Exciton migration to chain aggregates in conjugated polymers: influence of side-chain substitution

We have performed time-resolved photoluminescence (PL) measurements to study the transfer of excitons from non-interacting polymer chains to chain aggregates for thin films of polyindenofluorene with different attached side chains. The transfer time is shown to be fast (≈35 ps) and side-chain independent indicating that the substitution of different side chains does not affect the local concentration of aggregate sites within aggregate-containing domains, but rather the extent to which such domains are formed. We find the aggregate emission efficiency to be relatively high (≳20%) while still lower than the efficiency of emission from non-interacting chains.