Fig. 7From: Lead-free perovskite solar cells using Sb and Bi-based A3B2X9 and A3BX6 crystals with normal and inverse cell structuresSEM images observed for elemental analysis of A3BX6 films [Ag3BiI6: (a, b); Ag3BiI3(SCN)3: (c, d); Cu3BiI6: (e, f)] grown on different substrates [TiO2: (a, c, e); NiO: (b, d, f)]. The marked spots indicate the positions of elemental analysis, which is related to the results shown in Tables 8, 9, 10, 11, 12 and 13 Back to article page