Increased brightness and lifetime of polymer light-emitting diodes with polyaniline anodes

• Published in: Synthetic metals Vol. 80; no. 2; pp. 111 - 117
• Main Authors: Karg, S., Scott, J.C., Salem, J.R., Angdopoulos, M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30.06.1996; Amsterdam Elsevier Science; New York, NY
• Subjects: Application fields; Applied sciences; Charge injection; Degradation; Diodes; Electroluminescence; Electronics; Exact sciences and technology; Optoelectronic devices; Organic light-emitting diodes; Poly(2-methoxy,5-(2′-ethylhexyloxy)-1,4-phenylenevinylene); Polyaniline; Polymer industry, paints, wood; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Technology of polymers; Degradation; Organic light-emitting diodes; Charge injection; Electroluminescence; Polyaniline; Poly(2-methoxy,5-(2′-ethylhexyloxy)-1,4-phenylenevinylene); Diodes; Anode; Voltage current curve; Use; Phenylenevinylene derivative polymer; Electrode material; Experimental study; Quantum yield; Light emitting diode; Lifetime; Phenylene derivative polymer; Oxidation stability; Size effect; Electrical conductor; Comparative study; Electrical characteristic; Aniline polymer
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(96)03690-9

The properties of light-emitting diodes based on poly(2-methoxy,5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) with indium-tin oxide (ITO) anodes are compared with those in which a layer of polyaniline (PAni) is coated between the ITO and the emissive polymer. It is found that the PAni injection layer yields higher current, brighter emission and a lower rate of degradation than ITO. The electrical behavior is discussed in terms of bulk and contact current limitation. The improvement in degradation is attributed to reduced oxidation as the PAni layer provides a barrier for the passage of oxygen out of the oxide. In addition, improvement in microscopic short formation indicates planarization of the anode interface by the PAni film.