ja511010q_si_001.pdf (832.83 kB)
Phase-Selective Cation-Exchange Chemistry in Sulfide Nanowire Systems
journal contribution
posted on 2014-12-17, 00:00 authored by Dandan Zhang, Andrew B. Wong, Yi Yu, Sarah Brittman, Jianwei Sun, Anthony Fu, Brandon Beberwyck, A. Paul Alivisatos, Peidong YangAs a cation-deficient, p-type semiconductor, copper
sulfide (Cu2–xS) 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 Cu2–xS, an ongoing challenge in the synthesis of Cu2–xS materials for a specific application. Here, a detailed
transformation diagram of cation-exchange (CE) chemistry from cadmium
sulfide (CdS) into Cu2–xS 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 Cu2–xS were achieved. It is proposed that the evolution of Cu2–xS 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.