Efficient light emitting diodes with Teflon buffer layer

The polytetrafluoroethylene (Teflon) was utilized as buffer layer to improve the performance of organic light emitting diodes (OLEDs). In the ITO/Teflon/N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD)/tris(8-hydroxy-quinoline) aluminum (Alq(3))/Ca/Ag device, the Teflon film helped to enhance the hole tunneling injection and effectively impede indium diffusion from the ITO electrode. Compared with the devices without Teflon, the turn-on voltage was lowered by 1.5 V due to the introduction of Teflon buffer, and the optimized devices exhibited a luminous efficiency double that of the devices without Teflon layer, and the device lifetime proved to be dramatically increased. (C) 2002 Elsevier Science B.V. All rights reserved.