Photostimulated electron tunnel transfer in solid matrices

Tunnel recombination of photoseparated charges in frozen vitreous alcoholic solutions of zinc porphyrin (ZnP) and CCl₄ has been investigated. Considerable acceleration of the recombination in such systems when exposed to light in the ZnP⁺ or the CCl₄^? absorption band region is observed. Possible mechanisms which increase the charge recombination efficiency are considered in detail. The acceleration of the tunnel recombination of ZnP⁺ and CCl₄^? under irradiation in the porphyrin absorption band is shown to be due to energy transfer from an excited acceptor to a transferred electron. It is shown that data on the kinetics of photostimulated tunnel reactions can be used to determine the binding energy of a tunnelling electron.