Wenzhi Wang,Shuo Song,Jinkai Li,Bingqiang Cao,Zongming Liu
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.
Doping metal ions in inorganic halide perovskite (CsPbX3, X = Cl, Br, I) nanocrystals (NCs) endows the NCs with unique optical characteristics, and has thus attracted immense attention. However, controllable synthesis of high-quality doped perovskite NCs with tunable morphology still remains challenging. Here, we report a facile, effective and unified strategy for the controllable synthesis of Mn-doped CsPbCl3 quantum dots (QDs) and nanoplatelets (NPLs) via a single-step solvothermal method. The incorporation of Mn2+ into CsPbCl3 NCs introduces new broad photoluminescence (PL) emission from Mn2+ while maintaining the structure of host CsPbCl3 NCs nearly intact. The PL intensity, emission peak position and size of the NCs can be accurately adjusted by altering the experimental parameters such as Mn-to-Pb feed ratio and reaction time. Especially, by changing the amount of ligands, Mn-doped CsPbCl3 QDs, NPLs or their mixtures can be obtained. Both of the Mn-doped QDs and NPLs exhibit a size-dependent quantum confinement effect, which is confirmed by the relationship between the size of NCs and the exciton emission peaks. The solvothermal reaction condition plays an important role for the precise control of the structure, morphology and PL properties of the Mn-doped NCs. The as-prepared Mn-doped CsPbCl3 NPLs with thickness down to ∼2 nm exhibit a PL quantum yield (PLQY) of more than 22%. This work introduces a new strategy for the controllable synthesis of Mn-doped perovskite NCs, which provides ideas for the in-depth study of the dope-and-grow process and can be extended to approaches of doping other metal ions.
危险品化学品经营许可证（带存储）