掺杂立方AgBr乳剂介电频谱的研究Ⅱ.Ⅰ-离子的影响

本文测定了用0.1—2.0mool%的I^-进行表面掺杂的单分散立方AgBr乳剂的介电吸收谱。经分析证实,在本实验掺杂浓度范围内,99%以上的I^-取代了AgBr微晶表面层晶格上的Br^-。随I^-掺杂量的增大,样品的介电吸收峰明显向高频方向位移。当掺杂量为1mol%时,样品的介电吸收峰频率已很接近纯AgI乳剂的介电吸收峰频率。继续增大掺杂量,则介电吸收峰不再向高频方向位移。 由上述结果可以看到,在连续相介质保持不变的条件下,由界面极化效应产生的介电吸收峰的形状和频率位置受分散相颗粒表面层物质的组成与结构影响很大。用I^-对AgBr微晶进行表面掺杂,可以使AgBr微晶的表面电导率明显增大。

A STUDY OF THE DIELECTRIC SPECTRA OF DOPEDCUBIC SILVER BROMIDE EMULSIONSII THE EFFECT OF I- IONS

Dielectric spectra of the silver bromide emulsions doped with 0.1-2.0mol% I^- Ions in the surface region of the grains were studied. It was found that the absorption peak in the dielectric spectrum shifted markedly toward higher frequencies with the increase of the dopant concentration. At the dopant concentration of 1mol%, the frequency of the dielectric absorption peak of the sample was quite close to that of pure silver iodide emulsion- Increase of the dopant concentration beyond 1 mol% did not lead to further shift of the absorption peak.From the above experimental result, it was deduced that the frequency of the dielectric absorption peak was affected mainly by the composition and structure of the surface region of the grains in the dispersive phase.