Phosphonate functionalized oxadiazole derivative as an efficient electron transporting material for solution-processed blue electrophosphorescent devices

Abstract

An efficient electron transporting material, P-OXD (1,3-bis[(4-(4-diethylphosphoryl-butyl-phenyl))-1,3,4-oxidiazol-2-yl]phenylene), has been synthesized and thoroughly characterized. Due to its alcohol-soluble nature, P-OXD can be spin-coated atop the light emitting layer to form high quality film without dissolving the underlying layer. As a consequence, the double-layer blue electrophosphorescent device has been successfully fabricated, giving a peak luminous efficiency of 10.5 cd/A, and a maximum brightness of 8200 cd/m² with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.16, 0.33). The promising results indicate that P-OXD has a potential application in solution-processed multilayer polymer light-emitting diodes.