Improving the light extraction efficiency of polymeric light emitting diodes using two-dimensional photonic crystals

✍ Scribed by A.M. Adawi; R. Kullock; J.L. Turner; C. Vasilev; D.G. Lidzey; A. Tahraoui; P.W. Fry; D. Gibson; E. Smith; C. Foden; M. Roberts; F. Qureshi; N. Athanassopoulou

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 367 KB
• Volume: 7
• Category: Article
• ISSN: 1566-1199
• DOI: 10.1016/j.orgel.2006.02.002

✦ Synopsis

We have fabricated light emitting diodes based on a conjugated polymer, in which a planarized two-dimensional photonic crystal (PC) was inserted between the glass substrate and the ITO anode. Planarized PCs were fabricated into a highindex layer via interference lithography, followed by dry-etching and the spin-casting of a low-index glass. We characterize the electroluminescence (EL) emission from devices containing a PC, and compare this with photoluminescence (PL) generated from within the same structure. We show that LEDs incorporating the PC have an increased EL external quantum efficiency of (2.3 ± 1.0) times compared to a standard non-patterned control. This efficiency increase is in excellent agreement with PL measurements on similar structures, which also demonstrate relative increases in external emission intensity of 2.3 times.