Effective lewis base additive with S-donor for efficient and stable CsPbI2Br based perovskite solar cells

Abstract

• The coordination of S in TAA with Pb 2+ is more effective than O in AA. • The high crystallinity and efficient defects passivation are realized with TAA. • The PSC based on TAA exhibits the highest performance of 15.87% and improved stabilty. In perovskite solar cells, the Lewis acid-base additives function effectively in high crystalline perovskite film formation and defects passivation. Exploration of effective Lewis acid-base additive to prepare high quality inorganic CsPbI 2 Br perovskite films with few defects is quite imperative. Here, thioacetamide with S-donor and acetamide with O-donor as Lewis base additives are investigated. It is revealed that a high electron density on S results in better coordination ability with Pb 2+ in perovskite solution, leading to form high crystallinity film with lower defect states compared with O-donor. The inorganic CsPbI 2 Br based perovskite solar cells with thioacetamide additive exhibit the best performance of 15.87% (AM 1.5, 1 sun) and good ambient stability compared with the control device and device with acetamide. This work provides guidance for choosing and designing the effective additives for perovskite solar cells.