Changes in photoluminescence (PL) peak width and quantum yield (PLQY) with halide composition were compared for CsPb(Br_1−x I _x )₃ nanocrystals (NCs) prepared by hot-injection and ion-exchange methods. The hot-injection method produced single-phase cubic CsPb(Br_1−x I _x )₃ NCs for each iodide ratio. In contrast, a small amount of orthorhombic phase was observed at higher x for NCs prepared by the ion-exchange methods. The PL peak width of mixed-halide NCs at x = 0.55 was broader than those of CsPbBr₃ and CsPbI₃, possibly as a result of compositional inhomogeneity among the individual NCs. However, the maximum PL peak width occurred at larger x for the ion-exchange methods, possibly because of partial transition to orthorhombic phase from cubic phase for CsPb(Br_1−x I _x )₃ NCs. The minimum PLQY for the hot-injection method was 25.0% at x = 0.50, which was lower than the PLQYs of CsPbBr₃ and CsPbI₃ NCs (∼70%). In contrast, the minimum PLQY for the ion-exchange methods occurred at x = ∼0.3. Furthermore, the minimum PLQY was ∼10%, which was lower than 25.0% for the hot-injection method. The addition of halide solution for ion exchange might affect the adsorption state of surface modifiers, leading to the decreased PLQY.

比较了通过热注入和离子交换方法制备的CsPb(Br _{1− x} I _x ) ₃纳米晶体 (NC) 的光致发光 (PL) 峰宽和量子产率 (PLQY) 随卤化物成分的变化。对于每个碘化物比率，热注射方法产生单相立方 CsPb(Br _{1− x} I _x ) ₃ NCs。相比之下，对于通过离子交换方法制备的 NC，在较高的x下观察到少量正交相。混合卤化物 NCs 在x = 0.55处的 PL 峰宽比 CsPbBr ₃和 CsPbI _{3 的}峰宽更宽 ，可能是由于各个 NC 之间的成分不均匀所致。然而，对于离子交换方法，最大 PL 峰宽出现在较大的x处，这可能是因为 CsPb(Br _{1− x} I _x ) ₃ NCs从立方相部分转变为正交相。热注射法的最小 PLQY 在x = 0.50 时为 25.0%，低于 CsPbBr ₃和 CsPbI ₃ NCs 的PLQY （~70%）。相比之下，离子交换方法的最小 PLQY 发生在x = ~0.3。此外，最小 PLQY 为~10%，低于热注射方法的 25.0%。添加用于离子交换的卤化物溶液可能会影响表面改性剂的吸附状态，导致 PLQY 降低。