Electric field effects on fluorescence of pyrene in a homogeneously distributed system and in an oriented molecular system

Electric field effects on fluorescence of pyrene deposited in a mixed LB fi lm with a definite direction are very different from those of pyrene doped randomly in a polymer film. In polymer films, both the sharp structured mon omer fluorescence emitted from the locally excited state and the sandwich-t ype excimer fluorescence with a peak at similar to 470 nm are quenched by a n electric field, whereas another excimer fluorescence with a peak at simil ar to 415 nm is enhanced by an electric field. In LB films, the latter exci mer fluorescence is not affected by an electric field. (C) 2000 Elsevier Sc ience B.V. All rights reserved.