The influence of surface adsorption on the decay kinetics of photo-e.m.f. signals from AgBr-emulsion crystals

摘要

In the present study photo-e.m.f. (DEMBER) measurements were performed using surface manipulated AgBr micro crystals to get information about the effect of concentration and spatial distribution in interstitial silver ions Ag_i~+ on the transient photo charge. Treating experimental photo-e.m.f. decay curves by a bi-exponential rate law, the overall signal can be divided into two parts, a fast decay process that may be attributed to reactions in the subsurface and a nearly ten times slower process attributed to the reactions of charge carriers in the bulk. Both, preexponential factors U_1~o, U_2~o and rate constants k_1, K_2 of the whole process depend-in a different degree-on changes of surface situations, for instance pAg, amount of stabilizers or dyes adsorbed on the crystals.