Defect passivation via incorporation of sodium thiocyanate for achieving high-performance MAPbI3-based perovskite solar cells with enhanced stability

The high density of defects in MAPbI3 perovskite films brings about severe carrier nonradiative re-combination, which lowers the photovoltaic performance and the stability of MAPbI3-based perovskite solar cells (PSCs). To tackle this issue, we prepared stable and efficient MAPbI3-based PSCs with in-corporation of sodium thiocyanate (NaSCN). NaSCN can increase grain size and improve crystallization quality of the perovskite films due to an Ostwald ripening effect of SCN- and surface passivation of Na+ which can effectively passivate the defect states and inhibit nonradiative recombination for an ultimate improvement of the device performance and stability. The excellent characteristics lead to a significant enhancement of the power conversion efficiency (PCE) from 18.1 % to 19.4 % both for MAPbI3-based and Cs0.06MA0.15FA0.79PbI2.5Br0.5-based PSCs, respectively. The unencapsulated NaSCN-treated PSCs also shows a improved stability after aging under a relative humidity of 40 +/- 5 % for 15 days. (c) 2022 Elsevier B.V. All rights reserved.