Size-controllable enhanced energy transfer from an amphiphilic conjugated-ionic triblock copolymer to CdTe quantum dots in aqueous medium

In this work, we have studied the interaction in aqueous solution between a polyfluorene-containing amphiphilic conjugated - ionic triblock copolymer poly(2-(trimethylamino)ethyl methacrylate) - polyfluorene - poly(2- (trimethylamino)ethyl methacrylate) (PTMAEMA-PF-PTMAEMA) and CdTe quantum dots with emission maxima at 550, 580, and 610 nm. We demonstrate by steady-state photoluminescence spectra, photoluminescence excitation spectra, and time-resolved fluorescence spectra that efficient fluorescence resonance energy transfer has occurred from the polymer as the energy donor to CdTe quantum dots that served as acceptors. The Forster radius and average donor - acceptor distances are estimated from experimentally measured energy transfer efficiency. We have observed that a more effective FRET process occurred in the larger-sized QDs and polymer blended systems both from steady-state fluorescence spectra and time-resolved fluorescence spectra.