The blocking effect of charge recombination by sputtered and acid-treated ZnO thin film in dye-sensitized solar cells

Compact layer preventing the charge recombination has much attention in studies on efficiency enhancement of dye-sensitized solar cells (DSCs). Especially, the charge recombination at the interface between transparent conductive oxide (TCO) and an electrolyte plays an important role due to bad contact of TCO/TiO2 interface. Although TiO2 has been widely adopted as a source of the compact layer, ZnO compact layer was investigated in this study because of its unique properties. ZnO thin film was deposited by Zn sputtering without O2 gas in particular. For the sufficient oxidization of Zn film, the acid treatment was introduced and the thickness of the compact layer was controlled. As a result, the overall performance was much increased from 6.20% to 7.81% by the acid treatment and the thickness control of the compact layer.