Acta Chimica Sinica ›› 2013, Vol. 71 ›› Issue (05): 777-781.DOI: 10.6023/A13010022 Previous Articles     Next Articles



寇东星a, 刘伟庆a,b, 胡林华a, 陈双宏a, 黄阳a, 戴松元a   

  1. a 中国科学院新型薄膜太阳电池重点实验室 中国科学院等离子体物理研究所 合肥 230031;
    b 南昌航空大学测试与光电工程学院无损检测技术教育部重点实验室 南昌 330063
  • 投稿日期:2013-01-06 发布日期:2013-04-03
  • 通讯作者: 戴松元,
  • 基金资助:

    项目受国家重点基础研究发展计划(No. 2011CBA00700)、国家高技术研究发展计划(No. 2011AA050527)、国家自然科学基金(Nos. 21003130, 61204075, 21173228)、中国博士后科学基金(Nos. 20110490835, 2012T50581)和合肥物质科学研究院创新项目(No. Y05FCQ1125)资助.

Influence of Electrodeposition Post-Treatment on Microcosmic Performances in Dye-sensitized Solar Cells

Kou Dongxinga, Liu Weiqinga,b, Hu Linhuaa, Chen Shuanghonga, Huang Yanga, Dai Songyuana   

  1. a Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031;
    b Key Laboratory of Nondestructive Testing of Ministry of Education, School of Measuring and Optical Engineering, Nanchang Hangkong University, Nanchang 330063
  • Received:2013-01-06 Published:2013-04-03
  • Supported by:

    Project supported by the National Basic Research Program of China (Grant No. 2011CBA00700), the National High Technology Research and Development Program of China (Grant No. 2011AA050527), the National Natural Science Foundation of China (Grant No. 21003130, 61204075 and 21173228), Funds of the Hefei Institutes of Physical Science in Innovation Engineering (Grant No. Y05FCQ1125) and the China Postdoctoral Science Foundation (Grant Nos. 20110490835, 2012T50581).

Over the last decade, different techniques had been employed to prepare nanoporous TiO2 electrode, aiming to improve the electron transport and depress electron recombination processes in dye-sensitized solar cells (DSCs). An effective method was a post-treatment of the TiO2 films in which an extra layer of TiO2 was grown onto the TiO2 nanoparticles constituting the films. Different explanations of the working principle of this coating had been reported. In the present work, the influence of surface modification of TiO2 films on microcosmic performances of DSCs was investigated. Research was developed by the post-treatment of TiO2 films using electrodeposition method. Ti4+ oxide films were deposited on TiO2 electrode by anodic oxidative hydrolysis of acidic aqueous TiCl3 solutions. The pH was adjusted to 2.2 and the rate of oxidation of Ti3+ at the anode was controlled by an almost constant anodic current using constant potential rectifier. The processes of electron recombination, transport and band edge movement were detected by intensity-modulated photocurrent spectroscopy (IMPS)/intensity-modulated photovoltage spectroscopy (IMVS) and electrochemical impedance spectroscopy (EIS). It was found that the capacitance of TiO2 electrode evidently increased with increasing electrodeposition time at high potentials due to the risen density of shallow traps. As the formation of small particles on the surface of TiO2 films and the enhancement of particle connections, the post-treatment with different electrodeposition time improved the charge injection and transport processes and depressed the electron recombination effectively. IMPS/IMVS measurements indicated that the effects of surface modification almost relied on light intensities, which would perform more prominent function at low intensities. Additionally, the open-circuit photovoltage (Voc) was found to be mainly effected by the conduction band edge shift and the variation of charge recombination process. With increasing electrodeposition time, the conduction band was ordinally positive shift due to the increase of surface charge, which contributed an improvement of short-circuit current (Jsc) but a limitation of Voc. Overall, an optimal modification time was needed to achieve a higher Jsc and Voc.

Key words: dye-sensitized, solar cells, IMPS/IMVS, electron recombination, electrodeposition