Hefei National Laboratory for Physical Sciences at the Microscale, Hefei Science Center, National Synchrotron Radiation Laboratory & Synergetic Innovation Center of Quantum Information and Quantum Physics, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
Nanoscale. 2017 Jan 7;9(1):104-108. doi: 10.1039/c6nr08250e. Epub 2016 Dec 9.
We report a room-temperature colloidal synthesis of few-unit-cell-thick CsPbBr QWs with lengths over a hundred nanometers. The surfactant-directed oriented attachment growth mechanism was proposed to explain the formation of such CsPbBr QWs. Owing to the strong quantum confinement effect, the photoluminescence (PL) emission peak of few-unit-cell-thick CsPbBr QWs blue-shifted to 430 nm. The ensemble PL quantum yield (PLQY) of the few-unit-cell-thick CsPbBr QWs increased to 21.13% through a simple heat-treatment process. The improvement of PLQY was ascribed to the reduction of the density of surface trap states and defect states induced by the heat-treatment process. Notably, the dependence of the bandgap on the diameter with different numbers of unit cells was presented for the first time in 1-D CsPbBr QWs on the basis of the produced few-unit-cell-thick CsPbBr QWs.
我们报道了一种在室温下合成具有数百纳米长度的少数几个单元厚的 CsPbBr QWs 的胶体合成方法。提出了表面活性剂导向的定向附着生长机制来解释这种 CsPbBr QWs 的形成。由于强量子限制效应，少数几个单元厚的 CsPbBr QWs 的光致发光（PL）发射峰蓝移至 430nm。通过简单的热处理过程，少数几个单元厚的 CsPbBr QWs 的整体 PL 量子产率（PLQY）提高到 21.13%。PLQY 的提高归因于热处理过程中减少了表面陷阱态和缺陷态的密度。值得注意的是，首次在一维 CsPbBr QWs 中提出了不同单元数量的带隙与直径的依赖关系。
