Liquid-Phase Molecular Layer Deposition: Potential Applications to Multi-Dye Sensitization and Cancer Therapy

Abstract

Liquid-phase molecular layer deposition (LP-MLD) is a growth method for organic tailored materials, in which different kinds of molecules are sequentially connected with designated arrangements in the liquid phase. We applied LP-MLD to multi-dye sensitization of ZnO thin films. By LP-MLD, p-type dye molecules (rose bengal) and n-type dye molecules (crystal violet) were successively provided onto a ZnO surface to form a two-dye-molecule-stacked structure of n-type ZnO/p-type dye/n-type dye. Electrons in the p-type dye molecules were excited by green lights, and injected into ZnO to generate photocurrents. Electrons in the n-type dye molecules were excited by red lights, and injected into ZnO via the p-type dye molecules to generate photocurrents in the red light region, widening the photocurrent spectra. The photocurrents were enhanced when the light exposure was carried out by guided lights in the ZnO thin film, suggesting the prospect of the waveguide-type sensitized photo-voltaic device. LP-MLD is also expected to be applied to cancer therapy, where a human body and cancer cells are respectively regarded as an MLD chamber and substrates. © 2011 The Electrochemical Society.