JP2023540114A - Organic electroluminescent devices and display devices - Google Patents

Abstract

It belongs to the technical field of organic electroluminescence and relates to organic electroluminescence devices and display devices. The organic electroluminescent device includes an organic emissive layer, the organic emissive layer includes a host material and a doping dye, the host material is a wide bandgap material, the emissive layer includes a phosphorescent sensitizer, and a resonant dye. It consists of a host luminescent material containing a thermally activated delayed fluorescent material guest doping. The device according to the present invention adopts the method of co-doping the host with phosphorescent material and resonant thermally activated delayed fluorescent material, achieving 100% exciton utilization, and the manufactured OLEDs have high efficiency and low roll-off. It has the characteristics of [Selection diagram] Figure 1

Description

The present invention relates to an organic electroluminescent device and a display device, and specifically relates to an organic electroluminescent device that uses a phosphorescent material to sensitize thermally activated delayed fluorescence, which is a phosphorescent material, and belongs to the technical field of organic electroluminescence.

Organic Light Emitting Diode (OLED) is a device that achieves the purpose of emitting light by current drive, and its main characteristics are derived from the organic light emitting layer, when an appropriate voltage is applied. The electrons and holes combine in the organic light-emitting layer to generate excitons, and light of various wavelengths is emitted depending on the characteristics of the organic light-emitting layer. At present, the emissive layer consists of a host material and a doping dye, and the dye is mainly selected from conventional fluorescent and phosphorescent materials or Thermally Activated Delayed Fluorescence (TADF) materials.

Specifically, conventional fluorescent materials have the disadvantage of not being able to utilize triplet excitons, whereas phosphorescent materials introduce heavy metal atoms such as iridium or platinum to achieve the transition from singlet excitons to triplet states. However, phosphorescent materials cannot be the first choice for dyes because heavy metals such as iridium and platinum are extremely rare, expensive, and easy to cause environmental pollution. .

Thermally Activated Delayed Fluorescence (TADF) materials exhibit a reverse intersystem jump from triplet excitons to singlet states by absorbing environmental heat, compared to phosphorescent and conventional fluorescent materials. By realizing this and emitting fluorescence from the singlet state, 100% utilization of excitons can be realized without any heavy metals. Therefore, currently, 100% energy usage efficiency is achieved mainly by doping host materials into TADF materials. The transition to the singlet state, and the singlet excitons fluoresce back to the ground state, achieves 100% utilization of excitons without any heavy metals. Currently, higher luminous efficiency is mainly achieved by doping host materials into TADF materials. However, most TADF materials themselves also have certain deficiencies, such as too broad an emission spectrum, high device roll-off, and short lifetime.

To solve the above technical problems, the present invention provides an organic electroluminescent device that uses a phosphorescent material to sensitize a thermally activated delayed fluorescent material. Such an organic electroluminescent device of the present invention adopts a method of co-doping mainly with a phosphorescent material and a resonant thermally activated delayed fluorescent material, and achieves a 100% exciton utilization rate, and provides high efficiency to the manufactured OLEDs. It has the characteristics of efficiency and low roll-off.

The present invention includes a substrate, a first electrode, a second electrode, and an organic functional layer, the organic functional layer includes an organic light-emitting layer, and the organic light-emitting layer includes an organic electrolyte containing a host material and a light-emitting dye. providing a luminescent device, the emissive layer comprising a luminescent host material, a phosphorescent sensitizer, and a resonant thermally activated delayed fluorescent material used as a luminescent dye;

The triplet energy level of the host material in the emissive layer is higher than the triplet energy level of the phosphorescent sensitizer, and the triplet energy level of the host material is also higher than the triplet energy level of the resonant thermally activated delayed fluorescent material. higher than the energy level,

The triplet energy level of the phosphorescent sensitizer is higher than the triplet energy level of the resonant thermally activated delayed fluorescent material, and the HOMO energy level of the phosphorescent sensitizer is higher than the triplet energy level of the resonant thermally activated delayed fluorescent material. deeper than the HOMO energy level of

The resonant thermally activated delayed fluorescent material is a compound whose core structure uses a boron atom and/or a carbonyl group to form a resonant molecular structure with a nitrogen atom and/or an oxygen atom, respectively, and the singlet energy level of the compound is (S1) and triplet energy level (T1) satisfy the following formula,
ΔEst=S1-T1≦0.4eV,
The Stokes shift of the compound satisfies λ≦60 nm.

Specifically, in the organic electroluminescent device of the present invention, the resonant thermally activated delayed fluorescent material is selected from the structure shown in the following formula (1) or formula (2),

In formulas (1) and (2), ring A, ring B, ring C, and ring D each independently represent a C5 to C20 monocyclic aromatic ring or a fused aromatic ring, or a C4 to C20 monocyclic ring. represents either a heterocycle or a fused heterocycle,

In formula (2), ring E represents a C5 to C20 aromatic ring, the ring A and the ring B can be connected by a single bond, and the ring C and the ring D can be connected by a single bond. , can be connected by single bonds,

In formula (1), Y ¹ and Y ² are each independently N or B, and X ¹ , X ² , X ³ and X ⁴ are each independently NR ₁ or BR ₂ , and both Y ¹ and Y ² are N, X ¹ , X ² , X ³ and X ⁴ are all BR ₂ ,

In formula (2), Y ¹ and Y ² are each independently N or B, and X ¹ , X ² , X ³ and X ⁴ are each independently NR ₁ , BR ₂ , O or S and both Y ¹ and Y ² are B, then X ¹ , X ² , X ³ and X ⁴ are not NR ₁ at the same time,

In formulas (1) and (2), R ₁ is each independently linked to adjacent ring A, ring B, ring C, or ring D to form a ring, or not linked to each other. and are connected by a single bond when connected to form a ring, and each R ₂ is independently connected to adjacent ring A, ring B, ring C, or ring D. to form a ring, or to form a ring without being linked, or to be connected by a single bond when linked to form a ring, and the R ₁ and R ₂ are each independently substituted or unsubstituted, selected from a C6-C60 monocyclic aryl group, a C6-C60 fused ring aryl group, a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group, and When a substituent exists on R ¹ and R ² , the substituent is each independently deuterium, halogen, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 alkoxy group, cyano group, C6 to C30 arylamino group, C3 to C30 heteroarylamino group, C6 to C60 monocyclic aryl group, C6 to C60 fused ring aryl group, C6 to C60 aryloxy group, C5 to selected from any one of a C60 monocyclic heteroaryl group, a C5 to C60 fused ring heteroaryl group,

In formula (1 ⁾ and formula (2), the sum of R ^a , R ^b , and R ^c each independently represents the maximum possible substituent from a single substituent, and each independently, Hydrogen, deuterium, or halogen, substituted or unsubstituted C1 to C36 chain alkyl group, substituted or unsubstituted C3 to C36 cycloalkyl group, C1 to C10 alkoxy group, cyano group, C6 to C30 aryl Amino group, C3-C30 heteroarylamino group, substituted or unsubstituted C6-C60 monocyclic aryl group, C6-C60 fused ring aryl group, C6-C60 aryloxy group, C5-C60 monocyclic group When a substituent is selected from a heteroaryl group, a C5-C60 condensed ring heteroaryl group, and a trimethylsilicon group, and there is a substituent on the above R ^a , R ^b , R ^c and R ^d , the substituent are each independently selected from any one of a halogen, a C1 to C30 chain alkyl group, a cyano group, and a C6 to C60 monocyclic aryl group,

Preferably, in formulas (1) and (2), the ring A, ring B, ring C, and ring D each independently represent a C5 to C10 monocyclic aromatic ring or a fused aromatic ring, or a C4 to C10 More preferably, the ring A, ring B, ring C and ring D each independently represent a benzene ring, a naphthalene ring or a fluorene ring. Selected from either one.

Alternatively, in the organic electroluminescent device of the present invention, the resonant thermally activated delayed fluorescent material is selected from a structure as shown in the following formula (3) or formula (4),

In formula (3) and formula (4),

The R ²¹ to R ³¹ are each independently hydrogen, deuterium, substituted or unsubstituted halogen, a C1 to C30 chain alkyl group, a C3 to C30 cycloalkyl group, or a C1 to C10 alkoxy group. , C1 to C10 thioalkoxy group, carbonyl group, carboxyl group, nitro group, cyano group, amino group, C6 to C30 arylamino group, C3 to C30 heteroarylamino group, C6 to C60 monocyclic aryl group, selected from a C6-C60 fused ring aryl group, a C6-C60 aryloxy group, a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group, R ²¹ to R The two adjacent groups in ³¹ can be bonded to each other, and together with the adjacent benzene ring, one of a C5 to C30 5- or 6-membered aryl ring or a C5 to C30 5- or 6-membered heteroaryl ring can be bonded to each other. At least one hydrogen of the formed ring is a C6 to C30 arylamino group, a C3 to C30 heteroarylamino group, a C6 to C60 monocyclic aryl group, a C6 to C60 fused ring aryl group, a C6 to C60 fused ring aryl group, or a C6 to C60 fused ring aryl group. ~C60 aryloxy group, C5 to C60 monocyclic heteroaryl group, C5 to C60 fused ring heteroaryl group, halogen, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 can be substituted with any one of an alkoxy group, a C1 to C10 thioalkoxy group, a carbonyl group, a carboxyl group, a nitro group, a cyano group, and an amino group,

The X ⁵ , X ⁶ , X ⁷ and X ⁸ are each independently selected from NR, and the R is -O-, -S-, -C(-R')2- or through a single bond. R and R' each independently represent a substituted or unsubstituted C1-C30 chain alkyl group, C3-C30 cycloalkyl group, C1-C30 halogenated alkyl group, C1-C30 alkoxy group, C2-C30 alkenyl group, C3-C30 alkynyl group, C6-C60 monocyclic aryl group, C6-C60 fused ring aryl group, C6-C60 selected from an aryloxy group, a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group,

In formula (3), ring F represents a group ^{simultaneously} condensed to a six-membered ring structure consisting of B and X ⁵ and B and selected from one of a C60 monocyclic nitrogen heteroaromatic ring, a substituted or unsubstituted C5-C60 fused nitrogen heteroaromatic ring,

When a substituent exists in the above group, the substituent is each independently deuterium, halogen, cyano group, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 cycloalkyl group, selected from one of an alkoxy group, a C6-C30 arylamino group, a C3-C30 heteroarylamino group, a C6-C30 aryl group, a C3-C30 heteroaryl group,

Preferably, in formula (3), ring F represents one of a substituted or unsubstituted C13-C60 monocyclic nitrogen heteroaromatic ring, a substituted or unsubstituted C13-C60 fused nitrogen heteroaromatic ring,

Preferably, in formula (3) and formula (4), R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ are each independently Hydrogen, deuterium, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 2-methylbutyl group, n-pentyl group, s-pentyl group, cyclopentyl group, neopentyl group, n-hexyl group, cyclohexyl group, neohexyl group, n-heptyl group, cycloheptyl group, n-octyl group, cyclooctyl group, 2-ethylhexyl group, trifluoromethyl group, Pentafluoroethyl group, 2,2,2-trifluoroethyl group, phenyl group, naphthyl group, anthranyl group, benzanthranyl group, phenanthrenyl group, benzophenanthrenyl group, pyrenyl group, chrysene group, perylene group, fluoran thenyl group, tetracenyl group, pentacenyl group, benzopyrenyl group, biphenyl group, diphenyl group, terphenyl group, trimerized phenyl group, quarterphenyl group, fluorenyl group, spirobifluorenyl group, dihydrophenanthrenyl group, Dihydropyrenyl group, tetrahydropyrenyl group, trans or cis indenofluorenyl group, trimerized indenyl group, isotrimerized indenyl group, spirotrimerized indenyl group, spiroisotrimerized indenyl group, furyl group, benzofuryl group, isobenzofuryl group, dibenzofuryl group, thienyl group, benzothienyl group, isobenzothienyl group, dibenzothienyl group, pyrrolyl group, isoindolyl group, carbazolyl group, indenocarbazolyl group, pyridyl group, quinolinyl group group, isoquinolinyl group, acridinyl group, phenanthridinyl group, benzo-5,6-quinolinyl group, benzo-6,7-quinolinyl group, benzo-7,8-quinolinyl group, pyrazolyl group, indazolyl group, imidazolyl group, Benzimidazolyl group, naphthoimidazolyl group, phenanthroimidazolyl group, pyridinoimidazolyl group, pyrazinoimidazolyl group, quinoxalinoimidazolyl group, oxazolyl group, benzoxazolyl group, naphthoxazolyl group, anthraoxazolyl group, Phenanthrooxazolyl group, 1,2-thiazolyl group, 1,3-thiazolyl group, benzothiazolyl group, pyridazinyl group, benzopyridazinyl group, pyrimidinyl group, benzopyrimidinyl group, quinoxalyl group, 1,5-dia Zanthranyl group, 2,7-diazapyrenyl group, 2,3-diazapyrenyl group, 1,6-diazapyrenyl group, 1,8-diazapyrenyl group, 4,5-diazapyrenyl group, 4,5,9,10-tetraazapyrenyl group group, pyrazinyl group, phenazinyl group, phenothiazinyl group, naphthyridinyl group, azacarbazolyl group, benzocarbonyl group, phenanthrolinyl group, 1,2,3-triazolyl group, 1,2,4-triazolyl group, benzotriazolyl group group, 1,2,3-oxadiazolyl group, 1,2,4-oxadiazolyl group, 1,2,5-oxadiazolyl group, 1,2,3-thiadiazolyl group, 1,2,4-thiadiazolyl group, 1,2 ,5-thiadiazolyl group, 1,3,4-thiadiazolyl group, 1,3,5-triazinyl group, 1,2,4-triazinyl group, 1,2,3-triazinyl group, tetrazolyl group, 1,2,4 , 5-tetraazinyl group, 1,2,3,4-tetraazinyl group, 1,2,3,5-tetraazinyl group, purinyl group, pteridyl group, indolizinyl group, benzothiadiazolyl group, 9,9-dimethylacridinyl group or a combination of two of the aforementioned groups.

Alternatively, in the organic electroluminescent device of the present invention, the resonant thermally activated delayed fluorescent material has a structure represented by any one of the following formulas (5), (6), or (7). selected from

In formula (5), formula (6), and formula (7), the above R ¹ , R ³ , R ⁴ , R ^{6 , R 7 ,} R ⁹ , R 10 , R ¹² , R ¹³ , R ¹⁴ , R ^{15 ,} R ¹⁷ , R ¹⁸ , R ²⁰ , R ²² and R ²³ are each independently hydrogen, deuterium, substituted or unsubstituted halogen, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 alkoxy group, C1 to C10 thioalkoxy group, carbonyl group, carboxyl group, nitro group, cyano group, amino group, C6 to C30 arylamino group, C3 to C30 heteroarylamino group, C6- One group in a C60 monocyclic aryl group, a C6-C60 fused ring aryl group, a C6-C60 aryloxy group, a C5-C60 monocyclic heteroaryl group, or a C5-C60 fused ring heteroaryl group R ² , R ⁵ , R ⁸ , R ¹¹ , R ¹⁶ , and R ¹⁹ are each independently a hydrogen atom, or a substituted or unsubstituted methyl group, ethyl group, n-propyl group, Isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 2-methylbutyl group, cyclohexyl group, fluorine atom, trifluoromethyl group, cyano group, t-butylbenzene, methylphenyl group, phenyl group, triarylamine group, carbazolyl group, pyridyl group, furyl group, benzofuryl group, isobenzofuryl group, dibenzofuryl group, thienyl group, benzothienyl group, isobenzothienyl group, dibenzothienyl group, adamantane, tetrahydropyrrole group, R 21 is selected from substituents such as piperidine, silicon group, methoxy group, 9,9-dimethylacridinyl group, phenothiazinyl group, phenoxazinyl group, imidazolyl group, carbazolofuran, etc., and R ²¹ is hydrogen, fluorine, or cyano group. , or substituted or unsubstituted pyridyl group, phenyl group, fluorophenyl group, methylphenyl group, trimethylphenyl group, cyano phenyl group, trifluoromethyl group, triarylamine group, methyl group, ethyl group, n-propyl group group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 2-methylbutyl group, cyclohexyl group, adamantane, tetrahydropyrrole group, piperidine, silicon group, methoxy group, 9,9-dimethyl Substituents selected from acridinyl group, phenothiazinyl group, phenoxazinyl group, imidazolyl group, carbazolofuran, triarylamine group, carbazolyl group, fluorine atom, trifluoromethyl group, cyano group, pyridyl group, furyl group, etc. ,

When a substituent exists in the above group, the substituent is each independently deuterium, halogen, cyano group, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 cycloalkyl group, It is selected from one of an alkoxy group, a C6-C30 arylamino group, a C3-C30 heteroarylamino group, a C6-C30 aryl group, and a C3-C30 heteroaryl group.

The resonant thermally activated delayed fluorescent materials described in formulas (1) and (2) above can be preferably selected from the following specific structural compounds, and these compounds are representative Only things.

The resonant thermally activated delayed fluorescent materials described in formulas (3) and (4) above can be preferably selected from the following specific structural compounds, and these compounds are representative Only things.

本発明の有機エレクトロルミネッセンスデバイスにおいて、前記発光層中の燐光増感剤は、次の化合物から選択されることができる。

The resonance type thermally activated delayed fluorescent material described in the above formula (5), formula (6) or formula (7) can be preferably selected from the following specific structural compounds, and these compounds are only representative ones.

In the organic electroluminescent device of the present invention, the phosphorescent sensitizer in the light emitting layer can be selected from the following compounds.

In the organic electroluminescent device of the present invention, the host material contains at least one of a carbazolyl group, a carbolinyl group, a spirofluorenyl group, a fluorenyl group, a silicon group, and a phosphineoxy group.
The present invention does not limit the specific structure of the host material, and may not be limited to compounds shown in any one of the following structures.

In the present specification, the "substituted or unsubstituted" group may be substituted with one substituent or with multiple substituents, and when there are multiple substituents, different substituents may be substituted. Where the same expressions are concerned in the present invention, they have the same meaning and the selection ranges of substituents are all as stated above and will not be repeated here. In this specification, the expression Ca to Cb indicates that the number of carbon atoms in the group is a to b, and unless otherwise specified, the number of carbon atoms in the substituent is generally the same as the number of carbon atoms in the substituent. does not include the number of
As used herein, "independently" means that when there are multiple subjects, they may be the same or different.

As used herein, the substituted or unsubstituted C6-C60 aryl group includes a monocyclic aryl group and a fused ring aryl group, preferably a C6-C30 aryl group, more preferably a C6-C20 aryl group. The so-called monocyclic aryl group refers to a molecule containing at least one phenyl group, and when the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and connected by a single bond, Examples are phenyl, biphenyl, terphenyl, etc. Specifically, the biphenyl group includes 2-biphenyl group, 3-biphenyl group, and 4-biphenyl group, and the terphenyl group includes p-terphenyl-4-yl, p-terphenyl-3-yl , p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl. A fused ring aryl group refers to a group in which at least two aromatic rings are included in the molecule, and the aromatic rings are not independent of each other but share two adjacent carbon atoms and are fused to each other. Examples include naphthyl, anthracenyl, phenanthrenyl, indenyl, fluorenyl, fluoranthenyl, triphenylene, pyrenyl, perylene, chrysene, tetracene and derivatives thereof. The naphthyl group includes a 1-naphthyl group or a 2-naphthyl group, the anthracenyl group is selected from a 1-anthracenyl group, a 2-anthracenyl group and a 9-anthracenyl group, and the fluorenyl group includes a 1-fluorenyl group, selected from 2-fluorenyl group, 3-fluorenyl group, 4-fluorenyl group and 9-fluorenyl group, said pyrenyl group is selected from 1-pyrenyl group, 2-pyrenyl group and 4-pyrenyl group, and said tetracene is selected from 1-tetracene, 2-tetracene and 9-tetracene. The fluorene derivative groups include 9,9-dimethylfluorenyl group, 9,9-diethylfluorenyl group, 9,9-dipropylfluorenyl group, 9,9-dibutylfluorenyl group, 9, 9-dipentylfluorenyl group, 9,9-dihexylfluorenyl group, 9,9-diphenylfluorenyl group, 9,9-dinaphthylfluorenyl group, 9,9'-spirobifluorene and benzofluene selected from olenyl groups.

C3-C60 heteroaryl groups referred to herein include monocyclic heteroaryl groups and fused ring heteroaryl groups, preferably C3-C30 heteroaryl groups, more preferably C4-C20 heteroaryl groups, more preferably contains a C5-C12 heteroaryl group. A monocyclic heteroaryl group refers to a molecule containing at least one heteroaryl group, where the molecule contains one heteroaryl group and another group (e.g., aryl group, heteroaryl group, alkyl group, etc.). When included, the heteroaryl group and other groups are independent of each other and connected by a single bond, and examples of the monocyclic heteroaryl group include furyl group, thienyl group, pyrrolyl group, pyridyl group, etc. be able to. A fused ring heteroaryl group is a fused ring heteroaryl group that contains at least one aromatic heterocycle and one aromatic ring (aromatic heterocycle or aromatic ring) in the molecule, and the two are not independent of each other but are formed by two adjacent atoms. This means that they share a group that is fused with each other. Examples of fused ring heteroaryl groups include benzofuryl, benzothienyl, isobenzofuryl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl, acridinyl, isobenzofuryl, isobenzothienyl, and benzofuryl. Examples include carbazolyl group, azacarbazolyl group, phenothiazinyl group, phenazinyl group, 9-phenylcarbazolyl group, 9-naphthylcarbazolyl group, dibenzocarbazolyl group, indolocarbazolyl group, etc. .

As used herein, said heteroatom generally refers to an atom or group of atoms selected from N, O, S, P, Si and Se, preferably N, O, S. Examples of the halogen include fluorine, chlorine, bromine, and iodine.

The present invention provides an application of such an organic electroluminescent device of the invention as described above, said application being an application in an organic electronic device, said organic electronic device being an optical sensor, a solar cell, a lighting element, an organic Including thin film transistors, organic field effect transistors, organic thin film solar cells, information labels, electronic artificial skin sheets, sheet scanners or electronic paper.

The present invention simultaneously protects a display device comprising the above organic electroluminescent device of the present invention, said display device including, but not limited to, a display element, a lighting element, an information label, an electronic artificial skin sheet or an electronic paper. Not done.

In the organic electroluminescent device of the present invention, the emissive layer comprises an emissive host material, a phosphorescent sensitizer, and a resonant thermally activated delayed fluorescent material used as a luminescent dye, and the resonant thermally activated delayed fluorescent material comprises: It is a compound whose core structure uses a boron atom and/or a carbonyl group to form a resonant molecular structure with a nitrogen atom and/or an oxygen atom, respectively, and the singlet energy level (S1) of a resonant thermally activated delayed fluorescent material. The triplet energy level (T1) can satisfy the formula: ΔEst=S1−T1≦0.4 eV, and the Stokes shift of the resonant thermally activated delayed fluorescent material can satisfy λ≦60 nm. In the organic electroluminescent device of the present invention, it is particularly preferable to use a resonant thermally activated delayed fluorescent material having the above-mentioned specific structures such as the general formulas (1) to (7) of the present invention. After the organic electroluminescent device of the present invention is electrically excited, the external heavy atom effect of the phosphorescent sensitizer can be used to directly enhance the inverse intersystem crossing rate of the MR-TADF dye, or The triplet state of the dye can be converted to the triplet state of the phosphorescent sensitizer, and the triplet state of the phosphorescent sensitizer is further upconverted to the singlet state of the MR-TADF dye, and finally the MR- It also enhances the inverse intersystem crossing rate of the TADF dye. Therefore, the present invention can effectively solve the serious roll-off problem of MR-TADF devices under high brightness and effectively enhance the stability of organic electroluminescent devices. Moreover, after the organic electroluminescent device of the present invention is electrically excited, the phosphorescent sensitizer can capture high-energy triplet excitons, and its external heavy atom effect causes the triplet excitons of the phosphorescent sensitizer to The term exciton can rapidly transfer to the singlet state and triplet state of the MR-TADF dye, and at the same time can also directly enhance the reverse intersystem crossing rate of the MR-TADF dye, so the triplet exciton The concentration is significantly reduced, resulting in low efficiency roll-off and long lifetime of MR-TADF devices. Reference is made to FIG. 1 for a schematic diagram of the light emitting mechanism in the light emitting layer in the organic electroluminescent device of the present invention.

FIG. 2 is a diagram of the light emission mechanism of the organic electroluminescent device of the present invention, where FET is Forster energy transfer, DET is Dexter energy transfer, ISC is intersystem crossing, and RISC is inverse intersystem transfer. It is an intersection. FIG. 1 is a schematic structural diagram of an organic electroluminescent device manufactured in an example of the present invention.

As shown in FIG. 2, the organic electroluminescent device of the present invention includes an anode 2, a hole transport region 3, an organic light emitting layer 4, an electron transport region 5, and a cathode 6, which are sequentially deposited on a substrate 1.

Specifically, the substrate can be made of glass or polymeric materials that have excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin film transistors (TFTs) can also be provided on the substrate used as a display.

The anode can be formed by sputtering or depositing an anode material on the substrate, where the anode material is indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2). , oxide transparent conductive materials such as zinc oxide (ZnO), and any combination thereof can be used; the cathode can be made of magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium ( Metals or alloys such as Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof can be used.

The hole transport region, the light emitting layer, the electron transport region and the organic material layer of the cathode can be sequentially fabricated on the anode by methods such as vacuum thermal evaporation, spin coating, printing, etc. Here, the compounds used as the organic material layer can be small organic molecules, organic macromolecules and polymers, and combinations thereof.

The hole transport region 3, electron transport region 5, and cathode 6 of the present invention will be introduced. The hole transport region 3 is located between the anode 2 and the organic light emitting layer 4. The hole transport region 3 may be a hole transport layer (HTL) with a single layer structure, including a single hole transport layer containing only one compound and a single hole transport layer containing multiple compounds. The hole transport region 3 may have a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron block layer (EBL).

The material of the hole transport region 3 (including HIL, HTL and EBL) may be, for example, a phthalocyanine derivative such as CuPc, polyphenylene vinylene, polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), poly(3,4-ethylenedioxy Conductivity of polyaniline/poly(4-styrene sulfonate) (Pani/PSS), aromatic amine derivatives, etc. It can be selected from, but not limited to, polymers or polymers containing conductive dopants.

Here, the aromatic amine derivatives are compounds shown in the following HT-1 to HT-34. When the material of the hole transport region 3 is an aromatic amine derivative, it may be one or more of the compounds shown in HT-1 to HT-34.

The hole injection layer is located between the anode 2 and the hole transport layer. The hole injection layer may be made of a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of the above HT-1 to HT-3, or one or more compounds of the following HI1 to HI3, -34 can also be used to dope one or more of the following HI1 to HI3 compounds.

The electron transport region 5 may be a single-layer electron transport layer (ETL) including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing a plurality of compounds. The electron transport region 5 may have a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

In one embodiment of the present invention, the electron transport layer material can be selected from one or more combinations of ET-1 to ET-57 listed below, but is not limited thereto.

The structure of the light emitting device may include an electron injection layer located between the electron transport layer and the cathode 6, and the electron injection layer material may be LiQ, LiF, NaCl, CsF, _Li2O , _{Cs2CO3 ,} including but not limited to combinations of one or more of BaO, Na, Li, Ca.
The thickness of each of the above layers can be any conventional thickness of these layers in the art.

The light emitting layer will be introduced in detail below. When manufacturing the organic emissive layer 4, the organic emissive layer 4 is formed by codepositing a source of wide bandgap host material, a source of TADF dye and a source of phosphorescent sensitizer material.
Hereinafter, the organic electroluminescent device of the present invention will be further introduced through specific examples.
The method for manufacturing an organic electroluminescent device of the present invention includes the following steps.

1. The glass plate coated with anode material was sonicated with a commercial cleaning agent, rinsed with deionized water, ultrasonic deoiled with an acetone:ethanol mixed solvent, baked in a clean environment to completely remove moisture, and then exposed to ultraviolet light. Clean with light and ozone and bombard the surface with a low-energy positive ion beam.

2. The above glass plate with an anode was placed in a vacuum cavity, the vacuum was evacuated to 1×10 ⁻⁵ to 9×10 ⁻³ Pa, and a hole injection layer was deposited on the above anode layer at a vapor deposition rate of 0.1 to 0.5 nm. Vacuum deposition is performed at /s.
3. A hole transport layer is vacuum deposited on the hole injection layer at a deposition rate of 0.1 to 0.5 nm/s.

4. A light emitting layer containing a device host material, a TADF dye, and a phosphorescent sensitizer is vacuum deposited on the hole transport layer. Using the method of multi-source co-deposition, the deposition rate of the host material, the deposition rate of the TADF dye and the phosphorescent sensitizer material are adjusted to achieve a preset doping ratio of the dye.
5. The electron transport layer material of the device is vacuum deposited on the organic light emitting layer at a deposition rate of 0.1 to 0.5 nm/s.
6. LiF is vacuum deposited on the electron transport layer as an electron injection layer at a rate of 0.1 to 0.5 nm/s, and an Al layer is vacuum deposited as a cathode of the device at a rate of 0.5 to 1 nm/s.
The structural formulas of some organic materials used in examples of the invention are as follows.

Example 1
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)

Here, the anode is ITO, the material of the hole injection layer is HI-2, the general total thickness is 5-30 nm, in this example it is 10 nm, and the hole injection layer is HI-2. The material of the transport layer is HI-27, the total thickness is generally 5-500 nm, in this example 40 nm, and the host material of the organic emissive layer is the wide bandgap material W-7. The phosphorescent sensitizer material is PH-3 and the doping concentration is 10 wt%, the dye is the resonant TADF material MR-82 and the doping concentration is 1 wt%, and the organic light emitting layer The thickness is generally 1 to 200 nm, and in this example, it is 30 nm, the material of the electron transport layer is ET-53, and the thickness is generally 5 to 300 nm, and in this example, 30 nm, and the electron injection layer and cathode materials are LiF (0.5 nm) and metal aluminum (150 nm).

According to the above manufacturing steps and testing methods, device Examples 1 to 55 and Comparative Examples 1 to 9 of the present invention were completed, and for the specific design scheme of the light emitting layer, refer to the following Examples and Table 1.
Example 2
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-67: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, the only difference being that the phosphorescence sensitizer is different.
Example 3
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-5: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, the only difference being that the phosphorescence sensitizer is different.
Example 4
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-3: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The meaning of the device is almost the same as in Example 1, the only difference being that the host is different.
Example 5
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-67: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 4, the only difference is that the phosphorescence sensitizer is different.
Example 6
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-5: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 4, the only difference is that the phosphorescence sensitizer is different.
Example 7
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-19: 10wt% PH-3: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The meaning of the device is almost the same as in Example 1, the only difference being that the host is different.
Example 8
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-67:1wt%MR-82(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 7, the only difference is that the phosphorescence sensitizer is different.
Example 9
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-19: 10wt% PH-5: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 7, the only difference is that the phosphorescence sensitizer is different.
Example 10
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, and the only difference is that the type of resonant thermally activated delayed fluorescent material is different.
Example 11
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-7:10wt%PH-67:1wt%MR-802(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 10, the only difference being that the phosphorescence sensitizer is different.
Example 12
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-5: 1wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 10, the only difference being that the phosphorescence sensitizer is different.
Example 13
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-3: 1wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 10, the only difference being that the host is different.
Example 14
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-1:10wt%PH-67:1wt%MR-802(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 13, the only difference being that the phosphorescence sensitizer is different.
Example 15
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-5: 1wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 13, the only difference being that the phosphorescence sensitizer is different.
Example 16
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-3:1wt%MR-802(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 10, the only difference being that the host is different.
Example 17
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-67:1wt%MR-802(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 16, the only difference being that the phosphorescence sensitizer is different.
Example 18
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-5:1wt%MR-802(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 16, the only difference being that the phosphorescence sensitizer is different.
Example 19
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, and the only difference is that the type of resonant thermally activated delayed fluorescent material is different.
Example 20
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-7:10wt%PH-67:1wt%MR-1217(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 19, the only difference being that the phosphorescent sensitizer is different.
Example 21
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-5: 1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 19, the only difference is that the phosphorescence sensitizer is different.
Example 22
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-3: 1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The meaning of the device is almost the same as in Example 19, the only difference being that the host is different.
Example 23
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-67: 1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 22, the only difference being that the phosphorescent sensitizer is different.
Example 24
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-5: 1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 22, the only difference being that the phosphorescent sensitizer is different.
Example 25
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-3:1wt%MR-1217(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The meaning of the device is almost the same as in Example 19, the only difference being that the host is different.
Example 26
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-67:1wt%MR-1217(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 24, the only difference is that the phosphorescence sensitizer is different.
Example 27
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-5:1wt%MR-1217(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 25, the only difference being that the phosphorescence sensitizer is different.
Example 28
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, and the only difference is that the type of resonant thermally activated delayed fluorescent material is different.
Example 29
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-67: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 28, the only difference being that the phosphorescence sensitizer is different.
Example 30
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-5: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 28, the only difference being that the phosphorescent sensitizer is different.
Example 31
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-3: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 28, the only difference being that the host is different.
Example 32
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-67: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 31, the only difference being that the phosphorescence sensitizer is different.
Example 33
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-5: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 31, the only difference being that the phosphorescent sensitizer is different.
Example 34
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-3:1wt%MR-199(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 28, the only difference being that the host is different.
Example 35
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-67:1wt%MR-199(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 33, the only difference being that the phosphorescent sensitizer is different.
Example 36
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-5:1wt%MR-199(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 34, the only difference being that the phosphorescence sensitizer is different.
Example 37
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, and the only difference is that the type of resonant thermally activated delayed fluorescent material is different.
Example 38
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-67: 1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 37, the only difference being that the phosphorescent sensitizer is different.
Example 39
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-5: 1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 37, the only difference being that the phosphorescence sensitizer is different.
Example 40
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-3: 1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The meaning of the device is almost the same as in Example 37, the only difference being that the host is different.
Example 41
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-1:10wt%PH-67:1wt%MR-1084(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 40, the only difference being that the phosphorescence sensitizer is different.
Example 42
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-1: 10wt% PH-5: 1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 40, the only difference being that the phosphorescence sensitizer is different.
Example 43
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-3:1wt%MR-1084(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 37, the only difference being that the host is different.
Example 44
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-67:1wt%MR-1084(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 43, the only difference being that the phosphorescent sensitizer is different.
Example 45
The device structure of this example is as follows.

ITO/HI-2(10nm)/HT-27(40nm)/W-19:10wt%PH-5:1wt%MR-1084(30nm)/ET-53(30nm)/LiF(0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 43, the only difference being that the phosphorescent sensitizer is different.
Example 46
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 0.5wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm) /Al(150nm)
The significance of the device is almost the same as in Example 1, the only difference being that the doping concentration of the resonant thermally activated delayed fluorescent material is different.
Example 47
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 15wt% PH-3: 1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 1, the only difference being that the doping concentration of the phosphorescent sensitizer is different.
Example 48
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1.5wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm) /Al(150nm)
The significance of the device is almost the same as in Example 10, the only difference being that the doping concentration of the resonant thermally activated delayed fluorescent material is different.
Example 49
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 5wt% PH-3: 1wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 10, the only difference being that the doping concentration of the phosphorescent sensitizer is different.
Example 50
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 2wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as in Example 19, the only difference being that the doping concentration of the resonant thermally activated delayed fluorescent material is different.
Example 51
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 20wt% PH-3: 1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 19, the only difference being that the doping concentration of the phosphorescent sensitizer is different.
Example 52
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 0.3wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm) /Al(150nm)
The significance of the device is almost the same as in Example 28, the only difference being that the doping concentration of the resonant thermally activated delayed fluorescent material is different.
Example 53
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 25wt% PH-3: 1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 28, the only difference being that the doping concentration of the phosphorescent sensitizer is different.
Example 54
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 10wt% PH-3: 1.5wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm) /Al(150nm)
The significance of the device is almost the same as in Example 37, the only difference being that the doping concentration of the resonant thermally activated delayed fluorescent material is different.
Example 55
The device structure of this example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7: 30wt% PH-3: 1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 37, the only difference being that the doping concentration of the phosphorescent sensitizer is different.
Comparative example 1
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt% MR-802 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 1, the only difference being the absence of phosphorescence sensitizer.
Comparative example 2
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt% MR-82 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 10, the only difference being the absence of phosphorescence sensitizer.
Comparative example 3
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt% MR-1217 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 19, the only difference being the absence of phosphorescence sensitizer.
Comparative example 4
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt% MR-199 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 28, the only difference being the absence of phosphorescence sensitizer.
Comparative example 5
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt% MR-1084 (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Example 37, the only difference being the absence of phosphorescence sensitizer.
Comparative example 6
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt%TBPe (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Comparative Example 1, the only difference being that the light-emitting layer is converted to a conventional fluorescent dye.
Comparative example 7
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt%TTPA (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Comparative Example 1, the only difference being that the light-emitting layer is converted to a conventional fluorescent dye.
Comparative example 8
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt%TBR ^b (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Comparative Example 1, the only difference being that the light-emitting layer is converted to a conventional fluorescent dye.
Comparative example 9
The device structure of this comparative example is as follows.

ITO/HI-2 (10nm)/HT-27 (40nm)/W-7:1wt%DBP (30nm)/ET-53 (30nm)/LiF (0.5nm)/Al (150nm)
The significance of the device is almost the same as Comparative Example 1, the only difference being that the light-emitting layer is converted to a conventional fluorescent dye.
The performance of the organic electroluminescent device manufactured by the above process is measured as follows.

The following performance was measured for the devices manufactured in Examples 1 to 55 and Comparative Examples 1 to 9. The characteristics of the manufactured devices, such as current, voltage, brightness, emission spectrum, current efficiency, external quantum efficiency, etc., were synchronously tested by PR655 spectroscopic scanning luminance meter and Keithley K2400 digital source meter system, and the lifetime was determined by MC-6000 test. completed by.

1. Threshold voltage: The voltage is increased at a rate of 0.1 V per second, and the voltage at which the luminance of the organic electroluminescent device reaches 1 cd/m ² , that is, the threshold voltage is measured.

2. The life test of LT90 is as follows. By setting different test brightness, the brightness and lifetime decay curves of the organic electroluminescent device are obtained, thereby obtaining the lifetime value of the device under the required decay brightness. That is, the test brightness is set to 1000 cd/m ² , a constant current is maintained, and the unit for measuring the time until the brightness of the organic electroluminescent device decreases to 900 cd/m ² is time.
The above specific test results are shown in Table 1.

The electroluminescent external quantum efficiencies of the organic electroluminescent device structures of the present invention are all about 30%, indicating good color purity due to small efficiency roll-off and narrow half-width under high brightness. Additionally, the inventive device has a longer lifetime, presenting an overall advantage.

Embodiments of the present invention further provide a display device comprising the organic electroluminescent device provided above. Specifically, the display device may be any product or component having a display function, such as a display device such as an OLED display, and a television, digital camera, mobile phone, tablet, etc., including the display device. Since the display device has the same advantages over the prior art as the organic electroluminescent device described above, it will not be described in detail here.

Finally, each of the above embodiments is only used to explain the technical solution of the present invention, not to limit the present invention. Although the present invention has been described in detail with reference to the above-mentioned embodiments, those skilled in the art will be able to modify the technical solutions described in the above-mentioned embodiments or modify some or all of the technical features. Although it is still possible to carry out equivalent substitutions for do not have.

Claims (10)

An organic electroluminescent device comprising a substrate, a first electrode, a second electrode and an organic functional layer, the organic functional layer comprising an organic light emitting layer, the organic light emitting layer comprising a host material and a light emitting dye. hand,
The luminescent layer includes a luminescent host material, a phosphorescent sensitizer, and a resonant heat-activated delayed fluorescent material used as a luminescent dye;
The triplet energy level of the host material in the emissive layer is higher than the triplet energy level of the phosphorescent sensitizer, and the triplet energy level of the host material is also higher than the triplet energy level of the resonant thermally activated delayed fluorescent material. higher than the energy level,
The triplet energy level of the phosphorescent sensitizer is higher than the triplet energy level of the resonant thermally activated delayed fluorescent material, and the HOMO energy level of the phosphorescent sensitizer is higher than the triplet energy level of the resonant thermally activated delayed fluorescent material. deeper than the HOMO energy level of
The resonant thermally activated delayed fluorescent material is a compound whose core structure uses boron atoms and nitrogen atoms to form a resonant molecular structure, or the core structure uses boron atoms and oxygen atoms to form a resonant molecular structure. or a compound that forms a resonant molecular structure using a carbonyl group and a nitrogen atom, or a compound that forms a resonant molecular structure using a carbonyl group and an oxygen atom; The term energy level S1 and the triplet energy level T1 satisfy the following formula,
ΔEst=S1-T1≦0.4 eV,
The organic electroluminescent device, wherein a Stokes shift of the compound satisfies λ≦60 nm. The resonance type thermally activated delayed fluorescent material has the following formula (1) or formula (2):

(In formula (1) and formula (2), ring A, ring B, ring C, and ring D each independently represent a C5 to C20 monocyclic aromatic ring or a fused aromatic ring, a C4 to C20 monocyclic ring, represents either a heterocycle or a fused heterocycle,
In formula (2), ring E represents a C5 to C20 aromatic ring, and ring A and ring B are connected by a single bond or not connected by a single bond, and ring C and ring B are connected to each other by a single bond. and ring D are connected with a single bond or not connected with a single bond,
In formula (1), Y ¹ and Y ² are each independently N or B, and X ¹ , X ² , X ³ and X ⁴ are each independently NR ₁ or BR ₂ , and both Y ¹ and Y ² are N, then X ¹ , X ² , X ³ and X ⁴ are all BR ₂ ,
In formula (2), Y ¹ and Y ² are each independently N or B, and X ¹ , X ² , X ³ and X ⁴ are each independently NR ₁ , BR ₂ , O or S and both Y ¹ and Y ² are B, then X ¹ , X ² , X ³ and X ⁴ are not NR ₁ at the same time,
In formulas (1) and (2), R ₁ is each independently linked to adjacent ring A, ring B, ring C, or ring D to form a ring, or not linked to each other. and are connected by a single bond when connected to form a ring, and each R ₂ is independently connected to adjacent ring A, ring B, ring C, or ring D. to form a ring, or to form a ring without being linked, or to be connected by a single bond when linked to form a ring, and the R ₁ and R ₂ are each independently substituted or unsubstituted, selected from a C6-C60 monocyclic aryl group, a C6-C60 fused ring aryl group, a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group, and When a substituent exists on R ¹ and R ² , the substituent is each independently deuterium, halogen, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 alkoxy group, cyano group, C6 to C30 arylamino group, C3 to C30 heteroarylamino group, C6 to C60 monocyclic aryl group, C6 to C60 fused ring aryl group, C6 to C60 aryloxy group, C5 to selected from any one of a C60 monocyclic heteroaryl group, a C5 to C60 fused ring heteroaryl group,
In formula (1 ⁾ and formula (2), the sum of R ^a , R ^b , and R ^c each independently represents the maximum possible substituent from a single substituent, and each independently, Hydrogen, deuterium, or halogen, substituted or unsubstituted C1 to C36 chain alkyl group, substituted or unsubstituted C3 to C36 cycloalkyl group, C1 to C10 alkoxy group, cyano group, C6 to C30 aryl Amino group, C3-C30 heteroarylamino group, substituted or unsubstituted C6-C60 monocyclic aryl group, C6-C60 fused ring aryl group, C6-C60 aryloxy group, C5-C60 monocyclic group When a substituent is selected from a heteroaryl group, a C5-C60 condensed ring heteroaryl group, and a trimethylsilicon group, and there is a substituent on the above R ^a , R ^b , R ^c and R ^d , the substituent are each independently selected from any one of a halogen, a C1 to C30 chain alkyl group, a cyano group, and a C6 to C60 monocyclic aryl group,
Preferably, in formulas (1) and (2), the ring A, ring B, ring C, and ring D each independently represent a C5 to C10 monocyclic aromatic ring or a fused aromatic ring, or a C4 to C10 represents any one of a monocyclic heterocycle or a fused heterocycle,
More preferably, the ring A, ring B, ring C, and ring D are each independently selected from any one of a benzene ring, a naphthalene ring, and a fluorene ring.)
The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is selected from the structures shown in . The resonance type thermally activated delayed fluorescent material has the following formula (3) or formula (4):

(In formula (3) and formula (4),
The R ²¹ to R ³¹ are each independently hydrogen, deuterium, substituted or unsubstituted halogen, a C1 to C30 chain alkyl group, a C3 to C30 cycloalkyl group, or a C1 to C10 alkoxy group. , C1 to C10 thioalkoxy group, carbonyl group, carboxyl group, nitro group, cyano group, amino group, C6 to C30 arylamino group, C3 to C30 heteroarylamino group, C6 to C60 monocyclic aryl group, selected from a C6-C60 fused ring aryl group, a C6-C60 aryloxy group, a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group, R ²¹ to R The two adjacent groups in ³¹ do not bond to each other, or the two adjacent groups in R ²¹ to R ³¹ bond to each other, and together with the adjacent benzene ring, a C5 to C30 5- or 6-membered membered aryl ring, C5-C30 5-membered or 6-membered heteroaryl ring, the formed ring is not substituted with a substituent, or at least one hydrogen of the formed ring is C6-C30 C30 arylamino group, C3 to C30 heteroarylamino group, C6 to C60 monocyclic aryl group, C6 to C60 fused ring aryl group, C6 to C60 aryloxy group, C5 to C60 monocyclic heteroaryl group, C5 to C60 fused ring heteroaryl group, halogen, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 alkoxy group, C1 to C10 thioalkoxy group, carbonyl group, carboxyl substituted with one of a group, a nitro group, a cyano group, an amino group,
The X ⁵ , X ⁶ , X ⁷ and X ⁸ are each independently selected from NR, and the R is -O-, -S-, -C(-R')2- or through a single bond. R and R' are each independently a substituted or unsubstituted C1-C30 chain alkyl group, a C3-C30 cycloalkyl group, or a C1-C30 halogenated group. Alkyl group, C1-C30 alkoxy group, C2-C30 alkenyl group, C3-C30 alkynyl group, C6-C60 monocyclic aryl group, C6-C60 fused ring aryl group, C6-C60 aryloxy group , a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group,
In formula (3), ring F represents a group ^{simultaneously} condensed to a six-membered ring structure consisting of B and X ⁵ and B and selected from one of a C60 monocyclic nitrogen heteroaromatic ring, a substituted or unsubstituted C5-C60 fused nitrogen heteroaromatic ring,
When a substituent is present in the above group, the substituent is each independently deuterium, halogen, cyano group, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 cycloalkyl group, etc. selected from one of an alkoxy group, a C6-C30 arylamino group, a C3-C30 heteroarylamino group, a C6-C30 aryl group, a C3-C30 heteroaryl group,
Preferably, in formula (3), ring F represents one of a substituted or unsubstituted C13-C60 monocyclic nitrogen heteroaromatic ring, a substituted or unsubstituted C13-C60 fused nitrogen heteroaromatic ring,
Preferably, in formula (3) and formula (4), R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ are each independently Hydrogen, deuterium, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 2-methylbutyl group, n-pentyl group, s-pentyl group, cyclopentyl group, neopentyl group, n-hexyl group, cyclohexyl group, neohexyl group, n-heptyl group, cycloheptyl group, n-octyl group, cyclooctyl group, 2-ethylhexyl group, trifluoromethyl group, Pentafluoroethyl group, 2,2,2-trifluoroethyl group, phenyl group, naphthyl group, anthranyl group, benzanthranyl group, phenanthrenyl group, benzophenanthrenyl group, pyrenyl group, chrysene group, perylene group, fluoran thenyl group, tetracenyl group, pentacenyl group, benzopyrenyl group, biphenyl group, diphenyl group, terphenyl group, trimerized phenyl group, quarterphenyl group, fluorenyl group, spirobifluorenyl group, dihydrophenanthrenyl group, Dihydropyrenyl group, tetrahydropyrenyl group, trans or cis indenofluorenyl group, trimerized indenyl group, isotrimerized indenyl group, spirotrimerized indenyl group, spiroisotrimerized indenyl group, furyl group, benzofuryl group, isobenzofuryl group, dibenzofuryl group, thienyl group, benzothienyl group, isobenzothienyl group, dibenzothienyl group, pyrrolyl group, isoindolyl group, carbazolyl group, indenocarbazolyl group, pyridyl group, quinolinyl group group, isoquinolinyl group, acridinyl group, phenanthridinyl group, benzo-5,6-quinolinyl group, benzo-6,7-quinolinyl group, benzo-7,8-quinolinyl group, pyrazolyl group, indazolyl group, imidazolyl group, Benzimidazolyl group, naphthoimidazolyl group, phenanthroimidazolyl group, pyridinoimidazolyl group, pyrazinoimidazolyl group, quinoxalinoimidazolyl group, oxazolyl group, benzoxazolyl group, naphthoxazolyl group, anthraoxazolyl group, Phenanthrooxazolyl group, 1,2-thiazolyl group, 1,3-thiazolyl group, benzothiazolyl group, pyridazinyl group, benzopyridazinyl group, pyrimidinyl group, benzopyrimidinyl group, quinoxalyl group, 1,5-dia Zanthranyl group, 2,7-diazapyrenyl group, 2,3-diazapyrenyl group, 1,6-diazapyrenyl group, 1,8-diazapyrenyl group, 4,5-diazapyrenyl group, 4,5,9,10-tetraazapyrenyl group group, pyrazinyl group, phenazinyl group, phenothiazinyl group, naphthyridinyl group, azacarbazolyl group, benzocarbonyl group, phenanthrolinyl group, 1,2,3-triazolyl group, 1,2,4-triazolyl group, benzotriazolyl group group, 1,2,3-oxadiazolyl group, 1,2,4-oxadiazolyl group, 1,2,5-oxadiazolyl group, 1,2,3-thiadiazolyl group, 1,2,4-thiadiazolyl group, 1,2 ,5-thiadiazolyl group, 1,3,4-thiadiazolyl group, 1,3,5-triazinyl group, 1,2,4-triazinyl group, 1,2,3-triazinyl group, tetrazolyl group, 1,2,4 , 5-tetraazinyl group, 1,2,3,4-tetraazinyl group, 1,2,3,5-tetraazinyl group, purinyl group, pteridyl group, indolizinyl group, benzothiadiazolyl group, 9,9-dimethylacridinyl group polyhalogenated benzene, polycyanobenzene, polytrifluoromethylbenzene, or a combination of two said groups)
The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is selected from the structures shown in . The resonance type thermally activated delayed fluorescent material has the following formula (5), formula (6) or formula (7):

(In formula (5), formula (6), and formula (7),
The R ¹ , R ³ , R ⁴ , R ⁶ , R ⁷ , R ⁹ , R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R 15 , R ¹⁷ , R ¹⁸ , R ²⁰ , R ²² , ^{R 23 are} , Each independently hydrogen, deuterium, or substituted or unsubstituted halogen, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 alkoxy group, C1 to C10 thioalkoxy group , carbonyl group, carboxyl group, nitro group, cyano group, amino group, C6-C30 arylamino group, C3-C30 heteroarylamino group, C6-C60 monocyclic aryl group, C6-C60 fused ring aryl group , a C6-C60 aryloxy group, a C5-C60 monocyclic heteroaryl group or a C5-C60 fused ring heteroaryl group,
R ² , R ⁵ , R ⁸ , R ¹¹ , R ¹⁶ and R ¹⁹ are each independently a hydrogen atom, or a substituted or unsubstituted methyl group, ethyl group, n-propyl group, isopropyl group, n -Butyl group, isobutyl group, s-butyl group, t-butyl group, 2-methylbutyl group, cyclohexyl group, fluorine atom, trifluoromethyl group, cyano group, t-butylbenzene, methylphenyl group, phenyl group, triaryl Amine group, carbazolyl group, pyridyl group, furyl group, benzofuryl group, isobenzofuryl group, dibenzofuryl group, thienyl group, benzothienyl group, isobenzothienyl group, dibenzothienyl group, adamantane, tetrahydropyrrole group, piperidine, silicon group , methoxy group, 9,9-dimethylacridinyl group, phenothiazinyl group, phenoxazinyl group, imidazolyl group, carbazolofuran, etc.,
R ²¹ is hydrogen, fluorine, a cyano group, or a substituted or unsubstituted pyridyl group, phenyl group, fluorophenyl group, methylphenyl group, trimethylphenyl group, cyano phenyl group, trifluoromethyl group, triarylamine group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 2-methylbutyl group, cyclohexyl group, adamantane, tetrahydropyrrole group, piperidine, Silicon group, methoxy group, 9,9-dimethylacridinyl group, phenothiazinyl group, phenoxazinyl group, imidazolyl group, carbazolofuran, carbazolyl group, fluorine atom, trifluoromethyl group, cyano group, pyridyl group, furyl group, etc. selected from the substituents of
When a substituent is present in the above group, the substituent is each independently deuterium, halogen, cyano group, C1 to C30 chain alkyl group, C3 to C30 cycloalkyl group, C1 to C10 cycloalkyl group, etc. alkoxy group, C6-C30 arylamino group, C3-C30 heteroarylamino group, C6-C30 aryl group, C3-C30 heteroaryl group)
The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is selected from the structures shown in any one of the following. The resonance type thermally activated delayed fluorescent material has the following specific structural compound:

The organic electroluminescent device according to claim 1, wherein these compounds are representative. The phosphorescent sensitizer in the light emitting layer is the following compound:

The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is selected from any one of: The doping concentration of the resonant thermally activated delayed fluorescent material in the light emitting layer is 0.1 wt% to 30 wt%, and the doping concentration of the phosphorescent sensitizer in the light emitting layer is 1 wt% to 50 wt%,
Preferably, the doping concentration of the resonant thermally activated delayed fluorescent material in the emissive layer is 0.5 wt% to 10 wt%, and the doping concentration of the phosphorescent sensitizer in the emissive layer is 3 wt% to 30 wt%. and
More preferably, the doping concentration of the resonant thermally activated delayed fluorescent material in the emissive layer is 0.5 to 2 wt%, and the doping concentration of the phosphorescent sensitizer in the emissive layer is 5 to 15 wt%. The organic electroluminescent device according to claim 1. The host material in the light-emitting layer is selected from at least one compound selected from carbazole derivatives, carboline derivatives, spirofluorene derivatives, fluorene derivatives, silicone group-containing derivatives, phosphonooxy-containing derivatives, and sulfonyl-containing derivatives. 1. The organic electroluminescent device according to 1. Application of the organic electroluminescent device according to claim 1, comprising:
The application is in an organic electronic device, and the organic electronic device includes an optical sensor, a solar cell, a lighting element, an organic thin film transistor, an organic field effect transistor, an organic thin film solar cell, an information label, an electronic artificial skin sheet, and a sheet type. Application of the organic electroluminescent device according to claim 1, including a scanner or electronic paper. A display device,
comprising an organic electroluminescent device according to claim 1;
The display device is characterized in that the display device is a display element, a lighting element, an information label, an electronic artificial skin sheet, or an electronic paper.

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