Fig. 1: Perovskite surface structure and properties.
From: Stabilizing high-efficiency perovskite solar cells via strategic interfacial contact engineering
a, Constructed SHF adsorption model on the perovskite structure. b, Defect formation energy of the perovskite surface with and without SHF adsorption. PVK, perovskite. c, Planar Δρ for the PbI2-terminated surface of single SHF-adsorbed perovskite. d,e, KPFM maps of perovskites without (d) and with (e) SHF. The colour scale represents the surface potential (V). Image size, 5 μm × 5 μm. f,g, Integrated GIWAXS patterns on (001) peaks of perovskites without (f) and with (g) SHF for incident angles from 0.05° to 1.0°. h–k, Simulated energy-level diagrams of control (h and j) and SHF-containing (i and k) devices before and after dark equilibration. The SHF layer introduces a vacuum-level shift and enhances the electric field across C60, consistent with an increased built-in potential. WFb, bulk work function; WFs, surface work function; EF is the Fermi level energy; EC and EV are the conduction and valence band edges, respectively, and Evac is the vacuum energy level.
