Controllable conduction band-edge reconfiguration in quasi-2D perovskites enabled by dimensional engineering for encouraging electron-hole separation

Generally, the band-edge configurations of ABX3 perovskite (where A is MA+/FA+/Cs+ cation, B represents Pb2+ or Sn2+, and X is halogen, respectively) are constructed by the electronic states of B and X ions, implying that A-site cation has no significant contribution to the band edge. In current work, through first-principles calculation, we report the controllable conduction band (CB) edge reconfiguration of quasi-2D Dion-Jacobson α-CsPbI3 perovskites enabled by dimensional engineering for making A-site cations affect perovskite CB edge, which is based on rationally designed organic chain length (m) of A-site organic spacer cations and inorganic layer numbers (n). It is discovered that the energy level of organic CB would be moved up with the increase of m, and that of inorganic CB would be shifted down with the raise of n, allowing the dimensional engineering of quasi-2D perovskites with controllable CB-edge configuration. Consequently, the achieved CB-edge reconfiguration could endow the quasi-2D perovskites with encouraged carrier separation and in-plane transfer. The discovery of CB-edge reconfiguration in quasi-2D perovskites by dimensional engineering, which is highly meaningful to direct the exploration of advanced perovskites for efficient solar cells.