Semiconductor-solution interface, photo current

Electrons, generated near the semiconductor-electrolyte interface are unable to stay in this region because of the electric field there which drives them into the bulk of the TiOz crystal, out through the metallic contact, the external circuit (where the photo-current may be measured) and into the catalytically active metal. At the interface of this metal with the electrolyte solution, reaction occurs ... 

Actually, the electrochemistry of diamond dates back to the paper [11], A current-voltage curve of crystalline diamond electrode was first taken there, as well as the differential capacitance measured at the diamond/electrolyte solution interface. The diamond electrodes turned out to be photosensitive, and their photo-electrochemical behavior was compared with their semiconductor nature. 

More recently time-resolved techniques have been applied for studying photocarrier dynamics at the semiconductor-liquid interface. One of the main motivations is that such studies can lead to an estimation of the rate at which photo-induced charge carriers can be transferred from the semiconductor to a redox acceptor in the solution. This method is of great interest because rate constants for the transfer of photocarriers cannot be obtained from current-potential curves as in the case of majority carrier transfer (Section 7.3.5). The main aim is a detailed understanding of the carrier dynamics in the presence of surface states. The different recombination and transfer processes can be quantitatively analyzed by time-resolved photoluminescence emitted from the semiconductor following excitation by picosecond laser pulse. Two examples are shown in Fig. 7.60 [82, 83]. 

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