Flexible MAPbI3 perovskite solar cells with the high efficiency of 16.11% by low-temperature synthesis of compact anatase TiO2 film

Abstract Flexible perovskite solar cells (PSCs) have attracted much attention of the researchers due to their wide application. However, the great challenge in developing flexible PSCs is preparing the electron transport layer (ETL) at lower temperatures to meet with the processing requirements of plastic substrates. Herein, we introduce a facile sol-gel method for the preparation of the compact TiO2 (c-TiO2) ETL below 150 °C. By regulating the precursor solution concentration, annealing temperature and time of TiO2 ETL, we find that the c-TiO2 ETL exhibits the best photoelectric performance with the concentration of TiO2 precursor solution of 2 M, the annealing temperature of 150 °C and annealing time of 30 min, which exhibits the fastest electron extraction and lowest possibility of the charge carrier recombination. In final, a high power conversion efficiency of 16.11% is obtained with the planner structure of PEN/ITO/c-TiO2/MAPbI3/Spiro-OMeTAD/Au, which is the excellent one compared with the similar works, and the flexible PSCs also possess the good bending stability after 500 bending cycles.