![Figure 1, A: The ABX3 perovskite crystal structure, where typically A is an organic cation (grey), B is Pb2+ or Sn2+ (pink) and X is a halide anion (green). B: Perovskite thin films of different bandgap (Plamen Petkov for Scientific American)](https://outreach.phy.cam.ac.uk/sites/outreach.phy.cam.ac.uk/files/media/oe.png)
Alt Text:
Figure 1, A: The ABX3 perovskite crystal structure, where typically A is an organic cation (grey), B is Pb2+ or Sn2+ (pink) and X is a halide anion (green). B: Perovskite thin films of different bandgap (Plamen Petkov for Scientific American)