Electron. Mater. Lett., Vol. 11, No. 2 (2015), pp. 187-192 Preparation of Ternary Cd 1-x Zn x S Nanocrystals with Tunable Ultraviolet Absorption by Mechanical Alloying Qi Zhang, 1 Huihui Zhang, 1 Limin Liu, 1 Shaohua Li, 2 James B. Murowchick, 2 Clarissa Wisner, 3 Nickolas Leventis, 3 Zhonghua Peng, 2, * and Guolong Tan 1, * 1 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China 2 Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA 3 Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, USA (received date: 8 October 2014 / accepted date: 12 November 2014 / published date: 10 March 2015) 1. INTRODUCTION Alloyed semiconductor nanocrystals (NCs) enable band gap engineering through both size control and composition tuning. [1-3] Although wet chemical routes have shown to be viable and attractive in preparing alloyed NCs with controlled uniform size and shape, [3-6] mechanical alloying is a far simpler and more versatile technique in preparing composition-tunable NCs. [7-11] Starting from the corresponding elemental powders, chemically homogenous alloyed NCs with sizes less than 10 nm can be prepared by simple mechanical alloying. The composition of the resulting NCs can be precisely controlled by varying the elemental loading ratios. For example, we have recently demonstrated that ternary CdSe x S 1-x [12] and CdTe x Se 1-x [13] NCs in the entire composition range (x = 0 - 1) can be successfully prepared by mechanical alloying. The ternary CdSeS NCs exhibit strong absorption in the visible range, whereas the CdTeSe NCs extend the absorption to the near infrared (IR) range (up to 1400 nm). Here, we extend the same approach to prepare ternary Cd x Zn 1-x S NCs, where the cation atomic compositions are manipulated. The resulting NCs exhibit band gap energies ranging from the ultraviolet (UV) to the visible region depending on the atomic ratio of Cd to Zn. CdZnS alloys, with direct and wide band gaps ranging from 2.42 to 3.67 eV in their bulk state, are some of the most appealing materials for applications in photonics and optoelectronics. [5,14-18] Their NCs have narrow, tunable, and symmetric emission spectra and are photochemically stable. The band gap of CdZnS NCs is affected more by the composition than the size of the nanocrystals. [19,20] In this work, we report the synthesis of ternary Cd x Zn 1-x S NCs, their structural evolution during the mechanical alloying process, and their intrinsic optical spectra. Composition-tunable ternary Cd Zn S nanocrystals are among the most extensively studied alloyed semiconductor nanocrystals. However, they are almost exclusively prepared by wet chemical routes, which lead to surface- capped nanoparticles. Herein, we present a simple mechanical alloying process to prepare uncapped Zn Cd S nanocrystals throughout the entire composition range. The resulting nanocrystals have average sizes smaller than 9 nm, are chemically homogenous, and exhibit linear lattice parameter-composition and close-to-linear band-gap-composition relationships. Continuous lattice contraction of the Cd Zn S nanocrystals with the atomic Zn concentration results in a successional enlargement of their band gap energies expanding from the visible region to the ultraviolet (UV) region, demonstrating the ability for precise control of band gap engineering through composition tuning and mechanical alloying. Keywords: CdZnS, ternary semiconductor, nanocrystals, mechanical alloying, optics DOI: 10.1007/s13391-014-4327-8 *Corresponding author: PengZ@umkc.edu *Corresponding author: gltan@whut.edu.cn ©KIM and Springer