Fig. 4: Defect analysis and charge-carrier dynamics.
From: Homogeneous 2D/3D heterostructured tin halide perovskite photovoltaics
a, Steady-state PL spectra of the Cs0 and Cs5 THP films with the emission peak wavelengths labelled. b, Time-resolved PL decay profiles of the Cs0 and Cs5 THP films. τavg, average charge-carrier lifetime. c, Estimated electron (\({L}_{{\mathrm{D}}}^{{\mathrm{e}}}\)) and hole (\({L}_{{\mathrm{D}}}^{{\mathrm{h}}}\)) diffusion lengths of the Cs0 and Cs5 THP films.τQ and τ0 refer to the estimated average charge carrier lifetimes of perovskite films with and without a quenching layer. d, Urbach energy (EU) plots of the Cs0 and Cs5 THP films. hν, photon energy; α, absorption coefficient. e, Mott–Schottky plots of the Cs0 and Cs5 THPSCs. C, capacitance; Vbi, estimated built-in potential. f, Variation of the Sn4+ molar ratio across the Cs0 and Cs5 THP bulk films derived from depth XPS profiles with different etching time intervals, where the yellow, pink and light-blue regions denote the top surface, bulk film and bottom interface, respectively.
