title: Photovoltage mechanism for room light conversion of citrate stabilized silver nanocrystal seeds to large nanoprisms.
abstract: We investigate the photoconversion of aqueous 8 nm Ag nanocrystal seeds into 70 nm single crystal plate nanoprisms. The process relies on the excitation of Ag surface plasmons. The process requires dioxygen, and the transformation rate is first-order in seed concentration. Although citrate is necessary for the conversion, and is consumed, the transformation rate is independent of citrate concentration. We propose a mechanism that accounts for these features by coupling the oxidative etching of the seed and the subsequent photoreduction of aqueous Ag(+). The reduced Ag deposits onto a Ag prism of specific size that has a cathodic photovoltage resulting from plasmon "hot hole" citrate photo-oxidation. This photovoltage mechanism also explains recent experimental results involving single and dual wavelength irradiation and the core/shell synthesis of Ag layers on Au seeds.
authors.affiliation: Chemistry Department, Columbia University, New York, New York 10027, USA. xw2130@columbia.edu
authors.forename: Xiaomu
authors.initials: X
authors.lastname: Wu
authors.forename: Peter L
authors.initials: PL
authors.lastname: Redmond
authors.forename: Haitao
authors.initials: H
authors.lastname: Liu
authors.forename: Yihui
authors.initials: Y
authors.lastname: Chen
authors.forename: Michael
authors.initials: M
authors.lastname: Steigerwald
authors.forename: Louis
authors.initials: L
authors.lastname: Brus