Extended Data Fig. 7: Density-functional theory simulations of the graded single-crystal perovskites.
From: A fabrication process for flexible single-crystal perovskite devices
a, Calculation results showing electronic band structures of the graded single-crystal MAPb0.5+xSn0.5−xI3. All structures show direct bandgaps at the Γ point. The Fermi level is normalized to the VBM, to show the shrinking tendency of the bandgap. b, Calculated effective masses for electrons and holes in the graded single-crystal MAPb0.5+xSn0.5−xI3 with an increasing tin concentration. The decreasing effective masses indicate increasing mobilities of both electrons and holes. The enhancement for holes is more pronounced than for electrons. c, Graded single-crystal MAPb0.5+xSn0.5−xI3 (left) showing a graded bandgap in comparison with the flat bandgap of conventional MAPbI3 (right).
