Extended Data Fig. 1: Photon-counting performance of a typical FA0.7MA0.3PbI3 solar cell.

a, Typical J–V curve of a FA0.7MA0.3PbI3 solar cell. b, Schematic diagram of the photon-counting measurement system. CSP denotes the charge-sensitive preamplifier. c, Photon-counting performance of the FA0.7MA0.3PbI3 solar cell.