Pia Thomsen

This work deals with the synthesis of semiconductor- and semiconductor/metal-based nanocrystals and methods to assemble them into superordinate structures by controlled destabilization of the colloids. The investigation of influence of the material composition and the gelation methods on the structure and properties of the resulting networks plays a crucial role. In these gel-like networks (aerogels, hydrogels) with crystal-to-crystal contacts the charge carrier mobility has been shown to be increased, whereby new pathways for photoexcited electrons or holes are opened. The question of the internal charge carrier transfer mechanisms is illuminated as well as the photocatalytic properties of the structures, i.e. the hydrogen production ability in an aqueous medium, and the influence of different sacrificing agents. Photoelectrochemical (PEC) measurements are carried out to investigate the charge carrier dynamics and kinetics as well as to give insights into the structure-property relationship in the prepared materials.

-        Possible PEC methods:

·       Cyclovoltammetry

·       Linear sweep voltammetry

·       Intensity modulated photocurrent spectroscopy

·       Electrochemical impedance spectroscopy