Ultraviolet light induced degradation of luminescence in CsPbBr3 perovskite nanocrystals

Highlights: • The degradation of PL in CsPbBr₃ nanocrystals under UV illumination was studied. • The degradation was attributed to the photo-oxidation of lead atoms on NC surface. • The PbCO₃ and PbO phases were observed after long illumination time. • The change in PL intensity, peak energy, and linewidth as well as lifetimes under illumination was discussed. - Abstract: Perovskite nanocrystals (NCs) have been applied in light emitting diodes, but their stability is always the decisive factor to limit the practical application of devices. In this work, the influence of ultraviolet light illumination on the structural and luminescent properties of CsPbBr₃ NC films with emissions of 495 and 520 nm was studied. It was demonstrated that the CsPbBr₃ NC films exhibited significant degradation of photoluminescence (PL) under the illumination in air. The PbCO₃ and PbO phases in CsPbBr₃ NC films were observed after long illumination time with X-ray photoemission spectroscopy. The temperature-dependent PL spectra revealed that large amount of nonradiative traps were formed with increasing illumination time. The PL intensities, band energies, and bandwidths as well as PL lifetimes of the illuminated CsPbBr₃ NC films were analyzed. The experimental results indicated that the PL degradation was attributed to the photo-oxidation of NCs under the illumination.