Solar Energy, Vol.173, 752-758, 2018
Multi-layered TiO2 photoanodes from different precursors of nanocrystals for dye-sensitized solar cells
Multi-layered titanium dioxide photoanodes consisting of various layers treated by titanium tetrachloride and titanium isopropoxide are obtained for dye-sensitized solar cells. This process is successfully implemented to fabricate highly efficient photoanodes for dye-sensitized solar cells, demonstrating that performance of the cells is improved by optimizing the multi-layered titanium dioxide photoanodes. Charge-transfer kinetics of the devices is analyzed by impedance spectroscopy. The conversion efficiency of the devices is considerably boosted from 6.73% to 8.43% by tuning the photoanode structure from monolayer to multilayer. The best power conversion efficiency is obtained on the device with a photoanode composed of double pre-treated and one post treated layers of titanium dioxide. This enhanced efficiency is mainly attributed to the improved charge transfer process characterized by a larger resistance at electrolyte/photoanode interface, exhibiting a longer electron lifetime.