Laser writing of CsPbBr3 nanocrystals mediated by closely-packed Au nanoislands

Abstract

Metal halide perovskites have attracted great interest in recent years owing to their excellent luminescence properties. The low formation energy makes it possible to synthesize perovskites of different types via direct laser writing. Here, we report on the formation of metal halide perovskite (CsPbBr3) nanocrystals coupled to the surface plasmon resonances of gold (Au) nanoparticles by irradiating a polymer film doped with the precursors (CsBr and PbBr3) and coated on a thin Au film. The Au film, which is composed of closely-packed Au nanoislands deposited on a silica substrate, act as not only the absorber of 800-nm femtosecond laser pulses but also the heat source for synthesizing and annealing of CsPbBr3 nanocrystals. The formation of CsPbBr3 nanocrystals in the area of laser irradiation was confirmed by Raman scattering spectra measurements. In addition, closely-packed Au nanoislands are transformed into isolated Au nanoparticles which exhibit surface plasmon resonances at ~530 nm. The CsPbBr3 nanocrystals coupled to isolated Au nanoparticles emit two-photon-induced luminescence at ~513 nm, which is enhanced by the surface plasmon resonances through the Purcell effect. An optimal laser power for direct laser writing was determined and the decomposition of CsPbBr3 nanocrystals was observed if a large laser power was employed. Our results indicate the possibility for the formation and annealing of perovskite nanocrystals coupled to surface plasmon resonances by one-step laser writing and open new horizon for their practical applications in color display and optical memory.