基于FAPbBr3钙钛矿纳米晶体的非线性吸收和低阈值双光子泵浦放大自发辐射OA北大核心CSTPCD

Formamidinium lead bromide (FAPbBr3) nanocrystals (NCs) have been considered to be a good opto-electronic material due to their pure green emission,excellent stability and superior carrier transport characteristics.However,two-photon pumped amplified spontaneous emission (ASE) and the corresponding nonlinear optical prop-erties of FAPbBr3 NCs are scarcely revealed.Herein,we synthesized colloidal FAPbBr3 NCs with different sizes by changing the molar ratio of FABr/PbBr2 in the precursor solution,using ligand assisted precipitation (LARP) technol-ogy at room temperature.Photoluminescence (PL) and time resolved photoluminescence (TRPL) spectroscopy were measured to characterize their ASE properties.And their nonlinear optical properties were studied through the Z-scan technique and the two-photon excited fluorescence method.The stimulated emission properties including one-and two-photon pumped ASE have been realized from FAPbBr3 NCs.With large two-photon absorption coefficient (0.27 cm/GW) and high non-linear absorption cross-section (7.52×105 GM),ASE with threshold as low as 9.8 μJ/cm2 and 487 μJ/cm2 have been obtained from colloidal FAPbBr3 NCs using one-and two-photon excitations.These re-sults indicate that as a new possible green-emitting frequency-upconversion material with low thresholds,FAPbBr3 NCs hold great potential in the development of high-performance two-photon pump lasers.