All-inorganic CsPbX₃ (X = I, Br, Cl) perovskite quantum dots (QDs) are emerging as potential candidates for photoelectric devices such as light-emitting diodes (LEDs), solar cells etc. due to their outstanding optical properties including tunable bandgap, narrow size distribution and high photoluminescence (PL) quantum yield (QY). However, instability originated from the strong anion-exchange effect and the lower melting temperature hinders their further practical application. Here, blue emission CsPbBr_1.5Cl_1.5 QDs with peak wavelength ∼450 nm are prepared by means of hot injection method, and mesoporous silica particles are introduced to wrap them. On one hand, the silica coat, protecting the core QDs from oxygen and humidity somewhat, the stability of the PL QYs and the luminescence of the CsPbBr_1.5Cl_1.5 QDs, as well as the emission and vision properties of the devices based on these QDs are improved evidently. On the other hand, by integrating the prepared blue emission CsPbBr_1.5Cl_1.5 QDs or the silica-coated CsPbBr_1.5Cl_1.5 QDs as single downconverters on violet chips with emission wavelength 365 nm, surprisingly, we observe a new peak ∼550 nm in the PL spectrum of the resultant devices, except for the originate blue emission. We speculate that the new emission peak, which is helpful for the construction of white LEDs (WLEDs), is originated from the bromide-enriched majority domains resulted from the photo-induced segregation of CsPbBr_1.5Cl_1.5 QDs. The fabricated WLEDs based on CsPbBr_1.5Cl_1.5@SiO₂ QDs, in comparison with that based on CsPbBr_1.5Cl_1.5 QDs, exhibits stable color rendering index (CRI) with the least variation of 1.4, and stable color correlated temperature (CCT) with the least variation of 325 K. These results suggest that the large full width of half maximum of the new emission benefits for the construction of WLEDs, and mesoporous silica particles serving as coat layer hold great promise for the improvement of performance stability for the devices based on CsPbBr_1.5Cl_1.5@SiO₂ QDs.

全无机CsPbX ₃（X = I，Br，Cl）钙钛矿量子点（QDs）由于其出色的光学性能（包括可调性）而成为光电器件（例如发光二极管（LED），太阳能电池等）的潜在候选材料带隙，窄尺寸分布和高光致发光（PL）量子产率（QY）。但是，由于强烈的阴离子交换作用而产生不稳定性，并且较低的熔融温度阻碍了其进一步的实际应用。在这里，蓝色发射CsPbBr _1.5 Cl _1.5通过热注射法制备峰值波长〜450 nm的量子点，并引入介孔二氧化硅颗粒将其包裹。一方面，使用二氧化硅涂层可在一定程度上保护核心量子点免受氧气和湿气的侵害，并保护PL量子点的稳定性和CsPbBr _1.5 Cl _1.5量子点的发光，以及基于这些量子点的器件的发射和视觉特性明显改善。另一方面，通过集成制备的蓝色发射CsPbBr _1.5 Cl _1.5 QDs或二氧化硅涂层的CsPbBr _1.5 Cl _1.5令人惊奇的是，在发射波长为365 nm的紫罗兰色芯片上，QD作为单个下变频器，令人惊讶的是，除了发出的蓝光之外，我们在所得器件的PL光谱中观察到一个新的〜550 nm峰。我们推测，新的发射峰对白光LED（WLED）的构建很有帮助，它是由光诱导的CsPbBr _1.5 Cl _1.5 QDs分离引起的溴化物富集的多数域引起的。与基于CsPbBr _1.5 Cl _1.5的Ws相比，基于CsPbBr _1.5 Cl _1.5 @SiO ₂ QDs的WLEDs的制备QD表现出稳定的显色指数（CRI），变化最小，为1.4，稳定的显色温度（CCT），变化最小，为325K。 WLEDs的构造以及用作涂层的介孔二氧化硅颗粒对于改善基于CsPbBr _1.5 Cl _1.5 @SiO ₂ QDs的器件的性能稳定性具有广阔的前景。