Photoinduced charge separation in solid-state and molecular systems: Year three progress report

摘要

Our goal is to understand the role of intrinsic cyanometalate overlayers in modulating interfacial photoinduced charge transfer processes occurring at the cadmium chalconide/aqueous ferri-ferrocyanide interface. To accomplish this goal, detailed structural and charge transfer studies of (CdFe(CN)(sub 6))(sup 2- /1-) overlayers generated either intrinsically via photoelectrochemistry at the illuminated CdX/(Fe(CN)(sub 6))(sup 4-/32) (X=S or Se) interface, or synthesized as chemical modification layers on inert metal electrodes have been undertaken. From these studies, a picture has evolved which directly links charge transfer mediated cation intercalation processes to surface overlayer crystal structure, and overlayer structure to critical charge transfer parameters. We have discovered that a photoelectrochemical cell of composition n-CdSe /(1M) KCN provides a relatively unique environment for testing the dynamic effects of chemisorption processes on heterogeneous charge transfer at the semiconductor-liquid junction. Thus, our retrospective studies have provided for new insight into semiconductor photochemistry. In parallel with our photoelectrochemical projects we have also introduced work on the spatially resolved photodeposition of platinum metal on nonconducting and semiconducting substrates. This chemistry provides new opportunities for the design of semiconductor (or insulator)-metal heterostructures which have applications in solar energy conversion.