Photocurrent density, stabilization ratio

For the three systems considered, the stabilization ratio s was determined as a function of the total photocurrent density jph = Ipf/A (A = surface area) and the concentration of reducing agent y. In all cases, s was found to increase with increasing... 

Figure 1. Stabilization ratio s as a function of the photocurrent density jp at different concentrations of solved reducing agent y, n-InP/Fe(II)-EDTA (rotation speed of the electrode 1000 rpm)...

Measurements of the stabilization ratio s were performed on the GaAs photoanode in aqueous medium with 0.25 mol.dnr3 and with 4 mol.dm 3 LiCl, in three water + methanol mixtures with 18, 48 and 80 mol % methanol respectively, and in two water + acetonitrile mixtures with 13 and 42 mol % acetonitrile. The stabilization ratio s was measured as a function of the photocurrent density i and the concentration c of dissolved TMPD. The measurements were performed at a constant electrode potential V corresponding to high band bending, so that surface recombination can be neglected. All experiments were performed in acid medium as required for the solubility of TMPD and decomposition products of GaAs. 

In a 1980 paper [49], our group discussed several possible competition mechanisms leading to kinetics in which the stabilization ratio decreases with increasing photocurrent density. Four out of the resulting kinetic equations have been found to describe the experimental cases. These s(y, /) relations, the cases in which they were observed, and the corresponding mechanisms are described here (cases (i) to (iv)). 

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