ELECTROLUMINESCENCE

An overview is presented of research based on the observation by Arnol d and Azzi (1971) (Photochem Photobiol 14: 233-240), that an electric field induces charge-recombination luminescence in a suspension of pho tosynthetic membrane vesicles. The 'electroluminescence' signals from Photosystems I and II are discussed in relation to the shape of the ve sicles and the membrane potentials generated by the externally applied electric field. The use of the electroluminescence amplitude as a pro be to study the kinetics and energetics of charge separation, and of i ts kinetics to monitor the electric-field induced charge recombination process are reviewed. Currently unresolved issues regarding the emiss ion yield of electroluminescence are briefly discussed and the propert ies are summarized of the unexplained Photosystem II luminescence whic h is not sensitive to the membrane potential.