基于TiO2/多壁碳纳米管复合光阳极和SnO2/多壁碳纳米管非铂对电极的染料敏化太阳能电池电子传输的改善

Improvement of Electron Transport in Dye-Sensitized Solar Cells Based on TiO2/MWCNTs Composite Films as a Photoanode and SnO2/MWCNTs as a Pt-free Counter Electrode

为了提高TiO2光阳极的电子传输速率,在TiO2中负载了多壁碳纳米管(MWCNTs)。采用溶胶–凝胶水热法制备了TiO2/MWCNTs复合溶胶,利用电流体动力学方法制备了均匀的TiO2/MWCNTs复合薄膜,并用TiCl4对薄膜进行了优化。用扫描电子显微镜、透射电子显微镜、X射线衍射仪和紫外可见吸收光谱仪对样品进行了表征分析。利用电化学阻抗谱和电流密度–电压曲线分析了基于TiO2/MWCNTs复合光阳极和SnO2/MWCNTs对电极的染料敏化太阳能电池(DSSC)的光电性能。结果表明,MWCNTs的加入极大地加速了电子在薄膜中的传输,减少了电子与氧化态染料和I3–的复合;基于CNT-0.12(质量分数0.12%)复合光阳极的DSSC性能最佳(VOC=0.70 V,JSC=13.0 m A/cm2,ηFF=0.64,η=5.80%),与基于纯TiO2光阳极的DSSC(η=4.44%)相比,能量转换效率提高了30.6%。

In order to improve the electron transport rate of TiO2 photoanode,multi-walled carbon nanotubes(MWCNTs)were loaded in TiO2.TiO2/MWCNTs composite sols were formed by a sol–gel hydrothermal method,and the uniform TiO2/MWCNTs composite films were formed by an electro-hydrodynamic method.The films were optimized with TiCl4.The samples were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffractometer and ultraviolet–visible absorption spectroscopy.The photoelectric properties of dye-sensitized solar cells(DSSCs)based on TiO2/MWCNTs composite photoanodes and SnO2/MWCNTs counter electrode were analyzed by electrochemical impedance spectroscopy and current density–voltage curve measurement.The results show that the addition of MWCNTs considerably accelerates the transport of electrons in the films and decreases the recombination of electrons with oxidized dye and I3–;The DSSC with a CNT-0.12(0.12%,in mass)composite photoanode shows the optimal performance(i.e.,Voc=0.70 V,Jsc=13.0 m A/cm2,ηFF=0.64,η=5.80%),and the power conversion efficiency is 30.6%greater than that of DSSC with a pure TiO2 photoanode(i.e.,η=4.44%).