Fig. 5: Origin of photovoltaic performance improvement and device stability.
a, Light intensity-dependent VOC showing ideality factors (n) of 1.703 and 1.163 for SP β-CsPbI3 and PHJ100, respectively. b, PDS spectra showing the Urbach energies (EU) of 33.27 meV and 19.80 meV for SP β-CsPbI3 and PHJ100, respectively. c, ELQY. d, Temperature-dependent conductivity showing ion migration activation energies (Ea) of 0.79 eV and 1.66 eV and the transition temperatures of 260 K and 273 K for SP β-CsPbI3 and PHJ100, respectively. The inset in d shows the conductivity device with a lateral structure consisting of two Au (50 nm) electrodes with a length of 111 mm and spacing gap of 0.2 mm deposited on the surface of the perovskite film. e, Storage stability of PCE. Encapsulated devices were stored in nitrogen atmosphere at 25 °C and under dim light conditions. f, Performance evolution of encapsulated SP β-CsPbI3 and PHJ100 solar cells under continuous illumination. Up to 550 h stability was tested under 40% relative humidity (RH), 25 °C, constant xenon lamp-simulated solar illumination (100 mW cm−2) without a UV filter. The fitting lines in a, b and d were obtained by linear fitting of data points. f displays the mean, with 1.5× interquartile range whiskers.
