Proceedings of International Conference Asia-Pacific Hybrid and Organic Photovoltaics (AP-HOPV17)
Publication date: 7th November 2016
In the dye-sensitized solar cell, when light is irradiated on the dyes, electrons are excited and injected into the semiconductor electrode and the electrons diffuse to transparent conducting substrate.During the transport in the semiconductor, the electrons may recombine with oxidized dye or oxidized species in electrolyte solution. Regarding the recombination between the electrons in the semiconductor and the oxidized dyes, many papers claim that if the dyes lie on the semiconductor electrode, the recombination is likely to occur due to short distance between the dyes and the electrode. However, for the case of Zn phthalocyanine dye, we reported that the recombination was less likely to occur when the adsorption angle was small. However only the study was performed systematically on the effect of adsorption angle.The purpose of this study is to generalize the relationship between the adsorption angle of the dye and the reduction rate. In this study, the adsorption angle was changed by adding adsorption moiety to ortho or para position of phenyl ring in metal free organic dyes. Transient absorption measurement was used to measure the reduction rate of oxidized dyes. We found similar reduction rates regardless of the adsorption angle at room temperature. We found also temperature dependent reduction kinetics from the standing dyes but not from the lying dye.