Electronic States of Chemically Modified CdS Nanoparticles

Abstract

Semiconductor nanoparticles of inorganic materials have been studied extensively for their special properties which differ from those for both the individual molecules and bulk species due to the quantum size effect [1,2]. To prepare semiconductor nanoparticles, solution processes have been employed in many reports where the electronic states of semiconductor nanoparticles were investigated. The nanoparticles obtained by such methods contain organic ligands or capping agents at the surface. These capping agents could be utilized to give a specific function as well for stabilization. For example, ionization of the capping agent at a certain pH of solution could provide a charge effect in CdS nanoparticles [3]. We suggested previously that the bandgap energy of CdS nanoparticles capped with thiophenolate is commonly smaller than that with thioalcoholates [4]. In this chapter, an application of the capping agent to the preparation of a nanoparticle dimmer [5] and the analysis of the electronic states by the molecular orbital approach [6] will be described.