Ultraviolet light induced degradation of luminescence in CsPbBr3 perovskite nanocrystals

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.