SYNERGISM IN PHOTOCURRENT INDUCED BY SIMULTANEOUS ILLUMINATION OF PORPHYRIN SOLIDS WITH VISIBLE AND NEAR-INFRARED LIGHTS

Synergism in photocurrent is found when vacuum-sublimed films of porphyrins sandwiched between Al and Au electrodes are illuminated simultaneously with visible and near-infrared lights. Dependence of degree of the synergism observed with 5,10,15,20-tetraphenylporphyrinatozinc(II) on the wavelength of near-infrared light exhibits a clear structure in the spectral range where the porphyrin solid does not have any peaks of light absorption and photocurrent. The result strongly suggests the existence of energy states lying within the energy gap of the molecular solid.