Polythiophene-polyoxyethylene copolymer in polyfluorene-based polymer blends for light-emitting devices

Polyfluorene (PFO) films doped with different amount of a polythiophene-co-polyoxyethylene (Pt) polymer were studied with the aim to obtain white emission. The Fosrster resonant energy transfer (FRET) is the basic mechanism that takes place in the photoluminescence of these blends. The non-conducting poly(oxyethylene) behaves as a inert spacer leading to a larger donor-acceptor chromophores separation and then a better control of FRET efficiency. As result, the light-emitting device with the architecture Al/Ca/P1:PFO/PEDOT:PSS/ITO was found to be more efficient than either the devices using pure PFO or P1. Near white CIE coordinates of (0.26, 0.33) with a maximum luminance of 2500cd/m(2) were found for 2 wt.% device. A maximum external quantum efficiency of 1% was obtained, hence, suggesting that the enhancement of the electronic and optoelectronic properties could be achieved by incorporating P1 into the PFO. (C) 2008 Elsevier B.V. All rights reserved.