Exciton dynamics in disubstituted polyacetylenes

摘要

Exciton dynamics in luminescent poly(diphenylacetylene) (PDPA) derivatives with different substituents have been studied by time-resolved photoluminescence (PL) spectroscopy. Although their absorption and PL spectra are almost similar, PL of PDPA-nBu decays single-exponentially, whereas PL of PDPA-SiMe_3 decays faster with a suppressed exponential decay function indicating exciton dissociation, In the case of PDPA-nBu mixed with a non-luminescent polyphenylacetylene (PPA) derivative, PL decay of PDPA-nBu is significantly shortened. The experimental results show the influences of side chains on exciton confinement in the backbone/main chain. Efficient PL in PDPA-nBu is a result of effective exciton confinement on the main chain, but excitons migration or energy transfer to another main chain segments may take places.