2-PHOTON DELAYED FLUORESCENCE EMISSION FROM AGGREGATES OF RUBRENE IN LANGMUIR-BLODGETT-FILMS AT 77 K

Incorporation of non-amphiphilic rubrene molecules in Langmuir-Blodget t (LB) films mixed with stearic acid is reported here for the first ti me. Spectroscopic studies of rubrene in solution and in the LB films r eveals the formation of aggregates in the LB films. Morphological stud ies of the LB films clearly demonstrate the existence of microcrystall ine domains. Moreover, the observation of delayed fluorescence at low temperatures in the mixed films not only supports the existence of mic rocrystalline domains in the LB films but also suggest a two photon pr ocess. Copyright (C) 1996 Elsevier Science Ltd