fig5
Figure 5. Charge-transfer kinetics at the SnO2/perovskite interface. (A) UV-vis absorption spectra and (B) corresponding Tauc plots. UPS data for (C) secondary electron cutoff and (D) valence band region; (E) Energy-level alignment diagram; (F) KPFM images and (G) contact potential difference (CPD) values. UV-vis: Ultraviolet-visible; UPS: ultraviolet photoelectron spectroscopy; KPFM: Kelvin probe force microscopy; AA: L-aspartic acid; ABA: 4-aminobutyric acid; DBA: L-2,4-diaminobutyric acid.
