Letter pubs.acs.org/JPCL
Photocatalysis from Fluorescence-Quenched CdSe/Au Nanoheterostructures: A Size-Dependent Study Udit Soni, Puspanjali Tripathy, and Sameer Sapra* Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India S Supporting Information *
ABSTRACT: We report a systematic study of the electron-transfer process from CdSe quantum dots (QDs) to the Au tips as a function of the QD diameter and also the size of the Au-tip. For Au-tips smaller than ∼3 nm, that is, when they are still not metallic, a reduction in PL behavior is observed as the excited electrons are transferred from the QDconduction band to Au, with quenching being higher for larger tips and smaller QDs. A combination of steady state and time-resolved studies establish the mechanism of charge transfer that is further confirmed by dye-degradation studies, showing the possibility of ambient day light photocatalysis.
SECTION: Physical Processes in Nanomaterials and Nanostructures
H
is not a simple exercise like semiconductor or metal nanoparticles; rather, it needs a careful strategy to select materials for useful applications. For example, selection of size and shape of CdSe and size of Au are important to achieve a good light absorption and charge separation. Here we systematically study the changes in the charge-transfer process as a function of either the nanocrystal size or the Au-tip thickness, and very few such studies21 are reported until now. In the present study, we demonstrate a modified,15,22 facile and reproducible method for the synthesis of Au-tipped CdSe, where the size of Au domains is
