High-performance fully-ambient air processed perovskite solar cells using solvent additive

Abstract

Incredible progress in the efficiency of hybrid perovskite solar cells (PSCs) has nominated perovskites as a promising light-harvesting for new-generation photovoltaic devices. Additive engineering in PSCs is a valid and straightforward method to increase the surface quality of perovskite films. Herein, we prepared mixed cation of cesium (Cs)/formamidinium (FA)/methylammonium (MA) PSCs via an air-processed sequential deposition method. Acetonitrile (ACN) was used as an effective additive to improve the surface properties of perovskite layer. Our measurements demonstrated that with the incorporation of ACN in the FAI/MABr/MACl precursor surface defects on the perovskite film well passivated, and consequently, crystal grain size increased. A PCE of 15.64% was achieved for ACN-based PSCs higher than of 13.06% one for without additive devices. Additionally, ACN-containing devices showed a lower hysteresis effect as compared to the control devices. Most importantly, ACN additive based PSCs showed more stable behavior in ambient air, thermal, and humidity stability tests. This work introduces a simple approach for the fabrication of high-performance perovskite materials in ambient air.