Interfacial overvoltage of hole transfer

Since the overvoltage iip,sc for the generation and transport of holes is a negative quantity, the total overvoltage becomes negative when the magnitude of Ti p, sc exceeds t) h the condition usually occims with photoexcited n-type electrodes. This provides the basis for the fact that the potential for the onset of anodic hole transfer at photoexcited n-type electrodes is more cathodic (n ative) than the potential for the onset of anodic hole transfer at p-type electrodes of the same semiconductor or at metal electrodes. 

In general, the reaction cxurent of hole transfer i across the electrode interface is given by Eqn. 10- 5  

The interfadal overvoltage referred to the standard redox potential is defined, generally, by Eqn. 10-41  

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