冠醚对溴化银乳剂的增感作用

近年来,已有将冠醚化合物用于卤化银感光乳剂中的一些报道。为了改善卤化银感光材料的性能,我们将合成的一种新冠醚——N-对甲苯磺酰基-7-氮杂-1,4,10,13-四硫杂环十六烷(NTsTTH)用于卤化银乳剂中,发现它能提高卤化银乳剂的感光度。

THE SENSITIZATION OF SILVER BROMIDE EMULSION WITH CROWN COMPOUND

In the present work, it was found that N-toluensulfonyl-7-aza-1, 4, 10, 13-te-trathiacyclohexadecane (NTsTTH) can sensitize AgBr emulsion and the sensitivity-can be increased from 3 to 12.5. The growth of AgBr crystals under the action of NTsTIH was studied with transmitance electron microscopy (TEM), and it was found that NTsTTH acts as a modifier in crystals growth. The ionic conductivity of AgBr emulsion sensitized with NTsTTH decreases with increasing amount of NTsTTH. When excess NTsTTH was added to the emulsion, fog was significantly-increased. According to the results, a hypothetical sensitization mechanism was suggested: when NTsTTH is added to the emulsion, it will combine with the positively charged kink sites(Ag+) on the silver bromide microcrystal forming complex(1) which is possible to become sensitization centers. During this process(1) a disproportionate reaction may occur(2)Ag+ 4- NTsTTH--Ag(NTsTTH)+ (1)2Ag+ + NTsTTH--Ag(NTsTTH)2+ + Ag (2)and the Ag atoms may aggregate to form fog centers or reduction sensitization centers.