Phase-Selective Cation-Exchange Chemistry in Sulfide Nanowire Systems Dandan Zhang Andrew B. Wong Yi Yu Sarah Brittman Jianwei Sun Anthony Fu Brandon Beberwyck A. Paul Alivisatos Peidong Yang 10.1021/ja511010q.s001 https://acs.figshare.com/articles/journal_contribution/Phase_Selective_Cation_Exchange_Chemistry_in_Sulfide_Nanowire_Systems/2224558 As a cation-deficient, <i>p</i>-type semiconductor, copper sulfide (Cu<sub>2–<i>x</i></sub>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<sub>2–<i>x</i></sub>S, an ongoing challenge in the synthesis of Cu<sub>2–<i>x</i></sub>S materials for a specific application. Here, a detailed transformation diagram of cation-exchange (CE) chemistry from cadmium sulfide (CdS) into Cu<sub>2–<i>x</i></sub>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<sub>2–<i>x</i></sub>S were achieved. It is proposed that the evolution of Cu<sub>2–<i>x</i></sub>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. 2014-12-17 00:00:00 tunable crystal phases material systems cadmium sulfide crystal phases transformation diagram crystal phase copper sulfide CE process NW system reaction time applications demand Cu Sulfide Nanowire SystemsAs