Photovoltaic study of dye sensitized solar cells based on TiO2, ZnO:Al3+nanoparticles

Abstract

A technique to fabricate dye (rhodamine B) sensitized solar cells based on Titanium Oxide (TiO 2 ) and Zinc Oxide (ZnO) nanoparticles are reported. The TiO 2 was synthesized using the sol-gel method and the ZnO was synthesized by hydrolysis method to obtain nanoparticles of ~ 5 nm and 150 nm respectively. ZnO was doped with Al 3+ in order to enhance the photovoltaic efficiency to promote the electrons mobility. The photovoltaic conversion characterization of films of TiO 2 , ZnO and ZnO:Al 3+ nanoparticles is also reported. The generated photocurrent was measured by two methods; one of those uses a three electrode electrochemical cell and the other use an electronic array where the cells were exposed to UV lamp and the sun light. The role of the TiO 2 , ZnO and Al 3+ doped ZnO nanoparticles is discussed to obtain a better efficiency in the generation of photocurrent (PC). The results exhibited by the electrochemical cell method, efficiencies of 0.55 (PC=187 μA/cm 2 ) and 0.22 (PC=149 μA/cm 2 ) for TiO 2 and undoped ZnO respectively. However, when ZnO is doped with Al 3+ at the higher concentration the efficiency was 0.44. While using the electronic array the results exhibited efficiencies of 0.31 (PC=45 μA/cm 2 ) and 0.09 (PC=16 μA/cm 2 ) for TiO 2 and undoped ZnO respectively. However, when ZnO is doped with Al 3+ at the higher concentration the efficiency was 0.44 and 0.48 for electrochemical cell and electronic array respectively. This shows that Al 3+ enhances the photogenerated charge carriers increasing the mobility of electrons.