School of Physics, Shandong University, Jinan 250100, RP China.
Chemphyschem. 2012 Jan 16;13(1):147-54. doi: 10.1002/cphc.201100527. Epub 2011 Oct 24.
As an excellent bandgap-engineering material, the Cd(1-x)Zn(x)S solid solution, is found to be an efficient visible light response photocatalyst for water splitting, but few theoretical studies have been performed on it. A better characterization of the composition dependence of the physical and optical properties of this material and a thorough understanding of the bandgap-variation mechanism are necessary to optimize the design of high-efficience photocatalysts. In order to get an insight into these problems, we systematically investigated the crystal structure, the phase stability, and the electronic structures of the Cd(1-x)Zn(x)S solid solution by means of density functional theory calculations. The most energetically favorable arrangement of the Cd, Zn, S atoms and the structural disorder of the solid solution are revealed. The phase diagram of the Cd(1-x)Zn(x)S solid solution is calculated based on regular-solution model and compared with the experimental data. This is the first report on the calculated phase diagram of this solid solution, and can give guidance for the experimental synthesis of this material. Furthermore, the variation of the electronic structures versus x and its mechanism are elaborated in detail, and the experimental bandgap as a function of x is well predicted. Our findings provide important insights into the experimentally observed structural and electronic properties, and can give theoretical guidelines for the further design of the Cd(1-x)Zn(x)S solid solution.
作为一种优秀的能带工程材料，Cd(1-x)Zn(x)S 固溶体被发现是一种有效的可见光响应光催化剂，可用于水分解，但对其很少进行理论研究。为了优化高效光催化剂的设计，有必要更好地描述该材料的组成依赖性的物理和光学性质，并深入了解带隙变化机制。为了深入了解这些问题，我们通过密度泛函理论计算系统地研究了 Cd(1-x)Zn(x)S 固溶体的晶体结构、相稳定性和电子结构。揭示了 Cd、Zn、S 原子的最稳定排列和固溶体的结构无序。基于正则溶液模型计算了 Cd(1-x)Zn(x)S 固溶体的相图，并与实验数据进行了比较。这是该固溶体相图的首次计算报告，可以为该材料的实验合成提供指导。此外，详细阐述了电子结构随 x 的变化及其机制，并很好地预测了实验带隙随 x 的变化。我们的研究结果提供了对实验观察到的结构和电子性质的重要见解，并为进一步设计 Cd(1-x)Zn(x)S 固溶体提供了理论指导。
