Synchronous amelioration of SnO2surface aggregation and buried layer defects by sodium salts for high-efficiency and stable perovskite solar cells

The inclusion of BCA molecules in SnO 2 improves film coverage of ETL, regulates energy level, increases electron transport and migration ability, and enhances crystallization of perovskite. Overall, PSCs fabricated in open-air achieve a champion efficiency of 20.24%.