Control of TiO2 electron transport layer properties to enhance perovskite photovoltaics performance and stability

Abstract This study demonstrates the effect of electron collection and transportation for TiO2 electron transport layer (ETL) of the mesoscopic perovskite solar cells (PSCs). The influence of compact TiO2 layer (c-TiO2) with various spray cycles, the particle size effect of mesoporous TiO2 (meso-TiO2) film and post-treatment of TiO2 electrode for perovskite solar cells have been studied systematically. We further optimize the meso-TiO2 thickness to enhance the electron collection and transport efficiency and to reduce the anomalous J-V hysteresis phenomenon of PSCs. After adjusting the fabrication process of TiO2 ETL, the highest performance of small cell PSC shows the power conversion efficiency (PCE) of 19.39% in the reverse scan and 19.12% in the forward scan, respectively. A sub-module PSC within an active area of 11.7 cm2 exhibits impressive PCE of 16.03% under the illumination of 100 mW/cm2 (AM1.5G). Moreover, it also shows an outstanding PCE of 25.49% under the illumination of 6000 lx of T5 indoor light source.