(Europe Section Heinz Gerischer Award) The Physical Electrochemistry of Semiconductors

Abstract

Semiconductor photoelectrodes have remarkable differentiating properties from metal electrodes, including photo effects, simultaneous charge transfer from two different bands, different double layer structures, and effects of surface atoms and states. These differences play a profound role in the behavior of semiconductors as electrodes, as first recognized and developed by H. Gerischer in many instances. This presentation will discuss the use of contemporary methods of surface science including operando techniques to directly measure the band edge positions of semiconductor electrodes as proposed by Gerischer, will characterize mechanisms and rates of interfacial charge transfer within the model advanced by Gerischer, and will define the role of surface states as proposed by Gerischer in influencing the development of the double layer of the semiconductor/liquid interface, as well as the influence of monolayers of two-dimensional materials on interfacial energetics and kinetics of charge-transfer processes. The use of semiconductors to produce photo-driven fuel formation will also be described in detail for both oxidative and reductive processes in aqueous and non-aqueous solvents for both simple, one-electron outer sphere redox reactions as well as more complex multi-electron charge transfer processes associated with the direct production of fuels from sunlight.