Linkers for anchoring sensitizers to semiconductor nanoparticles

Organic and inorganic dyes anchored to semiconductor nanoparticles find important applications as photosensitizers in the preparation of solar cells and other optoelectronic systems. For many years research in this area has involved dyes that are bound to the surface of nanocrystalline semiconductors through one or more anchoring groups, forming donor-acceptor systems where the donor is usually the dye and the acceptor is the semiconductor. The design of linkers containing a bridge between the chromophore and the binding group is a more recent development in this field. Carefully designed linkers can be useful to fix the distance of the dye from the semiconductor surface, to tune the properties of the dye, to prevent aggregation of the chromophores, and to prepare models for interfacial electron transfer studies. More generally, this apperas to be a promising method for understanding electron transfer processes at the molecule-nanoparticle interface and eventually controlling them in a rational and predictable manner. This review describes the synthesis and properties of sensitizers consisting of chromophore-linkers arrays where the linkers are based on alkyl chains, rigid-rods, or tripod-shaped molecules. (C) 2004 Elsevier B.V. All rights reserved.