Methylammonium lead bromide (MAPbBr₃) nanocrystals have attracted great attention for potential optoelectronic applications. We synthesized highly emissive MAPbBr₃ nanoplatelets (NPLs) by using a facile ligand assisted reprecipitation method with short-chain ligands. They exhibit an excitation-dependent photoluminescence (PL) quantum yield (QY) with a maximum value of 98% upon ultraviolet (UV) excitation. The femtosecond transient absorption and temperature-dependent PL spectra confirmed the existence of continuous band at ∼350 nm and demonstrated that the PLQY of near unity originates from the efficient ultrafast energy-down-shift from this band to exciton state in N phase, which quenches nonradiative recombination via trap states.

甲基铵溴化铅（MAPbBr ₃）纳米晶体已经吸引了潜在的光电应用关注。我们通过使用具有短链配体的简便配体辅助再沉淀方法合成了高发射MAPbBr ₃纳米血小板（NPL ）。它们表现出与激发有关的光致发光（PL）量子产率（QY），在紫外线（UV）激发下的最大值达到98％。飞秒瞬态吸收和温度相关的PL光谱证实了在〜350 nm处存在连续谱带，并证明了接近统一的PLQY源自N相从该谱带到激子状态的有效超快能量下移，从而淬灭通过陷阱状态进行非辐射重组。