Unusual photoelectrochemical behaviour of surface-modified nanocrystalline semiconductors
|Konrad Szacilowski , Wojciech Macyk|
Jagiellonian University, Faculty of Chemistry, Ingardena 3, Kraków 30-060, Poland
Surface-modified nanocrystalline semiconductors have found numerous applications as (photo)catalysts, chemosensors and biomimetic light-harvesting antennae. Systems containing molecular switches attached to the surface of titania were recently described. Up to date there are no detailed reports on mechanisms and applications of photocurrent switching phenomena in cyanoferrate-modified titanium dioxide and cadmium sulfide. The increasing interest in molecular electronics stimulated the research on switching properties of some semiconductor composite materials.
This presentation concerns the photoelectrochemical properties of multicomponent photoelectrodes based on nanocrystalline titanium dioxide and cadmium sulfide modified with hexacyanoferrate complexes. Photocurrent responses were recorded as functions of applied potential and photon energy. The photocurrent can be switched between positive and negative values as a result of electron and/or photon energy changes. This new effect called PEPS (PhotoElectrochemical Photocurrent Switching) opens a possibility of new light-harvesting antennae, chemical switches and logic gates construction. Boolean logic analysis and a tentative mechanism of the device are presented. Complex switching patterns allow for simulation not only simple logic gates but also more complex logic systems.
Presentation: Keynote lecture at SMCBS'2005 Workshop, by Konrad Szacilowski
See On-line Journal of SMCBS'2005 Workshop
Submitted: 2005-08-04 09:29 Revised: 2009-06-07 00:44