Bis-carbazole compounds, methods of making and co-sensitization applications thereof

Abstract

The application discloses a kind of double carbazole compounds and its preparation method and co-sensitization application, specific preparation process is compound shown in formula II-1, formula II-2, formula II-3, formula II-4 or formula II-5 and cyanacetic acid are dissolved in solvent, basic substance is added, heated reflux reaction under stirring, after reaction, reaction liquid is concentrated to remove solvent, the obtained concentrate is dissolved in eluent and separated and purified by column chromatography silica gel, eluent is collected and eluent is evaporated, i.e. the target product such as compound of formula DSB-1, formula DSB-2, formula DSB-3, formula DSB-4 or formula DSB-5 is prepared, and it is used for preparing dye sensitization agent, the application is connected by alkyl chain double carbazole, and benzothiadiazole acceptor and aromatic heterocycle are introduced in a carbazole, another carbazole is introduced as bridge bond, cyanacetic acid is used as acceptor, double carbazole compound is synthesized, and new applicable material is added for the screening of dye sensitization agent.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical organic synthesis, and particularly relates to a biscarbazole compound, a preparation method thereof, and a co-sensitization application thereof. Background Art

[0002] DSSCs (dye-sensitized solar cells) are expected to replace traditional solar cells due to their low production cost, low environmental pollution and high photoelectric conversion efficiency. As one of the main components of DSSCs, dye sensitizers play an important role in absorbing light. Their flexible molecular design has always been the focus of research on improving battery performance. Traditional D-π-A structured dye sensitizers are limited by electron donors, conjugated bridges and electron acceptors, and their light absorption performance is still not ideal. In order to broaden the absorption spectrum, many new structures such as DA′-π-A, DD′-π-A, A′-π-D-π′-A, etc. have been reported. This method of introducing additional electron donors, electron acceptors and increasing the conjugated system can often effectively adjust the light absorption ability of dye molecules. Summary of the Invention

[0003] In response to the above-mentioned technical problems existing in the prior art, the present invention aims to provide a biscarbazole compound, a preparation method, and an application thereof. The biscarbazole compound can be co-sensitized with the metal dye sensitizer Z907. The assembled dye-sensitized solar cell has good photoelectric conversion efficiency, adding new applicable substances to the screening of dye sensitizer Z907 co-sensitizers.

[0004] The present invention provides a class of biscarbazole compounds, whose molecular structures are shown in Formula DSB-1, Formula DSB-2, Formula DSB-3, Formula DSB-4 or Formula DSB-5;

[0005]

[0006] The present invention also provides a method for preparing a biscarbazole compound, comprising the following steps: dissolving a compound represented by Formula II-1, Formula II-2, Formula II-3, Formula II-4, or Formula II-5 and cyanoacetic acid in a solvent, adding an alkaline substance, and heating under reflux under stirring for reaction; after completion of the reaction, concentrating the reaction solution to remove the solvent; dissolving the obtained concentrate in an eluent, and then separating and purifying it by column chromatography on silica gel; collecting the eluent, and evaporating the eluent to remove the eluent, thereby obtaining a target product such as a compound represented by Formula DSB-1, Formula DSB-2, Formula DSB-3, Formula DSB-4, or Formula DSB-5;

[0007] The structural formula of the compound represented by Formula II-1, Formula II-2, Formula II-3, Formula II-4 or Formula II-5 is as follows:

[0008]

[0009] Furthermore, the heating reflux reaction time is 6-10 hours.

[0010] Furthermore, the solvent is a mixed solution of at least two of chloroform, toluene and acetonitrile, preferably a mixed solution of toluene and acetonitrile.

[0011] Furthermore, the molar ratio of the compound represented by Formula II-1, Formula II-2, Formula II-3, Formula II-4 or Formula II-5, cyanoacetic acid and the alkaline substance is 1:1.2 to 5:12 to 61, preferably 1:2:20.

[0012] Furthermore, the basic substance is piperidine.

[0013] Furthermore, the ratio of the amount of the compound represented by Formula II-1, Formula II-2, Formula II-3, Formula II-4 or Formula II-5 to the solvent volume is 1:20-50, the unit of the amount of the substance is mmol, and the unit of volume is mL.

[0014] Furthermore, the eluent is a mixed solvent consisting of dichloromethane and methanol, and the volume ratio of dichloromethane to methanol is 12:1.

[0015] Furthermore, the synthesis method of the compound represented by formula (II-1), formula (II-2), formula (II-3), formula (II-4) or formula (II-5) is as follows:

[0016] A compound represented by formula (IVa), formula (IVb), formula (IVc), formula (IVd) or formula (IVe), a compound represented by formula (III), tetrakistriphenylphosphine palladium and potassium carbonate are dissolved in a mixed solvent of tetrahydrofuran and water, heated to reflux for reaction, and after the reaction is completed, cooled to room temperature, the reaction solution is poured into water, extracted with dichloromethane and dried, and the solvent is removed by rotary evaporation and then separated and purified by column chromatography to obtain a product represented by formula (II-1), formula (II-2), formula (II-3), formula (II-4) or formula (II-5).

[0017]

[0018] Furthermore, the column chromatography separation process: the concentrate is dissolved in the eluent and then separated and purified by column chromatography silica gel, the eluent is collected and the eluent is evaporated to remove the eluent, and then dried to obtain a solid powder product; when synthesizing the compound represented by formula (II-1), formula (II-2) or formula (II-3), the eluent is petroleum ether and dichloromethane in a volume ratio of 1:2; the eluent of formula (II-4) or formula (II-5) is dichloromethane and methanol in a volume ratio of 20:1.

[0019] Furthermore, the present invention also provides the use of biscarbazole compounds in dye sensitizers.

[0020] By employing the above-mentioned technology, the present invention achieves the following advantages compared to existing technologies: By linking biscarbazoles with alkyl chains, introducing a benzothiadiazole acceptor and an aromatic heterocycle into one carbazole, and introducing a benzene ring as a bridge into the other carbazole, with cyanoacetic acid as an acceptor, a biscarbazole compound is synthesized. The biscarbazole compound can be used as a co-sensitizer for Z907. Dye-sensitized solar cells co-sensitized with Z907 exhibit improved photoelectric conversion efficiency, adding new applicable substances to the screening of dye sensitizers. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0022] Example 1 Synthesis of the compound represented by formula (DSB-1):

[0023]

[0024] 1) Synthesis of the compound represented by formula (III)

[0025] Compound V (0.51 g, 1.36 mmol), compound VI (0.60 g, 1.50 mmol) and cesium carbonate (0.88 g, 2.72 mmol) were added to the reaction flask, and solvent DMF (20 ml) was added. The mixture was heated under reflux and reacted for 6 h. After the reaction was completed, the reaction solution was poured into a large amount of water and extracted with dichloromethane. The extraction was repeated three times, and the organic layers were combined. The mixture was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and the mixture was purified by column chromatography (V PE :V EA =5:1) to give an orange solid III (0.68 g, 70.1%).

[0026] Compound represented by formula III: melting point: 210-215°C. 1 H NMR (400MHz, CDCl3) δ10.08(d,J=4.3Hz,1H),8.63(d,J=1.5Hz,1H),8.37(t,J=1.6Hz,1H ),8.18(t,J=6.8Hz,2H),8.03-7.94(m,4H),7.87(d,J=8.2Hz,2H),7.71(dd,J=8.5,1.8Hz ,1H),7.65(d,J=7.6,2.2Hz,1H),7.53-7.46(m,2H),7.41(dd,J=8.4Hz,1H),7.35(t,J=4 .1Hz,2H),7.32(d,J=5.1Hz,1H),7.29(d,J=5.6Hz,2H),4.31-4.29(m,4H),2.04(bs,4H).

[0027] 2) Synthesis of the compound represented by formula (II-1)

[0028] Compound III (0.20 g, 0.28 mmol), phenylboronic acid IVa (0.07 g, 0.56 mmol), Pd(PPh3)4 (0.02 g) and K2CO3 (0.15 g, 1.12 mmol) were added to a Shrek reaction flask, and THF (5 ml) and H2O (1 ml) were added, heated under reflux, and reacted for 6 h. After the reaction was completed, the reaction solution was poured into a large amount of water and extracted with dichloromethane, repeated three times, and the organic layers were combined. It was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and the product was purified by column chromatography (V PE :V DCM =1:2) to obtain an orange solid II-1 (0.16 g, 83.4%).

[0029] Compound represented by formula II-1: melting point: 205-210°C. 1 H NMR (400MHz, CDCl3) δ10.08(s,1H),8.71(d,J=1.5Hz,1H),8.39(d,J=1.6Hz,1H),8.21(d,J=7.7Hz,1H),8. 18(d,J=7.7Hz,1H),8.10(dd,J=8.5,1.6Hz,1H),8.04-8.00(m,2H),7.98(d,J=8.3Hz,2H),7.89(dd,J=7.7 ,5.5Hz,3H),7.84(d,J=7.3Hz,1H),7.73(dd,J=8.5,1.7Hz,1H),7.60(t,J=7.6Hz,2H),7.53-7.48(m,3H), 7.45(d,J=8.5Hz,1H),7.38-7.35(m,3H),7.31(d,J=7.1Hz,2H),4.39-4.25(m,4H),2.07(d,J=7.7Hz,4H).

[0030] 3) Synthesis of the compound represented by formula (DSB-1)

[0031] Weigh compound II-1 (0.12 g, 0.17 mmol) and cyanoacetic acid (0.03 g, 0.34 mmol) into a reaction flask, add toluene (1 ml) and acetonitrile (3 ml) as solvents, then slowly add piperidine (0.2 ml) dropwise, heat under reflux, and react for 10 h. After the reaction is completed, the reaction solution is poured into a large amount of water and extracted with dichloromethane, repeated three times, and the organic layers are combined. Then wash with saturated NaCl solution, remove the solvent by rotary evaporation, and analyze by column chromatography (V DCM :V MeOH=12:1) to obtain DSB-1 (0.05 g, 37.5%) as an orange solid.

[0032] Compound represented by formula (DSB-1): melting point: 243-249°C. 1 H NMR (400MHz, DMSO) δ13.43(s,1H),8.81(s,1H),8.67(s,1H),8.37(s,1H),8.27(d,J=7.8Hz,1H),8 .24(d,J=7.7Hz,1H),8.16(d,J=8.5Hz,2H),8.10(dd,J=8.6,1.6Hz,1H),8.06-8.00(m,5H),7.98(d ,J=7.4Hz,1H),7.88(d,J=8.6Hz,1H),7.68(dd,J=8.6,3.3Hz,2H),7.63(d,J=8.3Hz,2H),7.59(d, J=7.6Hz,2H),7.51-7.45(m,3H),7.24(t,J=7.4Hz,2H),4.46(bs,4H),1.92(bs,4H).HRMS(ESI)m / z calcd for C 50 H 35 N5O2SNa + [M+Na] + 792.2409, found 792.2408.

[0033] Example 2 Synthesis of the compound represented by formula (DSB-2):

[0034]

[0035] 1) Synthesis of the compound represented by formula (II-2)

[0036] Compound III (0.20 g, 0.28 mmol), 2-thiopheneboronic acid IVb (0.07 g, 0.55 mmol), Pd(PPh3)4 (0.02 g) and K2CO3 (0.16 g, 1.12 mmol) were added to a Shrek reaction flask, and then solvents THF (5 ml) and H2O (1 ml) were added, heated under reflux, and reacted for 6 h. After the reaction was completed, the reaction solution was poured into a large amount of water and extracted with dichloromethane, repeated three times, and the organic layers were combined. It was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and the product was purified by column chromatography (V PE :V DCM =1:2) to obtain an orange solid II-2 (0.12 g, 62%).

[0037] Compound represented by formula (II-2): melting point: 236-240°C.1 H NMR (400MHz, CDCl3) δ10.07(s,1H),8.70(d,J=1.5Hz,1H),8.37(dd,J=1.6Hz,1H),8.2 4-8.15(m,3H),8.07(dd,J=8.5,1.7Hz,1H),8.02-7.94(m,3H),7.87(d,J=8.2Hz,2H),7 .82(d,J=7.4Hz,1H),7.74-7.69(m,1H),7.54-7.47(m,3H),7.42(d,J=8.5Hz,1H),7.3 9-7.33(m,3H),7.33-7.29(m,2H),7.27-7.25(m,1H),4.52-4.15(m,4H),2.05(bs,4H).

[0038] 2) Synthesis of the compound represented by formula (DSB-2)

[0039] Weigh II-2 (0.12 g, 0.17 mmol) and cyanoacetic acid (0.02 g, 0.22 mmol) in a reaction flask, add toluene (1 ml) and acetonitrile (3 ml) as solvents, then slowly add piperidine (0.2 ml) dropwise, heat under reflux, and react for 10 h. After the reaction is completed, the reaction solution is poured into a large amount of water and extracted with dichloromethane, repeated three times, and the organic layers are combined. Then wash with saturated NaCl solution, remove the solvent by rotary evaporation, and analyze by column chromatography (V DCM :V MeOH =12:1) to obtain DSB-2 (0.072 g, 55%) as an orange-yellow solid.

[0040] Compound represented by formula (DSB-2): melting point: 210-215°C. 1 H NMR (400MHz, DMSO) δ8.79(s,1H),8.65(s,1H),8.36(s,1H),8.26(d,J=7.6Hz,1H),8.22( d,J=7.9Hz,1H),8.19-8.11(m,4H),8.06(d,J=8.6Hz,1H),8.00(d,J=8.4Hz,2H),7.95(d J=7.5Hz,1H),7.85(t,J=8.6Hz,1H),7.75(d,J=4.3Hz,1H),7.67-7.58(m,4H),7.46(t,J=7.6 Hz,2H),7.29-7.27(m,1H),7.23(t,J=7.3Hz,2H),4.43(bs,4H),1.90(bs,4H).HRMS(ESI)m / z calcd forC 48 H33 N5O2S2Na + [M+Na] + 798.1973, found 798.1979.

[0041] Example 3 Synthesis of the compound represented by formula (DSB-3):

[0042]

[0043] 1) Synthesis of the compound represented by formula (II-3)

[0044] Compound III (0.20 g, 0.28 mmol), 2-furylboronic acid IVc (0.063 g, 0.56 mmol), Pd(PPh3)4 (20 mg) and K2CO3 (160 mg, 1.12 mmol) were added to a Shrek reaction flask, and then solvents THF (5 ml) and H2O (1 ml) were added, heated under reflux, and reacted for 6 h. After the reaction was completed, the reaction solution was poured into a large amount of water and extracted with dichloromethane, repeated three times, and the organic layers were combined. It was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and the product was purified by column chromatography (V PE :V DCM =1:2) to obtain an orange solid II-3 (0.11 g, 59%).

[0045] Compound represented by formula (II-3): melting point: 245-247°C. 1 H NMR (400MHz, CDCl3) δ10.09(s,1H),8.63(d,J=1.5Hz,1H),8.38(d,J=1.6Hz,1 H),8.24-8.13(m,3H),8.01-7.95(m,5H),7.87(d,J=8.2Hz,2H),7.72(dd,J=8 .5,1.8Hz,1H),7.67(d,J=7.6Hz,1H),7.53-7.46(m,3H),7.40(d,J=8.4Hz,1H ),7.37-7.34(m,3H),7.31(d,J=7.4Hz,2H),4.31-4.30(m,4H),2.05(bs,4H).

[0046] 2) Synthesis of the compound represented by formula (DSB-3)

[0047] Weigh compound II-3 (0.11 g, 0.16 mmol) and cyanoacetic acid (0.02 g, 0.22 mmol) into a reaction flask, add solvent toluene (1 ml) and acetonitrile (3 ml), then slowly add piperidine (0.2 ml) dropwise, heat under reflux, and react for 10 h. After the reaction is completed, the reaction solution is poured into a large amount of water and extracted with dichloromethane, repeated three times, and the organic layers are combined. Then wash with saturated NaCl solution, remove the solvent by rotary evaporation, and analyze by column chromatography (V DCM :V MeOH =12:1) to obtain orange solid compound DSB-3 (0.11 g, 88%).

[0048] Compound represented by formula (DSB-3): melting point: 213-217°C. 1 H NMR (400MHz, DMSO) δ8.74(s,1H),8.59(s,1H),8.24(d,J=7.6Hz,1H),8.20(d,J= 7.8Hz,1H),8.16-8.07(m,2H),8.05-8.00(m,3H),7.92(d,J=8.3Hz,2H),7.85-7. 79(m,2H),7.72(d,J=7.0Hz,1H),7.66(d,J=8.7Hz,1H),7.61-7.56(m,4H),7.47 -7.40(m,3H),7.24-7.17(m,2H),4.43-4.41(m,4H),1.89(bs,4H).HRMS(ESI)m / z calcd for C 48 H 33 N5O3SNa + [M+Na] + 782.2202, found 782.2195.

[0049] Example 4 Synthesis of the compound represented by formula (DSB-4):

[0050]

[0051] 1) Synthesis of the compound represented by formula (II-4)

[0052] Compound III (140 mg, 0.2 mmol), pyridine-4-boronic acid IVd (40 mg, 0.33 mmol), Pd(PPh3)4 (7 mg) and potassium carbonate (135 mg) were added to the reaction flask, and the nitrogen was replaced three times under vacuum. Then, a saturated potassium carbonate (41 mg, 0.3 mmol, 2 M) aqueous solution and THF (6 ml) were added as solvents. Under nitrogen protection, the mixture was heated under reflux and reacted for 6 h. After the reaction was completed, the reaction solution was poured into a large amount of water and extracted with dichloromethane, which was repeated three times. The organic layers were combined. The mixture was then washed with a saturated NaCl solution, the solvent was removed by rotary evaporation, and the mixture was purified by column chromatography (V DCM :V MeOH =20:1) to obtain an orange solid II-4 (80 mg, 57%).

[0053] Compound represented by formula (II-4): melting point: 245-247°C. 1 H NMR (400MHz, CDCl3) δ10.08(s,1H),8.82(d,J=6.0Hz,2H),8.73(d,J=1.5Hz,1H),8.38(d,J=1.5Hz,1H) ,8.21(d,J=7.7Hz,1H),8.18(d,J=7.7Hz,1H),8.09(dd,J=8.5,1.7Hz,1H),8.05(d,J=6.1Hz,2H),7.99 -7.95(m,3H),7.92(d,J=7.4Hz,1H),7.88(d,J=8.2Hz,2H),7.73(dd,J=8.5,1.8Hz,1H),7.53-7.48(m, 2H),7.44(d,J=8.6Hz,1H),7.38-7.34(m,3H),7.32(d,J=7.8Hz,2H),4.33-4.31(m,4H),2.06(bs,4H).

[0054] 2) Synthesis of the compound represented by formula (DSB-4)

[0055] Compound II-4 (63 mg, 0.09 mmol) and cyanoacetic acid (38 mg, 0.45 mmol) were added to the reaction flask and dissolved in a mixed solvent of acetonitrile (2 ml) and chloroform (2 ml). Piperidine (0.5 ml) was then slowly added dropwise and heated under reflux for 6 h. After the reaction was completed, the reaction solution was poured into a large amount of water and extracted with dichloromethane. The extraction was repeated three times and the organic layers were combined. The product was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and the product was purified by column chromatography (V DCM :V MeOH =12:1) to obtain DSB-4 (42 mg, 61%) as an orange solid.

[0056] Compound represented by formula (DSB-4): melting point: 240-243°C. 1 H NMR (400MHz, DMSO) δ8.83(d,J=1.4Hz,1H),8.79-8.73(m,2H),8.60(d,J=1.4Hz,1H ),8.25(t,J=8.8Hz,2H),8.15(d,J=7.6Hz,1H),8.12-8.03(m,4H),8.00(d,J=7.2Hz ,2H),7.93-7.91(m,3H),7.86-7.79(m,1H),7.74-7.57(m,4H),7.46(dd,J=14.1,6 .8Hz,2H),7.24(dd,J=14.3,7.1Hz,2H),4.45(bs,4H),1.92(bs,4H).HRMS(ESI)m / z calcd for C 49 H 35 N6O2S + [M+H] + 771.2542,found771.2540.

[0057] Example 5 Synthesis of the compound represented by formula (DSB-5):

[0058]

[0059] 1) Synthesis of the compound represented by formula (II-5)

[0060] Compound 4-(4-bromophenyl)pyridine (45 mg, 0.18 mmol), diboronic acid pyranoside (135 mg, 0.6 mmol), PdCl2(dppf) (10 mg) and potassium acetate (156 mg, 1.2 mmol) were added to the Shrek reaction flask, nitrogen was replaced three times under vacuum, and then solvent 1,4-dioxane (10 ml) was added. The reaction was heated for 5 hours to synthesize IVe. Compound III (140 mg, 0.2 mmol), Pd(PPh3)4 (15 mg) and saturated potassium carbonate (198 mg, 1.44 mmol, 2M) aqueous solution were added to the reaction system containing IVe, and the reflux reaction was continued for 5 hours. After the reaction was completed, the reaction solution was poured into water and extracted with dichloromethane, repeated three times, and the organic layers were combined. It was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and column chromatography (V DCM :V MeOH =20:1) to obtain an orange-yellow solid II-5 (70 mg, 48%).

[0061] Compound represented by formula (II-5): melting point: 190-194°C. 1H NMR (400 MHz, CDCl3) δ 1 H NMR(400MHz,Chloroform-d)δ10.08(s,1H),8.73(d,J=1.9Hz,1H),8.39(d,J=1.7Hz ,1H),8.23-8.15(m,4H),8.12-8.09(m,1H),7.98(d,J=8.3Hz,2H),7.93-7.86(m,4H ),7.74-7.64(m,4H),7.57(dd,J=7.4,1.5Hz,1H),7.51-7.46(m,4H),7.40-7.34(m, 2H),7.32(d,J=7.4Hz,2H),7.29(d,J=2.7Hz,2H),4.33-4.30(m,4H),2.06(bs,4H).

[0062] Synthesis of the compound represented by formula (DSB-5)

[0063] Compound II-5 (62 mg, 0.08 mmol) and cyanoacetic acid (34 mg, 0.4 mmol) were added to the reaction flask and dissolved in a mixed solvent of acetonitrile (2 ml) and chloroform (2 ml). Piperidine (0.2 ml) was then slowly added dropwise and heated under reflux for 6 h. After the reaction, the reaction solution was poured into a large amount of water and extracted with dichloromethane. The extraction was repeated three times and the organic layers were combined. The product was then washed with saturated NaCl solution, the solvent was removed by rotary evaporation, and the product was purified by column chromatography (V DCM :V MeOH =12:1) to obtain DSB-5 (34 mg, 48%) as an orange-yellow solid.

[0064] Compound represented by formula (DSB-5): melting point: 249-255°C. 1H NMR (400MHz, CDCl3) δ8.74-8.71(m,3H),8.37(d,J=1.5Hz,1H),8.21(d,J=7.4Hz,2H),8.18-8.16(m,3 H),8.11(dd,J=8.5,1.6Hz,1H),8.06(d,J=8.3Hz,2H),7.92(d,J=2.4Hz,2H),7.87(d,J=8.3Hz,2H),7 .82(d,J=8.4Hz,2H),7.74(dd,J=8.5,1.6Hz,1H),7.65(d,J=5.0Hz,2H),7.51(d,J=8.0Hz,1H),7.47( d,J=8.7Hz,2H),7.39-7.34(m,3H),7.31-7.29(m,2H),4.33-4.31(m,4H),2.06(bs,4H).HRMS(ESI)m / z calcd for C 55 H 39 N6O2S + [M+H] + 847.2855,found847.2853.

[0065] Example 6 Application of biscarbazole compounds as Z907 co-sensitizers:

[0066] When used as a dye sensitizer, the application includes the following steps:

[0067] The biscarbazole compound and the dye Z907 were dissolved in a CH3Cl-CH3OH mixed solvent to obtain a mixed solution of the biscarbazole compound and Z907 (concentration of 3×10 -4 mol·L -1 ); the volume ratio of CH3Cl and CH3OH in the CH3Cl-CH3OH mixed solvent is 10:1;

[0068] A double-layer TiO2 nanoparticle film prepared by screen printing was used as a photoelectrode: First, a layer of 20nm TiO2 particles with a thickness of 12μm was printed on the conductive glass FTO, and then calcined in a muffle furnace at 450℃ for 30min. After cooling to room temperature, the calcined film was immersed in 0.04mol·L -1 The film was pretreated with a TiCl4 aqueous solution at 70°C for 30 minutes, then removed from the TiCl4 aqueous solution and rinsed with water and ethanol, dried with a hair dryer, and calcined again at 450°C in a muffle furnace for 30 minutes to obtain a double-layer TiO2 nanoparticle film photoelectrode.

[0069] The double-layer TiO2 nanoparticle film photoelectrode obtained by calcination was cooled to 80°C and then immersed in the mixed solution of the biscarbazole compound and Z907 prepared in Example 1-5, and sensitized at room temperature for 24 hours to obtain a TiO2 electrode loaded with biscarbazole compound and Z907 compound.

[0070] Preparation of platinum counter electrode: The H2PtCl6 aqueous solution is printed on the FTO conductive glass by screen printing. The H2PtCl6 aqueous solution wets the surface of the FTO conductive glass, dries it, and then sintered it at 400°C in a muffle furnace for 20 minutes to obtain the platinum counter electrode.

[0071] The double-layer TiO2 nanoparticle film photoelectrode and the platinum counter electrode prepared above were assembled into a sandwich structure. Electrolyte was dripped into the edge of the sandwich structure and introduced into the battery by capillary permeation principle to form a dye-sensitized solar cell (DSSC). 2 Under high-intensity light irradiation, the current-voltage curve of the DSSC assembled with the biscarbazole compound and Z907 was measured, and the performance parameter results are shown in Table 1:

[0072] Table 1 Performance parameters of DSSCs assembled with biscarbazole compounds

[0073]

[0074]

[0075] As can be seen from Table 1, the dye-sensitized solar cells assembled with the biscarbazole compounds of the present invention and Z907 as dye sensitizers have good photoelectric conversion efficiency of 4.18-6.31%, which is higher than that of solar cells sensitized by Z907 alone, adding new applicable substances for the screening of co-sensitizers for Z907.

[0076] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept. The scope of protection of the present invention should not be regarded as limited to the specific forms described in the embodiments. The scope of protection of the present invention is also limited to the equivalent technical means that can be thought of by those skilled in the art based on the inventive concept.

Claims

1. A biscarbazole compound, characterized in that: Its molecular structure is shown in Formula DSB-1, Formula DSB-2, Formula DSB-3, Formula DSB-4 or Formula DSB-5; 2. A method for preparing a biscarbazole compound according to claim 1, characterized in that: The method comprises the following steps: dissolving a compound represented by formula II-1, formula II-2, formula II-3, formula II-4 or formula II-5 and cyanoacetic acid in a solvent, adding an alkaline substance, heating under reflux under stirring for reaction, concentrating the reaction solution to remove the solvent, dissolving the obtained concentrate in an eluent, and separating and purifying the concentrate by column chromatography on silica gel, collecting the eluent, and evaporating the eluent to obtain a target product such as a compound represented by formula DSB-1, formula DSB-2, formula DSB-3, formula DSB-4 or formula DSB-5; The structural formula of the compound represented by Formula II-1, Formula II-2, Formula II-3, Formula II-4 or Formula II-5 is as follows:

3. The method for preparing a biscarbazole compound according to claim 2, wherein: The heating reflux reaction time is 6-10h.

4. The method for preparing a biscarbazole compound according to claim 2, wherein: The solvent is a mixed solution of at least two of chloroform, toluene and acetonitrile.

5. The method for preparing a biscarbazole compound according to claim 4, wherein: The solvent is a mixed solution of toluene and acetonitrile.

6. The method for preparing a biscarbazole compound according to claim 2, wherein: The molar ratio of the compound represented by formula II-1, formula II-2, formula II-3, formula II-4 or formula II-5, cyanoacetic acid and the alkaline substance is 1:1.2~5:12~61.

7. The method for preparing a biscarbazole compound according to claim 6, wherein: The molar ratio of the compound represented by formula II-1, formula II-2, formula II-3, formula II-4 or formula II-5, cyanoacetic acid and the alkaline substance is 1:2:

20.

8. The method for preparing a biscarbazole compound according to claim 2, wherein: The basic substance is piperidine.

9. The method for preparing a biscarbazole compound according to claim 2, wherein: The ratio of the amount of the compound represented by Formula II-1, Formula II-2, Formula II-3, Formula II-4 or Formula II-5 to the solvent volume is 1:20-50, the unit of the amount of the substance is mmol, and the unit of volume is mL.

10. The method for preparing a biscarbazole compound according to claim 2, wherein: The eluent is a mixed solvent consisting of dichloromethane and methanol, and the volume ratio of dichloromethane to methanol is 12:

1.

11. Use of the biscarbazole compound according to claim 1 in preparing a dye sensitizer.

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