Monodisperse Formamidinium Lead Bromide Nanocrystals with Bright and Stable Green Photoluminescence

Bright green emitters with adjustable photoluminescence (PL) maxima in the range of 530-535 nm and full-width at half-maxima (FWHM) of 25 nm are particularly desirable for applications in television displays and related technologies. Towards this goal, we have developed a facile synthesis of highly monodisperse, cubic-shaped formamidinium lead bromide nanocrystals (FAPbBr3 NCs) with perovskite crystal structure, tunable PL in the range of 470-540 nm by adjusting the nanocrystal size (5-12 nm), high quantum yield (QY) of up to 85% and PL FWHM of 22 nm. High QYs are also retained in films of FAPbBr3 NCs. In addition, these films exhibit low thresholds of 142 µJ cm-2 for amplified spontaneous emission.