CN114695800A

CN114695800A - TADF sensitized organic electroluminescent device and display device containing same

Info

Publication number: CN114695800A
Application number: CN202011644283.5A
Authority: CN
Inventors: 赵鑫栋; 曹旭东; 张兆超; 李崇; 崔明
Original assignee: Jiangsu Sunera Technology Co Ltd
Current assignee: Jiangsu Sunera Technology Co Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-01

Abstract

The invention relates to the technical field of semiconductors, in particular to a TADF sensitized organic electroluminescent device and a display device comprising the same, wherein the organic electroluminescent device sequentially comprises the following components from bottom to top: the organic functional material layer sequentially comprises a substrate, a first electrode, an organic functional material layer and a second electrode from bottom to top: the light-emitting layer comprises a host material and a doping material; the host material comprises one or more organic materials, the host material at least comprises one space CT state TADF material, and the doping material is a boron-containing compound. The invention improves the efficiency and the service life of the organic electroluminescent device by selecting the main material of the luminous layer in the device and matching the main material of the luminous layer with the doping material.

Description

TADF sensitized organic electroluminescent device and display device containing same

Technical Field

The invention relates to the technical field of semiconductors, in particular to a TADF sensitized organic electroluminescent device and a display device comprising the same.

Background

The Organic Light Emitting Diode (OLED) device technology can be used for manufacturing novel display products and novel illumination products, is expected to replace the existing liquid crystal display and fluorescent lamp illumination, and has wide application prospect. In general, an organic electroluminescent device composed of several layers includes an anode, a cathode, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and an electron injection layer. When a voltage is applied to electrodes at both ends of the organic electroluminescent device as a current device, holes from the anode and electrons from the cathode are recombined in the organic light-emitting layer by the action of an electric field to form excitons, and the excitons relax to the ground state to release energy, thereby generating organic electroluminescence.

For the traditional fluorescence luminescence, due to the limitation of electron spin forbidden resistance, the theoretical internal quantum luminescence efficiency is only 25%, and the device efficiency far cannot meet the requirements in practical application. For a phosphorescent light-emitting device, the limitation of spin forbidden resistance can be broken through due to the existence of heavy metal atoms, the theoretical internal quantum efficiency of the device can reach 100%, but the price of the device is too high due to the existence of the heavy metal atoms, and the service life of the device is short.

In addition, the triplet-triplet annihilation mechanism is applied to the OLED device, which can effectively solve the problems of high price and short lifetime, but in this mechanism, two triplet excitons are required to be converted into one singlet exciton, so theoretically, the internal quantum efficiency is only 62.5%, and the device efficiency is still low. The sensitized fluorescence technology is considered as the next generation OLED technology, the problems of high material price and short service life of the device can be solved, meanwhile, the theoretical internal quantum efficiency can reach 100%, and the efficiency of the device can be greatly improved. But device performance is still at a lower device level due to immaturity between material systems and improper matching between materials.

Therefore, the design of novel functional materials and the reasonable collocation of the materials in the device have important significance for improving the performance of the device and promoting the commercial application of the OLED.

Disclosure of Invention

The object of the present invention is to provide a sensitized organic electroluminescent device having a high external quantum yield and a longer lifetime.

This object is achieved by a sensitized fluorescent organic electroluminescent device having the following composition,

a TADF sensitized organic electroluminescent device comprises the following components in sequence from bottom to top: a substrate, a first electrode, an organic functional material layer, a second electrode,

the organic functional material layer sequentially comprises from bottom to top: a hole transport region, a light emitting layer, and an electron transport region;

the hole transmission region comprises the following components in sequence from bottom to top: the hole injection layer comprises a hole transport layer material and a P-type dopant;

the light-emitting layer comprises a host material and a doping material;

the host material comprises one or more organic materials, the host material at least comprises one TADF material in a space CT state, and the doping material is a boron-containing compound.

Preferably, the transition rate (K) between inverses of the TADF material in the space CT state_RIST) Not less than 1 x 10⁵/s；

Preferably, the transition rate (K) between the inverses of the TADF material in the space CT state_RIsT) Not less than 1 x 10⁶/s。

Preferably, the HOMO level of the spatial CT-state TADF material is greater than the HOMO level of the boron-containing compound, and the absolute value of the difference between the HOMO level of the spatial CT-state TADF material and the HOMO level of the boron-containing compound is not greater than 0.2 eV; and/or the spatial CT state TADF material has an overlap in fluorescence emission spectrum and ultraviolet-visible light absorption spectrum of the boron-containing compound.

Preferably, the triplet energy level of the spatial CT state TADF material is greater than the singlet energy level of the boron-containing compound, and the difference is not less than 0.15 eV.

Preferably, the spatial CT-state TADF material has an overlap of HOMO and LUMO distributions based on quantum chemical computation of less than 20% and has a spatial bridging group, and the structure of the spatial CT-state TADF material is represented by general formula (1)

Wherein Ar is₁And Ar₂Respectively selecting a D-type structure and an A-type structure, wherein the D-type structure is shown as a general formula (2), and the A-type structure is shown as a general formula (3) or (4);

any substitution site of the general formula (2) and the general formula (4) can be connected with the general formula (1); l in the general formula (3)₁All of the other sites of (2) can be linked to the general formula (1);

x is O, S or N-R_a；Z、Z1、Z₂Each occurrence, identically or differently, being represented by a nitrogen atom or C-R₀(ii) a For example, in formula (1), Z may be N or C-R at each occurrence₀That is, Z in the formula (1) may be the same or different.

R_a、R₀、Ar₄-A_r5Identical or different represents hydrogen, deuterium, tritium, substituted or unsubstituted C₃～C₁₀Cycloalkyl, substituted or unsubstituted C₆～C₃₀Aryl of (2), substituted or unsubstituted C₅～C₃₀The heteroaryl group of (a); wherein R's adjacent to each other on the same aromatic ring₀Can be connected into a ring;

L、L₁is a single bond, substituted or unsubstituted C₆～C₃₀Arylene of (a), substituted or unsubstituted C₅～C₃₀The heteroarylene group of (a);

said substituted or unsubstituted C₅～C₃₀The heteroatom in the heteroaryl or heteroarylene of (a) is selected from N, S or O;

the substituent in the aforementioned "substituted or unsubstituted" is one or more selected from deuterium, tritium, cyano, methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, phenyl, naphthyl, naphthyridinyl, biphenylyl, terphenylyl, and pyridyl.

Preferably, the boron-containing compound comprises formula (5) and/or formula (6) and/or multimers thereof:

in the general formula (5) and the general formula (6),

R₁、R₂、R₃、R₄、R₅、R₆、R₇each independently represents a hydrogen atom, a fluorine atom, C₃-C₁₀Cycloalkyl radical, C₃-C₁₀Heterocycloalkyl radical, C₆-C₆₀Aryl or C₅-C₆₀A heteroaryl group; wherein said C₃-C₁₀Cycloalkyl radical, C₃-C₁₀Heterocycloalkyl radical, C₆-C₆₀Aryl or C₅-C₆₀Heteroaryl is optionally substituted with the following substituents: deuterium, tritium, halogen, cyano, C₁-C₁₀Alkyl radical, C₁-C₁₀Alkoxy radical, C₆-C₂₀Aryl or C₅-C₂₀A heteroaryl group; and R is₁、R₂、R₃Not simultaneously represented as a hydrogen atom; r₄、R₅、R₆、R₇Not simultaneously represented as hydrogen atoms.

Preferably wherein the boron-containing compound is selected from the group consisting of formula (7) and/or formula (8) and/or formula (9) and/or formula (10) and/or formula (11) and/or formula (12) and/or formula (13) and/or multimers thereof:

in the general formula (7) and the general formula (8):

R₈、R₉、R₁₀、R₁₁、R₁₂、R₁₃、R₁₄、R₁₅、R₁₆、R₁₇、R₁₈、R₂₁、R₂₂、R₂₃、R₂₄、R₂₅、R₂₆、R₂₇、R₂₈、R₂₉、R₃₀independently of each other is hydrogen, deuterium, protium, tritium, C₆-C₃₀Aryl radical, C₅-C₃₀Heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, or aryloxy, at least one hydrogen of which is optionally substituted with halogen, aryl, heteroaryl, or alkyl; c as mentioned above₆-C₃₀Aryl is preferably phenyl, naphthyl or anthracenyl; the aforementioned C₅-C₃₀Heteroaryl is preferably carbazolyl; the aforementioned alkyl group is preferably C₁-C₆An alkyl group;

or R₈～R₁₈Are optionally bonded to each other and form, together with the a-, b-or c-ring, an aryl or heteroaryl ring; r_23～25And R_28～30Are optionally bonded to each other and form, together with the g ring and/or the f ring, an aryl or heteroaryl ring; wherein at least one hydrogen in the formed aryl or heteroaryl ring is optionally substituted with aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, or aryloxy; said heteroaryl is preferably isoquinolinyl; the aforementioned alkyl group is preferably C₁-C₆An alkyl group;

X₁、X₂、X₃、X₄、X₅、X₆are respectively and independently represented as O, S, Se, N-R or B-R, and R is C₆-C₁₂Aryl radical, C₂-C₁₅Heteroaryl or C₁-C₆Alkyl radical, said C₆-C₁₂Aryl or C₂-C₁₅At least one hydrogen of the heteroaryl group is optionally substituted by C₁-C₆Alkyl substitution; or said R is optionally through-O-, -S-, -C (-Rg)₂-or a single bond to said a-, b-or C-ring, said Rg being selected from C₁-C₆An alkyl group;

R₁₉and R₂₀Are each independently hydrogen, C₁-C₆Alkyl or C₆-C₁₂An aryl group, a heteroaryl group,

Z₃and Z₄Are each independently aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, aryloxy, heteroaryloxy, arylthio or heteroarylthio, or at least one hydrogen of the above-mentioned groups is optionally substituted by aryl, heteroaryl, alkyl or alkyl-substituted silane groups, or Z₃Optionally through-O-, -S-, -C (-Rb)₂-or a single bond is bonded to said d ring, or Z₄Optionally through-O-, -S-, -C (-Rb)₂-or a single bond is bonded to said e-ring, said-C (-Rb)₂Rb of-is hydrogen or C₁-C₆An alkyl group thereof;

in the general formula (9) and the general formula (10),

X₇、X₈、X₉expressed as O, S, Se, C-Rc, wherein Rc of the C-Rc is cyano, C₆-C₃₀Aryl radical, C₆-C₃₀Heteroaryl or C₁-C₆Alkyl radical, said C₆-C₃₀Aryl or C₆-C₃₀Heteroaryl is optionally substituted with: c₁-C₆Alkyl or C₁-C₆Alkoxy, the substituents preferably being methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

R₃₁、R₃₂、R₃₃、R₃₄、R₃₅、R₃₆、R₃₇、R₃₈、R₃₉、R₄₀、R₄₁、R₄₃、R₄₄、R₄₅、R₄₆、R₄₇、R₄₈、R₄₉、R₅₀、R₅₁、R₅₂、R₅₃independently of one another are hydrogen, deuterium, protium, tritium, fluorine, aryl, heteroaryl, diarylamino, diheteroarylAmino, arylheteroarylamino, alkyl, alkoxy or aryloxy, or at least one hydrogen of these groups is optionally substituted by aryl, heteroaryl, alkyl or alkoxy; the aforementioned alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or a tert-butyl group; the aforementioned alkoxy group is preferably a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group or an ethylhexyloxy group;

or R₄₃、R₄₄、R₄₅、R₄₆Wherein two adjacent groups are optionally bonded to each other to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group; or R₅₀、R₅₁、R₅₂、R₅₃Wherein two adjacent groups are optionally bonded to each other to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group; c as mentioned above₆-C₃₀Aryl is preferably phenyl; or said C₆-C₃₀Aryl or C₆-C₃₀Heteroaryl is optionally substituted with: c₁-C₆Alkyl or C₁-C₆Alkoxy, preferably, said C₁-C₆Alkyl or C₁-C₆Alkoxy is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

in the general formula (11), X₁₀Is represented as O, S, Se, N-Rd, and Rd of the N-Rd is C₆-C₁₂Aryl radical, C₂-C₁₅Heteroaryl or C₁-C₆An alkyl group, a carboxyl group,

R₅₄、R₅₅、R₅₆、R₅₇、R₅₈、R₅₉、R₆₀、R₆₁、R₆₂、R₆₃、R₆₄、R₆₅、R₆₆each independently is hydrogen, fluoro, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, or aryloxy, or at least one hydrogen of said aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino is optionally substituted with aryl, heteroaryl, or alkyl;

or R₅₉、R₆₀、R₆₁、R₆₂Wherein two adjacent groups are optionally bonded to each other to form a ring, or R₆₃、R₆₄、R₆₅、R₆₆Wherein two adjacent groups are optionally bonded to each other to form a ring; said ring is preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group; or said C₆-C₃₀Aryl or C₆-C₃₀Heteroaryl is optionally substituted with: phenyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, or tert-butoxy;

in the general formula (12) and the general formula (13),

X₁₁y independently represent-O-, -S-or-N (Re) -, Re is same or different and is independently selected from hydrogen atom, cyano-group, C₁-C₂₀Alkyl radical, C₂-C₂₀Alkylene radical, C₆-C₃₀Aryl, or C containing one or more hetero atoms₂-C₃₀A heteroaryl group;

or said Re and adjacent Z₅Bonded to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group;

Z₅are identical or different and are independently from each other selected from nitrogen atoms or C-Rf;

rf represents a hydrogen atom, a deuterium atom, a tritium atom, a cyano group, a halogen, C₁-C₂₀Alkyl radical, C₆-C₃₀Aryl, or C containing one or more hetero atoms₂-C₃₀A heteroaryl group;

or Re and Rf are optionally bonded to each other to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group;

a is represented by C₁₄-C₄₀Aryl, C containing one or more hetero atoms₂-C₃₀A heteroaryl group;

or C above₁-C₂₀Alkyl radical, C₂-C₂₀Alkylene radical, C₆-C₃₀Aryl, C containing one or more hetero atoms₂-C₃₀Heteroaryl group, C₆-C₃₀Heteroaryl or C₁₄-C₄₀Aryl is optionally substituted with the following substituents: deuterium atom, tritium atom, cyano group, halogen atom, C₁-C₁₀Alkyl radical, C₆-C₃₀Aryl radical, C₂-C₃₀A heteroaryl group.

Preferably, the TADF material having a spatial CT state is selected from one or more of the following compounds:

preferably, the boron-containing compound is selected from at least one of the following compounds:

preferably, the weight ratio of the boron-containing compound/(boron-containing compound and host material) in the TADF sensitized organic electroluminescent device is 0.1% to 10%.

A full-color display device comprising three pixels of red, green and blue, the full-color display device pixel region comprising the sensitized organic electroluminescent device according to any one of claims 1 to 10.

Advantageous effects

The thermal activation delayed fluorescence material (TADF material) with the space CT state characteristic is used as the sensitization main body material of the fluorescence sensitization device, and the thermal activation delayed fluorescence material has the characteristics of high intersystem crossing speed, high fluorescence quantum yield and strong spectral stability.

The material has high intersystem crossing speed, so that the energy transfer efficiency between the host and the guest can be effectively increased, and quenching caused by exciton aggregation is reduced; the high fluorescence quantum yield indicates that the exciton utilization rate of the material is high, and the loss of luminous energy is reduced; the stable spectrum can ensure the stability of energy transfer between the host material and the guest material, so the device has the characteristics of high efficiency, small efficiency roll-off and long service life in terms of comprehensive performance expression of the device. In conclusion, the organic electroluminescent device of the present invention has advantages in that the luminous efficiency and the lifespan of the device are improved.

Drawings

Fig. 1 is a structural view of an organic electroluminescent device of the present invention.

In fig. 1, a substrate; 2. a first electrode; 3. a hole injection layer; 4. a hole transport layer; 5. an electron blocking layer; 6. a light emitting layer; 7. an electron transport layer; 8. an electron injection layer; 9. a second electrode; A. an electron transport region; B. a hole transport region.

FIG. 2 shows the fluorescence emission spectrum of the host material and the UV-VIS absorption spectrum of the dopant material of the blue light emitting device of the present invention. Wherein, UV-ultraviolet visible absorption spectrum and PL-fluorescence emission spectrum.

FIG. 3 shows the fluorescence emission spectrum of the host material of the green light emitting device of the present invention and the UV-visible absorption spectrum of the dopant material.

FIG. 4 shows the fluorescence emission spectrum of the host material and the UV-VIS absorption spectrum of the dopant material of the red light emitting device of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention are described in detail. However, these embodiments are merely exemplary, and the present invention is not limited thereto and is defined by the scope of the claims.

In the present invention, unless otherwise specified, all operations are carried out under ambient temperature and pressure conditions.

As used herein, "alkyl" refers to straight and branched chain alkyl groups having the specified number of carbon atoms, for example, from 1 to 20 carbon atoms (C)₁-C₂₀Alkyl), 1 to 10 carbon atoms (C)₁-C₁₀Alkyl), 1 to 6 carbon atoms (C)₁-C₆Alkyl) or 1 to 4 carbon atoms (C)₁-C₄Alkyl groups). E.g. C₁-C₆Alkyl groups include straight and branched chain alkyl groups of 1 to 6 carbon atoms. When referring to an alkyl residue having a particular number of carbons, it is intended to encompass all branched and straight chain forms having that number of carbons; thus, for example, "butyl" is meant to include n-butyl, sec-butyl, isobutyl, and tert-butyl; "propyl" includes n-propyl and isopropyl. Alkylene is a subset of alkyl and refers to the same residue as alkyl but with two points of attachment.

As used herein, "alkenyl" refers to an unsaturated branched or straight chain alkyl group having at least one carbon-carbon double bond derived by the removal of one molecule of hydrogen from the adjacent carbon atom of the parent alkyl group. The group may be in the cis or trans configuration of the double bond. Typical alkenyl groups include, but are not limited to: a vinyl group; propenyl, such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl (allyl), prop-2-en-2-yl; butenyl, e.g., but-1-en-1-yl, but-1-en-2-yl, 2-methylprop-1-en-1-yl, but-2-en-2-yl, but-1, 3-dien-1-yl, but-1, 3-dien-2-yl, and the like. In certain embodiments, alkenyl groups have 2 to 20 carbon atoms, and in other embodiments, 2 to 10, 2 to 8, or 2 to 6 carbon atoms. Alkenylene is a subset of alkenyl and refers to the same residue as alkenyl, but with two points of attachment.

As used herein, "alkoxy" refers to an alkyl group of the indicated number of carbon atoms attached through an oxygen bridge, for example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, 2-pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, 2-hexyloxy, 3-methylpentyloxy, and the like. Alkoxy groups typically have 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms connected by an oxygen bridge.

In the present invention, the term "cycloalkyl" is used to mean that two carbon atoms at both ends of a linear alkane are bonded to each other with a single valence, i.e., a cyclic structure is formed. Cycloalkyl groups are monocyclic, bicyclic, tricyclic or tetracyclic systems, and may include fused or bridged ring systems, examples of which include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like.

"Heterocycloalkyl" as used herein means a cycloalkyl group in which one or more carbon atoms have been replaced with a heteroatom other than carbon, for example N, O, S, Se or B, etc.

In the present invention, "aryl" is used to mean a group derived from an aromatic monocyclic or polycyclic hydrocarbon ring system by removing a hydrogen atom from a ring carbon atom. The aromatic monocyclic or polycyclic hydrocarbon ring system contains only hydrogen and carbon atoms, wherein at least one ring in the ring system is fully unsaturated, i.e. comprises a cyclic, delocalized (4n +2) pi-electron system according to Huckel theory. Examples include, but are not limited to, phenyl, naphthyl, anthryl, phenanthryl, condensed tetraphenyl, pyrenyl, biphenyl, terphenyl, m-terphenyl, chrysenyl, terphenylene, perylenyl, indenyl, and the like. Arylene is a subset of aryl and refers to the same residue as aryl, but with two points of attachment. In certain embodiments, aryl has 6 to 30 carbon atoms (C)₆-C₃₀Aryl) or having 14 to 40 carbon atoms (C)₁₄-C₄₀Aryl). Arylene is a subset of aryl and refers to the same residue as aryl, but with two points of attachment.

In the present invention, "heteroaryl" used means an aryl group consisting of at least one group selected from nitrogen, oxygen or sulfur. Examples include, but are not limited to, furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiadiazolyl, pyridyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuranyl, benzothienyl, benzimidazolyl, indolyl, quinolyl, isoquinolylA quinoline group, a quinazoline group, a quinoline group, a naphthyridine group, a benzoxazinyl group, a benzothiazinyl group, an acridinyl group, a phenazine group, a phenothiazinyl group, a phenazine group, a fluorene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a condensed ring of said group combinations thereof. Any one of these groups may be used as a substitution site. In certain embodiments, heteroaryl has 2 to 30 carbon atoms (C)₂-C₃₀Heteroaryl). Heteroarylene is a subset of heteroaryl and refers to the same residue as heteroaryl, but with two points of attachment.

In the present invention, "aryloxy" is used to mean an aryl group linked via an oxygen bridge, said aryl group having the above-mentioned definition.

In the present invention, "halogen" used means a chlorine atom, a fluorine atom, a bromine atom or the like.

In the present invention, the terms "diarylamino", "diheteroarylamino", "arylheteroarylamino" refer to an amino group substituted by two aryl groups, two heteroaryl groups or by one aryl group and one heteroaryl group, respectively, said aryl or heteroaryl groups having the above definitions.

In the present invention, unless otherwise specified, HOMO means the highest occupied orbital of a molecule, and LUMO means the lowest unoccupied orbital of a molecule. In addition, the "difference in HOMO energy levels" and "difference in LUMO energy levels" referred to in the present specification mean a difference in each energy value. Further, in the present invention, HOMO and LUMO energy levels are expressed in absolute values, and the comparison between the energy levels is also a comparison of the magnitude of the absolute values thereof, and those skilled in the art know that the larger the absolute value of an energy level is, the lower the energy of the energy level is.

Any numerical range recited herein is intended to include all sub-ranges subsumed within the range with the same numerical precision. For example, "1.0 to 10.0" is intended to include all sub-ranges between (and including 1.0 and 10.0) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, all sub-ranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limitation recited herein is intended to include all smaller numerical limitations subsumed therein, and any minimum numerical limitation recited herein is intended to include all larger numerical limitations subsumed therein. Accordingly, applicants reserve the right to modify the specification, including the claims, to specifically describe any sub-ranges that fall within the ranges specifically described herein.

In the present invention, when describing electrodes and organic electroluminescent devices, and other structures, terms such as "upper", "lower", "top", and "bottom" used to indicate orientation, merely indicate orientation in a certain specific state, and do not mean that the related structure can exist only in the orientation; conversely, if the structure is repositioned, e.g., inverted, the orientation of the structure is changed accordingly. Specifically, in the present invention, the "bottom" side of the electrode refers to the side of the electrode that is closer to the substrate during fabrication, while the opposite side that is further from the substrate is the "top" side.

The invention provides a TADF sensitized organic electroluminescent device, namely a sensitized fluorescent organic electroluminescent device, which sequentially comprises the following components from bottom to top: a substrate, a first electrode, an organic functional material layer, a second electrode,

the organic functional material layer sequentially comprises from bottom to top: a hole transport region, a light emitting layer, and an electron transport region,

the hole transmission region comprises the following components in sequence from bottom to top: the hole injection layer comprises a hole transport layer material and a P-type dopant, and preferably consists of the hole transport layer material and the P-type dopant;

the light-emitting layer comprises a host material and a doping material;

the host material may be one or more organic materials, the host material includes at least one TADF material in a space CT state, and the dopant material is a boron-containing compound.

The overlap of HOMO and LUMO distribution of the space CT state TADF material is less than 20% based on quantum chemical calculation, and the space CT state TADF material has a space bridging group, and has a structure shown in a general formula (1)

Ar is represented by the general formula (1)₁And Ar₂The substituents may be substituted on each of the two rings in the formula, or Ar₁And Ar₂One of the substituents is substituted for X, and the other substituent is substituted for Z on one of the rings on both sides in the general formula (1); but Ar is₁And Ar₂Not simultaneously on the same ring; the slash in the general formulas (2) to (4) represents a single bond, and any substitutable site in the general formula (2) can be used as a site bonded with the general formula (1); the general formula (3) represents L in the general formula (1) and the general formula (3)₁Bonding; the general formula (4) indicates that any substitutable site on the left and right rings in the general formula (4) can be used as a site for bonding with the general formula (1).

The organic electroluminescent device of the present invention may be a bottom emission organic electroluminescent device, a top emission organic electroluminescent device, and a stacked organic electroluminescent device, which is not particularly limited.

The invention will now be further elucidated with reference to the accompanying figure 1, in conjunction with a specific embodiment.

Substrate

According to the present invention, any substrate commonly used for organic electroluminescent devices can be used as the substrate of the organic electroluminescent device. Examples are transparent substrates, such as glass or transparent plastic substrates; opaque substrates, such as silicon substrates; flexible PI film substrate. Different substrates have different mechanical strength, thermal stability, transparency, surface smoothness, water resistance. The direction of use varies depending on the nature of the substrate. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

A first electrode

According to the present invention, the first electrode is formed on the substrate, and the first electrode and the second electrode may be opposite to each other. The first electrode may be an anode. The first electrode may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the first electrode is a transmissive electrode, it may be formed using a transparent metal oxide, such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), zinc oxide (ZnO), Indium Tin Zinc Oxide (ITZO), or the like. When the first electrode is a semi-transmissive electrode or a reflective electrode, it may include Ag, Mg, a1, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a metal mixture. The thickness of the first electrode layer depends on the material used and is typically 50-500nm, preferably 70-300nm and more preferably 100-200 nm.

According to the invention, the organic functional material layer arranged between the first electrode and the second electrode sequentially comprises a hole transport region, a light emitting layer and an electron transport region from bottom to top.

Hole transport region

The hole transport region may be disposed between the first electrode and the light emitting layer. The hole transport region may include a hole injection layer, a hole transport layer, and an electron blocking layer. For example, referring to fig. 1, the hole transport region may include a hole injection layer, a hole transport layer, and an electron blocking layer sequentially disposed on the first electrode from bottom to top. Further, according to the matching requirements of the devices, the hole transport layer between the electron blocking layer and the hole injection layer of the organic electroluminescent device can be a single film layer, and can also be a stacked structure of a plurality of hole transport materials.

Hole injection layer and hole transport layer

In the present invention, the hole injection layer covering the surface of the anode is also referred to as an anode interface buffer layer or a hole transport layer containing P-doping. By either name, this film material has a basic feature of containing a host organic material that conducts holes, and also a P-type dopant having a relatively large HOMO level (and correspondingly a large LUMO level). In order to smoothly inject holes from the anode into the light-emitting layer, the HOMO level of the host organic material for hole conduction used in the hole injection layer and the P-type dopant must have certain characteristics, so that the generation of a charge transfer state between the host material and the dopant is expected, the ohmic contact between the hole injection layer and the anode is realized, and the efficient injection from the electrode into the hole injection layer is realized, which are summarized as follows: the difference between the HOMO level of the host organic material for conducting holes used in the hole injection layer and the LUMO level of the P-type dopant is less than or equal to 0.4 eV. Therefore, for hole-type host materials with different HOMO levels, different P-type dopants need to be selected and matched to realize ohmic contact of the interface, and the hole injection effect is improved.

In one embodiment of the present invention, for better hole injection, the hole injection layer further comprises a P-type dopant having charge conductivity selected from the group consisting of: quinone derivatives such as Tetracyanoquinodimethane (TCNQ) and 2, 3, 5, 6-tetrafluoro-tetracyano-1, 4-benzoquinodimethane (F4-TCNQ); or hexaazatriphenylene derivatives, such as 2, 3, 6, 7, 10, 11-hexacyano-1, 4, 5, 8, 9, 12-hexaazatriphenylene (HAT-CN); or cyclopropane derivatives such as 4, 4 ', 4 "- ((1E, 1' E, 1" E) -cyclopropane-1, 2, 3-trimethylenetri (cyanoformylidene)) tris (2, 3, 5, 6-tetrafluorobenzyl); or metal oxides such as tungsten oxide and molybdenum oxide, but not limited thereto. Preferably, the P-type dopant is selected from at least one of the following P1-P10:

in the hole injection layer of the present invention, the ratio of the hole transporting host material to the P-type dopant is used in the range of 99: 1 to 95: 5, preferably 99: 1 to 97: 3, on a mass basis.

In an embodiment of the invention, the hole injection layer and the hole transport layer material are selected from the group consisting of,

the above compounds are prepared according to JP200056490A, JP2005263634A, JP2001316338A, CN105492574A, CN109314189A or are commercially available.

The thickness of the hole injection layer of the present invention may be 5 to 100nm, preferably 5 to 50nm and more preferably 5 to 20nm, but the thickness is not limited to this range. The thickness of the hole transport layer of the present invention may be 5 to 200nm, preferably 10 to 150nm and more preferably 20 to 100nm, but the thickness is not limited to this range.

Electron blocking layer

In the present invention, after forming a hole injection layer and a hole transport layer over a first electrode, an electron blocking layer of each light emitting pixel unit (e.g., a blue, green, or red light emitting pixel unit) is formed over the hole transport layer. In the invention, the space CT state TADF material has carbazole or carbazole polycyclic groups, and the HOMO energy level of the material is relatively deep, so that an electronic barrier layer material with deep HOMO energy level needs to be selected to match the material in the matching of the device structure, thereby being more beneficial to the injection of holes. Meanwhile, the electron blocking layer material is required to have a higher T1 energy level, so that energy loss caused by diffusion of excitons can be avoided, and the efficiency of the device can be improved. Therefore, it is necessary to select a suitable electron blocking layer material to match the material of the light emitting layer.

In the invention, the material of the electron blocking layer with HOMO energy level larger than 5.6eV and triplet state energy level higher than 2.6eV is preferentially selected.

In a preferred embodiment of the present invention, the electron blocking layer material of the sensitized fluorescent OLED device is selected from at least one of the following compounds:

the above compounds were prepared according to CN105061371B, CN108658953, CN109053698A or commercially available.

The thickness of the electron blocking layer of the present invention may be 1 to 200nm, preferably 5 to 20nm, but the thickness is not limited to this range.

Luminescent layer

In the invention, after the electron blocking layer is formed, a corresponding light-emitting layer is formed on the electron blocking layer, the light-emitting layer of the sensitized fluorescent OLED device can be made of single, double or three organic materials, and at least one spatial CT state TADF material in the invention is contained therein, and the doping material is a boron-containing compound.

In the present invention, the host material may be composed of a single, double or triple organic material, the triplet energy level (T1) of the first host material being higher than the singlet energy level (S1) of the second host by a difference of more than 0.15eV, preferably more than 0.2 eV. Therefore, the intermolecular spacing between the second host material (also called as a sensitizing material) and the doping material can be enlarged, which is beneficial to reducing or even preventing exciton concentration quenching effect caused by the second host material having higher triplet exciton density, and is also beneficial to reducing the energy transfer of Dexter, improving the utilization rate of excitons and further improving the efficiency of the device.

In the invention, the space CT-state thermal activation delayed fluorescent material (namely, the TADF material in the CT state) is used as a sensitization main body material of a fluorescence sensitization device, has the characteristics of high intersystem crossing speed, high fluorescence quantum yield and strong spectral stability, can more effectively utilize exciton energy, reduces exciton quenching and improves the efficiency and stability of the device.

In the present invention, the TADF material in the space CT state is selected from at least one compound of H-1 to H-362:

in a preferred embodiment of the present invention, in addition to the TADF material in the spatial CT state, the other host material in the luminescent layer may be selected from one or more of the following compounds:

the above compounds were prepared according to CN102870248A, CN105340101B, US20150001488a1, CN104488105A, CN105829320A or commercially available.

In the present invention, the dopant material is a boron-containing fluorescent material, which can be represented by general formula (5) or general formula (6) and their multimers:

in the general formula (5) and the general formula (6),

R₁、R₂、R₃、R₄、R₅、R₆、R₇each independently represents a hydrogen atom, a fluorine atom, C₃-C₁₀Cycloalkyl radical, C₃-C₁₀Heterocycloalkyl radical, C₆-C₆₀Aryl or C₅-C₆₀A heteroaryl group; wherein said C₃-C₁₀-cycloalkyl, C₃-C₁₀Heterocycloalkyl radical, C₆-C₆₀Aryl or C₅-C₆₀Heteroaryl is optionally substituted with the following substituents: deuterium, tritium, halogen, cyano, C₁-C₁₀Alkyl radical, C₁-C₁₀Alkoxy radical, C₆-C₂₀Aryl or C₅-C₂₀A heteroaryl group; and R is₁、R₂、R₃Not simultaneously represented as a hydrogen atom; r₄、R₅、R₆、R₇Not simultaneously represented as a hydrogen atom;

preferably wherein the boron-containing compound is selected from the group consisting of general formula (7) and/or general formula (8) and/or general formula (9) and/or general formula (10) and/or general formula (11) and/or general formula (12) and/or general formula (13) and/or multimers thereof:

in a preferred embodiment of the invention, the doping material comprises one or more compounds of DP-1 to DP-16:

the above compounds were prepared according to CN106905367A, CN110612304A, CN110719914A, CN107501311A, US20200066997a1, CN107619418A, WO2020039930a1, WO2020039708a1 or commercially available.

In the present invention, the doping proportion of the dopant material (boron-containing compound) is 0.1 to 10% by weight based on the total mass of the host and the dopant material in the light-emitting layer. The lower doping proportion can avoid energy loss caused by Dexter energy transfer caused by overhigh concentration of the doping material, thereby improving the efficiency of the device.

Preferably, the doping material is selected from DP-1, DP-2, DP-6, DP-7.

In a more preferred embodiment of the present invention, the TADF material in a spatially CT state in the light-emitting layer is selected from the group consisting of a combination of any one of H-11, H-20, H-319, H-359 and DP-2; a combination of any one of H-1, H-310, H-322, H-325, H362 and DP-6; a combination of any of H-82, H-208 and DP-7; any one of H-180, H-207, H-230, H207 and H-180 with DP-1. FIG. 2 shows the fluorescence emission spectra of H-11, H-20, H-319 and the UV-visible absorption spectrum of the doped material DP-7, FIG. 3 shows the fluorescence emission spectra of H-1, H-82 and the UV-visible absorption spectrum of the doped material DP-6, FIG. 4 shows the fluorescence emission spectra of H-180, H-207 and the UV-visible absorption spectrum of the doped material DP-1, and the fluorescence emission spectra of the TADF material in the spatial CT state and the UV-visible absorption spectrum of the doped material both have better overlap, which shows that there is a good energy transfer effect between the host and the dopant. In the present invention, the preferred, more preferred and most preferred compounds can be used in any combination according to the requirements in the sensitized fluorescent OLED device of the present invention.

When the device is used for forming a full-color display device, in the process of adopting a vacuum deposition process, red (R), green (G) and blue (B) light emitting layers need to be prepared at corresponding positions through the vacuum deposition process by using a light shielding mask plate, but when a spin coating process or a laser induction thermal imaging process is used, patterning through a light shielding mask is not needed.

The thicknesses of the red, green, and blue light emitting layers may be adjusted to optimize light emitting efficiency and driving voltage. The preferred thickness range is 5nm to 50nm, but the thickness is not limited to this range.

Electron transport region

According to the present invention, the electron transport region may include, but is not limited to, a hole blocking layer, an electron transport layer, and an electron injection layer disposed over the light emitting layer in this order from bottom to top.

Electron transport layer

The electron transport layer may be disposed over the light-emitting layer or, if present, the hole blocking layer. The electron transport layer material is a material that easily receives electrons of the cathode and transfers the received electrons to the light emitting layer. Materials with high electron mobility are preferred. As the electron transport layer of the organic electroluminescent device of the present invention, electron transport layer materials for organic electroluminescent devices known in the art can be used, for example, metal complexes of hydroxyquinoline derivatives represented by Alq3, BALq and Liq, various rare earth metal complexes, triazole derivatives, triazine derivatives such as 2, 4-bis (9, 9-dimethyl-9H-fluoren-2-yl) -6- (naphthalen-2-yl) -1, 3, 5-triazine (CAS number: 1459162-51-6), 2- (4- (9, 10-bis (naphthalen-2-yl) anthracen-2-yl) phenyl) -1-phenyl-1H-benzo [ d ] imidazole (CAS number: 561064-11-7, commonly known as ET1), an imidazole derivative, an oxadiazole derivative, a thiadiazole derivative, a carbodiimide derivative, a quinoxaline derivative, a phenanthroline derivative, a silicon-based compound derivative, and the like. The thickness of the electron transport layer of the present invention may be 10 to 80nm, preferably 20 to 60nm, and more preferably 25 to 45nm, but the thickness is not limited to this range.

Electron injection layer

The electron injection layer may be disposed over the electron transport layer. The electron injection layer material is generally a material preferably having a low work function so that electrons are easily injected into the organic functional material layer. As the electron injection layer material of the organic electroluminescent device of the present invention, electron injection layer materials for organic electroluminescent devices known in the art, for example, lithium; lithium salts such as lithium 8-hydroxyquinoline, lithium fluoride, lithium carbonate or lithium azide; or cesium salts, cesium fluoride, cesium carbonate or cesium azide. The thickness of the electron injection layer of the present invention may be 0.1 to 5nm, preferably 0.5 to 3nm, and more preferably 0.8 to 1.5nm, but the thickness is not limited to this range.

A second electrode

The second electrode may be disposed over the electron transport region. The second electrode may be a cathode. The second electrode may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the second electrode is a transmissive electrode, the second electrode may comprise, for example, Li, Yb, Ca, LiF/a1, a1, Mg, BaF, Ba, Ag, or compounds or mixtures thereof; when the second electrode is a semi-transmissive electrode or a reflective electrode, the second electrode may include Ag, Mg, Yb, A1, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/A1, Mo, Ti, or compounds or mixtures thereof.

The full-color organic electroluminescent device of the present invention may be of a top emission type, a bottom emission type, or a dual emission type depending on the materials used.

In the case where the organic electroluminescent device is of a top emission type, the first electrode may be a reflective electrode, and the second electrode may be a transmissive electrode or a semi-transmissive electrode. In the case where the organic electroluminescent device is of a bottom emission type, the first electrode may be a transmissive electrode or a semi-transmissive electrode, and the second electrode may be a reflective electrode.

The OLED is characterized in that the cathode and the anode exist, the electrodes are not all transparent, so that the OLED device is a microcavity and can affect the color and the light-emitting efficiency of light, the effect of the microcavity can be adjusted through the film thickness in the device, and the microcavity adjusting layer or the optical adjusting layer is used for adjusting the light-emitting color and the light-emitting efficiency.

In the process of manufacturing a full-color display device, the organic electroluminescent device of the present invention can be manufactured, for example, by sequentially laminating a first electrode, an organic functional material layer, and a second electrode on a substrate. In this regard, a physical vapor deposition method such as a sputtering method or an electron beam vapor method, or a vacuum evaporation method may be used, but is not limited thereto. Also, the above-mentioned compound can be used to form the organic functional material layer by, for example, a vacuum deposition method, a vacuum evaporation method, or a solution coating method. In this regard, the solution coating method means spin coating, dip coating, jet printing, screen printing, spraying, and roll coating, but is not limited thereto. Vacuum evaporation means that a material is heated and plated onto a substrate in a vacuum environment. In the present invention, it is preferable that the respective layers are formed by a vacuum evaporation method.

The material for forming each layer according to the present invention may be used as a single layer by forming a film alone, may be used as a single layer by forming a film in admixture with another material, or may be used as a laminated structure of layers formed alone, layers formed in admixture with each other, or a laminated structure of layers formed alone and layers formed in admixture with each other.

It is to be understood that there have been disclosed herein exemplary embodiments and, although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purposes of limitation. Unless otherwise indicated, the features, characteristics and/or elements described in connection with a particular embodiment may be used alone or in combination with the features, characteristics and/or elements described in connection with other embodiments.

Examples

The following examples are intended to better illustrate the invention, but the scope of the invention is not limited thereto.

For a clearer understanding of the present invention, the embodiments of the present invention will be described only for each pixel light emitting unit, but those skilled in the art will appreciate that each pixel light emitting unit may use the same hole injection layer and hole transport layer when forming a full-color organic electroluminescent device.

The various materials used in the examples and comparative examples are commercially available or can be obtained by methods known to the person skilled in the art (for example according to the methods in patents JP200056490A, JP2005263634A, JP2001316338A, CN105492574A, CN109314189A, CN105061371B, CN108658953, CN109053698A, CN102870248A, CN105340101B, US20150001488a1, CN104488105A, CN105829320A, CN106905367A, CN110612304A, CN110719914A, CN107501311A, US20200066997a1, CN107619418A, WO2020039930a1, WO2020039708a 1).

First, Synthesis example

Synthesis of intermediate 2-1

Adding 0.01mol of raw material A-1, 0.012mol of raw material B-1 and 100m of 1 toluene in a three-mouth bottle under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain an intermediate 1-1; elemental analysis Structure (molecular formula C)₃₀H₁₈ClNO): theoretical value C, 81.17; h, 4.09; c1, 7.99; n, 3.16; measurement value: c, 81.11; h, 4.12; c1, 7.97; and N, 3.18. LC-MS: measurement value: 444.13([ M + H)](+) of; accurate quality: 443.11.

weighing 0.005mol of intermediate 1-1 in a three-necked bottle under the protection of nitrogen, dissolving in 100ml of tetrahydrofuran, cooling to-78 ℃, adding 4ml of 1.6mol/L n-butyllithium tetrahydrofuran solution into a reaction system, reacting at-78 ℃ for 3h, adding 0.006mol of triisopropyl borate, reacting for 2h, raising the temperature of the reaction system to 0 ℃, adding 8ml of 2mol/L hydrochloric acid solution, stirring for 3h, completely reacting, adding diethyl ether for extraction, adding anhydrous magnesium sulfate into an extract, drying, rotary steaming, passing through a neutral silica gel column to obtain a target product intermediate 2-1; elemental analysis Structure (molecular formula C)₃₀H₂₀BNO₃): theoretical value C, 79.49; h, 4.45; n, 3.09; measurement value: c, 79.41; h, 4.49; and N, 3.12. LC-MS: measurement value: 454.11([ M + H)](+) of; accurate quality: 453.15.

synthesis of intermediate 4-1

Adding 0.01mol of raw material A-1, 0.012mol of raw material C-1 and 100ml of toluene in a three-neck flask under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, and separating the filtrateCarrying out reduced pressure rotary evaporation on the organic phase until no fraction is obtained, and passing through a neutral silica gel column to obtain an intermediate 3-1; elemental analysis Structure (molecular formula C)₃₆H₂₂ClNO): theoretical value C, 83.15; h, 4.26; cl, 6.82; n, 2.69; measurement value: c, 83.18; h, 4.24; c1, 6.84; and N, 2.68. LC-MS: measurement value: 520.22([ M + H)](+) of; accurate quality: 519.14.

weighing 0.005mol of intermediate 3-1 in a three-necked bottle under the protection of nitrogen, dissolving in 100ml of tetrahydrofuran, cooling to-78 ℃, adding 4ml of 1.6mol/L n-butyllithium tetrahydrofuran solution into a reaction system, reacting at-78 ℃ for 3h, adding 0.006mol of triisopropyl borate, reacting for 2h, raising the temperature of the reaction system to 0 ℃, adding 8ml of 2mol/L hydrochloric acid solution, stirring for 3h, completely reacting, adding diethyl ether for extraction, adding anhydrous magnesium sulfate into an extract, drying, rotary steaming, passing through a neutral silica gel column to obtain a target product intermediate 4-1; elemental analysis Structure (molecular formula C)₃₆H₂₄BNO₃): theoretical value C, 81.68; h, 4.57; n, 2.65; measurement value: c, 81.74; h, 4.54; and N, 2.62. LC-MS: measurement value: 530.12([ M + H)](+) of; accurate quality: 529.18.

synthesis of intermediate 5-1

Adding 0.01mol of raw material D-1, 0.012mol of raw material E-1 and 100ml of toluene in a three-neck flask under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain an intermediate 5-1; elemental analysis Structure (molecular formula C)₄₂H₂₈N₂): theoretical value C, 89.97; h, 5.03; n, 5.00; measurement value: c, 89.91; h, 5.06; and N, 5.03. LC-MS: measurement value: 561.31([ M + H)](+) of; accurate quality: 560.23.

synthesis of intermediate 6-1

Adding 0.01mol of raw material F-1, 0.012mol of raw material G-1 and 100ml of toluene in a three-neck flask under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain an intermediate 6-1; elemental analysis Structure (molecular formula C)₃₆H₂₃BrN₂): theoretical value C, 76.73; h, 4.11; n, 4.97; measurement value: c, 76.77; h, 4.14; and N, 4.98. LC-MS: measurement value: 563.11([ M + H ]](+) of; accurate quality: 562.10.

synthesis of Compound H-1

Adding 0.01mol of intermediate 2-1, 0.012mol of raw material F-1 and 100ml of toluene in a three-neck flask under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain a compound H-1; HPLC purity 99.38%, yield 69.9%; elemental analysis Structure (molecular formula C)₄₉H₂₉NO₃): theoretical value C, 86.58; h, 4.30; n, 2.06; measurement value: c, 86.44; h, 4.40; and N, 2.01. LC-MS: measurement value: 680.28([ M + H)](+) of; accurate quality: 679.21.

synthesis of Compound H-20

Adding 0.01mol of intermediate into a three-mouth bottle under the protection of nitrogenStirring and mixing the mixture of 4-1 parts of the precursor, 0.012mol of the raw material G-1 and 100ml of toluene, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain a compound H-20; HPLC purity 99.44%, yield 72.36%; elemental analysis Structure (molecular formula C)₅₅H₃₃NO₃): theoretical value C, 87.40; h, 4.40; n, 1.85; measurement value: c, 87.33; h, 4.46; n, 1.81. LC-MS: measurement value: 756.30([ M + H)](+) of; accurate quality: 755.25.

synthesis of Compound H-320

Adding 0.01mol of intermediate 5-1, 0.012mol of raw material H-1 and 100ml of toluene in a three-neck flask under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain a compound H-320; HPLC purity 99.64%, yield 70.37%; elemental analysis Structure (molecular formula C)₅₅H₃₄N₂O₂): theoretical value C, 87.51; h, 4.54; n, 3.71; measurement value: c, 87.52; h, 4.51; n, 3.73. LC-MS: measurement value: 755.30([ M + H)](+) of; accurate quality: 754.26.

synthesis of Compound H-325

Weighing 0.005mol of intermediate 6-1 in a three-necked bottle under the protection of nitrogen, dissolving in 100ml of tetrahydrofuran, cooling to-78 ℃, adding 4ml of 1.6mol/L n-butyllithium tetrahydrofuran solution into a reaction system, reacting at-78 ℃ for 3h, adding 0.006mol of triisopropyl borate, reacting for 2h, raising the temperature of the reaction system to 0 ℃, adding 8ml of 2mol/L hydrochloric acid solution, stirring for 3h, completely reacting, adding diethyl ether for extraction, adding anhydrous magnesium sulfate into an extract, drying, rotary steaming, passing through a neutral silica gel column to obtain a target product intermediate 7-1;

adding 0.01mol of intermediate 7-1, 0.012mol of raw material I-1 and 100ml of toluene in a three-neck flask under the protection of nitrogen, stirring and mixing, adding a mixed solution of 0.0005mol of Pd (PPh3)4, 0.015mol of potassium carbonate, 10ml of water and 1: 1 of ethanol, stirring and heating to 110 ℃, and carrying out reflux reaction for 24 hours; naturally cooling to room temperature, filtering, layering filtrate, taking an organic phase, carrying out reduced pressure rotary evaporation until no fraction is obtained, and passing through a neutral silica gel column to obtain a compound H-325; HPLC purity 99.12%, yield 68.96%; elemental analysis Structure (molecular formula C)₅₁H₃₃N₅): theoretical value C, 85.57; h, 4.65; n, 9.78; measurement value: c, 85.53; h, 4.66; n, 9.79. LC-MS: measurement value: 716.33([ M + H ]](+) of; accurate quality: 715.27.

the following compounds were prepared in analogy to the procedure of the materials Synthesis example, in which H-82, H-180, H-359, H-362 were prepared according to the synthesis of compound H-1, H-11, H-207, H-208 were prepared according to the synthesis of compound H-20, H-310, H-322 were prepared according to the synthesis of compound H-320, and H-319 was prepared according to the synthesis of compound H-325. The synthetic raw materials used (all provided by Zhongxiao Wangrun) are shown in the following table 1:

TABLE 1

Second, testing the properties of the material

HOMO energy level: the measurement is carried out by an IPS-3 measurement method, and the specific measurement steps are as follows:

vacuum evaporation equipment is used, and the vacuum degree is 1.0E^-5Pressure of PaControlling the evaporation rate to

Evaporating a sample on an ITO substrate, wherein the film thickness is 60-80 nm; the HOMO level of the sample film was then measured using an IPS-3 measuring device under a measurement environment of 10^-2A vacuum environment below Pa.

LUMO energy level: and calculating based on the difference between the HOMO energy level and the Eg energy level.

S1, T1 level:

test S1: sample No. 10^-5Selecting a fluorology-3 series fluorescence spectrometer of Horiba for testing to obtain a fluorescence spectrogram in the toluene solution of M at room temperature, selecting a starting peak position at a short wavelength as a tangent, wherein the corresponding wavelength at the intersection of a base line extension line at the short wavelength is lambda S, and obtaining an S1 value through a formula S1-1240/lambda S;

t1 test: sample No. 10^-5In the toluene solution of M, under the condition of 77K (liquid nitrogen), selecting a Fluorolog-3 series fluorescence spectrometer of Horiba, testing to obtain a phosphorescence spectrogram, selecting a starting peak position at a short-wave position as a tangent, wherein the corresponding wavelength at the intersection of a base line extension line at the short-wave position is lambda T, and obtaining a T1 value through a formula T1-1240/lambda T;

K_RISCand (3) testing:

sample preparation was performed by vacuum evaporation, the sample was doped in mCP at a concentration of 30 wt%,

the evaporation thickness is about 80nm, and after the preparation of the sample is finished, the sample is directly packaged by UV glue glass in a glove box filled with nitrogen; the fluorescence quantum yield is tested by using a Fluorolog-3 series fluorescence spectrometer of Horiba

In the transient fluorescence test, a NanoLED test module is selected to obtain the transient life tau p, the delay life tau d, the transient fluorescence ratio a and the delay fluorescence ratio b, and the formula is used

Obtaining the yield of transient fluorescence quantum by formula

Obtaining the yield of the delayed fluorescence quantum; k is derived from the following equation_RISC：

Table 1-1 shows the test results for each material.

TABLE 1-1

As shown in Table 1-1, the transition rate (K) between the inverses of the TADF material in the spatial CT state according to the present invention_RIST) Higher than 1 x 10⁵(s) and the HOMO and LUMO distributions overlap by less than 20%.

Second, application example-organic electroluminescent device

1. The molecular structural formula of the related material is shown as follows:

device example 1: the organic electroluminescent device was prepared as follows:

(1) using transparent glass as a substrate, coating ITO with the thickness of 150nm on the transparent glass as an anode layer, respectively ultrasonically cleaning the transparent glass with deionized water, acetone and ethanol for 15 minutes, and then treating the transparent glass in a plasma cleaner for 2 minutes;

(2) on the anode layer washed, a hole transport material HT-1 and a P-type dopant P1 were placed in two evaporation sources under a vacuum of 1.0E^-5Under the pressure of Pa, the evaporation rate of HT-1 is controlled to be

The P-type dopant has an evaporation rate of

Co-evaporating to form a hole injection layer with the thickness of 10 nm;

(3) evaporating a hole transport layer on the hole injection layer in a vacuum evaporation mode, wherein the thickness of the hole transport layer is HT-1 and the thickness is 60 nm;

(4) forming an electron blocking layer EB1 on the hole transport layer in a vacuum evaporation mode, wherein the thickness of the electron blocking layer EB1 is 10 nm;

(5) and evaporating a light-emitting layer material, namely a first host material H1-4 and a second host material H-11 on the electron blocking layer in a vacuum evaporation mode, wherein the doping material is DP-2, and the mass ratio is 70: 25: 5, the thickness is 40 nm;

(6) evaporating ET1 and Liq on the light-emitting layer by a vacuum evaporation method, wherein the mass ratio of ET1 to Liq is 50: 50, the thickness is 40nm, and the layer is used as an electron transport layer;

(7) evaporating LiF on the electron transport layer in a vacuum evaporation mode, wherein the thickness of the LiF is 1nm, and the LiF is an electron injection layer;

(8) on top of the electron injection layer, a1 was vacuum evaporated to a thickness of 80nm, which layer was the cathode layer.

Device examples 2-29: the procedure of example 1 was followed and the materials used and experimental parameters in each layer are shown in Table 2 for examples 2-29.

Device comparative examples 1 to 5: the procedure of example 1 was followed, and the materials used and experimental parameters for each layer are shown in Table 2 for comparative examples 1-5. Specific structures of the above-described device examples 1 to 29 and device comparisons 1 to 5 are shown in table 2.

TABLE 2

After the OLED light-emitting device was prepared as described above, the cathode and the anode were connected by a known driving circuit, and various properties of the device were measured. The device measurement performance results of examples 1 to 29 and comparative examples 1 to 5 are shown in table 3.

TABLE 3

The drive voltage, color coordinates (C1Ex and CIEy), external quantum efficiency of the device, and device half-width were tested using an IVL (current-voltage-luminance) test system (florida scientific instruments, su, inc); LT90 refers to the time it takes for the device brightness to decay to 90% of its original brightness; the life test system is an EAS-62C type OLED life test system of Japan scientific research Co.

As can be seen from the results of table 3, the examples of the present invention have higher external quantum efficiency and longer life span than the comparative examples. This shows that, by using the mixture of the host material and the dopant material of the present invention as the material of the light emitting layer, the combination advantageously increases the external quantum efficiency of the device, and prolongs the service life of the device.

To be made intoComparing the efficiency attenuation conditions of different devices at different current densities, and defining the efficiency attenuation coefficient

It was shown that the drive current was 10mA/cm²The ratio between the difference between the efficiency of the device and the maximum efficiency,

the larger the value, the more severe the efficiency roll-off of the device, and conversely, the problem of rapid decay of the device at high current densities is controlled. The efficiency attenuation coefficients were respectively applied to device examples 1 to 29 and device comparative examples 1 to 5

The measurement results are shown in table 4:

TABLE 4

From the data in table 4, it can be seen from the comparison of the efficiency attenuation coefficients of the examples and the comparative examples that the organic light emitting device of the present invention can effectively reduce the efficiency roll-off.

While the invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the described embodiments. But, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The foregoing embodiments are therefore to be considered in all respects illustrative and not restrictive.

Claims

1. A TADF sensitized organic electroluminescent device is characterized by comprising the following components in sequence from bottom to top: a substrate, a first electrode, an organic functional material layer, a second electrode,

the light-emitting layer comprises a host material and a doping material;

the host material comprises one or more organic materials, the host material at least comprises one space CT state TADF material, and the doping material is a boron-containing compound.

2. The TADF sensitized organic electroluminescent device according to claim 1, characterized in that the inter-inversion transition rate (K) of the TADF material in the spatial CT state_RIST) Not less than 1 x 10⁵S; preferably, the transition rate (K) between inverses of the TADF material in the space CT state_RIST) Not less than 1 x 10⁶/s。

3. The TADF-sensitized organic electroluminescent device according to claim 1, characterized in that the HOMO level of the spatially CT-state TADF material is greater than the HOMO level of the boron-containing compound, and the absolute value of the difference between the HOMO level of the spatially CT-state TADF material and the HOMO level of the boron-containing compound is not more than 0.2 eV; and/or the fluorescence emission spectrum of the TADF material in the spatial CT state has an overlap with the ultraviolet-visible absorption spectrum of the boron-containing compound.

4. The TADF-sensitized organic electroluminescent device according to claim 1, characterized in that the triplet level of the spatial CT-state TADF material is greater than the singlet level of the boron-containing compound by not less than 0.15 eV; preferably, the weight ratio of the boron-containing compound/(boron-containing compound and host material) is 0.1% to 10%.

5. The TADF-sensitized organic electroluminescent device according to claim 1, characterized in that said spatially CT-state TADF material has an overlap of HOMO and LUMO distributions based on quantum chemical calculations of less than 20% and has a spatial bridging group, and the structure of said spatially CT-state TADF material is represented by general formula (1)

any substitution site of the general formula (2) and the general formula (4) can be connected with the general formula (1); l in the general formula (3)₁All other sites of (3) can be linked to formula (1);

x is O, S or N-R_a；

Z、Z₁、Z₂Each occurrence, identically or differently, being represented by a nitrogen atom or C-R₀；

R_a、R₀、Ar₄、A_r5Identical or different is hydrogen, deuterium, tritium, substituted or unsubstituted C₃～C₁₀Cycloalkyl, substituted or unsubstituted C₆～C₃₀Aryl of (2), substituted or unsubstituted C₅～C₃₀The heteroaryl group of (a); wherein R's adjacent to each other on the same aromatic ring₀Can be connected into a ring;

L、L₁each represents a single bond, substituted or unsubstituted C₆～C₃₀Arylene of (a), substituted or unsubstituted C₅～C₃₀The heteroarylene group of (a);

6. The TADF-sensitized organic electroluminescent device according to claim 1, characterized in that said boron-containing compound comprises general formula (5) and/or general formula (6) and/or multimers thereof:

in the general formula (5) and the general formula (6),

R₁、R₂、R₃、R₄、R₅、R₆、R₇each independently represents a hydrogen atom, a fluorine atom, C₃-C₁₀Cycloalkyl radical, C₃-C₁₀Heterocycloalkyl radical, C₆-C₆₀Aryl or C₅-C₆₀A heteroaryl group; wherein said C₃-C₁₀Cycloalkyl radical, C₃-C₁₀Heterocycloalkyl radical, C₆-C₆₀Aryl or C₅-C₆₀Heteroaryl is optionally substituted with the following substituents: deuterium, tritium, halogen, cyano, C₁-C₁₀Alkyl radical, C₁-C₁₀Alkoxy radical, C₆-C₂₀Aryl or C₅-C₂₀A heteroaryl group; and R is₁、R₂、R₃Not simultaneously represented as a hydrogen atom; r is₄、R₅、R₆、R₇Not simultaneously represented as hydrogen atoms.

7. The TADF-sensitized organic electroluminescent device according to claim 6, wherein said boron-containing compound is selected from the group consisting of a multimer of formula (7) and/or formula (8) and/or formula (9) and/or formula (10) and/or formula (11) and/or formula (12) and/or formula (13) and/or thereof:

in the general formula (7) and the general formula (8):

or R₈～R₁₈Are optionally bonded to each other and form, together with the a-, b-or c-ring, an aryl or heteroaryl ring; r_23～25And R_28～30Are optionally bonded to each other and together with the g ring and/or the f ring form an aryl or heteroaryl ring; wherein at least one hydrogen in the formed aryl or heteroaryl ring is optionally substituted by aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, or aryloxy; the heteroaryl is preferably isoquinolinyl; the aforementioned alkyl group is preferably C₁-C₆An alkyl group;

X₁、X₂、X₃、X₄、X₅、X₆are respectively and independently represented as O, S, Se, N-R or B-R, and R is C₆-C₁₂Aryl radical, C₂-C₁₅Heteroaryl or C₁-C₆Alkyl radical, said C₆-C₁₂Aryl or C₂-C₁₅At least one hydrogen in the heteroaryl group is optionally substituted by C₁-C₆Alkyl substitution; or said R is optionally through-O-, -S-, -C (-Rg)₂-or a single bond to said a-, b-or C-ring, said Rg being selected from C₁-C₆An alkyl group;

Z₃and Z₄Are each independently aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, aryloxy, heteroaryloxy, arylthio or heteroarylthio, or at least one hydrogen of the above-mentioned groups is optionally substituted by aryl, heteroaryl, alkyl or alkyl-substituted silane groups, or Z₃Optionally through-O-, -S-, -C (-Rb)₂-or a single bond is bonded to said d ring, or Z₄Optionally through-O-, -S-, -C (-Rb)₂-or a single bond is bonded to said e-ring, said-C (-Rb)₂Rb of-is hydrogen or C₁-C₆An alkyl group;

in the general formula (9) and the general formula (10),

X₇、X₈、X₉is represented by O, S, Se, C-R_cWherein Rc of the C-Rc is cyano, C₆-C₃₀Aryl radical, C₆-C₃₀Heteroaryl or C₁-C₆Alkyl radical, said C₆-C₃₀Aryl or C₆-C₃₀Heteroaryl is optionally substituted with: c₁-C₆Alkyl or C₁-C₆Alkoxy, the substituent is preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxyA group, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

R₃₁、R₃₂、R₃₃、R₃₄、R₃₅、R₃₆、R₃₇、R₃₈、R₃₉、R₄₀、R₄₁、R₄₃、R₄₄、R₄₅、R₄₆、R₄₇、R₄₈、R₄₉、R₅₀、R₅₁、R₅₂、R₅₃each independently is hydrogen, deuterium, protium, tritium, fluorine, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, or aryloxy, or at least one hydrogen of these groups is optionally substituted with aryl, heteroaryl, alkyl, or alkoxy; the aforementioned alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or a tert-butyl group; the aforementioned alkoxy group is preferably a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group or an ethylhexyloxy group;

or R₄₃、R₄₄、R₄₅、R₄₆Wherein two adjacent groups are optionally bonded to each other to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group; or R₅₀、R₅₁、R₅₂、R₅₃Wherein two adjacent groups are optionally bonded to each other to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group; c as mentioned above₆-C₃₀Aryl is preferably phenyl; or said C₆-C₃₀Aryl or C₆-C₃₀Heteroaryl is optionally substituted with the following substituents: c₁-C₆Alkyl or C₁-C₆Alkoxy, preferably, said C₁-C₆Alkyl or C₁-C₆Alkoxy is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy;

in the general formula (11) described above,

X₁₀is represented as O, S, Se, N-Rd, and Rd of the N-Rd is C₆-C₁₂Aryl radical, C₂-C₁₅Heteroaryl or C₁-C₆Alkyl radical, R₅₄、R₅₅、R₅₆、R₅₇、R₅₈、R₅₉、R₆₀、R₆₁、R₆₂、R₆₃、R₆₄、R₆₅、R₆₆Each independently is hydrogen, fluoro, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, or aryloxy, or at least one hydrogen of said aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino is optionally substituted with aryl, heteroaryl, or alkyl;

or R₅₉、R₆₀、R₆₁、R₆₂Wherein two adjacent groups are optionally bonded to each other to form a ring, or R₆₃、R₆₄、R₆₅、R₆₆Wherein two adjacent groups are optionally bonded to each other to form a ring; said ring is preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group; or said C₆-C₃₀Aryl or C₆-C₃₀Heteroaryl is optionally substituted with the following substituents: phenyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, or tert-butoxy;

in the general formula (12) and the general formula (13),

X₁₁y independently represent-O-, -S-or-N (Re) -, Re is same or different and is independently selected from hydrogen atomCyano, C₁-C₂₀Alkyl radical, C₂-C₂₀Alkylene radical, C₆-C₃₀Aryl, or C containing one or more hetero atoms₂-C₃₀A heteroaryl group;

or said R_eTo adjacent Z₅Bonded to form a ring, preferably C₆-C₃₀Aryl or C₆-C₃₀A heteroaryl group;

or C above₁-C₂₀Alkyl radical, C₂-C₂₀Alkylene group, C₆-C₃₀Aryl, C containing one or more hetero atoms₂-C₃₀Heteroaryl group, C₆-C₃₀Heteroaryl or C₁₄-C₄₀Aryl is optionally substituted with the following substituents: deuterium atom, tritium atom, cyano group, halogen atom, C₁-C₁₀Alkyl radical, C₆-C₃₀Aryl radical, C₂-C₃₀A heteroaryl group.

8. The TADF sensitized organic electroluminescent device according to any one of claims 1 to 7, characterized in that the TADF material having a spatial CT state is selected from one or more of the following compounds:

9. the TADF-sensitized organic electroluminescent device according to any one of claims 1 to 7, characterized in that said boron-containing compound is selected from at least one of the following compounds:

10. a full-color display device comprising three pixels of red, green and blue, wherein the full-color display device pixel region comprises the sensitized organic electroluminescent device according to any one of claims 1 to 9.