基于Pechini溶胶-凝胶法的染料敏化太阳能电池的优化

doi:10.15541/jim20150576

摘要/Abstract

摘要：

采用Pechini溶胶-凝胶法一步反应工艺制备功能型的TiO₂薄膜, 基于界面电荷复合效应探讨Pechini型TiO₂膜厚对电池光电性能的影响机制, 并通过膜厚调控对电池性能进行优化。采用UV-Vis、电化学阻抗谱以及暗态I-V测试, 系统研究了TiO₂膜厚对染料吸附量、界面电子复合过程以及电池光电性能的影响规律。结果表明, 随着TiO₂膜厚增加, 染料吸附量增加引起电池光捕获效率和光电流增加; 同时, TiO₂膜中的电子寿命缩短, TiO₂/电解质界面的电子复合几率增大导致电池光电压下降。上述综合作用使得电池效率先增加后减小, 并在膜厚为10.7 μm时, 光电转化效率达到最佳值7.75%(相同工艺条件下常规方法为6.56%)。

关键词: 染料敏化太阳能电池, Pechini溶胶-凝胶法, TiO2膜厚, 界面电荷复合

Abstract:

Functional TiO₂ films were prepared by using a facile one-step Pechini Sol-Gel method. The intrinsical contribution mechanism of film thickness to the photo-to-electric performance of DSSC was explored with analysis of interfacial charge recombination effects, on which, the characteristics of DSSC were optimized via film thickness controlling. The influence of TiO₂ film thickness on dye absorption, charge recombination process and photovoltaic performance of DSSC were by UV-Vis, electrochemical impedance spectroscopy and I-V test under dark condition, respectively. The results show that as TiO₂ film thickness increases, the light harvesting efficiency and photocurrent of DSSC increase, which were induced by the enhancement of dye absorption. However, the photovoltage decreases gradually with the increaese of electron recombination probability. As an increase, combination of the positive and negative effects above enables the Pechini-type DSSC efficiency first increase and then decline, with an optimum efficiency of 7.75% at the film thickness of 10.7 μm, in contrast to 6.5% of the routine method.

Key words: dye-sensitized solar cells, pechini Sol-Gel method, TiO2 film thickness, interfacial charge recombination

中图分类号:

TM914

尹月锋, 梁桂杰, 张强, 潘峥, 李望南, 李在房. 基于Pechini溶胶-凝胶法的染料敏化太阳能电池的优化[J]. 无机材料学报, 2016, 31(7): 739-744.

YIN Yue-Feng, LIANG Gui-Jie, ZHANG Qiang, PAN Zheng, LI Wang-Nan, LI Zai-Fang. Optimization of Dye-sensitized Solar Cells Prepared by Pechini Sol-Gel Method[J]. Journal of Inorganic Materials, 2016, 31(7): 739-744.

图/表 7

图1 不同放大倍率常规方法(a~c)和Pechini方法(d~f)制备的TiO2薄膜的SEM照片

Fig. 1 Different magnification SEM images of routine TiO2 films (a,b,c) and Pechini films (d, e, f)

图2 常规方法(a)和Pechini方法(b)制备的TiO2薄膜的XRD图谱

Fig. 2 XRD patterns of TiO2 films of (a) routine-type and (b) Pechini-type

图3 N719在乙醇中的吸光度(a)及其在530 nm处的消光系数拟合图(b); (c) N719在解吸液中的吸光度

Fig. 3 Absorbance spectra of N719 dyes in ethanol (a) and the fitting plot of the extinction coefficient at 530 nm (b), and absor bance apectra of N7.9 dys in desorption solvent (c)

表1 染料吸附量、电化学阻抗及其电池的光电性能参数

Table 1 Absorbance, EIS and photo-to-electric parameters of DSSC prepared by Pechini Sol-Gel method

	Method type	Thickness /μm	Q /(×10^-7, mol·cm^-2)	R_ct2 /Ω	R_ct3 /Ω	f_min /Hz	τ_e /ms	V_oc /V	J_sc /(mA·cm^-2)	ff	η /%
S1	Routine	3.3±0.1	0.583	36.7	8.7	15.5	10.3	0.701	5.43	0.675	2.57
S1	Pechini	3.2±0.1	0.715	44.5	10.6	11.2	14.2	0.756	6.27	0.683	3.24
S2	Routine	4.5±0.2	0.978	22.9	8.3	23.0	6.9	0.693	8.92	0.679	4.20
S2	Pechini	4.4±0.2	1.318	35.3	7.9	14.5	11.0	0.720	9.31	0.722	4.84
S3	Routine	7.5±0.2	1.524	13.7	7.7	46.4	3.4	0.690	11.73	0.721	5.85
S3	Pechini	7.3±0.1	2.095	23.4	9.3	26.3	6.1	0.702	13.18	0.726	6.72
S4	Routine	10.9±0.2	2.230	10.1	10.8	83.3	1.9	0.658	13.39	0.744	6.56
S4	Pechini	10.7±0.4	3.768	16.7	7.6	35.0	4.5	0.685	15.22	0.743	7.75
S5	Routine	12.9±0.3	3.441	6.6	7.2	100.2	1.3	0.662	13.87	0.719	6.60
S5	Pechini	12.6±0.3	5.304	13.1	8.3	87.3	1.8	0.632	12.68	0.717	5.74

图4 光照(a)和暗环境下(b)Pechini型DSSC的I-V曲线, 光电流/光电压(c)以及光电转化效率(d)随膜厚的变化关系图

Fig. 4 I-V curves of Pechini-type DSSC(a) Under illumination of 100 mW/cm2; (b) Under dark condition. Plots of (c) photovoltage/photocurrent-film thickness and (d) conversion efficiency-film thickness

图5 暗态条件-0.7 V偏压下Pechini型DSSC的EIS图谱

Fig. 5 EIS spectra of Pechini-type DSSC with -0.7 V external bias potential under dark condition (a) Nyquist EIS; (b) Bode EIS. The top view in figure (a) is equivalent circuit of DSSC

图6 由Pechini法制备的DSSC的IPCE曲线

Fig. 6 IPCE curves of Pechini-type DSSC

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