Low temperature synthesis of ultra-green luminescent colloidal FAPbBr3 perovskite nanocrystals

According to the updated recommendation for displays standard (Rec. 2020), ultrapure green emitters with a narrow emission (below 25 nm) in the 525–535 nm spectral range are desired. However, finding an emitter material that can meet such requirements, is still challenging. To this purpose, organic–inorganic halide perovskites nanocrystals have been considered as promising high-color purity light emitters at a lower cost, that overcome the issues associated with conventional emitters. Herein, to reach these standards simultaneously, we have synthesized Formamidinium lead bromide perovskite nanocrystals (NCs) at room temperature by ligand-assisted reprecipitation (LARP). The obtained FAPbBr3 NCs coated with oleic acid and oleylamine show an average size of about 20 nm. FAPbBr3 NCs dispersions in hexane exhibited bright photoluminescence with a high quantum yield (74%). The color coordinates on CIE 1931 are (0.2, 0.75), with a corresponding strong green emission at 533 nm. The emission is characterized by an ultranarrow full width at half-maximum (FWHM = 22 nm), and long radiative lifetimes (≈82 ns). The synthesized FAPbBr3 NCs present ideal features toward solution-processable ultrapure green emitters.