卤化银乳剂微晶体的结构与性能研究 Ⅴ.八面体核壳复合结构乳剂的电性质与感光性能

STUDY ON THE STRUCTURE AND PROPERTIES OF SILVER HALIDE EMULSION MICROCRYSTALS Ⅴ. THE ELECTRIC PROPERTIES AND THE SENSITOMETRIC BEHAVIO-UR OF OCTAHEDRAL COMPOSITE CORE-SHELL EMULSION MICROCRYSTALS

本工作应用双注法制备了一系列不同碘含量的八面体核壳孔剂。测定了它们的光吸收,离子电导(介电损耗法)、光电导(微波光导法)和感光性能。结果表明:乳剂微晶体的光吸收和离子电导随着碘含量的增加而显著上升,光电导也随着碘含量的增加而增大,其光电子表减过程遵循二级反应动力学过程,光电子半衰期在碘含量为5mol％时为最大。在相同的化学敏化条件下,乳剂的感光度随碘含量增加而上升(碘含量0—12.5mol％)。

Three series of bromoiodide emulsion microcrystals with composite structure were prepared by double-jet method with automatic control pAg. The geometric properties, such as grain size, crystal habit, and the iodide distribution in the bulk and surface of microcrystal were determined as a function of iodide content, iodide introduction time and amount during the precipitation by STEM-EDS method. It was shown that the earlier the iodide was introduced and the more the iodide was incorporated, the more the iodide was enriched into the core of the microcrystals. In the microcrystals really exists the composite structure of iodide-rich and iodide-poor phases. With the iodide increase the grain size decreased, the crystal habit was transformed from regular octahedral to rounded octahedral, the iodide distribution was diffused step by step from the bulk to the surface, obscuring the boundary of composite structure of iodide-rich and iodide-poor phases.