Electroluminescent properties of MEH-PPV light-emitting diodes fabricated on the flexible substrate

Abstract

Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4- phenylene vinylene] (MEH-PPV) light-emitting diodes fabricated on flexible substrates were investigated for use in display applications. The electrical and optical properties of the light-emitting diodes on the flexible substrates were characterized in order to examine the key factors that determine the lifetime, turn-on, and operating voltage of the diode. These were then compared with the properties of light-emitting diodes on glass substrates. For operating the flexible diode in the ambient conditions, proper passivation layers composed of high-density polyethylene (HDPE) and metal layers were thermally coated on the diode. The longevity of the fabricated diode was considerably enhanced in this case. For the flexible substrate/poly(ethylene-dioxy)thiophene mixed with poly(stylene sulphonic acid) (PEDOT/PSS)/MEH-PPV/Ca/Al-Li with passivation layers, a luminance of 2000 cd/m(2) was obtained at a current density of 165 mA/cm(2) (6.5 V) in ambient conditions. (C) 2002 Elsevier Science B.V. All rights reserved.