Study on the preparation of nano-flaky anatase titania layer and their photovoltaic application

Titania (TiO2), known to have wide energy band gap, can greatly absorb dye if specific surface area can significantly be increased and hence the photovoltaic efficiency. Dye-sensitized solar cells (DSSC) based on mesoporous titania has been drawn much attention over the past few years. An attempt in this study is to employ micro-arc oxidation (MAO) process and alkali treatment to develop titania layer with very high specific surface area on pure titanium surface. Specimens were applied an anodic dc voltage at 400–500 V in a phosphate electrolytic solution during MAO process, followed by the alkali treatment in 1.25 M NaOH solution to produce nano-flaky anatase TiO2 on surface, with nano-flakes about 50 nm in dimension thus largely increase specific surface area. Result of photovoltaic efficiency measurement of the assembled DSSC device show that ultimate efficiency (0.23%) can be obtained for the specimen post-alkali treated in 1.25 M NaOH solution, which exhibits the highest surface area and thus the enhanced dye-absorbing efficiency.