Fig. 3: Properties of Y2O3 interlayer.
From: Yttrium oxide engineered substrate enables improved durability for perovskite solar cells
XPS spectra of Y2O3, (a) O 1 s and (b) Y 3 d peaks. KPFM for (c) bare FTO and (d) Y2O3-coated FTO. e UPS of Y2O3. f REELS of Y2O3. g Band structure diagram of Y2O3, where the EVBM, ECBM, and EVAC denote the energy level of VBM, CBM, and vacuum, respectively. h Energy diagrams of the Y2O3 interlayer, SnO2 and perovskite absorber. The red arrow illustrates carrier transport to the FTO via the Y2O3 interlayer. The black arrow illustrates back-recombination of the extracted carriers and hole carriers blocked by the Y2O3 interlayer.
