溴化银内敏乳剂灰化中心形成过程的研究

INVESTIGATION OF THE FORMING PROCESS OF FOGGING CENTERS IN THE AgBr EMULSION

制备铱内敏乳剂时,乳剂颗粒表面和内部都生成了灰化中心,并且灰化中心优先在颗粒内部生成。实验结果表明,灰化剂分子可能与乳剂颗粒表面的Ag^+作用生成单个的Ag原子,随后这些单个的Ag原子分解成Ag^+和电子,电子进入卤化银晶体的导带。因此,可以得出这样的结论:灰化剂分子提供的电子象光电子一样进入了卤化银晶体的导带,电子进入导带后,容易被敏化中心或晶体缺陷捕获而形成灰化中心。

Cubic silver bromide emulsions which were sensitized internally with (NH4)2 IrCl6 + K2PtCl5, (NH4)3 IrCl6, and Na2S2O3, respectively, were prepared. The emulsions were fogged by thiourea dioxide. It was found that fogging centers were formed in the interior of emulsion grain and grain surface, and fogging centers were formed preferentially in the interior of emulsion grain. It is suggested that fogging agent molecules collided with silver ions on the grain surface forming single isolated silver atom, which subsequently loses electrons to the conduction band of the crystal. Therefore, it is conclused that electron of fogging agent molecules are transfered to conduction band of silver halide crystal such as photo-electron in the conduction band of tht crystal, electrons of conduction band are trapped by sensitivity centers and lattice disorder forming fogging centers.