Fig. 2From: Lead-free perovskite solar cells using Sb and Bi-based A3B2X9 and A3BX6 crystals with normal and inverse cell structuresXRD patterns (a) and UV–vis absorption spectra (b) of grown solution processed (CH3NH3)3Bi2I9, (CH3NH3)3Sb2I9 and (CH3NH3)3SbBiI9 films on a glass substrate. The insets were the pictures of (CH3NH3)3Bi2I9, (CH3NH3)3Sb2I9 and (CH3NH3)3SbBiI9 filmsBack to article page