title: Large-scale synthesis and phase transformation of CuSe, CuInSe2, and CuInSe2/CuInS2 core/shell nanowire bundles.
abstract: Facile chemical approaches for the controllable synthesis of CuSe, CuInSe2 nanowire, and CuInSe2/CuInS2 core/shell nanocable bundles were developed. Hexagonal CuSe nanowire bundles with lengths up to hundreds of micrometers, consisting of many aligned nanowires with a diameter of about 10-15 nm, were prepared by reacting cubic Cu(2-x)Se nanowire bundles with a sodium citrate solution at room temperature. The CuSe nanowire bundles were then used as self-sacrificial templates for making bundles of tetragonal chalcopyrite CuInSe2 nanowires by reacting with InCl3 via a solvothermal process. Furthermore, bundles of CuInSe2/CuInS2 core/shell nanocables were obtained by adding sulfur to the reaction system, and the shell thickness of the polycrystalline CuInS2 in the nanocables increased with increasing S/Se molar ratios. It was found that the small radius of copper ions allows their fast outward diffusion from the interior to the surface of nanowires to react with sulfur atoms/anions and indium ions to form a CuInS2 shell. Enhanced optical absorption in the vis-NIR region of CuInSe2/CuInS2 core/shell nanocable bundles is demonstrated, which is considered beneficial for applications in optoelectronic devices and solar energy conversion.
authors.affiliation: Center of Super-Diamond and Advanced Films (COSDAF), and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Chun-Sing
authors.initials: CS
authors.lastname: Lee
authors.forename: Yong-Bing
authors.initials: YB
authors.lastname: Tang
authors.forename: Xue
authors.initials: X
authors.lastname: Chen
authors.forename: Zhen-Hua
authors.initials: ZH
authors.lastname: Chen
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Shuit-Tong
authors.initials: ST
authors.lastname: Lee
authors.forename: Weixin
authors.initials: W
authors.lastname: Zhang
authors.forename: Zeheng
authors.initials: Z
authors.lastname: Yang
mesh_terms: D003300:Copper / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053770:Nanowires / Q000737:chemistry*; D012643:Selenium / Q000737:chemistry*; D018036:Selenium Compounds / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D018036:Selenium Compounds; C101793:copper indium diselenide; D007204:Indium; C477347:cupric selenide; D003300:Copper; D012643:Selenium