多层结构卤化银微晶的设计及制备

Design and Production of Multi Structure Silver Halide Crystallite

卤化银乳剂的分辨率随卤化银微晶尺寸的减小而提高，但感光度急剧下降。研究表明：卤化银微晶的结构对感光度的影响很大。讨论了多层结构卤化银微晶的设计原理，用自动双注仪制备出多层结构卤化银微晶。ＴＥＭ和ＸＲＤ的分析表明：富碘层ＡｇＢｒ０．８３Ｉ０．１７中碘的分布不均匀，集中在晶粒的顶角处；尽管在制备壳层时没有加入碘离子，但ＸＰＳ分析结果证实，卤化银微晶的表面存在碘离子，说明碘离子有向外扩散的趋势。对所得的实验现象从理论上进行了解释。

With the decrease in the size of cubic silver halide crystallites, the resolution of silver halide photographic emulsion increases, meanwhile, its sensitivity decreases rapidly. The structure of silver halide microcystal grains has great influence on the sensitivity. In this paper, the design principle of multi structure silver bromo iodide is investigated. Silver halide photographic emulsion with multi structure grains is precipitated by auto controlled double jet machine. TEM and XRD analyses show that iodide rich layer is composed of AgBr 0.831 I 0.17 , in which iodide is not distributed uniformly and mainly located near the corners of the cubic core grains. XPS analysis shows that the surface of multi structure grains contains some iodide ions though no iodide has been added, suggesting that the iodide ions have the tendency of diffusing outwards. In addition, the experimental phenomena are explained in theory.