Highly efficient MEH-PPV-POSS based PLEDs through optimization of charge transport

We demonstrated highly efficient devices based on well-known poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] end capped with PUSS (MEH-PPV-POSS) polymer by combining of two approaches: (i) inserting of electron transport material (ETM) either between the emissive layer and cathode or into the emissive polymer, and (ii) doping of polymer with quantum clots (QDs). In order to overcome some handicaps, such as interchain interaction and imbalanced charge carrier fluxes, copper indium disulfide (CuInS2) QDs were incorporated into the polymer matrix, while N-arylbenzimidazoles trimer (TPBi) and 4,7-dipheyl-1,10-phenanthroline (Bphen) were used as ETMs. The best charge carrier balance and color purity were achieved by inserting 0.3 wt% CuInS2 into the polymer and 40 nm Bphen between the polymer and cathode with a current efficiency of 5.1 cd/A anti an external quantum efficiency of 1% which is above the average of literature. (C) 2012 Elsevier B.V. All rights reserved.