Mar 25, 2009
Water and ethanol modify polymer-based solar cells
In order to build up a more stable polymer electrolyte system for application in dye-sensitized solar cells (DSSC), it is necessary to introduce small molecule hydroxyl-rich additives (such as water and ethanol) into the PEO-PVDF/TiO2 composite electrolyte. These hydroxyl-rich small molecules are diffusive and act as cross-linking agents, which
Ying Yang and her colleagues supervised by Xing-Zhong Zhao at Wuhan University, China, are studying modification strategies to fabricate more stable dye-sensitized solar cell (DSSC) systems with PEO-PVDF based polymer electrolytes. One way of improving the conductivity of the polymer electrolyte and maintaining its stability, is to introduce a new continuous path for ion transportation. As the group explains, the cross-linking interactions between the liquid electrolyte and the polymer matrix is expected to form an ionic transport path of the quasi-solid state polymer electrolyte resembling that of a liquid system.
In a recent polymer electrolyte modification study, which was published in Nanotechnology, the authors used water and ethanol as cross-linking agents to improve the stability of quasi-solid-state DSSCs with PEO-PVDF electrolyte. The hydroxyl bonds present among PEO, TiO2, LiI and additives allow homogenous cross-linking networks to form in the electrolyte, which provide more efficient ion transport pathways. After optimization of the water and ethanol concentration, the best DSSC shows an energy conversion efficiency of about 5.8%, and is stable over 500 h when sealed with wax (see image for examples).
Zhao's group is currently focusing on the development of new polymer electrolyte systems such as polysaccharides, thermal setting and thermal plastic polymer electrolytes and ionic liquid electrolytes to drive up the performance and stability of DSSCs.
About the author
The work was performed at the University of Wuhan of China and supported by the Ministry of Science and Technology of China through Hi-Tech plan (funding No. 2006AA03Z347) and the National Nature Science Foundation of China (50125309). Prof. Xing-Zhong Zhao is the group leader of the Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education of China, Department of Physics at Wuhan University. He is the principal investigator of the DSSC project. Ying Yang is currently a PhD student supervised by Prof. Xing-Zhong Zhao, studying dye-sensitized solar cell (DSSC) with solid/quasi-solid polymer electrolyte in this group. Cong-Hua Zhou is a PhD student working on optimization counter electrode and anode electrode applied in DSSC. Sheng Xu is a PhD student researching on optimizing the preparation of porous titania film (using P25) applied in quasi-solid state DSSC. Dr Jing Zhang, formerly a PhD student of this lab, has now graduated from Wuhan University and works in Ningbo University of China as assistant professor. Dr Su-Juan Wu, a former PhD student of this group, has now graduated from Wuhan University and is working in Polytechniq University of Hong Kong as a post-doctorate fellow. Hao Hu is a PhD student, studying the thermosetting and thermoplastic polymer electrolyte system applied in DSSC. Bo-Lei Chen is a PhD student researching the organic synthesis of the ionic liquid and polymer. Qi-Dong Tai is a masters student researching on preparing the TiO2 colloid by hydrothermal. Zheng-Hua Sun is a masters student studying the synthesis of the ionic liquid. Dr Wei Liu is an associate professor working on microfluidic chips.