Structural Effect of TiO2 on the Performance of MAPbBr3 Solar Cells

Abstract

TiO2 is frequently used as electron transport layer in perovskite solar cells, and its structure can directly affect the performance of MAPbBr3 solar cells. It is necessary to investigate the structural effect of TiO2 to further understand the working mechanism of such kind solar cells. TiO2 thin films with different morphology were prepared by spin coating, and MAPbBr3 (MA = CH3NH3) thin films were further deposited on it through anti-solvent assisted crystallization approach. Then, energy band alignment between TiO2 and MAPbBr3 were characterized by X-ray photoelectron spectroscopy (XPS). According to the experimental results, TiO2 with different morphology possessed different electronic structures and yield different band alignment after contacting with MAPbBr3 perovskite layer. The difference of conduction band value between TiO2 and MAPbBr3 can directly affect the transport and collection feature of electrons, thereby governing the performance of the photovoltaic device.