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

Abstract

Organic-inorganic hybrid metal halide perovskite solar cells (PSCs) with planar heterojunction structures were fabricated. The traditional methylammonium lead iodide (CH3NH3PbI3, MAPbI3) was selected as the photovoltaic convert layer. The TiO2 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 TiO2 ETLs showed power conversion efficiencies of 13.4% and 16.1%, respectively. The detailed measurement results showed that the DC-PMS TiO2 ETL contained high-density chain-like structures, which consisted of nanosized anatase TiO2 nuclei. Compared with the short-circuit current of 20.08 mA/cm2 for PSCs with Sol-gel TiO2 ETL, the chain-like structure in the DC-PMS TiO2 ETL could effectively improve the short-circuit current to 22.11 mA/cm2. In addition, compared with the hysteresis index of 38.5% for PSCs with Sol-gel TiO2 ETL, the chain-like structure and higher surface potential of the DC-PMS TiO2 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.