Coupled photovoltaic junction-metal dissolution elements under mass and light flux variation

Our object is to describe the kinetics of semiconductor-based photoelectrochemical cells in terms of rigorously specified light and mass transport fluxes. In general, choosing the latter two experimentally controllable variables provides practical tests. The theory treats the total voltage applied across the semiconductor/solution interface as the sum of the voltage drop across the semiconductor and the potential associated with the electrochemical process. In particular, choosing the individually well-understood pair of elements (p-n Si, Hg dissolution) has allowed us here to test two aspects of the theory. One aspect requires an a priori model of both the semiconductor and electrochemical current-voltage responses. The second, more general approach describes the response in terms of the individual impedances of the semiconductor and electrochemical cell, and requires no detailed mechanistic knowledge. Agreement between experiment and theory for both approaches was excellent.