Efficientdeep-redorganiclight-emittingdiodes(OLEDs)wereinvestigatedbasedontheblendofpoly[2-methoxy-5-(2'-ethyl-hexyloxy)-l,4-phenylenevinylene](MEH-PPV)with4,7-bis(5-(7-(9H-carbazol-9-yl)-9,9-dioctyl-9H-fluoren-2-yl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole(compound1).Byoptimizingtheblendratio,theturn-onvoltageofthedeviceswassignificantlyreducedfrom4.9Vto2.4V.Ahighestexternalquantumefficiencyof2.56%wasachievedatablendratioof95:5(wt)forcompound1:MEH-PPV.TheCIEcoordinatewasmeasuredtobe(0.70,0.30),withtheluminescencepeakataround680nm.Basedonexperimentalobservationstheimprovementmechanismisdescribed.
