Synthesis of Au or Pt@Perovskite Nanocrystals via Interfacial Photoreduction

The surface modification of perovskite nanocrystals (NCs) (i.e., their decoration with noble metals) holds great promise with respect to the tailoring of their properties but has remained a challenge because perovskite NCs are extremely sensitive to water and alcohols. In this study, Au or Pt@CsPbBr3NCs were successfully synthesized by photoreduction at the water/hexane interface. First, Cs4PbBr6NCs were synthesized through the hot-injection method. Then, Cs4PbBr6was transformed into CsPbBr3and subjected to noble metal modification, both at the interface. The synthesized CsPbBr3NCs exhibited a cubic perovskite phase and had an average size of approximately 13.5 nm. The deposited Au and Pt nanoparticles were crystalline, with a face-centered cubic lattice and average diameters of approximately 3.9 and 4.4 nm, respectively. The noble metal modification process had almost no effect on the steady-state photoluminescence (PL) emission wavelength but affected the charge-recombination kinetics of the CsPbBr3NCs. Time-resolved PL decay spectral analysis indicated that the fluorescence lifetimes of the Au and Pt@CsPbBr3NCs were shorter than those of the pure CsPbBr3NCs, probably owing to the quenching of the free charges because of electron transfer from the perovskite to the noble metal nanoparticles.Keywords:perovskite nanocrystals;noble metal;interface;photoreduction