aryl or C3-C20 heteroaryl.

[0043] In this invention, The two asterisks in the figure represent two adjacent R0 connection sites.

[0044] More preferably, in formulas (1-1) and (1-2), X1, X2, X3, and X4 are each independently N; and / or R1 and R2 are each independently selected from hydrogen or any of the following substituted or unsubstituted groups:

[0045]

[0046]

[0047] The substitution of each of the above-mentioned substituted or unsubstituted groups refers to the independent substitution by one of the following groups: deuterium, halogen, cyano, C1-C5 chain alkyl, C3-C5 cycloalkyl, C6-C20 aryl or C3-C20 heteroaryl.

[0048] Preferably, at most four (e.g., 0, 1, 2, 3) of R1 and R2 are not hydrogen (e.g., at most two (e.g., 0, 1, 2) of R1 are not hydrogen, and at most two (e.g., 0, 1, 2) of R2 are not hydrogen); more preferably, at most two (e.g., 0, 1, 2) of R1 and R2 are not hydrogen (e.g., at most two (e.g., 0, 1, 2) of R1 are not hydrogen; or at most two (e.g., 0, 1, 2) of R2 are not hydrogen; or at most one (e.g., 0, 1) of R1 is not hydrogen, and at most one (e.g., 0, 1) of R2 is not hydrogen); even more preferably, at most one (e.g., 0, 1) of R1 and R2 is not hydrogen; even more preferably, all of R1 and R2 are hydrogen.

[0049] In this invention, The two asterisks in the figure represent two adjacent R1 or R2 connection sites, respectively.

[0050] More preferably, the main material is selected from the structure shown in formula (1-3) or formula (1-4):

[0051]

[0052] In equations (1-3) and (1-4), the definitions of X1, X2, X3, and X4 are the same as those in equation (1); the definitions of Z1, Z2, Z4 to Z8 are the same as those in equations (1-1) and (1-2).

[0053] R 11 ~R 16 R 21 ~R 26Each group is independently selected from hydrogen, deuterium, cyano, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) chain alkyl, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, C3-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) heterocyclic alkyl, C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, and C6-C30 (e.g., C6, C9, C10, C12, C14, etc.). One or a combination of two of the following: arylamino (C15, C16, C18, C20, C22, C24, C26, C28, etc.), aryl (C6-C30, e.g., C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), heteroaryl (C3-C30, e.g., C3, C4, C5, C6, C9, C10, C12, C14, C15, C16, C18, C20, C22, C24, C26, C28, etc.), and alkylsilyl (C1-C10, e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.);

[0054] More preferably, R 11 ~R 16 R 21 ~R 26 Each is independently selected from hydrogen or any of the following groups:

[0055]

[0056] More preferably, R 11 ~R 16 R 21 ~R 26 At most four (e.g., 0, 1, 2, 3) of them are not hydrogen (e.g., R). 11 ~R 16 At most two (e.g., 0, 1, 2) of them are not hydrogen, and R 21 ~R 26 At most two (e.g., 0, 1, 2) of them are not hydrogen.

[0057] More preferably, R 11 ~R 16 R 21 ~R 26 At most two (e.g., 0, 1, 2) of them are not hydrogen (e.g., R). 11 ~R 16 At most two (e.g., 0, 1, 2) of them are not hydrogen; or R 21 ~R26 At most two (e.g., 0, 1, 2) of them are not hydrogen; or R 11 ~R 16 At most one (e.g., 0 or 1) of them is not hydrogen, and R 21 ~R 26 At most one (e.g., 0 or 1) of them is not hydrogen;

[0058] More preferably, R 11 ~R 16 R 21 ~R 26 At most one (e.g., 0 or 1) of them is not hydrogen; more preferably, R 11 ~R 16 R 21 ~R 26 It is entirely composed of hydrogen.

[0059] In this invention, the "substituted or unsubstituted" group can replace one substituent or multiple substituents. When there are multiple substituents, they can be selected from different substituents. In this invention, when the same expression is used, they all have the same meaning, and the selection range of substituents is as shown above and will not be repeated one by one.

[0060] In this invention, "each of the substituents is independently not connected to the adjacent ring structure" means that the substituent is only connected to the C atom through a single bond; "each of the substituents is independently connected to the adjacent ring structure through chemical bonds to form a ring" means that the substituent, in addition to being connected to the C atom through chemical bonds, is also connected to the adjacent ring through chemical bonds, thereby forming a fused ring structure. The same descriptions will have the same meaning in the following text and will not be repeated.

[0061] In this invention, the expression of Ca to Cb represents that the group has a to b carbon atoms. Unless otherwise specified, the number of carbon atoms generally does not include the number of carbon atoms of the substituent.

[0062] In this invention, the "-" line on the group refers to the way the ring structure is drawn, indicating that the bonding site is located at any position on the ring structure where bonding can occur.

[0063] In this invention, "each independently" means that when there are multiple subjects, they can be the same or different from each other.

[0064] In this invention, unless otherwise specified, the description of chemical elements generally includes the concept of their isotopes. For example, the description of "hydrogen (H)" includes its isotopes. 1 H (protium or H), 2 The concept of H (deuterium or D); carbon (C) includes... 12 C 13C, etc., will not be elaborated further.

[0065] The heteroatoms in the heteroaryl group of this invention generally refer to atoms or groups of atoms selected from N, O, S, P, Si and Se, preferably from N, O and S.

[0066] Examples of halogens in this invention include fluorine, chlorine, bromine, and iodine.

[0067] In this invention, C6-C30 can all be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.

[0068] C3-C30 can all be C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.

[0069] C1-C30 can all be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C26 or C28, etc.

[0070] C1-C20 can all be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18, etc.

[0071] C3-C20 can all be C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18, etc.

[0072] C2-C20 can all be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18, etc.

[0073] In this invention, the C6-C60 aryl group, preferably C6-C30 aryl group, includes monocyclic aryl and fused-ring aryl groups; the monocyclic aryl group means that the group contains at least one phenyl group, and when it contains at least two phenyl groups, the phenyl groups are linked by single bonds, including but not limited to: phenyl, biphenyl, terphenyl, tetraphenyl, etc. The term "fused-ring aryl" refers to a group containing at least two aromatic rings, wherein the aromatic rings share two adjacent carbon atoms fused together. Exemplary examples include, but are not limited to: naphthyl (1-naphthyl, 2-naphthyl), anthraceneyl (1-anthrayl, 2-anthrayl, 9-anthrayl), phenanthryl, indene, fluorenyl and their derivatives (9,9-dimethylfluorenyl, 9,9-diethylfluorenyl, 9,9-dipropylfluorenyl, 9,9-dibutylfluorenyl, 9,9-dipentylfluorenyl, 9,9-dihexylfluorenyl, 9,9-diphenylfluorenyl, 9,9-dinaphthylfluorenyl, phenylmethylfluorenyl, spirodifluorenyl, benzo[a]fluorenyl, etc.), fluoranyl, triphenylene, pyrene (1-pyrene, 2-pyrene, 4-pyrene), peryl, Aryl groups include aryl groups, pheno-tetraphenyl (1-pheno-tetraphenyl, 2-pheno-tetraphenyl, 9-pheno-tetraphenyl), etc. It should be noted that monocyclic aryl groups and fused-ring aryl groups linked by single bonds also fall under the aryl group category, such as phenylnaphthyl, naphthylphenyl, and binaphthyl.

[0074] In this invention, the C3-C60 heteroaryl group, preferably a C3-C30 heteroaryl group, includes monocyclic heteroaryl groups or fused-ring heteroaryl groups. A monocyclic heteroaryl group means that the molecule contains at least one heteroaryl group. When the molecule contains one heteroaryl group and other groups (such as aryl, heteroaryl, etc.), the heteroaryl group and other groups are connected by a single bond, exemplarily including but not limited to: pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furanyl, thiophene, pyrroleyl, bipyridyl, phenylpyridinyl, pyridylphenyl, pyrimidinylphenyl, etc. The term "fused-ring heteroaryl" refers to a molecule containing at least one aromatic heterocycle and one aromatic ring (aromatic heterocycle or aromatic ring), and the two share two adjacent atoms fused together in a group. Examples include, but are not limited to: quinolinyl, isoquinolinyl, quinoxolinyl, quinazolinyl, benzofuranyl, benzothiophenyl, isobenzofuranyl, isobenzothiophenyl, indolyl, dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, carbazoleyl and its derivatives (N-phenylcarbazoleyl, N-naphthylcarbazoleyl, benzocarbazoleyl, dibenzocarbazoleyl, indolocarbazoleyl, azacarbazoleyl, etc.), acridineyl, phenothiazinyl, phenotoxazinyl, hydrogenated acridineyl, etc. It should be noted that heteroaryl groups connected by single bonds, as well as aryl groups connected by single bonds, also fall under the category of heteroaryl groups, such as phenyldibenzofuranyl, phenyldibenzothiophenyl, dibenzothiophenylphenyl, dibenzofuranylphenyl, etc.

[0075] Specific examples of the C6-C60 arylene group can be exemplified by removing one hydrogen atom from the aryl group examples above, resulting in a divalent group; specific examples of the C3-C60 heteroarylene group can be exemplified by removing one hydrogen atom from the heteroaryl group examples above, resulting in a divalent group.

[0076] The C1-C20 chain alkyl group, preferably C1-C10 chain alkyl group, includes, but is not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, neohexyl, 2-ethylhexyl, n-octyl, n-heptyl, n-nonyl, n-decyl, etc.

[0077] Specific examples of the C1-C20 alkoxy groups can be exemplified by the monovalent groups obtained by connecting the above-mentioned straight-chain or branched alkyl groups to O.

[0078] The C3-C20 cycloalkyl group mentioned in this invention is preferably a C3-C10 cycloalkyl group, such as cyclopropyl, cyclobutyl, cyclopentyl, tert-pentyl, cyclohexyl, adamantyl, etc.

[0079] The C2-C20 alkenyl group mentioned in this invention is preferably a C2-C10 alkenyl group, which contains at least one C=C, and includes, but is not limited to: vinyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, etc.

[0080] Specific examples of C2-C20 heterocyclic alkyl groups mentioned in this invention can be exemplified by groups formed by replacing at least one C atom in the aforementioned cycloalkyl group with a heteroatom (e.g., N, O, S, etc.), including but not limited to: epoxy group, oxetane group, tetrahydrofuranyl group, tetrahydrothiophenyl group, tetrahydropyrroleyl group, tetrahydropyranyl group, piperidinyl group, piperazineyl group, dioxaneyl group, morpholinyl group, etc.

[0081] Furthermore, in the tandem organic electroluminescent device of the present invention, the host material is selected from, but not limited to, the compounds shown below:

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] The preparation process of the main material in the charge generation layer of the present invention is simple and easy, the raw materials are readily available, it is suitable for mass production and scale-up, and it is very suitable for industrial applications.

[0106] In another aspect, the tandem organic light-emitting device of the present invention employs a special charge generation layer scheme disposed between adjacent light-emitting units in the device. It uses a special bisphenanthrene-line structure compound of formula (1) as the host material and an alkali metal compound as the dopant material, with metallic Li being the most preferred alkali metal compound. By coordinating the bisphenanthrene-line structure in the host material, the migration of alkali metal ions (such as Li ions) can be effectively suppressed, thus improving the device's voltage and lifespan. In the device of the present invention, the fused-linked structural group of formula (b) is introduced onto the bridged benzene ring of the special bisphenanthrene-line compound core structure of formula (1), which can improve electron transport performance, thereby reducing the device voltage and improving device efficiency and lifespan. The display device prepared using the tandem organic light-emitting device of the present invention has low operating voltage, high luminous efficiency, and better lifespan, meeting the current requirements of panel and display manufacturers for high-performance materials.

[0107] The tandem organic electroluminescent device of the present invention includes an electroluminescent unit comprising at least one of a hole transport layer, an electron blocking layer, an emissive layer, a hole blocking layer, and an electron transport layer.

[0108] As a second aspect of the invention, a display device is also protected, comprising the above-described series organic electroluminescent devices. Detailed Implementation

[0109] The technical solution of the present invention will be further described in more detail below. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof.

[0110] The method for obtaining the host material compound in the charge generation layer of the tandem organic electroluminescent device of the present invention:

[0111] The compounds represented by formula (1) of this invention can be obtained by known methods, such as by known organic synthesis methods. Example synthetic routes are given below, but those skilled in the art can also obtain them by other known methods. Representative synthetic routes for the compounds represented by the general formula of this invention are as follows:

[0112] or,

[0113]

[0114] The organic compounds of the present invention were synthesized in a representative manner and applied together with corresponding comparative compounds in organic electroluminescent devices to test the device performance under the same conditions.

[0115] The following synthetic examples of the present invention provide specific synthetic methods for representative compounds. The solvents, reagents, intermediates, and chemical reagents such as ethyl acetate, methanol, and ethanol used in the following synthetic examples can all be purchased or customized from the domestic chemical product market.

[0116] The following synthetic examples of the present invention provide specific synthetic methods for representative compounds. The solvents, reagents, intermediates, and chemical reagents such as ethyl acetate, methanol, and ethanol used in the following synthetic examples can all be purchased or customized from the domestic chemical product market.

[0117] Synthesis Example 1: Synthesis of M18

[0118]

[0119] At room temperature, M18-0 (20.0 g), Al (16.3 g), Pd(PPh3)4 (3.1 g), K2CO3 (14.7 g), and 1,4-dioxane / water (250 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (MeOH:DCM = 20:1, v:v) to obtain a crude product. The crude product was washed with petroleum ether to give 24.7 g of a white solid, with a yield of 80.7%.

[0120] Mass ion determined by mass spectrometry: 574.11 (theoretical value: 574.18).

[0121] Synthesis Example 2: Synthesis of M51

[0122]

[0123] Synthesis of intermediate M51-1:

[0124] At room temperature, M51-0 (20.0 g), A2 (16.7 g), Pd(PPh3)4 (3.2 g), K2CO3 (15.2 g), and 1,4-dioxane / water (500 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (PE:DCM = 50:1, v:v) to obtain a crude product. Ethanol was added and the mixture was stirred to obtain 20.7 g of a white solid, yielding 81.7%.

[0125] Mass spectrometry analysis determined the molecular ion mass to be 461.92 (theoretical value: 461.94).

[0126] M51 Synthesis:

[0127] At room temperature, M51-1 (10.0 g), Al (13.3 g), Pd(PPh3)4 (1.3 g), K2CO3 (6.0 g), and 1,4-dioxane / water (250 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (MeOH:DCM = 20:1, v:v) to obtain a crude product. The crude product was washed with petroleum ether to give 11.2 g of a white solid, yield 78.3%.

[0128] Mass ion determined by mass spectrometry: 660.20 (theoretical value: 660.23).

[0129] Synthesis Example 3: Synthesis of M123

[0130]

[0131] At room temperature, M123-0 (10.0 g), Al (27.6 g), Pd(PPh3)4 (2.6 g), K2CO3 (6.2 g), and 1,4-dioxane / water (500 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with plenty of water, the organic phase was dried and concentrated for column chromatography (PE:DCM = 50:1, v:v) to obtain a crude product. Ethanol was added and the mixture was stirred to give 15.3 g of a white solid, with a yield of 80.7%.

[0132] Mass ion determined by mass spectrometry: 840.21 (theoretical value: 840.27).

[0133] Synthesis Example 4: Synthesis of M157

[0134]

[0135] Synthesis of intermediate M157-1:

[0136] At room temperature, M157-0 (20.0 g), A3 (9.9 g), Pd(PPh3)4 (2.8 g), K2CO3 (13.4 g), and 1,4-dioxane / water (500 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with plenty of water, the organic phase was dried and concentrated for column chromatography (PE:DCM = 50:1, v:v) to obtain a crude product. Ethanol was added and the mixture was stirred to give 14.3 g of a white solid, with a yield of 81.3%.

[0137] Mass spectrometry analysis determined the molecular ion mass to be 361.96 (theoretical value: 361.91).

[0138] M157 Synthesis:

[0139] At room temperature, M157-1 (10.0 g), Al (16.9 g), Pd(PPh3)4 (1.6 g), K2CO3 (7.6 g), and 1,4-dioxane / water (250 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (MeOH:DCM = 20:1, v:v) to obtain a crude product. The crude product was washed with petroleum ether to give 12.2 g of a white solid, yield 78.8%.

[0140] Mass ion determined by mass spectrometry: 560.23 (theoretical value: 560.20).

[0141] Synthesis Example 5: Synthesis of M218

[0142]

[0143] Synthesis of intermediate M218-1:

[0144] At room temperature, M218-0 (20.0 g), A4 (15.4 g), Pd(PPh3)4 (3.2 g), K2CO3 (15.2 g), and 1,4-dioxane / water (500 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with plenty of water, the organic phase was dried and concentrated for column chromatography (PE:DCM = 50:1, v:v) to obtain a crude product. Ethanol was added and the mixture was stirred to obtain 21.3 g of a white solid, yield 88.7%.

[0145] Mass spectrometry analysis determined the molecular ion mass to be 437.86 (theoretical value: 437.94).

[0146] M218 Synthesis:

[0147] At room temperature, M218-1 (10.0 g), Al (14.0 g), Pd(PPh3)4 (1.3 g), K2CO3 (6.3 g), and 1,4-dioxane / water (250 ml, 4 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (MeOH:DCM = 20:1, v:v) to obtain a crude product. The crude product was washed with petroleum ether to give 11.4 g of a white solid, with a yield of 78.5%.

[0148] Mass spectrometry analysis determined the molecular ion mass to be 636.25 (theoretical value: 636.23).

[0149] Synthesis Example 6: Synthesis of M266

[0150]

[0151] Synthesis of intermediate M266-1:

[0152] At room temperature, M266-0 (20.0 g), A5 (20.0 g), Pd(PPh3)4 (3.7 g), K2CO3 (16.4 g), and 1,4-dioxane / water (500 ml, 5 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (MeOH:DCM = 20:1, v:v) to obtain a crude product. The crude product was washed with petroleum ether to give 28.5 g of a white solid, with a yield of 81.9%.

[0153] Mass ion determined by mass spectrometry: 584.21 (theoretical value: 584.26).

[0154] M266 Synthesis:

[0155] At room temperature, 10.0 g of M266-1, 3.7 g of A6, 1.0 g of Pd(PPh3)4, 4.7 g of K2CO3, and 500 ml of 1,4-dioxane / water (5 / 1, v / v) were added to a 1 L single-necked flask. The mixture was purged with nitrogen three times and heated to 90 °C overnight. The reaction mixture was cooled to room temperature, concentrated, and extracted with dichloromethane. After washing with copious amounts of water, the organic phase was dried and concentrated for column chromatography (MeOH:DCM = 20:1, v:v) to obtain a crude product. The crude product was washed with petroleum ether to give 8.4 g of a white solid, with a yield of 77.1%.

[0156] Mass spectrometry analysis determined the molecular ion mass to be 636.28 (theoretical value: 636.23).

[0157] This invention provides specific synthesis methods for the above-mentioned compounds. For compounds in the following examples (others) that are not given specific synthesis methods, they are also prepared by similar methods, which only require replacing the raw materials. These methods will not be elaborated here. Alternatively, those skilled in the art can also prepare them using other methods in the prior art.

[0158] Device Examples

[0159] Implementation

[0160] An OLED includes a first electrode and a second electrode, and an organic material layer located between the electrodes. This organic material layer can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, an electron transport region, a charge generation layer, etc.

[0161] In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0162] The first electrode can be formed by sputtering or depositing the material to be used as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), ytterbium (Yb), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof.

[0163] Organic material layers can be formed on electrodes using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as organic material layers can be small organic molecules, large organic molecules, polymers, and combinations thereof.

[0164] The hole transport region is located between the anode and the emissive layer. The hole transport region can be a single-layer hole transport layer (HTL), including single-layer hole transport layers containing only one compound and single-layer hole transport layers containing multiple compounds. Alternatively, the hole transport region can be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL); wherein the HIL is located between the anode and the HTL, and the EBL is located between the HTL and the emissive layer.

[0165] The material for the hole transport region may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives, wherein the aromatic amine derivatives include compounds shown in HT-1 to HT-51 below; or any combination thereof.

[0166]

[0167]

[0168]

[0169] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can be one or more compounds of HT-1 to HT-51 described above, or one or more compounds of HI-1 to HI-3 described below; it can also be one or more compounds of HT-1 to HT-51 doped with one or more compounds of HI-1 to HI-3 described below.

[0170]

[0171] The emissive layer includes luminescent dyes (i.e., dopants) that can emit different wavelengths of light, and may also include a host material. The emissive layer can be a monochromatic emissive layer emitting a single color such as red, green, or blue. Multiple monochromatic emissive layers of different colors can be arranged in a planar pattern according to pixel design, or they can be stacked together to form a colored emissive layer. When different colored emissive layers are stacked together, they can be separated from each other or connected to each other. The emissive layer can also be a single colored emissive layer that can simultaneously emit different colors such as red, green, and blue.

[0172] Depending on the technology used, the light-emitting layer material can be various, including fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescence materials. An OLED device can employ a single light-emitting technology or a combination of different technologies. These different light-emitting materials, categorized by technology, can emit light of the same color or different colors.

[0173] In one aspect of the invention, the light-emitting layer employs phosphorescent photoluminescence technology. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of pH-1 to pH-85.

[0174]

[0175]

[0176]

[0177]

[0178] In one aspect of the invention, the light-emitting layer employs phosphorescent photoluminescence technology. The phosphorescent dopant of the light-emitting layer may be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0179]

[0180]

[0181] In one aspect of the invention, the light-emitting layer employs thermally activated delayed fluorescence emission technology. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of PH-1 to PH-85 described above.

[0182] In one aspect of the present invention, an electron blocking layer (EBL) is located between the hole transport layer and the light-emitting layer. The electron blocking layer may employ, but is not limited to, one or more compounds of HT-1 to HT-51 described above, or one or more compounds of PH-47 to PH-77 described above; or a mixture of one or more compounds of HT-1 to HT-51 and one or more compounds of PH-47 to PH-77 may be employed.

[0183] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0184] When the device is a multilayer device, the electron transport layer material may also be selected from, but not limited to, one or more combinations of ET-1 to ET-73 listed below. Meanwhile, the charge generation layer may be selected from, but not limited to, one or more compounds of M1 to M288 and alkali metal complexes mentioned above.

[0185]

[0186]

[0187]

[0188]

[0189] In one aspect of the present invention, a hole blocking layer (HBL) is located between the electron transport layer and the light-emitting layer. The hole blocking layer may employ, but is not limited to, one or more compounds of ET-1 to ET-73, or one or more compounds of PH-1 to PH-46; or a mixture of one or more compounds of ET-1 to ET-73 and one or more compounds of PH-1 to PH-46 may be employed.

[0190] The device may also include an electron injection layer located between the electron transport layer and the cathode, and the electron injection layer material includes, but is not limited to, one or more combinations of the following.

[0191] LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg, Yb.

[0192] Device Example 1

[0193] A stacked organic electroluminescent device includes, sequentially arranged, an anode (ITO), a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, a charge generation layer, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and a cathode (Al). The fabrication method of this organic electroluminescent device is as follows:

[0194] (1) The glass substrate coated with ITO transparent conductive layer was ultrasonically treated in commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in acetone / ethanol mixed solvent, baked in a clean environment until the moisture was completely removed, cleaned with ultraviolet light and ozone, and bombarded with low-energy cation beam.

[0195] (2) Place the glass substrate with the anode in the vacuum chamber and evacuate it to a vacuum level of less than 1×10⁻⁶. -5 Pa, a mixture of compound HT-4:HI-3 (97 / 3, w / w) was vacuum-deposited on the above anodic layer as a hole injection layer at a deposition rate of 0.1 nm / s and a film thickness of 10 nm.

[0196] (3) The compound HT-4 was vacuum-deposited on the hole injection layer as a hole transport layer at a deposition rate of 0.1 nm / s and a total film thickness of 30 nm.

[0197] (4) The compound HT-40 was vacuum-deposited on the hole transport layer as an electron blocking layer at a deposition rate of 0.1 nm / s and a total film thickness of 5 nm.

[0198] (5) A light-emitting layer is vacuum-deposited on the electron blocking layer. The light-emitting layer includes a ternary mixture of PH-61:PH-3:GPD-12 (100:100:20, w / w / w), the deposition rate is 0.1 nm / s, and the total deposition thickness is 40 nm.

[0199] (6) The compound ET-23 was vacuum-deposited on the light-emitting layer as a hole blocking layer at a deposition rate of 0.1 nm / s and a total film thickness of 5 nm.

[0200] (7) A mixture of compound ET-69:ET-57 (50 / 50, w / w) was vacuum-deposited on the hole blocking layer as an electron transport layer at a deposition rate of 0.1 nm / s and a total film thickness of 25 nm.

[0201] (8) A charge generation layer is vacuum-deposited on the electron transport layer. The charge generation layer is a binary mixture of M18:Li (100:3, w / w), the deposition rate is 0.1 nm / s, and the thickness is 10 nm.

[0202] (9) Vacuum vapor deposit (2)-(7) layers on the charge generation layer in sequence;

[0203] (10) An Al layer with a thickness of 150 nm is vacuum-deposited on the electron transport layer as the cathode of the device at a deposition rate of 1 nm / s to obtain the organic electroluminescent device.

[0204] Device Examples 2-12, Device Comparative Examples 1-5

[0205] An organic electroluminescent device is disclosed, which differs from device example 1 only in that the compounds shown in Table 1 are used; the other layers, thickness, materials and preparation methods are the same as those in device example 1.

[0206] Comparative Example 1 uses a combination of M18 and Yb as the charge generation layer material to replace the combination of the compound and alkali metal of the present invention.

[0207] Devices in Comparative Examples 2-5 use existing compounds or D2-D5 and metal combinations prepared according to methods similar to Example 1 as charge generation layer materials instead of the compounds and alkali metal combinations of the present invention.

[0208]

[0209] Device testing methods (including equipment and testing conditions):

[0210] The organic electroluminescent devices prepared by the above process were subjected to the following performance measurements:

[0211] At the same current density, the lifetimes of the organic electroluminescent devices prepared in Examples 1-12 and Comparative Examples 1-5 were measured using a digital source meter and a PR650. Specifically,

[0212] The lifespan of the LT97 was tested as follows: using a luminance meter at 40mA / cm 2 The initial brightness value of the device under current density was measured. With a constant current, the time it took for the device brightness to drop to 97% of the initial brightness was measured in hours. The LT97 lifetime test value of Comparative Example 1 was recorded as 1.0. The ratio of the LT97 lifetime test value of other devices to the LT97 lifetime test value of Comparative Example 1 was calculated.

[0213] The driving voltage of the organic electroluminescent devices prepared in the examples and comparative examples was measured using a digital source meter at a current density of 10 mA / cm². 2 The external quantum efficiency (EQE%) of the device was measured using the integrating sphere method at the voltage.

[0214] The performance data of the organic electroluminescent devices prepared in the above-mentioned device embodiments and comparative examples are detailed in Table 1 below.

[0215] Table 1:

[0216]

[0217]

[0218] As can be seen from the data in Table 1, using the combination provided by this invention as the charge generation layer material for a series organic electroluminescent device, the device has significant advantages in terms of operating voltage, efficiency, and lifetime.

[0219] Compared to the combination of compound M18 and Yb, it performs better when combined with Li, indicating that the coordination between the host compound and Li is stronger, which can suppress the migration of metal ions under the action of an electric field and is beneficial to reducing the driving voltage.

[0220] Compared to compounds D2 and D3, the two phenanthroline groups in the doped host structure of this invention have a six-membered fused ring group on the intermediate bridging benzene ring. This ensures that the molecule presents a special stacking structure, which is beneficial to expanding the conjugated skeleton of the molecule, reducing the LUMO energy level, and improving electron mobility, thereby reducing the device voltage. At the same time, due to the improved electron transport performance of the compound, the ratio of holes and electrons in the device is more balanced, thus improving both efficiency and lifetime.

[0221] Compared to compounds D4 and D5, the compounds of this invention require meta-substitution on the central benzene ring, primarily because this substitution method is more conducive to coordination between the organic compound and the metal, enhancing the interaction forces and inhibiting metal ion migration. Meanwhile, compound D4 has two phenyl substituents, which affects the molecular packing structure and electron transport performance, resulting in a certain reduction in efficiency and lifetime compared to D5.

[0222] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A series organic electroluminescent device, comprising the following structure: an anode, a cathode, at least two electroluminescent units disposed between the anode and the cathode, and a charge generation layer disposed between two adjacent electroluminescent units, characterized in that: The charge-generating layer is formed by a host material and a dopant, wherein the dopant is an alkali metal, and the host material has a structure as shown in formula (1): In equation (1), Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8 are each independently N or CR0, and R0 is independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 heterocyclic alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C1-C20 alkylsilyl, substituted or unsubstituted C1-C20 alkylamino, substituted or Any one of the following: unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, substituted or unsubstituted C6-C60 arylamino, substituted or unsubstituted C3-C60 heteroarylamino, substituted or unsubstituted C6-C60 aryloxy, substituted or unsubstituted C6-C60 arylthio, substituted or unsubstituted C6-C60 silylaryl, wherein two adjacent R0s are not connected or are connected by a single bond, -CR 1 R 2 -、-O-、-S-、-NR 3 - Connected into a loop; R 1 R 2 R 3 Each of the following is independently selected from hydrogen, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; The groups of the structure of formula (b) are fused together at the positions of Z2 and Z3 or Z3 and Z4 in formula (1) at the positions indicated by the dashed lines; R1 and R2 are each independently selected from any one of hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 heterocycloalkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C6-C30 arylamino, and substituted or unsubstituted C1-C20 alkylsilyl. a and b are independent integers from 1 to 7; when a is greater than or equal to 2, R1 are either identical or different, and any two adjacent R1 are either not connected or form a cycle; when b is greater than or equal to 2, R2 are either identical or different, and any two adjacent R2 are either not connected or form a cycle. X1, X2, X3, and X4 are each independently N or CR3, and at least one of them is N. R3 is each independently any one of hydrogen, deuterium, substituted or unsubstituted C1-C20 chain alkyl, substituted or unsubstituted C3-C20 cyclic alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl. The substitution of each substituted or unsubstituted group in Z1 to Z8, R1, R2, and X1 to X4 above refers to the independent substitution by a group selected from one or a combination of two of the following groups: deuterium, halogen, cyano, nitro, hydroxyl, amino, aldehyde, ester, C1-C10 chain alkyl, C2-C10 alkenyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C2-C10 heterocycloalkyl, C1-C10 alkylsilyl, C1-C10 alkylamino, C6-C60 aryloxy, C6-C60 arylamino, C6-C30 aryl, or C3-C30 heteroaryl.

2. The tandem organic electroluminescent device according to claim 1, characterized in that, In the charge generation layer, the dopant is selected from at least one of lithium, sodium, and potassium; Preferably, the dopant includes lithium.

3. The tandem organic electroluminescent device according to claim 2, characterized in that, In the charge generation layer, the mass ratio of the host material to the dopant is 1:(1%-30%). Preferably, the mass ratio of the host material to the dopant is 1:(1%-10%); More preferably, the mass ratio of the host material to the dopant is 1:(1%-5%).

4. The tandem organic electroluminescent device according to claim 2, characterized in that, The thickness of the charge generation layer is 1-30 nm, preferably 5-20 nm, and more preferably 8-15 nm.

5. The tandem organic electroluminescent device according to claim 2, characterized in that, The main material has a structure as shown in formula (1-1) or formula (1-2): The definitions of X1, X2, X3, and X4 are the same as those in equation (1); the definitions of a and b are the same as those in equation (1). In formula (1-1), Z1 and Z4 to Z8 are each independently selected from N or CR0, and R0 is each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C10 chain alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C2-C10 heterocyclic alkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C1-C10 alkylsilyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted The C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 arylthio, substituted or unsubstituted C6-C30 silylaryl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 aryloxy, substituted or unsubstituted C3-C30 heteroaryl; when Z4 to Z8 are selected from CR0, two adjacent R0s are not connected or are connected by a single bond, -CR 1 R 2 -、-O-、-S-、-NR 3 - Connected into a loop, R 1 R 2 R 3 Each of the following is independently selected from hydrogen, substituted or unsubstituted C1-C5 chain alkyl, substituted or unsubstituted C6-C15 aryl, and substituted or unsubstituted C3-C15 heteroaryl; Preferably, when Z4 to Z8 are selected from CR0, at least one of the R0s is not hydrogen; or preferably, when Z4 to Z8 are selected from CR0, at most three of the R0s are not hydrogen. Preferably, Z4 is selected from CR0, where R0 is not hydrogen, and Z5 to Z8 are selected from CH; or Z5 is selected from CR0, where R0 is not hydrogen, and Z4, Z6 to Z8 are selected from CH; or Z6 is selected from CR0, where R0 is not hydrogen, and Z4 to Z5, Z7 to Z8 are selected from CH; or Z7 is selected from CR0, where R0 is not hydrogen, and Z4 to Z6, Z8 are selected from CH. Alternatively, preferably, Z5 and Z7 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected, and Z4, Z6, and Z8 are selected from CH; or Z5 and Z6 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or are connected to form a ring, and Z4, Z7 to Z8 are selected from CH; or Z6 and Z7 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or are connected to form a ring, and Z4 to Z5 and Z8 are selected from CH; or Z7 to Z8 are selected from CR0, neither of the two R0s is hydrogen, and the two R0s are not connected or are connected to form a ring, and Z4 to Z6 are selected from CH. Alternatively, preferably, Z4, Z6, and Z7 are selected from CR0, none of the three R0s are hydrogen, the R0s in Z6 and Z7 are not connected or are connected in a ring, and Z5 and Z8 are selected from CH; or Z5, Z6, and Z7 are selected from CR0, none of the three R0s are hydrogen, the R0s in Z5 and Z6 are not connected or are connected in a ring, the R0s in Z6 and Z7 are not connected or are connected in a ring, and Z4 and Z8 are selected from CH; or Z5, Z7, and Z8 are selected from CR0, none of the three R0s are hydrogen, the R0s in Z7 and Z8 are not connected or are connected in a ring, and Z4 and Z6 are selected from CH; or Z6, Z7, and Z8 are selected from CR0, none of the three R0s are hydrogen, the R0s in Z6 and Z7 are not connected or are connected in a ring, the R0s in Z7 and Z8 are not connected or are connected in a ring, and Z4 to Z5 are selected from CH; R1 and R2 are each independently selected from any one of hydrogen, deuterium, cyano, substituted or unsubstituted C1-C10 chain alkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C2-C10 heterocycloalkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, and substituted or unsubstituted C1-C10 alkylsilyl. Preferably, R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; In formula (1-2), Z1, Z2, and Z5-Z8 are each independently selected from N or CR0, and R0 is each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C10 chain alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C2-C10 heterocyclic alkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C1-C10 alkylsilyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted The C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 arylthio, substituted or unsubstituted C6-C30 silylaryl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 aryloxy, substituted or unsubstituted C3-C30 heteroaryl; when Z2, Z5 to Z8 are selected from CR0, two adjacent R0s are not connected or are connected by a single bond, -CR 1 R 2 -、-O-、-S-、-NR 3 - Connected into a loop, R 1 R 2 R 3 Each of the following is independently selected from hydrogen, substituted or unsubstituted C1-C5 chain alkyl, substituted or unsubstituted C6-C15 aryl, and substituted or unsubstituted C3-C15 heteroaryl; Preferably, when Z2, Z5 to Z8 are selected from CR0, at least one of the R0s is not hydrogen; or preferably, when Z2, Z5 to Z8 are selected from CR0, at most three of the R0s are not hydrogen. Preferably, Z2 is selected from CR0, where CR0 is not hydrogen, and Z5 to Z8 are selected from CH; or Z8 is selected from CR0, where CR0 is not hydrogen, and Z2, Z5 to Z7 are selected from CH. Alternatively, preferably, Z7 is selected from CR0, where R0 is not hydrogen, and Z2, Z5-Z6, and Z8 are selected from CH; or Z6 is selected from CR0, where R0 is not hydrogen, and Z2, Z5, and Z7-Z8 are selected from CH; or Z6 and Z8 are selected from CR0, where neither of the two R0s is hydrogen, and the two R0s are not connected, and Z2, Z5, and Z7 are selected from CH; or Z7 and Z8 are selected from CR0, where neither of the two R0s is hydrogen, and the two R0s are not connected or are connected in a ring, and Z2, Z5-Z6 are selected from CH; or Z6 and Z7 are selected from CR0, where neither of the two R0s is hydrogen, and the two R0s are not connected or are connected in a ring, and Z2, Z5, and Z8 are selected from CH; or Z5-Z6 are selected from CR0, where neither of the two R0s is hydrogen, and the two R0s are not connected or are connected in a ring, and Z2, Z7-Z8 are selected from CH. Alternatively, preferably, Z2, Z6, and Z7 are selected from CR0, all three R0s are not hydrogen, the R0s in Z6 and Z7 are not connected or are connected in a ring, and Z5 and Z8 are selected from CH; or Z6, Z7, and Z8 are selected from CR0, all three R0s are not hydrogen, the R0s in Z6 and Z7 are not connected or are connected in a ring, the R0s in Z7 and Z8 are not connected or are connected in a ring, and Z2 and Z5 are selected from CH; or Z5, Z6, and Z8 are selected from CR0, all three R0s are not hydrogen, the R0s in Z5 and Z6 are not connected or are connected in a ring, and Z2 and Z7 are selected from CH; or Z5, Z6, and Z7 are selected from CR0, all three R0s are not hydrogen, the R0s in Z5 and Z6 are not connected or are connected in a ring, the R0s in Z6 and Z7 are not connected or are connected in a ring, and Z2 and Z8 are selected from CH. R1 and R2 are each independently selected from any one of hydrogen, deuterium, cyano, substituted or unsubstituted C1-C10 chain alkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C2-C10 heterocycloalkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, and substituted or unsubstituted C1-C10 alkylsilyl. Preferably, R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; The substitution of each of the above-mentioned substituted or unsubstituted groups refers to the independent substitution by one selected from deuterium, halogen, cyano, C1-C10 chain alkyl, C2-C10 alkenyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 alkylsilyl, C6-C20 aryl or C3-C20 heteroaryl.

6. The tandem organic electroluminescent device according to claim 5, characterized in that, In formula (1-1), at most one of Z1, Z4 to Z8 is N; more preferably, at most one of Z1, Z5 to Z8 is N; more preferably, at most one of Z1, Z5 and Z7 is N. In equation (1-2), at most one of Z1, Z2, Z5 to Z8 is N; more preferably, at most one of Z1, Z5 to Z8 is N; more preferably, at most one of Z1, Z6, Z8 is N. Preferably, in formulas (1-1) and (1-2), Z1, Z2, and Z4 to Z8 are each independently selected from CR0, and R0 is each independently selected from hydrogen, halogen, cyano, or any of the following substituted or unsubstituted groups, wherein "*" represents a linking site: *-CH3, *-CD3, The substitution of each of the above-mentioned substituted or unsubstituted groups refers to the independent substitution by one of the following groups: deuterium, halogen, cyano, C1-C5 chain alkyl, C3-C5 cycloalkyl, C6-C20 aryl or C3-C20 heteroaryl.

7. The tandem organic electroluminescent device according to claim 4 or 5, characterized in that, In equations (1-1) and (1-2), X1, X2, X3, and X4 are each independently represented by N; And / or R1 and R2 are each independently selected from hydrogen or any of the following substituted or unsubstituted groups: *-CH3, *-CD3, The substitution of each of the above-mentioned substituted or unsubstituted groups refers to the independent substitution by one of the following groups: deuterium, halogen, cyano, C1-C5 chain alkyl, C3-C5 cycloalkyl, C6-C20 aryl or C3-C20 heteroaryl. Preferably, at most four of R1 and R2 are not hydrogen; more preferably, at most two of R1 and R2 are not hydrogen; more preferably, at most one of R1 and R2 is not hydrogen; most preferably, all of R1 and R2 are hydrogen.

8. The tandem organic electroluminescent device according to claim 5, characterized in that, The main material is selected from the structure shown in formula (1-3) or formula (1-4): In equations (1-3) and (1-4), the definitions of X1, X2, X3, and X4 are the same as those in equation (1); the definitions of Z1, Z2, Z4 to Z8 are the same as those in equations (1-1) and (1-2). R 11 ~R 16 R 21 ~R 26 Each is independently selected from one or a combination of two of the following: hydrogen, deuterium, cyano, C1-C10 chain alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C2-C10 heterocycloalkyl, C2-C10 alkenyl, C6-C30 arylamino, C6-C30 aryl, C3-C30 heteroaryl, and C1-C10 alkylsilyl. More preferably, R 11 ~R 16 R 21 ~R 26 Each is independently selected from hydrogen or any of the following groups: *-CH3, *-CD3, More preferably, R 11 ~R 16 R 21 ~R 26 At most four of them are not hydrogen; more preferably, R 11 ~R 16 R 21 ~R 26 At most two of them are not hydrogen; further preferably, R 11 ~R 16 R 21 ~R 26 At most one of them is not hydrogen; most preferably, R 11 ~R 16 R 21 ~R 26 It is entirely composed of hydrogen.

9. The tandem organic electroluminescent device according to claim 1 or 2, characterized in that, The host material is selected from the compounds shown below:

10. The tandem organic electroluminescent device according to claim 1, characterized in that, The electroluminescent unit includes at least one of a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, and an electron transport layer.

11. A display device comprising the tandem organic electroluminescent device of claim 1.

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