Short duration high temperature thermal processing to reduce interfacial trapping states in perovskite solar cells obtained by a green route

Abstract Short duration high temperature thermal processing (SDTP) using ethyl acetate as an alternate to chlorobenzene, is implemented in the fabrication of CH3NH3PbI3 perovskite solar cells. Charge transfer dynamics at the TiO2/perovskite interface is found to benefit from short-duration (8 s) SDTP at 230 °C due to changes in morphology, grain size, and interfacial characteristics. SDTP at 230 °C decreases the band gap and work function of the material. Surface photovoltage and electrochemical impedance spectroscopy studies show that the density of trap states at the surface and/or TiO2/perovskite interface is lowest for the film annealed at 230 °C (8 s). Improvements in charge transfer dynamics increased the short circuit current density from 17.64 to 21.59 mA/cm2, resulting in power conversion efficiency of 14.03%.