We report synthesis of magnetic Fe3O4 nanoparticles (MNPs) based on two phase method and their application in organic light-emitting devices (OLEDs) as blend with emissive Polyfluorene (PFO) matrix. Two phase method allows to successively synthesizing oleic acid capped MPNs with 5-10 nm particle size. Colloidal MNPs can be easily mixed with emissive polymer solutions to obtain a blend for OLED application. The electroluminescence efficiency increases by doping with MNPs into emissive layer. Different dopant concentrations varied from 0.4% to 2% were monitored. It was observed that the electroluminescence increases up to 1% v/v doping ratio. The luminance of OLEDs increased from 15.000 cd/m² to 24.000 cd/m² in comparison pristine device with 1% MNP doped device.
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