沸石Y中的水分子增强了溴化铯铯量子点Na 4 Cs 6 PbBr 4 8+的光致发光特性,The Journal of Physical Chemistry C

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沸石Y中的水分子增强了溴化铯铯量子点Na ₄ Cs ₆ PbBr ₄⁸⁺的光致发光特性
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2021-03-05 , DOI: 10.1021/acs.jpcc.0c11580
Raees Ahmad ₁ , Joon Young Kim ₁ , Gi Beom Park ₁ , Nam Ho Heo ₁ , Karl Seff ₂

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通过使Cs ₄₉ Na ₂₂ -Y与PbBr ₂在混合有机溶剂中反应来制备Pb，Br，H，Cs，Na-Y沸石，并通过晶体学确定其单晶的结构。大约26％的超级笼在其中心处具有四面体PbBr ₄^2-离子。每一个由6根铯包围⁺离子，其中的每一个在两个溴之间桥接^-离子对PbBr的每个边缘₄^2-四面体。这四个Br与每个^-离子也债券中的Na ⁺附近的6元环的中心离子。结果是Na ₄ Cs ₆ PbBr ₄⁸⁺量子点对称性43（QD）米（Ť _d）。这种沸石的超笼（Si / Al = 1.69）的平均电荷为8.9–，几乎平衡了该量子点的8+电荷。相邻超笼中QD之间的12环桥（Cs ⁺ –H ₂ O–Cs ⁺）中的水分子形成四面体排列QD的域。这些QD和这些域都可以通过电子显微镜直接看到。这些量子点在被紫外线辐射激发时会在528 nm处急剧发光（绿色，FWHM = 17.8 nm）。Pb，Br，H，Cs，Na-Y及其发光在大气中是完全稳定的；桥接的水分子增强了发光并提供了稳定性。结构细化是在空间群做的Fd 3m（a = 24.889（4）Å），其中886个唯一反射的F _o >3σ（F _o）至最终误差指数R ₁ = 0.077。通过能量色散X射线分析确认了其组成。

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Water Molecules in Zeolite Y Enhance the Photoluminescent Properties of Its Cesium Lead Bromide Quantum Dots, Na4Cs6PbBr48+

Zeolite Pb,Br,H,Cs,Na-Y was prepared by the reaction of Cs₄₉Na₂₂-Y with PbBr₂ in a mixed organic solvent, and the structure of a single crystal of it was determined crystallographically. About 26% of its supercages hold a tetrahedral PbBr₄^2– ion at their centers. Each is surrounded by six Cs⁺ ions, each of which bridges between the two Br^– ions on each edge of the PbBr₄^2– tetrahedron. Each of these four Br^– ions also bonds to a Na⁺ ion near the center of a 6-ring. The result is a Na₄Cs₆PbBr₄⁸⁺ quantum dot (QD) of symmetry 4̅3m (T_d). The supercage in this zeolite (Si/Al = 1.69) has an average charge of 8.9–, which nearly balances the 8+ charge of this QD. Water molecules in 12-rings bridge (Cs⁺–H₂O–Cs⁺) between QDs in adjacent supercages to form domains of tetrahedrally arranged QDs. Both these QDs and these domains are seen directly by electron microscopy. These QDs, when excited by UV radiation, luminesce sharply at 528 nm (green, FWHM = 17.8 nm). Pb,Br,H,Cs,Na-Y and its luminescence are entirely stable in the atmosphere; the bridging water molecules enhance the luminescence and provide that stability. Structure refinement was done in the space group Fd3̅m (a = 24.889(4) Å) with the 886 unique reflections for which F_o > 3σ(F_o) to the final error index R₁ = 0.077. Its composition was confirmed by energy dispersive X-ray analysis.

更新日期：2021-03-18

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