Fabrication And Characterization Of Polyfluorene-based Polymer White Light-emitting Device

Organic light-emitting diode for its environment-friendly and the realization of largearea display has been recognized as the most promising high-tech area. Conventional lightsources like incandescent filament lamps in which a major part of the energy is wasted asheat and is a less energy efficient technology is being phased out. Other technologies like gasfilled electrical discharge lamps are more efficient but are polluting. Therefore there is aneed for energy efficient and clean light source and solid state lighting is one of the ways toaddress the problem. White organic light-emitting diode for its environment-friendly and therealization of large area display has been recognized as the most promising in high-tech area.When it comes to industrial application for white organic light-emitting diode, how toget high-performance devices is the key problem. Although research in this area has alreadyachieved some progress, however devices with high-efficiency, excellent spectral properties,and well-stability are still rarely reported. Also, the working mechanism of the white lightemitting device is still underground. In this paper, devices with a higher energy-emitting host(blue emission) material S-BP-3and doped with a lower energy emitting guest (dye, dopantor acceptor) material S-OP-3was fabricated and characterized.Through these devices wehope to solve the phase separation of the polymer blends and obtain stable white emissionspectra.Linear polymer polyfluorene material(PFO) was Synthesized by Suzuki reaction. Inorder to make high-performance white light-emitting device, we study the basic physicalproperties of polymer PFO, such as UV-visible absorption spectra and fluorescence spectra.White device with a blend layer of S-BP-3and S-OP-3, the turn on voltage is4.37V, themaximum current efficiency reaches1.36cd/A, the color-rendering index is (0.36,0.31).And white device doped S-OP-3into polyfluorene, the turn on voltage is3.79V, themaximum brightness is2178cd/m~2, the maximum current efficiency reaches1.94cd/A, thecolor-rendering index is (0.35,0.31).White EL with simultaneous blue and orange emission was observed and was attributedto the F rster energy transfer and charge trapping from the blue host to the orange dopant.The EL efficiencies of these polymers could be improved by enhancing the PL quantum efficiency of the orange dopant unit.