title: Phase-selective cation-exchange chemistry in sulfide nanowire systems.
abstract: As a cation-deficient, p-type semiconductor, copper sulfide (Cu(2-x)S) shows promise for applications such as photovoltaics, memristors, and plasmonics. However, these applications demand precise tuning of the crystal phase as well as the stoichiometry of Cu(2-x)S, an ongoing challenge in the synthesis of Cu(2-x)S materials for a specific application. Here, a detailed transformation diagram of cation-exchange (CE) chemistry from cadmium sulfide (CdS) into Cu(2-x)S nanowires (NWs) is reported. By varying the reaction time and the reactants' concentration ratio, the progression of the CE process was captured, and tunable crystal phases of the Cu(2-x)S were achieved. It is proposed that the evolution of Cu(2-x)S phases in a NW system is dependent on both kinetic and thermodynamic factors. The reported data demonstrate that CE can be used to precisely control the structure, composition, and crystal phases of NWs, and such control may be generalized to other material systems for a variety of practical applications.
authors.affiliation: Department of Chemistry, ‡Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: Dandan
authors.initials: D
authors.lastname: Zhang
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Wong
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.forename: Sarah
authors.initials: S
authors.lastname: Brittman
authors.forename: Jianwei
authors.initials: J
authors.lastname: Sun
authors.forename: Anthony
authors.initials: A
authors.lastname: Fu
authors.forename: Brandon
authors.initials: B
authors.lastname: Beberwyck
authors.forename: A Paul
authors.initials: AP
authors.lastname: Alivisatos
authors.forename: Peidong
authors.initials: P
authors.lastname: Yang