AGGREGATE FLUORESCENCE IN CONJUGATED POLYMERS

We study the dynamics of optical excitations in solid films of ladder- type poly(para-phenylene) (LPPP). A low-energy emission band is observ ed in the photoluminescence spectrum of solid films of this rr-conjuga ted polymer, which is absent in LPPP solutions. We show that the low-e nergy luminescence can be attributed to aggregates between subunits of the polymer chains. Energy transfer into aggregate states strongly af fects the dynamics of excitations in solid LPPP. We further discuss th e influence of non-radiative defects on the dynamics.