Temperature Dependence of Relative Quantum Efficiency of Spectral Sensitization in Silver Halide Photography

Abstract

Relative quantum efficiency of spectral sensitization (∅_r) is one of the most important properties for the understanding of the mechanism of spectral sensitization in photography. Then, temperature dependence of ∅_r in silver bromide emulsions was studied with a series of spectrally sensitizing dyes with variation of their electronic energy levels. It was found that the dyes with high efficiency exhibited small temperature coefficient, and that the reverse was also ture. High efficiency of spectral sensitization and its small temperature coefficient was achieved by using the dyes whose lowest vacant levels were high, and by using a supersensitizer. It has been suggested that the acceleration of the dissociation of molecular excitons in dye aggregate results in high efficiency and low temperature dependence of spectral sensitization.