On the behavior of photoholes in silver halide emulsion grains

Experimental results on transient photoconductivity in AgBr emulsion grains as observed by a radiowave photoconductivity technique are reported. The decay component of the photoconductivity over several tens of microseconds observed using hole-injecting dyes is ascribed to photoholes in accord with the result reported by Kellogg, Hodes, and Muenter. We study dependence of the decay time of photoholes on grain size, excitation intensity, and pH and pAg of reaction solutions during AgBr precipitation. Hole traps in AgBr emulsion grains are ascribed to silver clusters in the grains. We discuss hole-trapping properties of some extrinsic centers detected by the technique.