LUMINESCENCE OF PHOTOGRAPHIC AGBR1-XIX MICROCRYSTALS

Ionic conductivity (dielectric loss) and luminescence measurements wer e carried out on cubic iodide doped AgBr microcrystals (dg = 0.6 mum). Luminescence measurements under stationary conditions showed that exc itation of AgBr1-xIx microcrystals (0.005 less-than-or-equal-to x1- le ss-than-or-equal-to 0.05) with light of wavelengths below 470 nm produ ced a characteristic luminescence band in the emission spectrum. The m aximum of this band is centred at 550 nm. The time resolved measuremen ts at 77 K demonstrated that the mean lifetime of the luminescence sig nal decreases if the iodide content in the AgBr microcrystals increase s. The decay kinetics are multiexponential. Based on this fact differe nt rate laws were tested. The best fit between the calculated and expe rimental curve was obtained with an exponential distribution in DELTAG +/- (free enthalpy of activation.)