Graphene Frameworks Promoted Electron Transport in Quantum Dot-Sensitized Solar Cells

详细信息    查看全文

• 作者：Yanyan Zhu ; Xin Meng ; Huijuan Cui ; Suping Jia ; Jianhui Dong ; Jianfeng Zheng ; Jianghong Zhao ; Zhijian Wang ; Li Li ; Li Zhang ; Zhenping Zhu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：August 27, 2014
• 年：2014
• 卷：6
• 期：16
• 页码：13833-13840
• 全文大小：467K
• ISSN：1944-8252

文摘

Graphene frameworks (GFs) were incorporated into TiO₂ photoanode as electron transport medium to improve the photovoltaic performance of quantum dot-sensitized solar cells (QDSSCs) for their excellent conductivity and isotropic framework structure that could permit rapid charge transport. Intensity modulated photocurrent/photovoltage spectroscopy and electrochemical impedance spectroscopy results show that the electron transport time (蟿_d) of 1.5 wt % GFs/TiO₂ electrode is one-fifth of that of the TiO₂ electrode, and electron lifetime (蟿_n) and diffusion path length (L_n) are thrice those of the TiO₂ electrode. Results also revealed that the GFs/TiO₂ electrode has a shorter electron transport time (蟿_d), as well as longer electron lifetime (蟿_n) and diffusion path length (L_n), than conventional 2D graphene sheets/TiO₂ electrode, thus indicating that GFs could promote rapid electron transfer in TiO₂ photoanodes. Photocurrent鈥搗oltage curves demonstrated that when incorporating 1.5 wt % GFs into TiO₂ photoanode, a maximum power conversion efficiency of 4.2% for QDSSCs could be achieved. This value was higher than that of TiO₂ photoanode and 2D graphene sheets/TiO₂ electrode. In addition, the reasons behind the sensitivity of photoelectric conversion efficiency to the graphene concentration in the TiO₂ were also systematically investigated. Our results provide a basic understanding of how GFs can efficiently promote electron transport in TiO₂-based solar cells.

Keywords:

quantum dot sensitized solar cells; photoanode; graphene frameworks; electron transport; 2D graphene