Daniel A. Clayton,† Diane M. Benoist,† Yan Zhu,†,‡ and Shanlin Pan†,* †
The University of Alabama, Department of Chemistry, Tuscaloosa, Alabama 35487-0336 and ‡School of Chemical Engineering and Technology, Wuhan University of Technology, Wuhan, 430070, China
t is known that electronically excited silver nanostructures can emit photoluminescence (PL) under visible light irradiation.1⫺7 Strong fluorescence is from excited Ag atoms, dimers, trimers, and other aggregation states of Ag atoms. Nearinfrared6 and visible7 PL from silver nanowire (NW) arrays show broad emission spectrum under visible light excitation. Such interesting PL can be used to develop new optoelectronic devices and biosensors that can help unravel many mysteries underlying the complex characteristics of a biological system because silver clusters show strong, size dependent emission and are easy to make. Fluorescence silver clusters and nanoparticles have been prepared from silver oxide by photoactivation,2 sputtering,3 and encapsulation of silver clusters in a soft template (e.g., cytosine oligonucleotide,8 dendrimer,9 and poly(acrylic acid))10 by chemical reduction9 or photoreduction methods.11 Silver NWs have interesting electrical and optical properties that can be used in a variety of applications12 including transparent electrodes,13,14 gas sensors,15 biomolecular sensing,16 photonic structures that can launch optical signals at a scale without optical refraction limits,17,18 plasmonic antennae for surface-enhanced Raman scattering (SERS),19⫺22 and fluorescence23⫺25 of a dye molecule approximated to a Ag NW surface. Ag NWs are usually made by using template methods. The templates used for nanowire synthesis are usually made of hard materials, including porous alumina26 and highly ordered pyrolytic graphite (HOPG)27 and soft materials, such as polyvinylpyrrolidone (PVP),28,29 cetyltrimethylammonium bromide (CTAB),30 polysaccharide,31 and DNA oligonucleotide.32 Despite
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ARTICLE
Photoluminescence and Spectroelectrochemistry of Single Ag Nanowires
ABSTRACT We present strong photoluminescence from single Ag nanowires (NWs), their disordered blinking
behavior, and their dependence on substrate potential. The stochastic bursts (
