CN109734928B

CN109734928B - Space charge transfer dendritic fluorescent material, preparation method thereof and organic electroluminescent device

Info

Publication number: CN109734928B
Application number: CN201910007984.9A
Authority: CN
Inventors: 王利祥; 王兴东; 邵世洋; 王淑萌; 吕剑虹
Original assignee: Changchun Institute of Applied Chemistry of CAS
Current assignee: Changchun Institute of Applied Chemistry of CAS
Priority date: 2019-01-04
Filing date: 2019-01-04
Publication date: 2021-08-17
Anticipated expiration: 2039-01-04
Also published as: CN109734928A

Abstract

The invention provides a dendritic fluorescent polymer compound which has a structure shown in a formula (I) or (II). The invention designs a dendritic fluorescent material with space charge transfer effect, which is obtained by taking hexaphenylbenzene with space restriction effect as a core and introducing three dendritic electron donor units and three electron acceptor units at the periphery. The electron donor and the electron acceptor are spatially separated, so that the fluorescent material has very low singlet state-triplet state energy level difference, further shows obvious thermal activation delayed fluorescence effect, can realize effective utilization of triplet state excitons when being used as a luminescent material of a solution processing type organic electroluminescent device, has high device luminous efficiency, and solves the technical problem of low device efficiency of the traditional dendritic fluorescent material based on chemical bond charge transfer.

Description

Space charge transfer dendritic fluorescent material, preparation method thereof and organic electroluminescent device

Technical Field

The invention relates to the field of organic light-emitting materials, in particular to a dendritic fluorescent high-molecular compound, a preparation method thereof and an organic electroluminescent device, and especially relates to a dendritic fluorescent material with a space charge transfer effect, a preparation method thereof and an organic electroluminescent device.

Background

Organic Light Emitting Devices (OLEDs) are generally composed of a cathode, an anode, and organic layers interposed between the cathode and the anode, that is, the device is composed of a transparent ITO anode, a hole injection layer (TIL), a Hole Transport Layer (HTL), a light Emitting Layer (EL), a Hole Blocking Layer (HBL), an Electron Transport Layer (ETL), an Electron Injection Layer (EIL), and a cathode, and 1 to 2 organic layers may be omitted as needed. The action mechanism is that voltage is formed between two electrodes, one side is injected from a cathode electron, the other side is injected from an anode hole, the electron and the hole are recombined in a light-emitting layer to form an excited state, the excited state returns to a stable ground state, and the device emits light. Due to the characteristics of rich colors, fast response, capability of preparing flexible devices and the like, the organic electroluminescent device is considered to be the next generation of flat panel display and solid illumination technology with the greatest development prospect. OLEDs can be classified into two major classes, i.e., small organic molecule devices and high organic molecule devices, according to the types of light-emitting materials. The organic polymer device can be prepared into low-cost and large-area preparation equipment in a solution processing (such as spin coating, printing and the like), so that the organic polymer device has a wide application prospect in the fields of display and illumination.

As a new generation display technology competitively developed internationally, OLEDs have characteristics of self-luminescence, high contrast, ultra-thinness, and the like in terms of display quality, and have advantages of easy realization of large screen and flexible display, and the like in terms of processing, compared with Liquid Crystal Display (LCD). Regarding organic electroluminescent materials, most of the currently commercialized OLED display screens adopt organic small-molecule luminescent materials based on a vacuum evaporation process, and the materials have high device efficiency, but have the disadvantages of low utilization rate, high cost and the like. In contrast, solution processable (e.g., inkjet printing and roll-to-roll printing) organic electroluminescent materials have the advantages of reduced production cost and energy consumption, easy preparation of large-sized display screens, and the like, but have the disadvantage of low device efficiency.

At present, the OLED luminescent materials used in the solution processing technology mainly include two types, i.e., a polymer luminescent material and a dendritic luminescent material. Among them, the polymer light emitting material has excellent solution processability, but has disadvantages of difficulty in purification, poor batch stability, and the like. Compared with a high-molecular luminescent material, the dendritic luminescent material is a luminescent material with a determined chemical structure, and the molecular size and the topological structure of the dendritic luminescent material can be accurately controlled in synthesis; meanwhile, the dendritic luminescent material also has good film-forming property and solution processing property, and luminescent materials with different luminescent wavelengths can be obtained by selecting different central cores, different dendritic construction units and different peripheral modification groups, so that the dendritic luminescent material is one of OLED material systems with development prospects.

At present, dendritic fluorescent materials mainly focus on fluorescent materials based on a chemical bond charge transfer luminescence principle, namely, an electron donor (D) and an electron acceptor (A) are directly connected by a conjugate unit, and the regulation of luminescence color and the improvement of luminescence efficiency of the dendritic fluorescent materials are realized by regulating and controlling the charge transfer intensity between the electron donor and the electron acceptor. However, such materials have a problem in that it is difficult to achieve the utilization of triplet excitons through the thermally activated delayed fluorescence effect, resulting in low device efficiency.

Therefore, how to find a more suitable material to solve the above-mentioned defects of the above-mentioned dendrimer in terms of material design and device performance has become one of the many problems to be solved by the prospective researchers in the field.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a dendritic fluorescent polymer compound, a method for preparing the same, and an organic electroluminescent device, in particular, a dendritic fluorescent material having a space charge transfer effect, wherein the dendritic fluorescent polymer compound has a very low singlet-triplet energy level difference, exhibits a significant thermal activation delayed fluorescence effect, can realize effective utilization of triplet excitons, and thus has high device light-emitting efficiency.

The invention provides a dendritic fluorescent polymer compound which has a structure shown in a formula (I) or (II),

wherein the content of the first and second substances,

is a dendritic electron donor, A is an electron acceptor;

m is 0 or 1, n is 1, 2, 3 or 4;

x is selected from the group consisting of-C (R ') -, -Si (R ') -, -N (R ') -, -O-, -S-, -SO-, -SO₂One or more of-B (R '), -P (R ') -, and-PO (R ') -;

r 'and R' are each selected from H, halogen, -CF₃-CN, substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₆～C₂₀Aryl and substituted or unsubstituted C₂～C₂₀One or more of the heteroaryl groups of (a);

r is selected from H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₁～C₂₀Alkoxy, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₅～C₂₀Heterocycloalkyl, substituted or unsubstituted C₆～C₂₀Aryl and substituted or unsubstituted C₂～C₂₀One or more of the heteroaryl groups of (a);

a is selected from substituted or unsubstituted C₂～C₆₀Nitrogen-containing aromatic heterocycle, substituted or unsubstituted C₂～C₆₀With boron-containing heteroaromatic ring, substituted or unsubstituted C₂～C₆₀The aromatic heterocycle containing carbonyl, substituted or unsubstituted C₂～C₆₀Sulfur sulfone-containing aromatic heterocycle, substituted or unsubstituted C₂～C₆₀And substituted or unsubstituted C₂～C₆₀One or more of the imide group-containing aromatic rings of (a).

Preferably, the dendritic electron donor is selected from one or more of a dendritic carbazole unit, a dendritic arylamine unit and a dendritic bridged arylamine unit;

said substituted C₁～C₂₀Alkyl or substituted C₁～C₂₀In the alkoxy group of (a), the substitution may be:

one or more non-adjacent carbon atoms are substituted with one or more of O, S, Si and-CO-O-; and/or the presence of a gas in the gas,

one or more hydrogen atoms are substituted by F;

said substituted or unsubstituted C₅～C₂₀Heterocycloalkyl, substituted or unsubstituted C₂～C₂₀In the heteroaryl group of (a), the heteroatom is selected from the group consisting of-C (R') -,-one or more of-Si (R ' R ") -, -B (R ') -, -N (R ') -, -P (R ') -, and-PO (R ') -.

Preferably, the

Is selected from any one or more of the formulas (I/II-I) to (I/II-IX):

wherein R is₁Selected from substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₅～C₂₀And substituted or unsubstituted C₆～C₂₀One or more of aryl groups of (a);

a is selected from any one or more of formulas (I/II-a) to (I/II-h):

wherein Ar is₁And Ar₂Each independently selected from substituted or unsubstituted C₁～C₆₀Alkyl, substituted or unsubstituted C₁～C₆₀Alkoxy, substituted or unsubstituted C₅～C₆₀Cycloalkyl, substituted or unsubstituted C₅～C₆₀And a substituted or unsubstituted C₅～C₆₀One or more of the polycyclic aromatic ring systems of (a);

Z₁、Z₂、Z₃、Z₄and Z₅Each independently selected from a carbon atom or a nitrogen atom;

Z₆selected from nitrogen atoms or oxygenAn atom.

Preferably, R is selected from H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₁～C₂₀Alkoxy, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₅～C₂₀And substituted or unsubstituted C₆～C₂₀One or more of aryl groups of (a);

one or more non-adjacent carbon atoms are substituted with O and/or S.

Preferably, the

One or more selected from the group consisting of those represented by the formulae (1) to (26);

preferably, a is selected from any one or more of formula (27) to formula (57);

preferably, the dendritic fluorescent polymer compound has a structure shown in any one of formulas I-1 to 33 or a structure shown in any one of formulas II-1 to 8;

the invention provides a preparation method of the dendritic fluorescent polymer compound, which comprises the following steps:

1) under protective atmosphere, performing Sonogashira coupling reaction on an iodo-compound X-1 and p-bromophenylacetylene to obtain an intermediate X-2;

2) under protective atmosphere, carrying out cyclotrimerization reaction on the intermediate X-2 obtained in the step to respectively obtain an intermediate X-3 and an intermediate X-4;

3) under protective atmosphere, carrying out a first Buchwald-Hartwig reaction on the intermediate X-3 obtained in the step and an arylamine compound X-5 to obtain a dendritic fluorescent high molecular compound with a specific structure shown in a formula (I);

under protective atmosphere, carrying out a second Buchwald-Hartwig reaction on the intermediate X-4 obtained in the step and an arylamine compound X-5 to obtain a dendritic fluorescent high molecular compound with a specific structure of a formula (II);

preferably, the temperature of the Sonogashira coupling reaction is 40-80 ℃;

the time of the Sonogashira coupling reaction is 16-30 h;

the temperature of the cyclotrimerization reaction is 100-140 ℃;

the time of the cyclotrimerization reaction is 40-60 h;

the temperature of the first Buchwald-Hartwig reaction is 90-130 ℃;

the first Buchwald-Hartwig reaction time is 16-30 h;

the temperature of the second Buchwald-Hartwig reaction is 90-130 ℃;

the time of the second Buchwald-Hartwig reaction is 16-30 h.

The invention also provides an organic electroluminescent device, which comprises an electroluminescent material; the electroluminescent material comprises the dendritic fluorescent polymer compound according to any one of the above technical schemes or the dendritic fluorescent polymer compound prepared by the preparation method according to any one of the above technical schemes.

The invention provides a dendritic fluorescent polymer compound which has a structure shown in a formula (I) or (II). Compared with the prior art, the invention aims at the defect that the conventional dendritic fluorescent material is difficult to realize the utilization of triplet excitons through the thermal activation delayed fluorescence effect, so that the device efficiency is lower.

The present invention is based on the study of the conventional dendrimer compounds, and it is considered that the degree of overlap between the electron donor (D) and the electron acceptor (A) is large, and it is difficult to realize a small Δ E_STAnd in turn, it is difficult to achieve the utilization of triplet excitons through the thermally activated delayed fluorescence effect, resulting in low device efficiency. The invention creatively designs a dendritic fluorescent material with space charge transfer effect, which adopts hexaphenylbenzene with space restriction effect as a core and obtains the space charge transfer dendritic fluorescent material by introducing three dendritic electron donor units and three electron acceptor units at the periphery. The electron donor and the electron acceptor are spatially separated, so that the compound has very low singlet-triplet energy level difference and further showsThe method has the advantages that the remarkable thermal activation delayed fluorescence effect is achieved, when the method is used as a luminescent material of a solution processing type organic electroluminescent device, the triplet excitons can be effectively utilized, the device luminescent efficiency is high, and the technical problem that the device efficiency of the traditional dendritic fluorescent material based on chemical bond charge transfer is low is solved.

Experimental results show that the dendritic fluorescent macromolecular compound provided by the invention has lower singlet state-triplet state energy level difference, delta E_STThe fluorescent material is only 0.04-0.15 eV, so that the fluorescent material has a remarkable thermal activation delayed fluorescence effect, can realize effective utilization of triplet excitons, has high device luminous efficiency, and can prepare an efficient electroluminescent device, the maximum current efficiency of the electroluminescent device prepared by taking the space charge transfer dendritic fluorescent material provided by the invention as a luminescent material can reach 40.6cd/A at most, and the maximum external quantum efficiency can reach 14.2%.

Drawings

FIG. 1 is a fluorescence spectrum of a fluorescent material I-1 prepared in an example of the present invention in a toluene solution;

FIG. 2 is a fluorescence spectrum of the fluorescent material I-4 prepared in the example of the present invention in a toluene solution;

FIG. 3 is a fluorescence spectrum of the fluorescent material I-5 prepared in the example of the present invention in a toluene solution;

FIG. 4 is a fluorescence spectrum of the fluorescent material I-17 prepared in the example of the present invention in a toluene solution;

FIG. 5 is a graph showing fluorescence (298K) and phosphorescence (77K) spectra of a thin film prepared by doping fluorescent material I-5 prepared in example of the present invention in polystyrene (1 wt%);

FIG. 6 is a graph of transient fluorescence decay curve (298K) of a thin film prepared by doping fluorescent material I-5 prepared in an example of the present invention in polystyrene (1 wt%);

fig. 7 is structural formulas of a host material, TSPO1, and TmPyPB in an organic electroluminescent device prepared in example 15 of the present invention;

FIG. 8 is an electroluminescence spectrum of an electroluminescence device produced in example 16 of the present invention;

FIG. 9 is a graph of current efficiency vs. luminance characteristics of an electroluminescent device prepared in example 16 of the present invention;

FIG. 10 is an electroluminescence spectrum of an electroluminescence device produced in example 17 of the present invention;

FIG. 11 is a graph showing current efficiency-luminance characteristics of an electroluminescent device produced in example 17 of the present invention;

FIG. 12 is an electroluminescence spectrum of an electroluminescence device produced in example 18 of the present invention;

fig. 13 is a graph of current efficiency versus luminance characteristics of an electroluminescent device prepared in example 18 of the present invention.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.

All the raw materials of the present invention are not particularly limited in their purity, and the present invention preferably employs a purity which is conventional in the field of analytical purification or organic electroluminescent materials.

All compounds of the present invention, whose structural expressions and abbreviations belong to the common structural expressions and abbreviations in the art, are clearly and unambiguously understood in the field of their related uses, and those skilled in the art can clearly, exactly and uniquely understand them according to the structural expressions and abbreviations.

wherein the content of the first and second substances,

is a dendritic electron donor, A is an electron acceptor;

m is 0 or 1, n is 1, 2, 3 or 4;

In the present specification, "-substituent" in the structural formula means that the substituent may be at any position of the group.

The non-conjugated fluorescent polymer compound of the present invention is preferably a non-conjugated fluorescent polymer compound having a space charge transfer effect, and has a structure of formula (I) or (II). Wherein m is 0 or 1, and n is 1, 2, 3 or 4.

The invention

The dendritic electron donor unit is preferably one or more selected from a dendritic carbazole unit, a dendritic arylamine unit and a dendritic bridging arylamine unit, more preferably any one or more selected from formulas (I/II-I) to (I/II-IX), more preferably any one selected from formulas (I/II-I) to (I/II-IX), particularly preferably any one or more selected from formulas (1) to (26), and more particularly any one selected from formulas (1) to (26). The above formulas (I/II-I) to (I/II-IX) and (1) to (26) are as described above, and are not described in detail herein.

In the structural formulae of the above dendritic electron donor units of the present invention, said X preferably represents a hetero atom, preferably selected from the group consisting of-C (R ') -, -Si (R ') -, -N (R ') -, -O-, -S-, -SO-, -SO₂One or more of- (O-X) -, -B (R ') -, -P (R') -, and-PO (R ') -, more preferably-C (R') -, -Si (R ') -, -N (R') -, -O-, -S-, -SO-)₂-, -B (R ') -, -P (R ') -, or-PO (R ') -.

Wherein R 'and R' are each selected from H, halogen, -CF₃-CN, substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₆～C₂₀Aryl and substituted or unsubstituted C₂～C₂₀More preferably H, halogen, -CF₃-CN, substituted or unsubstituted C₃～C₂₀Alkyl, substituted or unsubstituted C₅～C₂₀Alkoxy, substituted or unsubstituted C₈～C₂₀Aryl, substituted or unsubstituted C₅～C₂₀More preferably H, halogen, -CF₃-CN, substituted or unsubstituted C₅～C₂₀Alkyl, substituted or unsubstituted C₁₀～C₂₀Alkoxy, substituted or unsubstituted C₁₀～C₂₀Aryl, substituted or unsubstituted C₈～C₂₀Any one or more of the heteroaryl groups of (a).

In the present invention, R is preferably selected as a surface group, preferably from H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₁～C₂₀Alkoxy, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₅～C₂₀Heterocycloalkyl, substituted or unsubstituted C₆～C₂₀Aryl and substituted or unsubstituted C₂～C₂₀More preferably H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₃～C₂₀Alkyl, substituted or unsubstituted C₃～C₂₀Alkoxy, substituted or unsubstituted C₅～C₂₀Cycloalkyl, substituted or unsubstituted C₇～C₂₀Heterocycloalkyl, substituted or unsubstituted C₈～C₂₀Aryl, substituted or unsubstituted C₅～C₂₀More preferably H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₅～C₂₀Alkyl, substituted or unsubstituted C₅～C₂₀Alkoxy, substituted or unsubstituted C₈～C₂₀Cycloalkyl, substituted or unsubstituted C₁₀～C₂₀Heterocycloalkyl, substituted or unsubstituted C₁₀～C₂₀Aryl, substituted or unsubstituted C₈～C₂₀More preferably H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁₀～C₂₀Alkyl, substituted or unsubstituted C₁₀～C₂₀Alkoxy, substituted or unsubstituted C₁₀～C₂₀Cycloalkyl, substituted or unsubstituted C₁₂～C₂₀Heterocycloalkyl, substituted or unsubstituted C₁₂～C₂₀Aryl, substituted or unsubstituted C₁₀～C₂₀Any one or more of the heteroaryl groups of (a). In particular, it may be selected from H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₁～C₂₀Alkoxy, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₅～C₂₀And substituted or unsubstituted C₆～C₂₀One or more of aryl groups of (a).

In the present invention, among the substituents represented by R, the substituted C₁～C₂₀Alkyl or substituted C₁～C₂₀In the alkoxy group of (b), the substitution may preferably be:

one or more non-adjacent carbon atoms are substituted with one or more of O, S, Si and-CO-O-; and/or one or more hydrogen atoms are replaced by F; more preferably one or more non-adjacent carbon atoms are replaced by O and/or S.

Said substituted or unsubstituted C₅～C₂₀Heterocycloalkyl, substituted or unsubstituted C₂～C₂₀In the heteroaryl group of (a), the heteroatom may be preferably selected from one or more of-C (R ') -, -Si (R') -, -B (R ') -, -N (R') -, -P (R ') -, and-PO (R') -.

A in the context of the present invention is an electron acceptor unit, preferably a self-substituted or non-substituted C₂～C₆₀Nitrogen-containing aromatic heterocycle, substituted or unsubstituted C₂～C₆₀With boron-containing heteroaromatic ring, substituted or unsubstituted C₂～C₆₀The aromatic heterocycle containing carbonyl, substituted or unsubstituted C₂～C₆₀Sulfur sulfone-containing aromatic heterocycle, substituted or unsubstituted C₂～C₆₀And substituted or unsubstituted C₂～C₆₀More preferably C which is substituted or unsubstituted₅～C₆₀Nitrogen-containing aromatic heterocycle, substituted or unsubstituted C₅～C₆₀With boron-containing aromatic heterocycles, substitutions orUnsubstituted C₅～C₆₀The aromatic heterocycle containing carbonyl, substituted or unsubstituted C₅～C₆₀Sulfur sulfone-containing aromatic heterocycle, substituted or unsubstituted C₅～C₆₀The aromatic heterocycle containing the phosphono group, substituted or unsubstituted C₅～C₆₀More preferably C which is substituted or unsubstituted₈～C₅₀Nitrogen-containing aromatic heterocycle, substituted or unsubstituted C₈～C₅₀With boron-containing heteroaromatic ring, substituted or unsubstituted C₈～C₅₀The aromatic heterocycle containing carbonyl, substituted or unsubstituted C₈～C₅₀Sulfur sulfone-containing aromatic heterocycle, substituted or unsubstituted C₈～C₅₀And substituted or unsubstituted C₈～C₅₀More preferably C which is substituted or unsubstituted₁₀～C₃₀Nitrogen-containing aromatic heterocycle, substituted or unsubstituted C₁₀～C₃₀With boron-containing heteroaromatic ring, substituted or unsubstituted C₁₀～C₃₀The aromatic heterocycle containing carbonyl, substituted or unsubstituted C₁₀～C₃₀Sulfur sulfone-containing aromatic heterocycle, substituted or unsubstituted C₁₀～C₃₀And substituted or unsubstituted C₁₀～C₃₀Any one or more of the imide group-containing aromatic rings of (a).

In the present invention, A may be preferably selected from any one or more of the formulae (I/II-a) to (I/II-h), more preferably from any one or more of the formulae (27) to (57), and still more preferably from any one of the formulae (27) to (57). The above formulas (I/II-a) to (I/II-h) and (27) to (57) are as described above, and are not described in detail herein.

In the structural formula of the above electron acceptor unit of the present invention, Ar₁And Ar₂Each independently selected from substituted or unsubstituted C₁～C₆₀Alkyl, substituted or unsubstituted C₁～C₆₀Alkoxy, substituted or unsubstituted C₅～C₆₀Cycloalkyl, substituted or unsubstituted C₅～C₆₀And a substituted or unsubstituted C₅～C₆₀More preferably from substituted or unsubstituted C₃～C₆₀Alkyl, substituted or unsubstituted C₃～C₆₀Alkoxy, substituted or unsubstituted C₈～C₆₀Cycloalkyl, substituted or unsubstituted C₈～C₆₀And a substituted or unsubstituted C₈～C₆₀More preferably from substituted or unsubstituted C₅～C₆₀Alkyl, substituted or unsubstituted C₅～C₆₀Alkoxy, substituted or unsubstituted C₁₀～C₆₀Cycloalkyl, substituted or unsubstituted C₁₀～C₆₀And a substituted or unsubstituted C₁₀～C₆₀More preferably from substituted or unsubstituted C₁₀～C₅₀Alkyl, substituted or unsubstituted C₁₀～C₅₀Alkoxy, substituted or unsubstituted C₁₅～C₅₀Cycloalkyl, substituted or unsubstituted C₁₅～C₅₀And a substituted or unsubstituted C₁₅～C₅₀More preferably from substituted or unsubstituted C₁₅～C₄₀Alkyl, substituted or unsubstituted C₁₅～C₄₀Alkoxy, substituted or unsubstituted C₂₀～C₄₀Cycloalkyl, substituted or unsubstituted C₂₀～C₄₀And a substituted or unsubstituted C₂₀～C₄₀One or more of the polycyclic aromatic ring systems of (a).

Wherein Z is₁、Z₂、Z₃、Z₄And Z₅Each independently is preferably selected from a carbon atom or a nitrogen atom; z₆Preferably from nitrogen or oxygen atoms.

In the present invention, in the electron acceptor unit represented by A, the above structure may be substituted with one or more substituents, which may be the same or different at each occurrence, said substituents being preferably selected from H, halogen, -CF₃、-CN、-NO₂One or more of a straight chain containing 1 to 22 carbon atoms, a branched chain containing 1 to 22 carbon atoms, a cycloalkyl group containing 1 to 22 carbon atoms and an alkoxy chain containing 1 to 22 carbon atoms. Wherein one or more non-adjacent carbon atoms of said 1 to 22 carbon atoms may be substituted by O, S, Si, -CO-O-; one or more hydrogen atoms of the 1 to 22 carbon atoms may be substituted by F.

In the present invention, Ar of the electron acceptor unit represented by A₁And Ar₂The monocyclic or polycyclic aromatic ring system, which does not necessarily have only aryl groups, may also be interrupted by short nonaromatic units, e.g. sp 3-hybridized carbon atoms, preferably from C₆～C₃₀Aryl of (C)₂～C₃₀Heteroaryl of (A), C₁₂～C₅₀Of (a) an arylamine group.

The invention provides a space charge transfer dendritic fluorescent material, an electron donor unit and an electron acceptor unit of the material are spatially separated, the luminescence of the material is derived from the space charge transfer from the electron donor to the electron acceptor, and the material is characterized in that the material is easy to realize smaller delta E_STAnd the remarkable thermal activation delayed fluorescence effect, and is beneficial to the effective utilization of triplet excitons when being applied to the organic electroluminescent diode. Compared with the prior dendritic fluorescent material based on the chemical bond charge transfer luminescence principle, the space charge transfer dendritic fluorescent material provided by the invention is easy to realize the space separation of an electron donor and an electron acceptor, thereby being easy to realize smaller delta E_STAnd a significant delayed fluorescence effect, thereby realizing higher luminous efficiency of the device.

In order to further clarify and complete the technical scheme, the dendritic fluorescent polymer compound preferably has a structure shown in any one of formulas I-1 to 33 or a structure shown in any one of formulas II-1 to 8. The above formulas I-1 to 33 and II-1 to 8 are as described above, and are not described herein again.

The invention also provides a preparation method of the dendritic fluorescent polymer compound, which comprises the following steps:

the structure and material of the dendritic fluorescent polymer compound in the preparation method and the corresponding preferred principle can correspond to the material and structure of the dendritic fluorescent polymer compound and the corresponding preferred principle, and are not described in detail herein.

In the invention, firstly, under a protective atmosphere, an iodo-compound X-1 and p-bromophenylacetylene are subjected to Sonogashira coupling reaction to obtain an intermediate X-2.

The protective atmosphere is not particularly restricted by the present invention, and may be a conventional protective atmosphere well known to those skilled in the art, which may be selected and adjusted by those skilled in the art according to production conditions, quality requirements and product requirements, and is preferably an inert gas, more preferably argon.

In principle, the definition and reaction parameters of the Sonogashira coupling reaction are not particularly limited, and can be selected and adjusted according to production conditions, quality requirements and product requirements, wherein the definition and reaction parameters of the Sonogashira coupling reaction are well known by the technicians in the field, and the temperature of the Sonogashira coupling reaction is preferably 40-80 ℃, more preferably 50-70 ℃, and more preferably 55-65 ℃. The time of the Sonogashira coupling reaction is preferably 16-30 h, more preferably 18-28 h, and more preferably 20-25 h.

The present invention is not particularly limited to other raw materials or reagents for the Sonogashira coupling reaction, and conventional auxiliary raw materials or reagents for such coupling reaction, which are well known to those skilled in the art, may be selected and adjusted according to the production situation, quality requirements and product requirements.

According to the invention, the intermediate X-2 obtained in the above step is subjected to cyclotrimerization reaction under a protective atmosphere to respectively obtain an intermediate X-3 and an intermediate X-4.

The definition and reaction parameters of the cyclotrimerization reaction are not particularly limited in principle, and can be selected and adjusted by the skilled in the art according to the production condition, the quality requirement and the product requirement, so that the purity and the yield of the intermediate product and the final product are better ensured, and the temperature of the cyclotrimerization reaction is preferably 100-140 ℃, more preferably 110-130 ℃, and more preferably 115-125 ℃. The time of the cyclotrimerization reaction is preferably 40-60 h, more preferably 43-58 h, and more preferably 45-55 h.

The invention is not particularly restricted to other starting materials or reagents for the cyclotrimerization reaction, as are customary auxiliary starting materials or reagents for such coupling reactions, which are known to the person skilled in the art, and which can be selected and adjusted by the person skilled in the art according to the production situation, the quality requirements and the product requirements.

For further clear and complete technical scheme, the reaction routes of the steps 1) and 2) are preferably shown in formula 1, and formula 1 is the reaction route of the steps 1) and 2) in the preparation method of the dendritic fluorescent macromolecular compound provided by the invention.

Finally, under a protective atmosphere, carrying out a first Buchwald-Hartwig reaction on the intermediate X-3 obtained in the step and an arylamine compound X-5 to obtain a dendritic fluorescent high molecular compound with a specific structure shown in a formula (I);

and (3) carrying out a second Buchwald-Hartwig reaction on the intermediate X-4 obtained in the step and an arylamine compound X-5 in a protective atmosphere to obtain the dendritic fluorescent high molecular compound with the structure of the formula (II).

The definition and reaction parameters of the first Buchwald-Hartwig reaction are not particularly limited in principle, and the Buchwald-Hartwig reaction known by the person skilled in the art can be selected and adjusted according to the production condition, quality requirement and product requirement, and in order to better ensure the purity and yield of intermediate products and final products, the temperature of the first Buchwald-Hartwig reaction is preferably 90-130 ℃, more preferably 100-120 ℃, and more preferably 105-115 ℃. The time of the first Buchwald-Hartwig reaction is preferably 16-30 h, more preferably 18-28 h, and more preferably 20-25 h.

The present invention is not particularly limited with respect to the other starting materials or reagents for the first Buchwald-Hartwig reaction, as are conventional auxiliary starting materials or reagents for such coupling reactions well known to those skilled in the art, which can be selected and adjusted by those skilled in the art according to the production situation, quality requirements and product requirements.

The definition and reaction parameters of the second Buchwald-Hartwig reaction are not particularly limited in principle, and the Buchwald-Hartwig reaction known by the person skilled in the art can be selected and adjusted according to the production condition, quality requirement and product requirement, and in order to better ensure the purity and yield of intermediate products and final products, the temperature of the second Buchwald-Hartwig reaction is preferably 90-130 ℃, more preferably 100-120 ℃, and more preferably 105-115 ℃. The time of the second Buchwald-Hartwig reaction is preferably 16-30 h, more preferably 18-28 h, and more preferably 20-25 h.

The present invention is not particularly limited to the other starting materials or reagents for the second Buchwald-Hartwig reaction, which are conventional auxiliary starting materials or reagents for such coupling reactions well known to those skilled in the art, and can be selected and adjusted by those skilled in the art according to the production situation, quality requirements and product requirements.

For further clear and complete technical scheme, the reaction route of step 3) is preferably shown in formula 2, and formula 2 is the reaction route of step 3) in the preparation method of the dendritic fluorescent polymer compound provided by the invention.

The steps of the invention provide a method for synthesizing the space charge transfer dendritic fluorescent material, which comprises the steps of firstly synthesizing aryl bromide containing an electron acceptor unit, then synthesizing hexaphenyl bromide containing the electron acceptor through cobalt-catalyzed cyclization reaction, and finally introducing a dendritic electron donor unit through Buchwald-Hartwig reaction to obtain the fluorescent material. The invention provides an electroluminescent device based on the fluorescent material. The fluorescent material is used as an electroluminescent layer, so that ideal luminous efficiency can be obtained, and the requirement of preparing a luminescent device by solution processing is met.

The structure and material of the dendritic fluorescent polymer compound in the organic electroluminescent device method and the corresponding preferred principle can correspond to the material and structure of the dendritic fluorescent polymer compound and the corresponding preferred principle, and are not described in detail herein.

The dendritic fluorescent polymer compound in the present invention is preferably used as a light emitting material in an organic electroluminescent device, and more preferably is an electroluminescent material.

Under the above preferred conditions, the structure of the organic electroluminescent device is:

a substrate;

an anode disposed on the substrate;

the organic layers are arranged on the anode, the number of the organic layers is more than or equal to 1, and at least one of the organic layers is an organic electroluminescent layer; the organic electroluminescent layer comprises one or more fluorescent materials disclosed by the invention;

a cathode disposed on the organic layer.

The substrate is not particularly required, preferably glass or plastic, and the thickness of the substrate is preferably 0.3-0.7 mm.

According to the invention, the anode is a material susceptible to hole injection, preferably a conductive metal or conductive metal oxide, more preferably indium tin oxide.

The organic layers may be 1 or more, and at least one of the organic layers is an organic electroluminescent layer; the organic electroluminescent layer comprises one or more fluorescent materials disclosed by the invention. In the present invention, it is preferable that the fluorescent material directly constitutes the organic electroluminescent layer as a light-emitting material.

The cathode is preferably a metal including, but not limited to, calcium, magnesium, barium, aluminum, and silver, preferably aluminum.

In order to improve the performance and efficiency of the device, the organic layer between the anode and the organic electroluminescent layer preferably further comprises a hole injection layer, a hole transport layer and an electron blocking layer; the organic layer between the organic electroluminescent layer and the cathode preferably further comprises a hole blocking layer and an electron injection/transport layer. The materials and thicknesses of the hole injection layer, the hole transport layer, the electron blocking layer, the hole blocking layer, and the electron injection/transport layer are not particularly limited in the present invention and may be selected according to materials and thicknesses well known to those skilled in the art.

The preparation method of the organic electroluminescent device is not particularly limited, and can be carried out according to the following method:

forming an anode on the substrate;

forming one or more organic layers including an organic electroluminescent layer on the anode;

forming a cathode on the organic layer;

the organic electroluminescent layer comprises one or more of the fluorescent materials of the present invention.

In the process of preparing the organic electroluminescent device, the anode is first formed on the substrate, and the present invention does not specifically limit the formation manner of the anode, and may be performed according to a method well known to those skilled in the art. The substrate is not particularly required, preferably glass or plastic, and the thickness of the substrate is preferably 0.3-0.7 mm. According to the invention, the anode is a material susceptible to hole injection, preferably a conductive metal or conductive metal oxide, more preferably indium tin oxide.

After the anode is obtained, an organic layer is formed on the anode. The organic electroluminescent layer in the organic layer comprises one or more of the fluorescent materials of the present invention. The organic electroluminescent layer and the organic layers below the organic electroluminescent layer may be formed on the anode by solution spin coating, inkjet printing, offset printing, or three-dimensional printing. After the organic light emitting layer is formed, a hole blocking layer and an electron injection/transport layer can be formed on the surface of the organic light emitting layer by vacuum evaporation or spin coating.

After the organic layer is prepared, a cathode is prepared on the surface thereof, and the cathode is formed by a method known to those skilled in the art, including but not limited to vacuum deposition. The cathode is preferably a metal including, but not limited to, calcium, magnesium, barium, aluminum, and silver, preferably aluminum.

The invention provides a dendritic fluorescent polymer compound, a preparation method and application thereof (specifically an organic electroluminescent device), and the dendritic fluorescent polymer compound is a dendritic fluorescent material with space charge transfer effect. The electron donor and the electron acceptor are spatially separated, so that the fluorescent material has very low singlet state-triplet state energy level difference, further shows obvious thermal activation delayed fluorescence effect, can realize effective utilization of triplet state excitons when being used as a luminescent material of a solution processing type organic electroluminescent device, has high device luminous efficiency, and solves the technical problem of low device efficiency of the traditional dendritic fluorescent material based on chemical bond charge transfer.

The space charge transfer dendritic fluorescent material provided by the invention has space charge transfer luminescence from a dendritic electron donor unit to an electron acceptor unit, the luminescence peak position is positioned in a visible light range, and the luminescence color can be changed by changing the chemical structure of the dendritic electron donor unit or the electron acceptor unit so as to cover the visible light range from blue light to green light, yellow light and red light. Meanwhile, the space charge transfer dendritic fluorescent material provided by the invention has small singlet state-triplet state energy level difference, so that the space charge transfer dendritic fluorescent material can show a remarkable thermal activation delayed fluorescence effect, and can realize effective utilization of triplet state excitons when being used as a luminescent material of a solution processing type organic electroluminescent device, so that the space charge transfer dendritic fluorescent material has high device luminescent efficiency, and can be used for preparing a high-efficiency electroluminescent device.

Experimental results show that the dendritic fluorescent macromolecular compound provided by the invention has lower singlet state-triplet state energy level difference, delta E_STThe maximum current efficiency of an electroluminescent device prepared by taking the space charge transfer dendritic fluorescent material provided by the invention as a luminescent material can reach 40.6cd/A at most, and the maximum external quantum efficiency can reach 14.2%.

In order to further illustrate the present invention, the following will describe a dendritic fluorescent polymer compound and a method for preparing the same, and an organic electroluminescent device in detail with reference to the following examples, but it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and the detailed embodiments and specific procedures are given, only for further illustrating the features and advantages of the present invention, not for limiting the claims of the present invention, and the scope of the present invention is not limited to the following examples.

Example 1

The chemical structure and the synthetic route of I-1 are as follows:

(1) preparation of intermediate 3: a500 ml three-necked flask was charged with 1(8.71g, 20mmol), 2(4.35g, 24mmol), tetrakistriphenylphosphine palladium (1.16g, 1mmol), cuprous iodide (0.38g, 2mmol) and triphenylphosphine (0.53g, 2mmol), and after replacement of argon, 100ml of anhydrous oxygen-free tetrahydrofuran and 100ml of triethylamine were introduced, respectively, and reacted at 60 ℃ for 24 hours. And cooling to room temperature, adding 100mL of dilute hydrochloric acid and dichloromethane for extraction, washing twice with dilute hydrochloric acid solution, and washing with deionized water for multiple times. The organic phase was separated, and subjected to column separation and solvent removal to obtain 5.3g of the compound having the structure shown in intermediate 3, with a yield of 54%.

(2) Preparation of intermediate 4 and intermediate 5:

intermediate 3(3.2g, 6.6mmol), dicobalt octacarbonyl (0.45g, 1.32mmol) and 30ml1, 4-dioxane were added to a 50ml Schlenk flask under argon atmosphere and reacted at 120 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated and separated by column separation and desolventization to give 1.12g of the compound of the structure shown by intermediate 4 in 36% yield and 0.71g of the compound of the structure shown by intermediate 5 in 22% yield.

(3) And preparing a fluorescent material I-1:

intermediate 4(0.44g, 0.3mmol), 6(0.51g, 1) was added to a 50ml Schlenk flask under an argon atmosphere.8mmol)，Pd₂(dba)₃(83mg，0.09mmol)，t-Bu₃PHBF₄(105mg, 0.36mmol), t-BuONa (0.35g, 3.6mmol), followed by 20mL of toluene and reaction at 110 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase is separated out, and the fluorescent material I-10.31g is obtained by column separation and desolventizing separation, with the yield of 50%. C147H126N12 elemental analysis (%). C, 85.68; h, 6.16; n, 8.16; MALDI-TOF (m/z):2059

Example 2

The synthetic route is as follows:

intermediate 5(0.44g, 0.3mmol), 6(0.51g, 1.8mmol), Pd were added to a 50ml Schlenk flask under an argon atmosphere₂(dba)₃(83mg，0.09mmol)，t-Bu₃PHBF₄(105mg, 0.36mmol), t-BuONa (0.35g, 3.6mmol), followed by 20mL of toluene and reaction at 110 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated, and column separation and desolventization gave fluorescent material II-10.29g with 47% yield. C147H126N12 elemental analysis (%). C, 85.68; h, 6.16; n, 8.16; MALDI-TOF (m/z):2059

Example 3

The synthetic route is as follows:

the preparation of example 3 was identical to that of example 1, with reference to the preparation feed ratio and the reaction procedure of material I-1 in example 1, and 6 was changed to 7 to obtain fluorescent material I-2 with a yield of 45%. C243H216N18 elemental analysis (%): C, 86.13; h, 6.43; n, 7.44; MALDI-TOF (m/z):3385.7

Example 4

The synthetic route is as follows:

the preparation of example 4 was the same as example 1, and the production yield of fluorescent material I-3 was 25% by changing 6 to 8 with reference to the preparation feed ratio and reaction procedure of material I-1 in example 1. Elemental analysis (%) -C435H 396N 30-C, 86.44; h, 6.60; n, 6.95; MALDI-TOF (m/z):6039.2

Example 5

The synthetic route is as follows:

the preparation of example 5 was identical to that of example 1, with reference to the preparation feed ratio and reaction procedure of material I-1 in example 1, and 6 was changed to 9 to obtain fluorescent material I-4 with a yield of 45%. C132H96N12 elemental analysis (%). C, 85.69; h, 5.23; n, 9.08; MALDI-TOF (m/z):1848.8

Example 6

The synthetic route is as follows:

the preparation of example 6 was the same as that of example 2, and the production yield of fluorescent material II-3 was 47% by changing 6 to 9 with reference to the preparation charge ratio and reaction procedure of material II-1 in example 2. C132H96N12 elemental analysis (%). C, 85.69; h, 5.23; n, 9.08; MALDI-TOF (m/z):1848.8

Example 7

The synthetic route is as follows:

the preparation of example 7 was the same as that of example 1, and the production yield of fluorescent material I-5 was 48% by changing 6 to 10 with reference to the preparation feed ratio and reaction procedure of material I-1 in example 1. C222H174N18 elemental analysis (%). C, 86.18; h, 5.67; n, 8.15; MALDI-TOF (m/z):3091.4

Example 8

The synthetic route is as follows:

example 8 was prepared in the same manner as in example 1 except that 6 was changed to 11 to obtain a fluorescent material I-8 in a yield of 45% with reference to the preparation charge ratio and the reaction procedure of the material I-1 in example 1. C195H120N18O9 elemental analysis (%). C, 81.92; h, 4.23; n, 8.82; o, 5.04; MALDI-TOF (m/z):2857

Example 9

The synthetic route is as follows:

the preparation of example 9 was carried out in the same manner as in example 1, except that 6 was changed to 12 to obtain a fluorescent material I-11 in a yield of 55% with reference to the preparation feed ratio and the reaction procedure of the material I-1 in example 1. C129H96N12Si3 elemental analysis (%). C, 81.61; h, 5.10; n, 8.85; si, 4.44; MALDI-TOF (m/z):1896.7

Example 10

The synthetic route is as follows:

example 10 was prepared in the same manner as in example 1 except that 6 was changed to 13 to obtain a fluorescent material I-12 in a yield of 45% with reference to the preparation charge ratio and the reaction procedure of the material I-1 in example 1. C213H174N18Si9 elemental analysis (%). C, 78.99; h, 5.42; n, 7.78; si, 7.81; MALDI-TOF (m/z):3235.2

Example 11

The synthetic route is as follows:

(1) preparation of intermediate 15: a500 ml three-necked flask was charged with 14(2.78g, 6mmol), 2(1.31g, 7.2mmol), tetrakis (triphenylphosphine) palladium (0.35g, 0.3mmol), cuprous iodide (0.11g, 0.6mmol) and triphenylphosphine (0.16g, 0.6mmol), and after replacement of argon, 100ml of anhydrous oxygen-free tetrahydrofuran and 100ml of triethylamine were injected, respectively, and reacted at 60 ℃ for 24 hours. And cooling to room temperature, adding 100mL of dilute hydrochloric acid and dichloromethane for extraction, washing twice with dilute hydrochloric acid solution, and washing with deionized water for multiple times. The organic phase was separated, and subjected to column separation and solvent removal to obtain 1.71g of the compound having the structure shown by intermediate 15, with a yield of 55%.

(2) Preparation of intermediate 16 and intermediate 17:

intermediate 15(1.55g, 3mmol), dicobalt octacarbonyl (0.20g, 0.6mmol) and 20ml1, 4-dioxane were added to a 50ml Schlenk flask under argon atmosphere and reacted at 120 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated and separated by column separation and desolventization to give 0.59g of the compound of the structure shown by intermediate 16 in 38% yield and 0.70g of the compound of the structure shown by intermediate 17 in 45% yield.

(3) And preparing a fluorescent material I-15:

intermediate 16(0.15g, 0.1mmol), 10(0.28g, 0.45mmol), Pd were added to a 50ml Schlenk flask under argon atmosphere₂(dba)₃(27mg，0.03mmol)，t-Bu₃PHBF₄(34mg, 0.12mmol), t-BuONa (0.11g, 1.2mmol), followed by 20mL of toluene, and reaction at 110 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated, and column separation and desolventization gave 60% yield of fluorescent material I-150.12 g. C228H186N18 elemental analysis (%). C, 86.17; h, 5.90; n, 7.93; MALDI-TOF (m/z):3175.5

Example 12

The synthetic route is as follows:

(1) preparation of intermediate 19: 18(3.43g, 6mmol), 2(1.31g, 7.2mmol), tetrakis (triphenylphosphine) palladium (0.35g, 0.3mmol), cuprous iodide (0.11g, 0.6mmol) and triphenylphosphine (0.16g, 0.6mmol) were added to a 500 ml three-necked flask, and after replacement of argon, 100ml of anhydrous oxygen-free tetrahydrofuran and 100ml of triethylamine were injected, respectively, and reacted at 60 ℃ for 24 hours. And cooling to room temperature, adding 100mL of dilute hydrochloric acid and dichloromethane for extraction, washing twice with dilute hydrochloric acid solution, and washing with deionized water for multiple times. The organic phase was separated, and 2.2g of the compound having the structure shown in intermediate 19 was obtained by column separation and solvent removal, with a yield of 58%.

(2) Preparation of intermediate 20 and intermediate 21:

intermediate 19(1.87g, 3mmol), dicobalt octacarbonyl (0.20g, 0.6mmol) and 20ml1, 4-dioxane were added to a 50ml Schlenk flask under argon atmosphere and reacted at 120 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated and separated by column separation and desolventization to give 0.37g of the compound of the structure shown by intermediate 20 in 20% yield and 0.81g of the compound of the structure shown by intermediate 21 in 43% yield.

(3) And preparing a fluorescent material I-17:

intermediate 20(0.19g, 0.1mmol), 10(0.28g, 0.45mmol), Pd were added to a 50ml Schlenk flask under an argon atmosphere₂(dba)₃(27mg，0.03mmol)，t-Bu₃PHBF₄(34mg, 0.12mmol), t-BuONa (0.11g, 1.2mmol), followed by 20mL of toluene, and reaction at 110 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated, and column separation and desolventization gave 49% yield of fluorescent material I-170.17 g. C228H168F18N18 elemental analysis (%). C, 78.20; h, 4.84; f, 9.77; n, 7.20; MALDI-TOF (m/z):3499.3 example 13

The synthetic route is as follows:

(1) preparation of intermediate 23: 22(2.09g, 6mmol), 2(1.31g, 7.2mmol), tetrakis (triphenylphosphine) palladium (0.35g, 0.3mmol), cuprous iodide (0.11g, 0.6mmol) and triphenylphosphine (0.16g, 0.6mmol) were added to a 500-ml three-necked flask, and after replacement of argon, 100ml of anhydrous oxygen-free tetrahydrofuran and 100ml of triethylamine were injected, respectively, and reacted at 60 ℃ for 24 hours. And cooling to room temperature, adding 100mL of dilute hydrochloric acid and dichloromethane for extraction, washing twice with dilute hydrochloric acid solution, and washing with deionized water for multiple times. The organic phase was separated, and subjected to column separation and solvent removal to obtain 1.21g of the compound having the structure shown by intermediate 23, with a yield of 50%.

(2) Preparation of intermediate 24 and intermediate 25:

intermediate 23(1.20g, 3mmol), dicobalt octacarbonyl (0.20g, 0.6mmol) and 20ml1, 4-dioxane were added to a 50ml Schlenk flask under argon atmosphere and reacted at 120 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated and separated by column separation and desolventization to give 0.24g of the compound of the structure shown by intermediate 24 in 20% yield, 0.50g of the compound of the structure shown by intermediate 25 in 41% yield.

(3) And preparing a fluorescent material I-26:

intermediate 24(0.12g, 0.1mmol), 10(0.28g, 0.45mmol), Pd were added to a 50ml Schlenk flask under an argon atmosphere₂(dba)₃(27mg，0.03mmol)，t-Bu₃PHBF₄(34mg, 0.12mmol), t-BuONa (0.11g, 1.2mmol), followed by 20mL of toluene, and reaction at 110 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated, and column separation and desolventization were carried out to obtain fluorescent material I-260.11 g with a yield of 40%. Elemental analysis (%) for C201H159N15O 3C, 85.23; h, 5.66; n, 7.42; o, 1.69; MALDI-TOF (m/z):2830.3 example 14

The synthetic route is as follows:

(1) preparation of intermediate 27: 26(2.72g, 6mmol), 2(1.31g, 7.2mmol), tetrakis (triphenylphosphine) palladium (0.35g, 0.3mmol), cuprous iodide (0.11g, 0.6mmol) and triphenylphosphine (0.16g, 0.6mmol) were added to a 500 ml three-necked flask, and after argon gas was replaced, 100ml of anhydrous oxygen-free tetrahydrofuran and 100ml of triethylamine were injected, respectively, and reacted at 60 ℃ for 24 hours. And cooling to room temperature, adding 100mL of dilute hydrochloric acid and dichloromethane for extraction, washing twice with dilute hydrochloric acid solution, and washing with deionized water for multiple times. The organic phase was separated, and subjected to column separation and solvent removal to obtain 1.50g of a compound having a structure represented by intermediate 27, with a yield of 50%.

(2) Preparation of intermediate 28 and intermediate 29:

intermediate 27(1.50g, 3mmol), dicobalt octacarbonyl (0.20g, 0.6mmol) and 20ml1, 4-dioxane were added to a 50ml Schlenk flask under argon atmosphere and reacted at 120 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated and separated by column separation and desolventization to give 0.30g of the compound of the structure shown by intermediate 28 in 20% yield and 0.59g of the compound of the structure shown by intermediate 29 in 39% yield.

(3) And preparing a fluorescent material I-30:

intermediate 28(0.15g, 0.1mmol), 10(0.28g, 0.45mmol), Pd were added to a 50ml Schlenk flask under an argon atmosphere₂(dba)₃(27mg，0.03mmol)，t-Bu₃PHBF₄(34mg, 0.12mmol), t-BuONa (0.11g, 1.2mmol), followed by 20mL of toluene, and reaction at 110 ℃ for 24 hours. Cooled to room temperature, added with deionized water and dichloromethane 100mL for extraction, and washed with deionized water several times. The organic phase was separated, and column separation and desolventization gave 38% yield of fluorescent material I-300.12 g. C231H210B3N9 elemental analysis (%). C, 88.23; h, 6.73; b, 1.03; n, 4.01; MALDI-TOF (m/z):3142.7 Performance test was performed on fluorescent materials I-1, I-4, I-5, and I-17 prepared in the examples of the present invention.

Referring to Table 1, Table 1 shows the photophysical properties of the fluorescent materials I-1, I-4, I-5 and I-17 prepared in the examples of the present invention.

TABLE 1

As shown in Table 1, the space charge transfer dendritic fluorescent material provided by the invention has space charge transfer luminescence from the dendritic electron donor unit to the electron acceptor unit, the luminescence peak positions are all positioned in a visible light range, and the luminescence color can be changed by changing the chemical structure of the dendritic electron donor unit or the electron acceptor unit so as to cover the visible light range from blue light to green light, yellow light and red light. For example, the toluene solution of I-1 has a luminescence peak at 444nm, and is blue light emission; the luminescent peak position of the toluene solution of I-5 is 507nm and is green light emission, and the luminescent peak position of the toluene solution of I-17 is 551nm and is yellow light emission. On the other hand, the space charge transfer dendritic fluorescent material provided by the invention has small singlet state-triplet state energy level difference (0.01 eV-0.15 eV), thereby showing a remarkable thermal activation delayed fluorescence effect, being applied to an organic electroluminescent device and being beneficial to the utilization of triplet state excitons, and having high luminous efficiency.

The fluorescent materials I-1, I-4, I-5 and I-17 prepared in the examples of the invention were characterized.

Referring to fig. 1, fig. 1 is a graph showing a fluorescence spectrum of a fluorescent material I-1 prepared in an example of the present invention in a toluene solution.

Referring to fig. 2, fig. 2 is a graph showing the fluorescence spectrum of the fluorescent material I-4 prepared in the example of the present invention in a toluene solution.

Referring to fig. 3, fig. 3 is a graph showing the fluorescence spectrum of the fluorescent material I-5 prepared in the example of the present invention in a toluene solution.

Referring to FIG. 4, FIG. 4 is a graph showing the fluorescence spectrum of fluorescent material I-17 prepared in the example of the present invention in toluene solution.

Referring to FIG. 5, FIG. 5 is a graph showing fluorescence (298K) and phosphorescence (77K) spectra of a film prepared by doping polystyrene (1 wt%) with fluorescent material I-5 prepared in an example of the present invention.

Referring to FIG. 6, FIG. 6 is a graph showing a transient fluorescence decay curve (298K) of a film prepared by doping polystyrene (1 wt%) with the fluorescent material I-5 prepared in the example of the present invention.

Example 15

Example of the device: spin-coating poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid) (PEDOT/PSS) on indium tin oxide supported on a glass substrate, and annealing at 120 ℃ for 30 min; then preparing the fluorescent material prepared by the invention and the main material shown in figure 6 into chlorobenzene solution, spin-coating at the speed of 1200 r/min for 1min, annealing at 80 ℃ for 30min, and forming a light-emitting layer of 40nm-60nm on PEDOT/PSS; then at 4X 10^-4And sequentially depositing TSPO1, TmPyPB and a LiF/Al cathode under the vacuum degree of Pa to obtain the organic electroluminescent device, wherein TSPO1 and TmPyPB are respectively used as a hole blocking layer and an electron transport layer. The specific device structure is PEDOT, PSS (40nm)/EML (40nm-40nm)/TSPO1(8nm)/TmPyPB (42nm)/LiF (1nm)/Al (100 nm).

Referring to fig. 7, fig. 7 is a structural formula of a host material, TSPO1, and TmPyPB in an organic electroluminescent device prepared in example 15 of the present invention. Including Host-I, Host-II, TSPO1 and TmPyPB.

Example 16

The obtained electroluminescent device is characterized and tested for performance by taking the fluorescent material I-4 as an example.

Referring to fig. 8, fig. 8 is an electroluminescence spectrum of an electroluminescence device produced in example 16 of the present invention.

Referring to fig. 9, fig. 9 is a graph of current efficiency versus luminance characteristics of an electroluminescent device prepared in example 16 of the present invention.

Referring to table 2, table 2 shows performance parameters of electroluminescent devices prepared in example 16 of the present invention.

TABLE 2

Example 17

The obtained electroluminescent device is characterized and tested for performance by taking the fluorescent material I-5 as an example.

Referring to fig. 10, fig. 10 is an electroluminescence spectrum of an electroluminescence device produced in example 17 of the present invention.

Referring to fig. 11, fig. 11 is a graph showing current efficiency-luminance characteristics of an electroluminescent device prepared in example 17 of the present invention.

Referring to table 3, table 3 shows the performance parameters of the electroluminescent device prepared in example 17 of the present invention.

TABLE 3

Example 18

The obtained electroluminescent device is characterized and tested for performance by taking the fluorescent material I-15 as an example.

Referring to fig. 12, fig. 12 is an electroluminescence spectrum of an electroluminescence device produced in example 18 of the present invention.

Referring to fig. 13, fig. 13 is a graph of current efficiency-luminance characteristics of an electroluminescent device prepared in example 18 of the present invention.

Referring to table 4, table 4 shows the performance parameters of the electroluminescent device prepared in example 18 of the present invention.

TABLE 4

The present invention provides a dendritic fluorescent material with space charge transfer effect and a method for preparing the same, and an organic electroluminescent device, which are described in detail above, and the principle and embodiments of the present invention are explained herein by using specific examples, and the description of the above examples is only for helping to understand the method of the present invention and the core idea thereof, including the best mode, and also for enabling any person skilled in the art to practice the present invention, including making and using any device or system, and implementing any method in combination. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A dendrimer, characterized in that the dendrimer has the structure of formula (I) or (II),

wherein the content of the first and second substances,

is a dendritic electron donor, A is an electron acceptor;

n is 1, 2, 3 or 4;

the above-mentioned

Is selected from any one or more of the formulas (I/II-I) to (I/II-IX):

a is selected from substituted or unsubstituted C₂～C₆₀Nitrogen-containing aromatic heterocycle, substituted or unsubstituted C₂～C₆₀With boron-containing heteroaromatic ring, substituted or unsubstituted C₂～C₆₀The aromatic heterocycle containing carbonyl, substituted or unsubstituted C₂～C₆₀Sulfur sulfone-containing aromatic heterocycle, substituted or unsubstituted C₂～C₆₀And substituted or unsubstituted C₂～C₆₀One or more of the imide group-containing aromatic rings of (a);

said substituted or unsubstituted C₅～C₂₀Heterocycloalkyl, substituted or unsubstituted C₂～C₂₀In the heteroaryl group of (a), the heteroatom is selected from one or more of-Si (R ') -, -B (R ') -, -N (R ') -, -P (R ') -, and-PO (R ') -;

said substituted C₁～C₂₀Alkyl or substituted C₁～C₂₀In the alkoxy group, the substitution means that one or more nonadjacent carbon atoms in the alkyl group or the alkoxy group are O, S, Si and-one or more substitutions in CO-O-; and/or one or more hydrogen atoms are replaced by F.

2. A dendrimer, characterized in that the dendrimer has the structure of formula (I) or (II),

wherein the content of the first and second substances,

is a dendritic electron donor, A is an electron acceptor;

n is 1, 2, 3 or 4;

the above-mentioned

Is selected from any one or more of the formulas (I/II-I) to (I/II-IX):

said substituted C₁～C₂₀Alkyl or substituted C₁～C₂₀In the alkoxy group of (a), the substitution means that one or more nonadjacent carbon atoms in the alkyl group or the alkoxy group are substituted with one or more of O, S, Si and-CO-O-; and/or one or more hydrogen atoms are replaced by F;

a is selected from any one or more of formulas (I/II-a) to (I/II-h):

Z₆selected from nitrogen atoms or oxygen atoms.

3. The dendrimer compound according to any one of claims 1 to 2, wherein R is selected from the group consisting of H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₁～C₂₀Alkoxy, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted or unsubstituted C₅～C₂₀And substituted or unsubstituted C₆～C₂₀One or more of aryl groups of (a);

said substituted C₁～C₂₀Alkyl or substituted C₁～C₂₀In the alkoxy group of (a), the substitution means that one or more nonadjacent carbon atoms in the alkyl group or the alkoxy group are substituted with O and/or S.

4. The dendrimer compound according to any one of claims 1 to 2, wherein the fluorescent polymer is

5. a dendrimer, characterized in that the dendrimer has the structure of formula (I) or (II),

wherein the content of the first and second substances,

is a dendritic electron donor, A is an electron acceptor;

n is 1, 2, 3 or 4;

the above-mentioned

Is selected from any one or more of the formulas (I/II-I) to (I/II-IX):

r is selected from H, halogen, -CF₃、-CN、-NO₂Substituted or unsubstituted C₁～C₂₀Alkyl, substituted or unsubstituted C₁～C₂₀Alkoxy, substituted or unsubstituted C₃～C₂₀Cycloalkyl, substituted orUnsubstituted C₅～C₂₀Heterocycloalkyl, substituted or unsubstituted C₆～C₂₀Aryl and substituted or unsubstituted C₂～C₂₀One or more of the heteroaryl groups of (a);

a is selected from any one or more of formula (27) to formula (57);

6. the dendrimer compound according to any one of claims 1 to 2, wherein the dendrimer compound has a structure represented by any one of formulae I-1 to I-35, or a structure represented by any one of formulae II-1 to II-8;

7. a method for preparing a dendrimer compound according to any one of claims 1, 2, or 5, comprising the steps of:

8. the preparation method of claim 7, wherein the temperature of the Sonogashira coupling reaction is 40-80 ℃;

the time of the Sonogashira coupling reaction is 16-30 h;

the temperature of the cyclotrimerization reaction is 100-140 ℃;

the time of the cyclotrimerization reaction is 40-60 h;

the temperature of the first Buchwald-Hartwig reaction is 90-130 ℃;

the first Buchwald-Hartwig reaction time is 16-30 h;

the temperature of the second Buchwald-Hartwig reaction is 90-130 ℃;

the time of the second Buchwald-Hartwig reaction is 16-30 h.

9. An organic electroluminescent device comprising an electroluminescent material; the electroluminescent material comprises the dendritic fluorescent polymer compound as set forth in any one of claims 1 to 6 or the dendritic fluorescent polymer compound prepared by the preparation method as set forth in any one of claims 7 to 8.