Mechanism of Electron Trapping in Silver Bromide Photographic Grains

Abstract

The temperature dependence of the electron lifetime and of the time for decay of an internal applied electric field in the silver bromide microcrystals of a simple photographic emulsion has been measured by the technique employing flash exposure of the emulsion in pulsed electric fields. Activation energies were found to be 0.236±0.012 eV for the electron lifetime and 0.245±0.008 for the field-decay time. The agreement of the temperature dependence of the two processes, together with the observation that the room-temperature values of these two times are, without exception, nearly equal in measurements made on a variety of other emulsions, supports the hypothesis that the mechanism of permanent electron-trapping involves the motion of the silver ion to a temporarily trapped electron to form a stable center. These results are not consistent with the alternative suggestion, namely, that the electron is captured at a preexisting deep trap consisting of a silver ion associated with a crystal imperfection.

The role of FA:K+ and FA:Na+ defects in laser light generation and color image formation at the (100) and (110) surface sites of AgCl and AgBr.

“…The role of irregular surface defects, such as ledge or kink type defects, in latent image formation has been the subject of several investigations. 7 It has been postulated that these sites are places where a latent image cluster could preferentially form.…”

Photographic Sensitization of the AgBr(100) Surface and the Effect of Au and S in Latent Image Formation: A Detailed Theoretical Mechanism

“…However, ledge or kink type defects can be formed on the surface (15). These point defects have been the subject of several investigations in latent image formation (16}18).…”

Theoretical study of laser light generation and color image formation:FA1:Cs+andFA2:Li+centers at the low coordination (100) and (110) surfaces of AgCl and AgBr

“…Sensitizing dyes are thus required to have the abilities to absorb light at a desired wavelength and to transfer electrons from their excited states to the conduction band of silver halides. The role of irregular surface defects, such as ledge or kink-type defects, in latent image formation has been the subject of several investigations [5]. It has been postulated that these sites are places where a latent image cluster could form preferentially.…”