Water-Stable All-Inorganic Perovskite Nanocrystals with Nonlinear Optical Properties for Targeted Multiphoton Bioimaging

CsPbX3nanocrystals have been employed in various optoelectronic applications, such as light-emitting diodes and solar cells. Nevertheless, widespread application of CsPbX3nanocrystals has been largely restricted by their poor aqueous stability. Despite the tremendous efforts focused on encapsulating the CsPbX3nanocrystals, it is still very challenging to achieve CsPbX3nanocrystals with good aqueous stability. This work describes the preparation and encapsulation methods for CsPbBr3/SiO2/mPEG-DSPE nanocrystals that can be readily dispersed in water and biological buffers. To the best of our knowledge, this is the first work that reports multiphoton emissions from CsPbBr3/SiO2/mPEG-DSPE nanocrystals in water. The protection afforded by the silica shell and phospholipid micelles enables the CsPbBr3/SiO2/mPEG-DSPE nanocrystals in aqueous solution to exhibit enhanced long-term stability and better shielding against ultrasonication treatment and continuous light irradiation than bare CsPbBr3nanocrystals. The toxicity of the CsPbBr3/SiO2/mPEG-DSPE nanocrystals has been evaluated in various cell lines. Subsequently, the encapsulated nanocrystals were used for targeted single and multiphoton imaging of cancer cells. This work not only describes the preparation of water-stable CsPbBr3nanocrystals but also paves the way for their applications in multiphoton bioimaging applications.