Fig. 3: Phase stability of WBG perovskites under rapid solar-thermal cycling.

In situ photoluminescence evolution as a function of time during thermal cycling, excited with a 450 nm laser for (a) control perovskite thin film and (b) DP perovskite thin films. The white line represents the temperature evolution, following the same time scale, with corresponding temperatures indicated. c Time-dependent peak position extracted from the in situ PL spectra, where the characteristic temperatures are indicated. d Selective defect density of control and DP perovskite thin films during thermal cycling.