Recovery of photoluminescence efficiency of $CsPbBr_3$ nanocrystals/siloxane composite film with high luminescence stability

Abstract

Perovskite nanocrystals are excellent photoluminescent materials as materials having high luminous efficiency and narrow emission line width, but have low structural stability and do not maintain good optical properties for a long time. In this paper, we introduced silica-like siloxane resin to synthesize perovskite NCs/siloxane composite film passivated by chemical bonds. The composite films were tested for photoluminescence stability by observing changes in PL quantum yield in ambient at RT, in water, at high temperature and high humidity condition, and at high temperature and low humidity condition. The composite films showed long-term emission stability over 60 days. And PL QY of the film was observed to be greatly increased in the presence of water. The fluorescence lifetime spectrometry analysis on film allowed monitoring the lifetime of the composite film was greatly increased, and it was confirmed that the trap sites were suppressed by water. This means that the degradation of the perovskite NCs was prevented due to the high stability of the composite film in water, and the recovery effect of water was acted on the composite film.