阅读说明：本技术 一种阶梯式能量传递结构的纯有机光敏染料及其制备方法和应用 (Pure organic photosensitive dye with stepped energy transfer structure and preparation method and application thereof ) 是由 宋亚坤 王豪 陈濛濛 高春园 冯国正 李帅磊 杨迪 刘汇洋 吴黄溢 刘军辉 郭旭 于 2021-09-14 设计创作，主要内容包括：本发明公开一种阶梯式能量传递结构的纯有机光敏染料及其制备方法和应用,以N,N’-二苯基-N,N’-二(4-甲基苯基)-4,4’-联苯二胺(TPB)为电子供体,以吡咯并吡咯二酮(DPP)为第一电子受体,以氰基乙酸为第二电子受体的新型D-π-A-π-A型纯有机光敏染料,N,N’-二苯基-N,N’-二(4-甲基苯基)-4,4’-联苯二胺(TPB)的“双螺旋桨”的空间结构能有效抑制染料堆积,将其作为电子供体银日到染料结构中,能够有效防止染料堆积和抑制界面电子复合。与此同时,TPB基团具有较强的供电子能力,能够有效提高染料的光电性能。用本发明的有机光敏染料制备的太阳能电池,利于敏化太阳能电池的工业化和大规模推广。(The invention discloses a pure organic photosensitive dye with a stepped energy transfer structure and a preparation method and application thereof, n, N ' -diphenyl-N, N ' -di (4-methylphenyl) -4,4 ' -biphenyldiamine (TPB) is taken as an electron donor, the novel D-pi-A type pure organic photosensitive dye taking pyrrolopyrrole-Dione (DPP) as a first electron acceptor and cyanoacetic acid as a second electron acceptor has a space structure of double propellers of N, N ' -diphenyl-N, N ' -bis (4-methylphenyl) -4,4 ' -biphenyldiamine (TPB) and can effectively inhibit dye accumulation, and the dye can be used as an electron donor for silver to enter the dye structure and can effectively prevent dye accumulation and inhibit interface electron recombination. Meanwhile, the TPB group has stronger electron donating capability, and can effectively improve the photoelectric property of the dye. The solar cell prepared by the organic photosensitive dye is beneficial to industrialization and large-scale popularization of sensitized solar cells.)

1. A pure organic photosensitive dye with a stepped energy transfer structure is characterized in that: has the structural formula shown as follows:

2. a preparation method of pure organic photosensitive dye with a stepped energy transfer structure is characterized by comprising the following steps:

firstly, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a Vilsmeier reagent, then dropwise adding a mixed solution of a compound 1 and a reaction solvent into the Vilsmeier reagent, and carrying out Vilsmeier reaction to obtain a compound 2; the synthetic route is as follows:

under the protection of nitrogen, dissolving the compound 2 and the compound 3 in dry dimethyl sulfoxide in the presence of tetrahydrofuran and strong base, and carrying out a Wittig reaction to obtain a compound 4, wherein the synthetic route is as follows:

step three, in the presence of a solvent of tertiary amyl alcohol and metallic sodium, and under the catalysis of ferrous chloride, adding a compound 4 and a compound 5 into the solvent of the tertiary amyl alcohol, and carrying out reflux reaction to obtain a compound 6, wherein the synthetic route is as follows:

and step four, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a Vilsmeier reagent, then dropwise adding a dichloromethane solution of a compound 6 into the Vilsmeier reagent, and carrying out Vilsmeier reaction to obtain a compound 7, wherein the synthetic route is as follows:

and step five, under the protection of nitrogen, mixing the compound 7 with cyanoacetic acid in the presence of acetonitrile, adding a catalyst piperidine, and carrying out Knoevenagel condensation reaction to obtain a target dye compound 8, wherein the synthetic route is as follows:

3. the method for preparing pure organic photosensitive dye with stepped energy transfer structure according to claim 2, wherein:

firstly, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a first Vilsmeier reagent, then dropwise adding a mixed solution of a compound 1 and a reaction solvent into the first Vilsmeier reagent, wherein the reaction temperature is 0-45 ℃, and carrying out Vilsmeier reaction for 10-16 h to obtain a compound 2; compound 1: phosphorus oxychloride: the molar ratio of N, N' -dimethylformamide is 1: 1-2: 2-4;

and secondly, under the protection of nitrogen, dissolving the compound 2 and the compound 3 in a dry reaction solvent in the presence of tetrahydrofuran and strong base, and carrying out Wittig reaction for 4-10 h to obtain a compound 4, wherein the molar ratio of the compound 2 to the compound 3 is 1: 1-5;

step three, adding a compound 4 and a compound 5 into a tertiary amyl alcohol solvent under the catalysis of ferrous chloride in the presence of the tertiary amyl alcohol solvent and sodium metal, and performing reflux reaction for 1-5 hours to obtain a compound 6, wherein the molar ratio of the compound 4 to the compound 5 is 1: 1-4;

step four, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a second Vilsmeier reagent, then dropwise adding a mixed solution of a compound 6 and a reaction solvent into the second Vilsmeier reagent, wherein the reaction temperature is 0-45 ℃, and performing Vilsmeier reaction for 8-16h to obtain a compound 7;

and step five, under the protection of nitrogen, mixing the compound 7 with cyanoacetic acid in the presence of acetonitrile, adding a catalyst piperidine, and carrying out Knoevenagel condensation reaction for 8-10 h to obtain a target dye compound 8, wherein the molar ratio of the compound 7 to the cyanoacetic acid is 1: 1 to 5.

4. The method for preparing pure organic photosensitive dye with stepped energy transfer structure according to claim 3, wherein: in the second step, the reaction solvent is dimethyl sulfoxide, N' -dimethylformamide or trichloromethane.

5. The method for preparing pure organic photosensitive dye with stepped energy transfer structure according to claim 4, wherein: in the second step, the strong base is sodium hydride or potassium tert-butoxide.

6. The method for preparing pure organic photosensitive dye with stepped energy transfer structure according to claim 3, wherein: in the first step and the fourth step, the reaction solvent is dichloromethane, 1, 2-dichloroethane or trichloromethane.

7. The method for preparing pure organic photosensitive dye with stepped energy transfer structure according to claim 3, wherein: in the fifth step, the target product compound 8 is post-treated by the following steps: and after the reaction is completed, steaming to obtain a crude product, and separating by adopting flash column chromatography, wherein the eluent is a mixed solution of dichloromethane and ethanol to obtain the organic dye.

8. The method for preparing pure organic photosensitive dye with stepped energy transfer structure according to claim 7, wherein: the leacheate is prepared from dichloromethane and ethanol, wherein the dichloromethane: the volume ratio of ethanol is 15-40: 1.

9. the use of the pure organic photosensitive dye with stepped energy transfer structure according to claim 1 in the preparation of dye-sensitized solar cells, wherein: the preparation method of the battery comprises the following steps: preparation of TiO by knife coating₂The film is prepared from FTO conductive glass with a substrate of sheet resistance of 15 omega and TiO₂The film consists of an upper layer and a lower layer, comprises a transparent layer at the bottom layer and a scattering layer at the upper layer, is calcined at 450 ℃ for 30 minutes, and is soaked into a dye bath of the synthesized dye when the temperature is reduced to 80 ℃; the dye bath adopts ethanol: the volume ratio of DMF is 4: 1 as solvent, the dye concentration is 0.25mM, and the co-adsorbent cholic acid concentration is 10 mM; the electrolyte adopts 3-methoxy propionitrile: the volume ratio of acetonitrile is 4: 1 as a solvent, containing 1.0M 1-hexyl-3-methylimidazolium iodide, 30mM lithium iodide, 30mM iodine, 0.1M guanidine thiocyanate and 0.5M 4-tert-butylpyridine in the respective concentrations; the synthesized organic dye compound 8 and the reference dye are respectively used as photosensitive dyes, the battery is assembled according to the battery preparation steps, and then the photoelectric performance of the battery is tested according to the same conditions.

Technical Field

The invention belongs to the technical field of dye-sensitized solar cell sensitizers, and particularly relates to a pure organic photosensitive dye with a stepped energy transfer structure, and a preparation method and application thereof.

Background

Dye-sensitized solar cells (DSCs) are one of the important research directions of solar cells, and the working principle and basic structure thereof areProfessor et al first proposed in 1991, developed for more than two decades to date, and had a maximum efficiency of 14.3%, which is a relatively promising solar cell. The cell has simple manufacturing process, low cost and no need of expensive industrial equipment and high-cleanliness factory building, and the nano TiO used for the photo-anode of the cell₂The semiconductor film, the electrolyte and other materials are safe and nontoxic. These advantages in line with the development trend of solar cells make DSCs increasingly receive the attention of scientists at home and abroad. With the mature research of the basic materials and the perfection of the device preparation process, the DSCs are expected to become one of the main solar cell products and to be widely applied in the near future.

DSCs mainly comprises transparent conductive glass and nano TiO₂The dye-sensitized solar cell comprises a porous semiconductor film, a dye photosensitizer, an electrolyte, a counter electrode and the like. In the cell, a dye sensitizer plays a role in collecting energy, and as a sunlight trapping agent, the performance of the dye sensitizer plays an important role in the photoelectric conversion efficiency of the DSCs.

After more than 20 years of research, the photoelectric conversion efficiency of the photosensitive dye is continuously refreshed. The photosensitive dyes are mainly divided into two categories of metal complex dyes and pure organic dyes. The metal complex dye has the characteristics of higher chemical stability, outstanding oxidation-reduction property, good spectral response characteristic and the like. In the year of 1993,the research group synthesizes a red dye-N3, the photoelectric conversion efficiency of DSCs based on N3 reaches 10%, and the red dye becomes a dye which breaks through 10% of the photoelectric conversion efficiency in the research history of sensitized solar cells. The N719 dye is synthesized on the basis of further optimizing the structure of N3, and the photoelectric conversion efficiency reaches 11.18 percent of the original record. N3 and N719 were the most used dyes in the earlier two studies, and also in the study of dye-sensitized solar cells. In the year of 2009, the inventor had a study of,two thiophene groups are introduced into a dye auxiliary ligand to prepare a dye CYC-B11, and the molar extinction coefficient of the dye at the position of a maximum absorption peak of 554nm reaches 2.42 multiplied by 10³m²·mol^-1Under the irradiation of AM1.5, the Jsc of the dye is 20.05mA cm^-2Voc is 743mV, and the photoelectric conversion efficiency reaches 11.5%. In the year 2011 of the human body,the dye YD2-o-C8 is synthesized by introducing long-chain alkoxy on YD-2 by the group and optimizing the structure, and the photoelectric conversion efficiency of DSCs based on YD2-o-C8 reaches 12.3%.

The pure organic dye sensitizer has the advantages of various molecular structures, high molar extinction coefficient, easily available raw materials, low cost and easy degradation compared with metal complex dyes, and is a photosensitive dye with great prospect for practical application. Recent studies have led to a great increase in the photoelectric conversion efficiency of solar cells prepared with organic dyes as sensitizers. In 2009, Zhang J L synthesized triarylamine dye C217 using a 4, 4' -dialkoxytriphenylamine group as an electron donor, EDOT-linked thiophene as a pi-bridge. In 2010, Zeng W D further optimized the structure of C217, and synthesized triarylamine dye C219. In 2015, the ADEKA-1 and a triphenylamine pure organic dye LEG4 were synthesized by Kenji Kakiag et al, and a battery device was prepared by a co-sensitization method, and the dye was the most efficient photosensitive dye so far. Therefore, the pure organic photosensitive dye containing triphenylamine groups has excellent sensitization performance, and compared with the adverse factors of long synthesis route, difficult purification, high price and the like of metal complexes, the organic photosensitive dye overcomes the defects, and especially the application of the dye is more beneficial to industrialization and large-scale popularization of sensitized solar cells. Therefore, the development of pure organic dyes is more and more emphasized by researchers, and has good development potential.

Disclosure of Invention

The invention aims to provide a pure organic photosensitive dye with a stepped energy transfer structure, which solves the problems in the prior art, and the organic photosensitive dye is a novel D-pi-A type pure organic photosensitive dye which takes N, N ' -diphenyl-N, N ' -di (4-methylphenyl) -4,4 ' -biphenyldiamine (TPB) as an electron donor, pyrrolopyrroledione (DPP) as a first electron acceptor and cyanoacetic acid as a second electron acceptor.

The invention relates to a pure organic photosensitive dye with a stepped energy transfer structure, which has the following structural formula:

another object of the present invention is to provide a method for preparing a pure organic photosensitive dye with a stepped energy transfer structure, which comprises the following steps:

firstly, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a Vilsmeier reagent, then dropwise adding a mixed solution of a compound 1 and a reaction solvent into the Vilsmeier reagent, and carrying out Vilsmeier reaction to obtain a compound 2; the synthetic route is as follows:

under the protection of nitrogen, dissolving the compound 2 and the compound 3 in dry dimethyl sulfoxide in the presence of tetrahydrofuran and strong base, and carrying out a Wittig reaction to obtain a compound 4, wherein the synthetic route is as follows:

step three, in the presence of a solvent of tertiary amyl alcohol and metallic sodium, adding a compound 4 and a compound 5 into the solvent of the tertiary amyl alcohol under the catalysis of ferrous chloride, and carrying out reflux reaction to obtain a compound 6, wherein the synthetic route is as follows:

and step four, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a Vilsmeier reagent, then dropwise adding a dichloromethane solution of a compound 6 into the Vilsmeier reagent, and carrying out Vilsmeier reaction to obtain a compound 7, wherein the synthetic route is as follows:

and step five, under the protection of nitrogen, mixing the compound 7 with cyanoacetic acid in the presence of acetonitrile, adding a catalyst piperidine, and carrying out Knoevenagel condensation reaction to obtain a target dye compound 8: TPB-DPP-S-1, the synthetic route is as follows:

as a preferred scheme, step one, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a first Vilsmeier reagent, dropwise adding a mixed solution of a compound 1 and a reaction solvent into the first Vilsmeier reagent, wherein the reaction temperature is 0-45 ℃, and performing Vilsmeier reaction for 10-16 h to obtain a compound 2; compound 1: phosphorus oxychloride: the molar ratio of N, N' -dimethylformamide is 1: 1-2: 2-4;

and secondly, under the protection of nitrogen, dissolving the compound 2 and the compound 3 in a dry reaction solvent in the presence of tetrahydrofuran and strong base, and carrying out Wittig reaction for 4-10 h to obtain a compound 4, wherein the molar ratio of the compound 2 to the compound 3 is 1: 1-5;

and step three, adding a compound 4 and a compound 5 into the solvent in the presence of a solvent tert-amyl alcohol and metallic sodium under the catalysis of ferrous chloride, and performing reflux reaction for 1-5 hours to obtain a compound 6, wherein the molar ratio of the compound 4 to the compound 5 is 1: 1-4;

step four, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a second Vilsmeier reagent, then dropwise adding a mixed solution of a compound 6 and a reaction solvent into the second Vilsmeier reagent, wherein the reaction temperature is 0-45 ℃, and performing Vilsmeier reaction for 8-16h to obtain a compound 7;

and step five, under the protection of nitrogen, mixing the compound 7 with cyanoacetic acid in the presence of acetonitrile, adding a catalyst piperidine, and carrying out Knoevenagel condensation reaction for 8-10 h to obtain a target dye compound 8, wherein the molar ratio of the compound 7 to the cyanoacetic acid is 1: 1 to 5.

Preferably, in the second step, the reaction solvent is dimethyl sulfoxide, N' -dimethylformamide or trichloromethane.

Preferably, in the second step, the strong base is sodium hydride or potassium tert-butoxide.

Preferably, in the first step and the fourth step, the reaction solvent is dichloromethane or 1, 2-dichloroethane or trichloromethane.

Preferably, in the fifth step, the target product compound 8 is post-treated by the following steps: and after the reaction is completed, steaming to obtain a crude product, and separating by adopting flash column chromatography, wherein the eluent is a mixed solution of dichloromethane and ethanol to obtain the organic dye.

Preferably, the leacheate is prepared from dichloromethane and ethanol, wherein the molar ratio of dichloromethane: the volume ratio of ethanol is 15-40: 1.

the third purpose of the scheme is to provide an application of pure organic photosensitive dye with a stepped energy transfer structure in the preparation of dye-sensitized solar cells, and the cell preparation steps are as follows: preparation of TiO by knife coating₂The film is prepared from FTO conductive glass with a substrate of sheet resistance of 15 omega and TiO₂The film consists of an upper layer and a lower layer, comprises a transparent layer at the bottom layer and a scattering layer at the upper layer, is calcined at 450 ℃ for 30 minutes, and is soaked into a dye bath of the synthesized dye when the temperature is reduced to 80 ℃; the dye bath adopts ethanol: the volume ratio of DMF is 4: 1 as solvent, the dye concentration is 0.25mM, and the co-adsorbent cholic acid concentration is 10 mM; the electrolyte adopts 3-methoxy propionitrile: the volume ratio of acetonitrile is 4: 1 as a solvent, containing 1.0M 1-hexyl-3-methylimidazolium iodide, 30mM lithium iodide, 30mM iodine, 0.1M guanidine thiocyanate and 0.5M 4-tert-butylpyridine in the respective concentrations; the synthesized organic dye compound 8 and the reference dye are respectively used as photosensitive dyes, the battery is assembled according to the battery preparation steps, and then the photoelectric performance of the battery is tested according to the same conditions.

Compared with the prior art, the invention has at least the following beneficial effects:

the space structure of double propellers of N, N ' -diphenyl-N, N ' -di (4-methylphenyl) -4,4 ' -biphenyldiamine (TPB) can effectively inhibit dye accumulation, and the dye accumulation can be effectively prevented and interface electron recombination can be inhibited by taking the dye as an electron donor. Meanwhile, the TPB group has stronger electron donating capability, and can effectively improve the photoelectric property of the dye.

TPB is used as an electron donor, cyanoacetic acid is used as an electron acceptor, DPP derivatives with different structures are introduced to be used as a pi bridge, so that the photochemical band gap of the dye is adjusted, the spectral response range of the dye is widened, and the intramolecular multistage electron transfer is realized, so that the electron transfer efficiency and the photoelectric conversion efficiency of a battery device are improved.

Thirdly, the organic dye provided by the invention is applied to the dye-sensitized solar cell, and the test result shows that: the short-circuit current of the battery device is 11.15mA/cm²The open-circuit voltage is 684mV, the fill factor is 0.74, and the photoelectric conversion efficiency reaches 5.21%, so the method has practical significance on the efficiency of the dye-sensitized solar cell.

Drawings

FIG. 1 shows the organic dye prepared in example 1 dissolved in dichloromethane (concentration 1X 10)^-5M) ultraviolet-visible absorption spectrum.

FIG. 2 shows the organic dye prepared in example 1 in TiO₂Ultraviolet spectrum on film.

FIG. 3 is a J-V curve of the dye prepared in example 1 applied to a dye-sensitized solar cell.

Fig. 4 is an IPCE curve of the dye prepared in example 1 applied to a dye-sensitized solar cell.

Detailed Description

The present invention will be explained in more detail with reference to the following examples, but it should be noted that the present invention is not limited to the following examples.

This scheme provides a cascaded energy transfer structure's pure organic photosensitive dye, has following structure:

the scheme also provides a preparation method of the pure organic photosensitive dye with the stepped energy transfer structure,

firstly, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a first Vilsmeier reagent, then dropwise adding a mixed solution of a compound 1 and a reaction solvent into the first Vilsmeier reagent, wherein the reaction temperature is 0-45 ℃, and carrying out Vilsmeier reaction for 10-16 h to obtain a compound 2; pouring the mixture into a certain amount of ice water after the reaction is finished, adjusting the pH value to be neutral by using a NaOH aqueous solution, stirring for 0.5h, adding dichloromethane with the same volume as the ice water for extraction, combining organic layers, washing by using water, adding anhydrous magnesium sulfate for drying, and purifying by using column chromatography; wherein compound 1: phosphorus oxychloride: the molar ratio of N, N' -dimethylformamide is 1: 1-2: 2-4, wherein the Vilsmeier reaction temperature is 0-45 ℃, and the reaction time is 10-16 h; the reaction solvent used in this step is dichloromethane or 1, 2-dichloroethane or trichloromethane. Preferably, dichloromethane is used. Preferably, the concentration of the dichloromethane solution of the compound 1 is 0.8 mol/L.

And secondly, under the protection of nitrogen, dissolving the compound 2 and the compound 3 in a dry reaction solvent in the presence of tetrahydrofuran and strong base, carrying out Wittig reaction for 4-10 h at normal temperature to obtain a compound 4, after the reaction is finished, pouring the reaction liquid into a certain amount of ice water, stirring for 1h, combining organic layers with dichloromethane, adding anhydrous magnesium sulfate for drying, and carrying out reduced pressure distillation to remove the solvent to obtain a yellow solid crude product containing the cis-trans isomer. Dissolving the crude product with tetrahydrofuran, adding a small amount of iodine, and carrying out reflux reaction for 9 hours. Adding a certain amount of NaOH solution with the mass fraction of 15%, stirring for 1h, removing residual iodine, extracting with dichloromethane, combining organic layers, adding anhydrous magnesium sulfate, drying, distilling under reduced pressure to remove a solvent to obtain a yellow solid, and purifying a crude product by column chromatography, wherein in the step, the molar ratio of a compound 2 to a compound 3 is 1: 1 to 5. The Wittig reaction time is 4-10 h. The strong base used in the reaction is sodium hydride or potassium tert-butoxide. The reaction solvent in the step is dimethyl sulfoxide or N, N' -dimethylformamide or trichloromethane. Preferably, dimethyl sulfoxide may be used.

And step three, adding a compound 4 and a compound 5 into the solvent in the presence of a solvent tert-amyl alcohol and metal sodium under the catalysis of ferrous chloride, performing reflux reaction for 1-5 hours to obtain a compound 6, pouring the solution into a certain amount of deionized water after the reaction is finished, and filtering to obtain a crude product. Purifying by column chromatography, and separating to obtain compound 6. In this step, the molar ratio of compound 4 to compound 5 is 1: 1 to 4.

Step four, under the protection of nitrogen, slowly dropwise adding phosphorus oxychloride into dry N, N' -dimethylformamide to prepare a second Vilsmeier reagent, then dropwise adding a mixed solution of a compound 6 and a reaction solvent into the second Vilsmeier reagent, wherein the reaction temperature is 0-45 ℃, and performing Vilsmeier reaction for 8-16h to obtain a compound 7; pouring the mixture into a certain amount of ice water after the reaction is finished, adjusting the pH value to be neutral by using a NaOH aqueous solution, stirring for 0.5h, adding dichloromethane with the same volume as the ice water for extraction and liquid separation, combining organic layers, adding anhydrous magnesium sulfate for drying, and purifying by adopting column chromatography, wherein in the step, the compound 6: phosphorus oxychloride: the molar ratio of N, N' -dimethylformamide is 1: 1-12: 1 to 12. The reaction solvent used in this step is dichloromethane or 1, 2-dichloroethane or chloroform, preferably dichloromethane.

And step five, under the protection of nitrogen, mixing the compound 7 with cyanoacetic acid in the presence of acetonitrile, adding a catalyst piperidine, heating and refluxing, carrying out Knoevenagel condensation reaction for 8-10 h to obtain a target dye compound 8, and carrying out aftertreatment on the target product compound 8 through the following steps: and after the reaction is completed, steaming to obtain a crude product, and separating by adopting flash column chromatography, wherein the eluent is a mixed solution of dichloromethane and ethanol to obtain the organic dye. In this step, the molar ratio of compound 7 to cyanoacetic acid is 1: 1 to 5. The Knoevenagel condensation reaction time is 8-10 h. The volume ratio of the leacheate is dichloromethane: 15-40% of ethanol: 1.

the synthetic route of the invention is as follows:

the design idea of the technical scheme is as follows: the design of the scheme synthesizes a novel D-pi-A type pure organic photosensitive dye which takes TPB as an electron Donor (Donor, D), DPP as a first electron Acceptor (Acceptor, A) and cyanoacetic acid as a second electron Acceptor, wherein N, N ' -diphenyl-N, N ' -di (4-methylphenyl) -4,4 ' -biphenyldiamine (TPB) and derivatives thereof are taken as important triphenylamine derivatives, and the novel D-pi-A type pure organic photosensitive dye has the advantages of higher molar extinction coefficient, excellent hole transmission performance, stronger electron donating capability and the like, and can be applied to the structural design of a sensitizing dye as an electron donating group to improve the performance of the sensitizing dye.

The pyrrolopyrrole-Dione (DPP) is a typical electron-deficient nitrogen heterocyclic compound, has a planar bicyclic conjugated structure, and has unique optical stability and thermal stability. As a bridge group, the plane bicyclic conjugated structure with electron deficiency can realize the multi-level electron transfer in molecules, effectively broaden the absorption spectrum of the donor-acceptor dye, and increase the sunlight absorption range of the device and the photocurrent and photoelectric conversion efficiency of the device.

The scheme also provides an application of the pure organic photosensitive dye with the stepped energy transfer structure in the preparation of the dye-sensitized solar cell, and the application specifically comprises the following steps:

the preparation method of the battery comprises the following steps: preparation of TiO by knife coating₂The film is prepared from FTO conductive glass with a substrate of sheet resistance of 15 omega and TiO₂The film consists of an upper layer film and a lower layer film, comprises a transparent layer at the bottom layer and a scattering layer at the upper layer, is calcined at 450 ℃ for 30 minutes, and is soaked into a dye bath of the synthesized dye when the temperature is reduced to 80 ℃; the dye bath adopts ethanol: the volume ratio of DMF is 4: 1 as solvent, the dye concentration is 0.25mM, and the co-adsorbent cholic acid concentration is 10 mM; the electrolyte adopts 3-methoxy propionitrile: the volume ratio of acetonitrile is 4: 1 as a solvent, containing 1.0M 1-hexyl-3-methylimidazolium iodide, 30mM lithium iodide, 30mM iodine, 0.1M guanidine thiocyanate and 0.5M 4-tert-butylpyridine in the respective concentrations;

a battery testing step: the synthesized organic dye compound 8 and the reference dye are respectively used as photosensitive dyes, the battery is assembled according to the battery preparation steps, and then the photoelectric performance of the battery is tested according to the same conditions.

It is to be noted that compound 1, compound 3 and compound 5 used in the following examples were obtained by the prior art, wherein compound 1 was prepared according to the patent (grant No.: CN 108276300 a); compound 3 is prepared according to the patent (grant: US 4256878A); compound 5 is according to the literature "Wang, Xiaohua; jiang, Bin; du, Chenche, et al, fluorinated dithio-diketopyrrolopyrrole, a new building block for organic optoelectronic materials, New Journal of Chemistry2019,43(41),16411, 16420 ".

Example 1

Step one, under the protection of nitrogen, dry N, N' -dimethylformamide DMF (6.24g,85.28mmol) is added into a 100mL four-mouth bottle, and phosphorus oxychloride (9.87g,64.38mmol) is slowly added dropwise, and the temperature is controlled below 0 ℃. After the dropwise addition, the ice bath was removed, and the mixture was stirred at room temperature for 1 hour to obtain a Vilsmeier reagent. A solution of 50mL1, 2-dichloroethane containing Compound 1(20.00g,38.74mmol) was added dropwise to the reaction flask. The reaction was stirred at 15 ℃ for 14 h. Pouring the mixture into 400mL of ice water after the reaction is finished, adjusting the pH value to be neutral by using NaOH aqueous solution, stirring the mixture for 0.5h, adding 400mL of dichloromethane for extraction, combining organic layers, washing the organic layers with water, adding anhydrous magnesium sulfate for drying, and separating the mixture by adopting column chromatography (a silica gel column, and eluent is petroleum ether/ethyl acetate (30: 1)) to obtain a compound 2 (yellow solid, 10.60g, the yield is 50%); 1H NMR (300MHz, CDCl)₃):δ(ppm)2.33(s,3H),2.36(s,3H),7.02-7.05(m,5H),7.09(d,8H,J＝8.5),7.16(t,4H),7.235(t,2H),7.42(d,2H,J＝9.0),7.50(d,2H,J＝8.5),7.66(d,2H,J＝8.5),9.80(s,1H)；MS(ESI,m/z):[M+]calcd for C₃₉H₃₂N₂O,544.7；found,544.6。

Step two, under the protection of nitrogen, dissolving compound 3(6.97g,15.00mmol) and compound 2(2.58g,4.74mmol) in 240mL of dried dimethyl sulfoxide (DMSO), and cooling to below 0 ℃ in an ice bath. Potassium tert-butoxide (1.60g,14.22mmol) was dissolved in 20mL of dry Tetrahydrofuran (THF) and slowly added dropwise thereto with the reaction temperature controlled at 5 ℃ or lower. After the dropwise addition, the reaction was carried out at normal temperature (25 ℃) for 8 hours with stirring. After the reaction is finished, the reaction solution is poured into 400mL of ice water, stirred for 1h and usedDichloromethane, combined organic layers and anhydrous magnesium sulfate (MgSO)₄) Drying, and distilling under reduced pressure to remove the solvent to obtain a yellow solid crude product containing cis-trans isomers. The crude product was dissolved in 80mL THF, a small amount of iodine was added, and the reaction was refluxed for 9 h. Adding 75mL of NaOH solution with the mass fraction of 15%, stirring for 1h, removing residual iodine, extracting with dichloromethane, combining organic layers, and adding anhydrous magnesium sulfate (MgSO)₄) Drying, distilling under reduced pressure to remove solvent to obtain yellow solid, purifying the crude product by column chromatography (silica gel column, eluent petroleum ether/dichloromethane 15:1), and separating to obtain compound 4 (yellow solid, 2.71g, yield 88%); 1H NMR (DMSO,300MHz): δ (ppm)2.33(s,3H),2.34(s,3H),6.94(d,1H, J ═ 15.0Hz),6.99(s,1H),7.01(M,1H),7.08(M,2H),7.13(d,6H, J ═ 5.0Hz),7.15(d,5H, J ═ 10Hz),7.24(d,2H),7.37(d,4H, J ═ 10Hz),7.48(d,1H),7.55(d,4H),7.77(d,2H) [ M + H ]]calcd for C₄₅H₃₅N₃S,649.3；found,650.4.

Step three, after removing the surface oxidation layer of the metallic sodium (0.62g, 0.027mol), adding the metallic sodium into 60mL of tertiary amyl alcohol, and adding 0.05g of anhydrous ferrous chloride into the tertiary amyl alcohol. After stirring and heating to reflux to form a yellow clear solution, compound 4(8.45g, 0.013mol) and compound 5(3.08g, 0.013mol) were added and the reaction was refluxed for 2 h. After the reaction, the solution was poured into 300mL of deionized water and filtered to obtain the crude product. Purification by column chromatography (silica gel column, eluent petroleum ether/dichloromethane 25:1) isolated to give compound 6 (yellow solid, 4.58g, 42% yield); 1H NMR (DMSO,300MHz): δ (ppm)2.33(s,3H),2.34(s,3H),6.94(d,1H, J ═ 15.0Hz),6.99(s,1H),7.00(t,1H),7.08(d,2H),7.13(d,6H, J ═ 5.0Hz),7.15(d,4H, J ═ 10Hz),7.19(s,2H),7.24(t,2H),7.36(t,1H),7.37(d,4H, J ═ 10Hz),7.43(d,1H),7.55(d,4H),7.77(d,2H),7.85(d,2H),7.95(s,1H) [ M + H ], 1H ], and]calcd for C₅₄H₄₀N₄O₂S₂,840.3；found,841.4.

step four, under the protection of nitrogen, dissolving the compound 6(1.88g, 2.24mmol) in 25mL of dry dichloromethane and N, N' -dimethylformamide (DMF, 1.96g,26.88mmol), cooling to below 5 ℃ in an ice bath, slowly dropwise adding dry phosphorus oxychloride (3.47g,22.63mmol), and controlling the reaction temperatureStirring and reacting for 10h at the temperature of 15 ℃, pouring into 400mL of ice water after the reaction is finished, adjusting the pH value to be neutral by using a NaOH aqueous solution, stirring for 0.5h, adding 400mL of dichloromethane for extraction and liquid separation, combining organic layers, adding anhydrous magnesium sulfate for drying, and separating by adopting column chromatography (a silica gel column, and eluent is petroleum ether/ethyl acetate which is 20:1) to obtain a compound 7 (orange solid, 1.19g, yield 61%); 1H NMR (DMSO,300MHz): δ (ppm)2.33(s,3H),2.34(s,3H),6.95(d,1H, J ═ 15.0Hz),6.99(s,1H),7.00(t,1H),7.08(d,2H),7.13(d,6H, J ═ 5.0Hz),7.15(d,4H, J ═ 10Hz),7.19(s,2H),7.24(t,2H),7.37(d,4H, J ═ 10Hz),7.43(d,1H),7.55(d,4H),7.77(d,2H),7.85(d,1H),7.95(s,1H),8.15(d,1H),9.84(s,1H) [ M + H ]]calcd for C₅₅H₄₀N₄O₃S₂,868.3；found,869.4.

Step five, under nitrogen protection, a 50mL four-necked flask was charged with Compound 7(2.00g,2.30mmol), cyanoacetic acid (0.59g,6.90mmol), 0.20mL piperidine and 25mL acetonitrile, and heated under reflux for 8 h. After the reaction is finished, performing rotary evaporation to obtain a crude product, and separating by adopting a flash column chromatography (silica gel column, eluent is dichloromethane: ethanol: 30:1) to obtain a target dye compound 8 (red solid, 1.74g, yield 81%); 1H NMR (DMSO,300MHz): δ (ppm)2.33(s,3H),2.34(s,3H),6.95(d,1H, J ═ 15.0Hz),6.99(s,1H),7.00(t,1H),7.08(d,2H),7.13(d,6H, J ═ 5.0Hz),7.15(d,4H, J ═ 10Hz),7.19(s,2H),7.24(t,2H),7.37(d,4H, J ═ 10Hz),7.43(d,1H),7.55(d,4H),7.77(d,2H),7.85(d,1H),8.13(d,1H),8.20(d,1H),8.61(s,1H),12.56(s,1H) [ M]calcd for C₅₈H₄₁N₅O₄S₂,935.3；found,935.4.

Example 2

Step one, under nitrogen protection, dry DMF (5.66g,77.48mmol) was added to a 100mL four-necked flask and POCl was slowly added dropwise₃(5.94g,38.74mmol) and the temperature was controlled to 0 ℃ or lower. After the dropwise addition, the ice bath was removed and the mixture was stirred at room temperature for 1 hour to obtain a Vilsmeier reagent. A solution containing Compound 1(20.00g,38.74mmol) in 50mL of dichloromethane was added dropwise to the reaction flask. The reaction was stirred at 0 ℃ for 16 h. Pouring into 400mL of ice water after the reaction is finished, adjusting the pH value to be neutral by using NaOH aqueous solution, stirring for 0.5hExtracting with 400mL of dichloromethane, combining organic layers, washing with water, drying with anhydrous magnesium sulfate, separating by column chromatography (silica gel column, eluent petroleum ether/ethyl acetate: 30:1) to obtain compound 2 (yellow solid, 5.30g, yield 25%),

step two, under the protection of nitrogen, dissolving the compound 3(2.32g,5.00mmol) and the compound 2(2.72g,5.00mmol) in 250mL of dry N, N' -dimethylformamide, and cooling to below 0 ℃ in an ice bath. Potassium tert-butoxide (1.60g,14.22mmol) was dissolved in 20mL of dry tetrahydrofuran and slowly added dropwise thereto, with the reaction temperature being controlled at 5 ℃ or lower. After the dropwise addition, the reaction was carried out at normal temperature (25 ℃) for 10 hours with stirring. After the reaction is finished, pouring the reaction liquid into 400mL of ice water, stirring for 1h, then using dichloromethane, combining organic layers, adding anhydrous magnesium sulfate for drying, and removing the solvent through reduced pressure distillation to obtain a yellow solid crude product containing cis-trans isomers. The crude product was dissolved in 80mL tetrahydrofuran, and a small amount of iodine was added and reacted under reflux for 9 h. 75mL of a 15% NaOH solution was added and stirred for 1h to remove residual iodine, the combined organic layers were extracted with dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was removed by distillation under reduced pressure to give a yellow solid, and the crude product was purified by column chromatography (silica gel column, eluent petroleum ether/dichloromethane 15:1) to give compound 4 (yellow solid, 2.00g, yield 62%).

Step three, after removing the surface oxidation layer of the metallic sodium (0.62g, 0.027mol), adding the metallic sodium into 60mL of tertiary amyl alcohol, and then adding 0.05g of anhydrous ferrous chloride into the tertiary amyl alcohol. After stirring and heating to reflux, a yellow clear solution was formed, compound 4(8.44g, 0.013mol) and compound 5(6.17g, 0.026mol) were added and the reaction was refluxed for 5 h. After the reaction, the solution was poured into 300mL of deionized water and filtered to obtain the crude product. Purification by column chromatography (silica gel column, eluent petroleum ether/dichloromethane 25:1) isolated to give compound 6 (yellow solid, 4.14g, 38% yield).

Step four, under the protection of nitrogen, dissolving the compound 6(4.20g,5mmol) in 25mL of dried 1, 2-dichloroethane and DMF (0.37g,5mmol), cooling to below 5 ℃ in ice bath, and slowly adding dropwise dried POCl₃(0.77g,5mmol) and the reaction temperature is controlled at 0 ℃ and the mixture is stirredAfter 16h, after the reaction is finished, the mixture is poured into 400mL of ice water, the pH value is adjusted to be neutral by using NaOH aqueous solution, 400mL of dichloromethane is added for extraction and liquid separation after stirring for 0.5h, organic layers are combined and anhydrous magnesium sulfate is added for drying, and separation is carried out by column chromatography (silica gel column, eluent is petroleum ether/ethyl acetate 20:1) to obtain a compound 7 (orange solid, 0.66g, yield 15%).

Step five, under nitrogen protection, a 50mL four-necked flask was charged with Compound 7(4.35g,5.00mmol), cyanoacetic acid (0.43g,5.00mmol), 0.20mL of piperidine and 25mL of acetonitrile, and the mixture was heated under reflux for 10 h. After the reaction, the crude product was obtained by rotary evaporation, and then separated by flash column chromatography (silica gel column, eluent dichloromethane: ethanol: 15:1) to obtain the target dye compound 8 (red solid, 1.20g, yield 26%).

Example 3

Step one, under nitrogen protection, dry DMF (11.33g,154.96mmol) was added to a 100mL four-necked flask and POCl was slowly added dropwise₃(11.88g,77.48mmol) and the temperature was controlled to 0 ℃ or lower. After the dropwise addition, the ice bath was removed and the mixture was stirred at room temperature for 1 hour to obtain a Vilsmeier reagent. A solution containing Compound 1(20.00g,38.74mmol) in 50mL of trichloroethane was added dropwise to the reaction flask. The reaction was stirred at 45 ℃ for 10 h. After the reaction, the mixture was poured into 400mL of ice water, the pH value was adjusted to be neutral by using an aqueous NaOH solution, the mixture was stirred for 0.5h, 400mL of dichloromethane was added for extraction, organic layers were combined and washed with water, anhydrous magnesium sulfate was added for drying, and separation was performed by column chromatography (silica gel column, eluent petroleum ether/ethyl acetate: 30:1) to obtain compound 2 (yellow solid, 6.32g, yield 30%).

Step two, under the protection of nitrogen, dissolving the compound 3(11.61g,25.00mmol) and the compound 2(2.72g,5.00mmol) in 250mL of dry chloroform, and cooling to below 0 ℃ in ice bath. Sodium hydride (0.34g,14.00mmol) was dissolved in 20mL of dry tetrahydrofuran and slowly added dropwise to the above solution, with the reaction temperature controlled below 5 ℃. After the dropwise addition, the reaction was carried out at room temperature (25 ℃ C.) with stirring for 4 hours. After the reaction is finished, the reaction solution is poured into 400mL of ice water and stirred for 1 hour, dichloromethane is used, organic layers are combined, anhydrous magnesium sulfate is added for drying, and the solvent is removed through reduced pressure distillation to obtain a yellow solid crude product containing cis-trans isomers. The crude product was dissolved in 80mL of tetrahydrofuran, and a small amount of iodine was added to the solution to conduct a reflux reaction for 9 hours. 75mL of a 15% NaOH solution was added and stirred for 1 hour to remove residual iodine, the combined organic layers were extracted with dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was removed by distillation under reduced pressure to give a yellow solid, and the crude product was purified by column chromatography (silica gel column, eluent petroleum ether/dichloromethane 15:1) to give compound 4 (yellow solid, 2.22g, yield 68%).

Step three, after removing the surface oxidation layer of the metallic sodium (0.62g, 0.027mol), adding the metallic sodium into 60mL of tertiary amyl alcohol, and adding 0.05g of anhydrous ferrous chloride into the metallic sodium. After stirring and heating under reflux to form a yellow clear solution, compound 4(8.45g, 0.013mol) and compound 5(12.34g, 0.052mol) were added and reacted under reflux for 1 h. After the reaction, the solution was poured into 300mL of deionized water and filtered to obtain the crude product. Purification by column chromatography (silica gel column, eluent petroleum ether/dichloromethane 25:1) isolated to give compound 6 (yellow solid, 3.49g, 32% yield).

Step four, under the protection of nitrogen, dissolving the compound 6(4.21g,5mmol) in 25mL of dried 1, 2-dichloroethane and DMF (4.39g,60mmol), cooling to below 5 ℃ in ice bath, and slowly adding dropwise dried POCl₃(9.20g,60mmol), stirring and reacting at 45 ℃ for 8h, pouring the mixture into 400mL ice water after the reaction is finished, adjusting the pH value to be neutral by using NaOH aqueous solution, stirring for 0.5h, adding 400mL dichloromethane for extraction and separation, combining organic layers, adding anhydrous magnesium sulfate for drying, and separating by adopting column chromatography (silica gel column, eluent is petroleum ether/ethyl acetate 20:1) to obtain a compound 7 (orange solid, 0.82g, yield 19%).

Step five, under nitrogen protection, a 50mL four-necked flask was charged with Compound 7(4.35g,5.00mmol), cyanoacetic acid (2.13g,25.00mmol), 0.20mL of piperidine and 25mL of acetonitrile, and the mixture was heated under reflux for 10 h. After the reaction, the crude product was obtained by rotary evaporation, and then separated by flash column chromatography (silica gel column, eluent dichloromethane: ethanol: 40:1) to obtain dye compound 8 (red solid, 1.67g, yield 36%).

It is to be noted that since the products of each step of examples 2 and 3 are the same as those of example 1, the product characterization data of each step of examples 2 and 3 are the same as those of example 1.

The test data for each example is illustrated below:

first, the ultraviolet absorption spectrum of the organic dye compound 8 prepared in examples 1 to 3 is shown in FIG. 1, from which it is seen that the dye compound has two distinct absorption peaks at 355nm and 536nm and molar extinction coefficients of 5.58X 10⁴M^-1cm^-1And 5.41X 10⁴M^-1cm^-1Therefore, the dye has larger absorption wavelength and higher molar extinction coefficient, thereby being beneficial to the dye to fully absorb and utilize the sunlight in the long-wave range.

Second, as shown in FIG. 2, when the dye is adsorbed on TiO₂After the film surface, dyes and TiO₂The complex surface effect and the stacking effect among dyes can change the absorption spectrum of the dyes, and two phenomena of red shift and blue shift can occur. Dye molecule in TiO₂The accumulation of the surface is disadvantageous to the photoelectric conversion performance of the dye.

Thirdly, as shown in FIG. 3, FIG. 3 is TiO₂SEM photograph of the cut surface of the film shows that the film thickness is about 3 μm.

Data on the UV absorption of dyes in methylene chloride solution in TiO₂The uv absorption data of the film surface and the difference between the two are summarized in table 1.

TABLE 1 neutralization of TiO by dyes in solution₂Ultraviolet absorption spectrum data on film

As can be seen from Table 1, the dye compound 8 is present in TiO compared to the UV absorption spectrum in solution₂The uv absorption spectrum of the film surface is only blue-shifted by 3 nm. Similar dye structures have been reported in the literature (D.P.Hagberg, T.Marinoado, K.I.M.Karlsson, Qin, G.Boschloo, T.Brinck, A.Hagfeldt, and L.Sun, J.org.chem.,2007,72, 9550-9556), it can be seen that the dyes of this document are in TiO since TPB with a double propeller structure is not used as electron donating group₂The ultraviolet absorption spectrum of the surface generates blue shift of 48nm, which is higher than that of the dye compound 8 in the scheme. It can be seen by comparison that the TPB as the electron donating group can effectively inhibit the accumulation of dye molecules.

Example 4

The embodiment provides an application of the organic dye compound 8 prepared in the embodiments 1 to 3 in preparing a dye-sensitized solar cell, and the specific steps are as follows:

preparation of TiO by knife coating₂The film (particle size 20nm) and the substrate are FTO conductive glass with sheet resistance of 15 omega. TiO 2₂The photoanode consists of two films, the bottom layer is a 10 μm transparent layer and the top layer is a 3 μm scattering layer. Calcining at 450 deg.C for 30min, and soaking into the solution (dye bath) of the synthesized dye when the temperature is reduced to 80 deg.C for 12 h. The dye bath adopts a mixed solution with the volume ratio of ethanol/DMF (dimethyl formamide) being 4/1 as a solvent, the dye concentration is 0.25mM, and the co-adsorbent cholic acid concentration is 10 mM. The electrolyte used was a 3-methoxypropionitrile/acetonitrile 4/1 mixture as a solvent, containing 1.0M 1-hexyl-3-methylimidazolium iodide (MHMII), 30mM lithium iodide (LiI), 30mM iodine, 0.1M guanidine thiocyanate (gunns) and 0.5M 4-tert-butylpyridine (TBP), respectively. The battery test conditions are as follows: standard light intensity (AM 1.5, 100mW cm)^-2) Provided by a solar simulator (Oriel, 91192). The voltammetry of the cell was recorded by a potentiostat (Princeton Applied Research, 263A) with a window area of 0.15cm². In this case, the unit M means mol/L and mM means mmol/L.

Table 2 data for photovoltaic performance of dye-sensitized solar cells based on dye compound 8 and reference dye N719

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.