阅读说明：本技术 一类咔唑-吩噻嗪有机染料及其在染料敏化太阳能电池中的应用 (Carbazole-phenothiazine organic dye and application thereof in dye-sensitized solar cell ) 是由 密保秀 谈天雯 高志强 于 2019-06-05 设计创作，主要内容包括：本发明涉及一类咔唑-吩噻嗪有机染料及其在染料敏化太阳能电池中的应用,此类纯有机染料具有吩噻嗪和咔唑基团,且吩噻嗪与咔唑基团通过对位或邻位苯连接,具有如下图所示通式。将本发明的染料应用于染料敏化太阳能器件中,获得较高的光电转化效率。本发明染料制备方法较为简单,成本低廉,其制备电池光电转化效率高,具有商业化应用前景。(the invention relates to a carbazole-phenothiazine organic dye and application thereof in a dye-sensitized solar cell. The dye is applied to a dye-sensitized solar device to obtain higher photoelectric conversion efficiency. The dye preparation method is simple, low in cost, high in photoelectric conversion efficiency of the prepared battery, and has a commercial application prospect.)

1. a carbazole-phenothiazine organic dye is characterized in that: the organic dye has the following structural formula 1 or structural formula 2:

wherein Ar1, Ar2, Ar3 and Ar4 are respectively and independently selected from a hydrogen atom, an aromatic hydrocarbon group, crown ether, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 and alkoxy of C1-C20, and R is selected from a hydrogen atom, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 or alkoxy of C1-C20.

2. A class of carbazole-phenothiazine organic dyes according to claim 1 characterised in that: the organic dye conforms to a structural formula 1, wherein Ar1, Ar2, Ar3 and Ar4 are hydrogen atoms, and R is selected from the hydrogen atoms, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 or alkoxy of C1-C20.

3. A class of carbazole-phenothiazine organic dyes according to claim 2, characterized in that: the organic dye is in accordance with a structural formula 1, and R is ethyl or 2-ethylhexyl.

4. a class of carbazole-phenothiazine organic dyes according to claim 3 characterised in that: the organic dye with R as ethyl has the following structure

The organic dye with R being 2-ethylhexyl has the following structure

5. A class of carbazole-phenothiazine organic dyes according to claim 1 characterised in that: the dye conforms to a structural formula 2, wherein Ar1, Ar2, Ar3 and Ar4 are hydrogen atoms, and R is selected from the hydrogen atoms, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 or alkoxy of C1-C20.

6. A class of carbazole-phenothiazine organic dyes according to claim 6, characterized in that: the organic dye is in accordance with a structural formula 2, and R is ethyl or 2-ethylhexyl.

7. A class of carbazole-phenothiazine organic dyes according to claim 6, characterized in that: the organic dye with R as ethyl has the following structure

The organic dye with R being 2-ethylhexyl has the following structure

8. a dye-sensitized solar cell prepared using a carbazole-phenothiazine organic dye of one class according to claims 1 to 8, characterized in that: the photosensitizer of the organic dye-sensitized solar cell is the o/p-carbazole-phenylene-phenothiazine pure organic dye as defined in any one of claims 1 to 8.

Technical Field

the invention relates to a carbazole-phenothiazine organic dye and application thereof in a dye-sensitized solar cell, belonging to the technical field of organic photoelectric materials and organic photoelectric conversion application.

Background

since the introduction of nanotechnology and the creation of dye-sensitized solar cells (DSSCs) in 1991, DSSCs have become a hotspot in current scientific research due to the advantages of high theoretical efficiency, simple preparation method, low production cost, safety, no toxicity and the like.

the DSSC is a solar cell device utilizing a combination of a wide band gap oxide semiconductor and a sensitizer dye, and its structure mainly comprises four parts: photoanode, dye, electrolyte and electrode. When sunlight irradiates on the dye sensitizer, the dye is transited from a ground state to an excited state, electrons at the LUMO energy level are injected into a conduction band of the nano semiconductor material and then reach an electrode, and a current loop is formed through an external circuit, so that solar energy is converted into electric energy. In DSSCs, the dye molecule acts to absorb sunlight, acting as a carrier of energy, and the performance of the sensitizer directly affects the efficiency of the cell.

currently, dye sensitizers are mainly classified into two types, metal complex dyes and pure organic dyes. Although metal complex dyes perform well in devices, their use with rare earth metals, complex synthesis and purification, and low molar extinction coefficients limit future large-scale commercial production. The development of another pure organic dye has made a significant breakthrough since the D-pi-A structure which is helpful for light-induced charge separation is proposed. The pure organic dye has the advantages of high molar extinction coefficient, various structures, no dependence on rare earth metal, convenient synthesis and purification and the like, thereby being a class of rapidly developed dyes. However, the efficiency with which currently known organic dye sensitizers collect and convert solar energy still does not meet the increasing energy demand of people. Therefore, the development of an organic dye sensitizer having high photoelectric conversion efficiency is of great practical significance.

Research shows that reasonable dye molecule design (i.e., (i) having groups capable of firmly adsorbing to the surface of a semiconductor, (ii) having a redox potential more positive than that of an electrolyte, (iii) having a LUMO energy level more negative than that of a conduction band of a semiconductor, (iv) having a more stable oxidation state and excited state, and (iv) having a wider spectral response to sunlight) will result in a high performance dye sensitizer, and thus a high efficiency DSSCs. The pure organic dye provided by the invention is expected to commercialize the dye-sensitized solar cell by virtue of the advantages of wide absorption spectrum, simple synthesis and high cell manufacturing efficiency.

Disclosure of Invention

The invention aims to: aiming at the defects in the prior art, the carbazole-phenothiazine organic dye and the dye-sensitized solar cell device thereof are provided, and the device can effectively absorb visible light and has high photoelectric conversion efficiency.

In order to achieve the above object, the present invention provides a carbazole-phenothiazine organic dye having the following structural formula 1 or structural formula 2:

Wherein Ar1, Ar2, Ar3 and Ar4 are respectively and independently selected from a hydrogen atom, an aromatic hydrocarbon group, crown ether, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 and alkoxy of C1-C20, and R is selected from a hydrogen atom, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 or alkoxy of C1-C20.

In the above organic dye, a phenothiazine group is contained. The phenothiazine group has electron-rich sulfur atoms and nitrogen atoms and forms a non-planar butterfly-shaped conjugated structure, and the structure can effectively inhibit molecular aggregation. When the molecule changes to an oxidized state, the phenothiazine ring changes to a relatively planar state again, which is advantageous for the transfer of charge within the molecule. Phenothiazine is introduced into molecules of the dye sensitizer to be used as a pi bridge, so that the electron-donating capability of the molecules can be effectively increased. Different functional groups can be introduced in the aspect of modification of the N position of a phenothiazine group, so that the solubility and the absorption wavelength of molecules can be effectively adjusted, and the morphology of the molecules on the surface of a semiconductor is improved. Meanwhile, if a longer alkyl chain is connected, a tighter hydrophobic environment can be created, and the dye is prevented from being dissociated due to contact with water vapor, so that the organic dye has good environmental universality.

In conclusion, the organic dye provided by the invention has better light absorption capacity and good molecular electron donating capacity, and is beneficial to charge transfer in molecules. At the same time, the cyanoacrylate functional group enables the dye to be firmly adsorbed to the semiconductor. Therefore, the dye-sensitized solar cell with excellent performance and high photoelectric conversion efficiency can be obtained by introducing the dye-sensitized solar cell into the dye-sensitized solar cell.

Further, in one technical scheme, the dye conforms to a structural formula 1, wherein Ar1, Ar2, Ar3 and Ar4 are hydrogen atoms, and R is selected from the group consisting of hydrogen atoms, straight-chain alkyl groups of C1-C20, branched-chain alkyl groups of C1-C20 or alkoxy groups of C1-C20. Preferably, R in the formula I is ethyl or 2-ethylhexyl.

further, the organic dye in which R is ethyl has the following structure, and for convenience of explanation, the dye in which R is ethyl is hereinafter named pCBPTZ-n2,

The organic dye in which R is 2-ethylhexyl has the following structure, and for convenience of explanation, the dye in which R is 2-ethylhexyl is hereinafter named pCBPTZ-b8,

Further, in another technical scheme, the dye conforms to a structural formula 2, wherein Ar1, Ar2, Ar3 and Ar4 are hydrogen atoms, and R is selected from the group consisting of hydrogen atoms, straight-chain alkyl groups of C1-C20, branched-chain alkyl groups of C1-C20 or alkoxy groups of C1-C20. Preferably, R in the formula II is ethyl or 2-ethylhexyl.

Further, the organic dye in which R is ethyl has the following structure, and for convenience of explanation, the dye in which R is ethyl is hereinafter named oCBPTZ-n2,

The organic dye in which R is 2-ethylhexyl has the following structure, and for convenience of explanation, the dye in which R is 2-ethylhexyl is hereinafter named oCBPTZ-b8,

A dye-sensitized solar cell prepared from carbazole-phenothiazine organic dye, wherein a photosensitizer of the organic dye-sensitized solar cell is the o/p-carbazole-phenylene-phenothiazine organic dye as claimed in any one of claims 1 to 8. The organic dye-sensitized solar cell structure mainly comprises transparent conductive glass, a nano titanium dioxide porous semiconductor film, a photosensitizer, an electrolyte and a transparent counter electrode. The pure organic dye-sensitized solar cell mainly comprises transparent conductive glass, a nano titanium dioxide porous semiconductor film, a photosensitizer, an electrolyte and a transparent counter electrode,

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

1. The organic dye provided by the invention has strong conjugation effect, and increases the electron-donating ability and the light-absorbing ability of molecules.

2. The connection mode of carbazole and phenothiazine is changed, the absorption wavelength of molecules can be effectively adjusted, and the appearance of the molecules on the surface of a semiconductor is improved.

3. the N-position substituent of the phenothiazine group is changed, the solubility and the absorption wavelength of the molecule can be effectively adjusted, the appearance of the molecule on the surface of a semiconductor is improved, and the dye has environmental universality.

4. The invention provides a dye-sensitized solar cell which can effectively absorb visible light, has high photoelectric conversion efficiency and is expected to commercialize the dye-sensitized solar cell.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a spectrum of the ultraviolet visible absorption (UV/vis) of the dye pCBPTZ-n2 in methylene chloride solution in example 1 of the present invention.

FIG. 2 is a graph of the ultraviolet visible absorption (UV/vis) spectrum of the dye oCBPTZ-b8 in methylene chloride solution in example 2 of the present invention.

FIG. 3 is a spectrum of the ultraviolet visible absorption (UV/vis) of the dye pCBPTZ-b8/oCBPTZ-n2 in methylene chloride solution in example 3 of the present invention.

Fig. 4 is a current-voltage graph for preparing a dye-sensitized solar cell based on the dye oCBPTZ-b8 in example 4 of the present invention.

FIG. 5 is a graph of current versus voltage for cells prepared based on the dyes pCBPTZ-n2, pCBPTZ-b8, or oCBPTZ-n2 of example 5 of the present invention.

FIG. 6 is a J-V plot of the structural formula of a class of carbazole-phenothiazine dyes plus oCBPTZ-b8 in accordance with the present invention.

Detailed Description

The following detailed description of specific embodiments of the invention is provided, but it should be understood that the scope of the invention is not limited to the specific embodiments.

The carbazole-phenothiazine organic dye provided by the invention has the following structural formula 1 or structural formula 2:

wherein Ar1, Ar2, Ar3 and Ar4 are respectively and independently selected from a hydrogen atom, an aromatic hydrocarbon group, crown ether, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 and alkoxy of C1-C20, and R is selected from a hydrogen atom, straight-chain alkyl of C1-C20, branched-chain alkyl of C1-C20 or alkoxy of C1-C20.

The invention also provides a preparation method of the carbazole-phenothiazine organic dye, which comprises the following three steps:

the first step is as follows: the synthesis of the phenothiazine pi bridge comprises the following specific processes:

dissolving phenothiazine, halogenated hydrocarbon and strong base solid in an organic solvent at a molar ratio of 1:0.5-4.5:0.5-3, reacting at room temperature for 6-10 hours, quenching, extracting an organic phase, and separating by silica gel column chromatography to obtain phenothiazine derivative A; dissolving the phenothiazine derivative A in a second organic solvent, and dropwise adding a treated mixed solution of phosphorus oxychloride and N, N-dimethylformamide at 50-70 ℃, wherein the treatment method comprises the steps of mixing and stirring the phosphorus oxychloride and the N, N-dimethylformamide to be reddish brown, stopping reaction for 15-20 hours, extracting an organic phase, and performing silica gel column chromatography to separate to obtain a phenothiazine derivative B substituted by 3-aldehyde group; and dissolving the phenothiazine derivative B in a third organic solvent, adding an N-bromosuccinimide bromine reagent in batches, reacting for 5-8 hours under a zero-temperature condition, extracting an organic phase after the reaction is finished, and performing silica gel column chromatography to separate to obtain a phenothiazine derivative C. The phenothiazine derivative C has the following molecular structure:

Wherein Ar1 is selected from a hydrogen atom, a straight-chain alkyl group of C1-C20, a branched-chain alkyl group of C1-C20 or an alkoxy group of C1-C20, Ar4 and Ar5 are respectively and independently selected from a hydrogen atom, an aromatic hydrocarbon group, crown ether, a straight-chain alkyl group of C1-C20, a branched-chain alkyl group of C1-C20 and an alkoxy group of C1-C20;

the second step is as follows: the coupling of electron donor and phenothiazine pi bridge includes the following steps:

Dissolving the phenothiazine derivative C and the phenylboronic acid derivative D in an organic solvent, and adding a potassium carbonate/potassium fluoride solution and tetrakis (triphenylphosphine) palladium; reacting the reaction solution at 60-150 ℃ for 10-30 hours under the protection of nitrogen, cooling to room temperature, pouring into water, extracting an organic phase, and separating by silica gel column chromatography to obtain an intermediate E. The molecular formulas are respectively as follows:

Wherein R is selected from a hydrogen atom, a linear alkyl group of C1-C20, a branched alkyl group of C1-C20 or an alkoxy group of C1-C20, Ar1, Ar2, Ar3 and Ar4 are respectively and independently selected from a hydrogen atom, an aromatic hydrocarbon group, crown ether, a linear alkyl group of C1-C20, a branched alkyl group of C1-C20 and an alkoxy group of C1-C20 which have no influence on each other;

The third step: the synthesis of the electron acceptor cyanoacrylate comprises the following specific processes:

mixing the intermediate E with cyanoacetic acid in an organic solvent, adding a catalyst, wherein the molar ratio n (C) of the intermediate E, the cyanoacetic acid and the catalyst is n (NC-COOH) and n (catalyst) is 1:1.0-5.0:0.5-1.5, reacting for 6-20 hours at 60-150 ℃, after the reaction is finished, cooling the reaction solution to room temperature, extracting an organic phase, and separating by silica gel column chromatography to finally obtain the organic dye.

All the steps are carried out in an anhydrous oxygen-free nitrogen environment.

the organic solvent in the first step is acetonitrile, dimethyl sulfoxide or N, N-dimethylformamide, and the second organic solvent is dichloromethane or chloroform; the organic solvent in the second step is tetrahydrofuran, toluene or ethylbenzene; the organic solvent in the third step is glacial acetic acid, acetic acid or formic acid, and the catalyst is acetate.

In the above step, the phenothiazine derivative C has the following molecular structure:

Wherein R is selected from a hydrogen atom, a linear alkyl group of C1-C20, a branched alkyl group of C1-C20 or an alkoxy group of C1-C20; preferably, in the above technical solution, R of the phenothiazine derivative C is ethyl or hexyl.

Phenylboronic acid derivative D has the following formula: