Improving efficiency and stability of perovskite solar cells by SiO2 layer incorporation

Abstract

A hydrophobicity silicon dioxide (SiO 2 ) layer inserting in perovskite and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) interface to form PEDOT:PSS/SiO 2 composite films. The formed hydrophobicity SiO 2 films fabricated by a new and easy solution-process approach with a chemical reaction by sodium silicate. The PEDOT:PSS/SiO 2 films present good transmittance and outstanding surface morphology. The SiO 2 films also slow down CH 3 NH 3 PbI 3 perovskite degradation, as well as promote charge carrier collection and reduce charge carrier recombination, what leads to high efficiency and excellent stability of the device. The 5 mg/mL SiO 2 based CH 3 NH 3 PbI 3 devices present a superior power conversion efficiency of 16% with an improved short-circuit current density of 20.31 mA/cm 2 and a considerable fill factor of 76.3% compared to the pure PEDOT:PSS based CH 3 NH 3 PbI 3 devices. Moreover no obvious hysteresis and good reproducibility was reported for devices based on the 5 mg/mL SiO 2 . The 5 mg/mL SiO 2 -based CH 3 NH 3 PbI 3 device shows remarkable stability, which shows that 90% of the initial efficiency remains after 140 days at room temperature. The devices based on CH 3 NH 3 PbI 3-x Cl x perovskite film also be fabricated by using PEDOT:PSS (with or without 5 mg/mL SiO 2 ), the CH 3 NH 3 PbI 3-x Cl x device based on PEDOT:PSS/SiO 2 transporting layer also shows superior performance, this result verify the universality of PEDOT:PSS/SiO 2 transporting layer. • A new and easy solution-process approach forming PEDOT:PSS/SiO 2 composite films with the chemical reaction of Na 2 SiO 3 . • The SiO 2 films slow down perovskite degradation, as well as promote charge carrier collection and reduce charge carrier recombination. • The 5 mg/mL SiO 2 based devices present a superior power conversion efficiency of 16% compared to the pure PEDOT:PSS based devices with an average power conversion efficiency of 13.5%. • The 5 mg/mL SiO 2 -based device reached remarkable stability, it was shown that 90% of the initial efficiency remains after 140 days at room temperature.