The Investigation Of Photoelectron Characteristics In Silver Halide Doped With Formate Ions

The temporal behavior of photoelectrons generated by 35ps laser pulses in cubic silver halide emulsion doped with formate ions has been measured with the microwave absorption and dielectric spectrum detection technique, and the time-resolved spectra of photoelectrons in emulsion with different doping conditions were detected. The hole-trap effect of formate ions and the relationship between photoelectron decay characteristics and doping conditions were discussed. The chemically and spectrum sensitized doped emulsion was studied simply.On basis of the photoelectron-decay spectra of cubic AgCl doped with formate ions, the influence of doping conditions on photoelectron decay was studied. By analysis of the temporal behavior of free photoelectrons and shallow trapped photoelectrons in cubic AgCl emulsion with uniformly doped formate ions, the result shows that using the method of uniformly doping, appropriate concentration of formate ions can act as hole traps effectively, but the effect is not very obvious. Through the photoelectron-decay curves in AgCl with different doping concentrations and positions, it is gained that the hole-trap effect of formate ions is much more obvious when they are doped near the surface of the grain. This is because the concentration of silver cations near the surface is greater than the interior of the grain. When the doping position is near the surface, after the hole traps capturing photo-holes, the electrons escaped from pairing recombination and produced by formate ions after capturing holes can reduce silver cations. It is indicated that the doped formate ions can improve the efficiency of latent image formation of AgCl emulsion, when they are doped near the surface of the grain. Additionally, the chemically and spectrum sensitized doped emulsion was detected, and it is proved that the formate ions can also act as hole traps.Based on the time-resolved spectra of photoelectrons in cubic AgBr emulsion doped with formate ions, the influence of different doping conditions on photoelectron decay was analyzed, and the optimal doping concentration and position were founded.