Fig. 4: Devices performance and stability.

a J–V curves, b statistics for photovoltaic parameters including the JSC, VOC, PCE, and FF distribution collected from 20 devices for PSCs based on the control, CE-Cs and CE-Rb perovskite films. The box represents values within the range of 25–75%, the dots represent the median and the line segment represents the value range within 1.5 times of interquartile range. c J–V curve of large-area PSC (area, 64.8 cm2) based on CE-Rb. d The EQE spectra and corresponding integrated JSC, e operational stability and f long-term thermal stability of the three PSCs.