KINETIC-ANALYSIS OF TRIPLET ENERGY MIGRATION IN POLY[(2-NAPHTHYLALKYL METHACRYLATE)-CO-(METHYL METHACRYLATE)]S AND POLY[(9-PHENANTHRYLMETHYL METHACRYLATE)-CO-(METHYL METHACRYLATE)] SOLID FILMS

Triplet energy migration in chromophoric polymer films has been investigated by phosphorescence spectroscopy. Poly[(2-naphthylalkyl methacrylate)-co-(methyl methacrylate)] and poly[(9-phenanthrylmethyl methacrylate)-co-(methyl methacrylate)] films show phosphorescence spectra from 'triplet trap sites''. The emission is slightly red-shifted from the monomer phosphorescence with a vibrational structure which is different from that of the triplet excimer. The energy migration rate in these systems is complex since the trap site shave various energy levels depending on the amplitude of interaction energies. The kinetic analysis was made on the basis of Bassler's model in which the site energies have a Gaussian distribution. The simulations are in good agreement with experimental data in a temperature range of 115-165 K. The results provide strong evidence for the hopping mechanism of trapped excitons among a distribution of energy sites for a particular energy level.