Investigation of photoelectron action in cubic AgCl emulsion doped with formate ions

摘要

In recent years, the formate ion (HCO_2~-) as a kind of hole-to-electron converter has attracted much attention of photographic researchers. The formate ions can trap photo-generated holes, eliminate or reduce the electron loss caused by electron—hole recombination in latent image formation process. Through the hole-to-electron conversion, it can also release an extra electron or electron carrier, improving photosensitivity. In this paper the microwave absorption and dielectric spectrum detection technique is used to detect the time evolution behaviour of free photoelectrons generated by 35ps laser pulses in cubic AgCl emulsions doped with formate ions. The influence of different doping conditions of formate ions on the photoelectron decay kinetics of AgCl is analysed. It is found that when the HCO_2~- content is 10~(-3) mol/mol Ag and the doping position is 90% the electron decay time and lifetime reach their maxima due to the efficient trap of holes by formate ions.