Systematic investigation of transparent organic light-emitting diodes depending on top metal electrode thickness

作者：Lee Jonghee^*; Hofmann Simone; Furno Mauro; Thomschke Michael; Kim Yong Hyun; Luessem Bjoern; Leo Karl

来源：Organic Electronics, 2011, 12(8): 1383-1388.

DOI：10.1016/j.orgel.2011.05.006

• Organic light-emitting diodes (OLEDs)
• Transparent OLEDs (TOLEDs)
• Metal cathode
• Lambertian

We investigate the optical characteristics of transparent organic light-emitting diodes (TOLEDs) with thickness variation of the top metal electrode. We find that the thickness variation of the top cathode shows a different influence on the bottom and top side emissions, respectively. The overall efficiency which is the sum of the bottom and top emissions can be enhanced up to 17.7% of external quantum efficiency (EQE) and 25.1 lm/W of power efficiency (PE) at a driving current density of 15 mA/cm(2). Furthermore, we carefully investigate the angular distribution of the bottom and top side emissions separately with a spectrogoniometer. We find that both considerably differ from a Lambertian assumption and exhibit opposite trends, depending on the top metal cathode thickness.

• 出版日期2011-8