Fig. 4: Stability performance of PSCs.

a Evolution of power conversion efficiency of the pristine (blue) and chelated (orange) CsPbI2Br devices without encapsulation. The devices were stored under ambient atmosphere with controlled humidity (RH, 15 ± 3%). b Long-term stability of the pristine (blue) and chelated (orange) devices under continuous 100 mW cm−2 white LED illumination in nitrogen glovebox. All devices configurations are FTO/c-TiO2/perovskite/P3HT/Au. Normalized PL spectra of the (c) pristine and (d) chelated CsPbI2Br films under continuous one sun equivalent illumination for 10 min. All perovskite films were deposited on glass substrates.