Caesium lead bromide perovskite nanocrystals (PNCs) are synthesized using a room-temperature sonochemical method. By mixing equimolar of CsBr and PbBr₂ in Dimethylformamide (DMF), PNCs of CsPbBr₃ structure are formed. Under an identical reaction condition, when EuBr₂ is introduced with the CsBr/PbBr₂ precursor, the resulted product (Eu-PNCs) becomes zero-dimensional Cs₄PbBr₆ nanocrystals. In addition to the typical green emission observed in both CsPbBr₃ and Cs₄PbBr₆, Eu-PNCs has a blue emission band. The overall photoluminescence quantum yield is much higher than the pristine PNCs. We perform detailed analysis of the crystal structure and luminescence properties of the nanocrystals with and without EuBr₂ modification. An X-ray absorption fine structure analysis reveals the local structure of Eu in the PNCs. We propose that the cation-solvent interaction strongly influences the crystallization process of ternary Cs_xPb_yBr_z, and the formation of Eu-solvent complexes further modifies the PNCs surface resulting in unique luminescence properties.

溴化铯铅钙钛矿纳米晶体（PNCs）使用室温声化学方法合成。通过在二甲基甲酰胺（DMF）中混合等摩尔的CsBr和PbBr ₂，形成CsPbBr ₃结构的PNC 。在相同的反应条件下，将EuBr ₂与CsBr / PbBr ₂前体一起引入时，所得产物（Eu-PNCs）变为零维Cs ₄ PbBr ₆纳米晶体。除了在CsPbBr ₃和Cs ₄ PbBr _6中观察到的典型绿色发射之外，Eu-PNC具有蓝色发射带。整体光致发光量子产率比原始PNC高得多。我们对具有和不具有EuBr ₂修饰的纳米晶体的晶体结构和发光特性进行了详细的分析。X射线吸收精细结构分析揭示了PNC中Eu的局部结构。我们提出阳离子-溶剂相互作用强烈影响三元Cs _x Pb _y Br _z的结晶过程，并且Eu-溶剂配合物的形成进一步修饰了PNCs表面，从而产生了独特的发光特性。