Effects of TiO2:MgO-Mixed Overlayer on the Performance of Dye-Sensitized Solar Cells

Abstract

Photovoltaic performance of dye-sensitized solar cells (DSSCs) with a mixed overlayer composed of TiO2 and MgO was investigated in detail. The surface of photoelectrode (TiO2) films was modified with a TiCl4:MgCl2 mixed aqueous solutions with various molar ratios and then calcining to produce the surface-modified TiO2 photoelectrodes (Ti:Mg-TiO2/FTO). The highest power conversion efficiency was obtained from DSSC with Ti:Mg(3:7)-TiO2/FTO, which was prepared from the mixed solution with the molar ratio of 3:7 (TiCl4:MgCl2). An enhancement in short-circuit photocurrent (Jsc) and open-circuit voltage (Voc) of DSSC with Ti:Mg(3:7)-TiO2/FTO was achieved, compared to those of the reference device with bare TiO2/FTO. The incorporation of the mixed overlayer on the nanoporous TiO2 photoelectrode led to an improvement in both the light harvesting efficiency and the electron collection efficiency, thereby increasing the Jsc value. The increase in Voc value of the device with Ti:Mg(3:7)-TiO2/FTO was due to the reduced charge recombination between photo-injected electrons and I-3 ions. Copyright © 2016 American Scientific Publishers.