Improving the performance of perovskite solar cells via TiO2 electron transport layer prepared by direct current pulsed magnetron sputtering

Organic-inorganic hybrid metal halide perovskite solar cells (PSCs) with planar heterojunction structures were fabricated. The traditional methylammonium lead iodide (CH ₃NH ₃PbI ₃, MAPbI ₃ ) was selected as the photovoltaic convert layer. The TiO ₂ electron transport layer (ETL) was prepared by the sol-gel and direct current pulsed magnetron sputtering (DC-PMS) technologies. PSCs with Sol-gel and DC-PMS TiO ₂ ETLs showed power conversion efficiencies of 13.4% and 16.1%, respectively. The detailed measurement results showed that the DC-PMS TiO ₂ ETL contained high-density chain-like structures, which consisted of nanosized anatase TiO ₂ nuclei. Compared with the short-circuit current of 20.08 mA/cm ² for PSCs with Sol-gel TiO ₂ ETL, the chain-like structure in the DC-PMS TiO ₂ ETL could effectively improve the short-circuit current to 22.11 mA/cm ². In addition, compared with the hysteresis index of 38.5% for PSCs with Sol-gel TiO ₂ ETL, the chain-like structure and higher surface potential of the DC-PMS TiO ₂ ETL could effectively reduce the hysteresis index to 14.9%. Finally, because of the whole room temperature preparation process, DC-PMS technology is an ideal candidate for flexible application of PSCs, which could be applied to the organic substrate without resistance to high temperature.