Photosensitization of Colloidal ZnO Semiconductor System with Hypocrellin A

Abstract

UV-visible spectroscopy and fluorescence quenching measurements have been employed to study electron transfer from excited Hypocrellin A (HA) into the conduction band of a colloidal ZnO semiconductor. The adsorption of HA on the surface of ZnO colloidal particles and the electron transfer process from its singlet excited state to the conduction band of colloidal ZnO semiconductor were examined under experimental conditions. Exciting HA with visible light could induce electron transfer from its singlet excited state into conduction band of colloidal ZnO semiconductor. Adsorption of HA onto the surface of colloidal ZnO semiconductor extended its absorption spectrum further into the visible region, the quenching behavior were observed as the colloidal ZnO semiconductor was added and determined by fluorescence quenching method.