ZnO Nanoparticle Size-dependent Excitation of Surface Raman Signal from Adsorbed Molecules: Observation of a Charge-Transfer Resonance

• NCJ Number: 255361
• Journal: Applied Physics Letter Volume: 91 Dated: 2007 Pages: 221106
• Author(s): Zhihua Sun; Bing Zhao; John R. Lombardi
• Date Published: 2007
• Length: 0 pages
• Grant Number(s): 2006-DN-BX-K034
• Agencies: NIJ-Sponsored
• Award: Development of Advanced Raman Spectroscopy Methods and Databases for the Evaluation of Trace Evidence and the Examination of Questioned Documents

Annotation

This article reports on a project that found by observing the Raman intensity of several molecules (4-mercaptopyridine and 4-mercaptobenzoic acid) adsorbed on the surface of ZnO nanocrystals as a function of particle size in the range of 18–31nm diameter, a large increase in intensity near 28nm occurred. 

Abstract

This is an indication of a size-dependent charge-transfer resonance. This effect is interpreted by the authors as due to formation of a charge-transfer complex between a surface-bound exciton and the adsorbed molecule. (publisher abstract modified)