The effect of TiO2 photo anode film thickness on photovoltaic properties of dye-sensitized solar cells

Abstract

A new strategy for enhancing the efficiency of TiO 2 dye-sensitized solar cells (DSSCs) by doping foreign ion into TiO 2 lattice structure via low temperature hydrolysis process is reported. DSSCs are based on a semiconductor (i.e., TiO 2 ), formed between a photo-sensitized anode and an electrolyte. In order to reach high conversion efficiency, it is important to increase the electron injection and optical absorption. One promising solution to increase the DSSCs efficiency is to decrease the wide band gap of TiO 2 by doping a foreign ion into TiO 2 structure. In the present work, Cu-doped TiO 2 nanoparticles and thin films with different Cu:Ti rations are reported. The effect of dopant on photovoltaic performance of dye-sensitized solar cells were analyzed. The nanoparticles were synthesized via low temperature hydrolysis method, followed by thermal treatment at 773 K for 1 hr. X-ray diffraction and scanning electron microscopy (SEM) analyses revealed that the synthesized samples had uniform grains in nanometer scale. It was found that, 1.0wt.% Cu-doped TiO 2 DSSC (C2) had the highest power conversion efficiency of 2.87%. This can be related to achievement of an optimum condition balance among the electron injection, dye-absorption and light scattering effect. The applied method exhibited superior potential for synthesis of Cu-doped TiO 2 nanoparticles and films utilized as DSSCs.