Single silica-coated Mn-doped CsPbCl3 perovskite quantum dots with enhanced stability and excellent optical properties
Halide perovskite quantum dots (QDs) have been considered to be a potential emitting materials for illumination and display applications. Unfortunately, the toxicity and poor stability can greatly limit their practical application. Herein, the Mn 2+ -doped CsPbCl 3 and SiO 2 -coated Cs(Pb,Mn)Cl 3 perovskite QDs have been developed to solve the tricky problem without affecting their optical properties . Firstly, the mono-dispersed pure CsPbCl 3 perovskite QDs with cubic morphologies are prepared by using a modified hot-injection method, as a control group. Next, the low-Pb content Cs(Pb,Mn)Cl 3 perovskite QDs with distinctive dual emission peaks has been successfully obtained, including the CsPbCl 3 host emission and the Mn 2+ emission. Based on this, a new strategy for synthesizing single Cs(Pb,Mn)Cl 3 @SiO 2 core-shell QDs with their initial cubic morphology and optical properties has been developed, which using the Cs(Pb,Mn)Cl 3 nanoparticles as a precursor and choosing the APTES as the surface ligand. Photo-stability tests indicate that the Cs(Pb,Mn)Cl 3 and Cs(Pb,Mn)Cl 3 @SiO 2 perovskite QDs are markedly more stable than the pure CsPbCl 3 QDs, indicating that the crystal engineering and host packaging are all effective way to improve the stability. Meanwhile, the PL intensity of Cs(Pb,Mn)Cl 3 @SiO 2 dispersed in a mixed solution of toluene and water can retained 63% of the initial value even after 14 h, which are much higher than Cs(Pb,Mn)Cl 3 (31%). Therefore, the Cs(Pb,Mn)Cl 3 after SiO 2 coating is the more effective way to improve stability than that of the Mn 2+ doping. This work not only provides a simple and reliable synthesis way to synthesize the single core-shell particles, which can be suitable for other perovskite systems, but also compares the two methods of the crystal engineering and the host packaging to improve the stability of perovskite QDs for practical application.
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