Fig. 2: Characterizations of improved Sn-Pb perovskite quality.

a Energy level diagrams of the HSCs/perovskite. EF and EVAC correspond to Fermi and vacuum levels, respectively. ECBM and EVBM correspond to the energy of the valence band maximum and conduction band minimum, respectively. b Top-view SEM images of Sn-Pb perovskite films deposited on different HSCs. c SEM and d corresponding photoluminescence (PL) mapping images of buried interfaces of Sn-Pb perovskite films deposited on different HSCs.