Photovoltage enhancement of dye sensitised solar cells by using ZnO modified TiO2 electrode

Abstract

A ZnO modified TiO₂ (ZnO/TiO₂) film was prepared by immersing TiO₂ electrodes in Zn(Ac)₂ aqueous solution. The open circuit voltage of a dye sensitised solar cell (DSSC) with the ZnO/TiO2 film electrode has a dramatic enhancement, compared to the DSSC with the TiO₂ film electrode. However, the short circuit current density of the DSSC with the ZnO/TiO₂ film electrode is lower than that with TiO₂ electrode. The film electrodes were characterised by SEM, EDX and UV-vis, and the photoelectric performance of DSSCs were measured. The photovoltage enhancement is attributed to the formation of a flat-band potential energy barrier by ZnO at TiO₂/electrolyte interface. The decline of the photocurrent with ZnO/TiO₂ film electrode is due to poor dye absorption on larger particles of ZnO.