In Situ Observation of a Photodegradation-Induced Blueshift in Perovskite Nanocrystals Using Single-Particle Spectroscopy Combined with Atomic Force Microscopy

摘要

Inorganic cesium lead halide perovskite nanocrystals (PNCs) are gaining attention due to their remarkable optical and electronic properties. However, because of their ionic properties, PNCs are unstable in a moist ambient atmosphere. In previous research, a blueshift in the photoluminescence (PL) of a single PNC upon photoirradiation was reported, which was attributed to the photodegradation of the PNC. Although it was postulated that the PNC size was reduced by photodegradation, direct observations and a verification of the correlation between the blueshift and the size during the photodegradation process have not yet been conducted. Herein, we successfully investigated the photodegradation process of CsPbBr3 PNCs at the single-particle level by monitoring the size change. We used atomic force microscopy (AFM) in tandem with single-particle spectroscopy to observe the PNC size and the spectral shift of a single CsPbBr3 PNC. It was clearly demonstrated that the PL spectrum was blueshifted, and the size of the individual PNC was decreased upon continuous photoirradiation.