Spectroscopic studies of energy transfer in fluorene co-polymer blend nanoparticles

► Single particle spectroscopy is used to study nanomorphologies of donor/acceptor polymer nanoparticles. ► Energy transfer efficiencies reveal that components phase separate into ∼20-40 nm domains. ► Pressure-dependent emission spectra also confirm that phase purity is high. ► The results provide important insights into the interface structure of these new functional polymer forms.