High efficiency red electrophosphorescent polymer light-emitting diode

This work reports on the fabrication of an efficient polymer light-emitting device by applying iridium (Ir) complex, dibenzo[f,h]-quinoxaline iridium (acetylacetonate) [Ir(DBQ)2(acac)], as the phosphorescent dopant, poly(9-vinylcarbazole) as the matrix layer, and 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-(1,3,4-oxadiazole) as the electron transport material. The trapping of charge carriers at the Ir(DBQ)2(acac) dopant sites dominates the electroluminescence (EL) of the devices. The device emits red electrophosphorescence centered at 610 nm, exclusively from the Ir dopant and an EL efficiency of 8.5 cd/A (1287 cd/m2) biased at 14.5 mA/cm2.