“Researchers have made significant progress in the field of optoelectronics, synthesizing formamidinium lead bromide (FAPbBr3) nanocrystals with different sizes using ligand-assisted precipitation technology at room temperature. The study revealed their two-photon pumped amplified spontaneous emission and nonlinear optical properties, with a large two-photon absorption coefficient and high non-linear absorption cross-section. These findings indicate that FAPbBr3 nanocrystals could be a promising green-emitting frequency-upconversion material for the development of high-performance two-photon pump lasers.”