Exceptionally efficient organic light emitting devices using high refractive index substrates.
Organic light emitting devices (OLEDs) are now used in commercial cell phones and flat screen displays, but may become even more successful in lighting applications, in which large area, high efficiency, long lifetime and low cost are essential. Due to the relatively high refractive index of the organic layers, conventional planar bottom emitting OLEDs have a low outcoupling efficiency. Various approaches for enhancing the optical outcoupling efficiency of bottom emitting OLEDs have been introduced in the literature. In this paper we demonstrate a green bottom emitting OLED with a record external quantum efficiency (42%) and luminous efficacy (183 lm/W). This OLED is based on a high index substrate and a thick electron transport layer (ETL) which uses electrical doping. The efficient light outcoupling is modeled by optical simulations.
Mladenovski
Saso
S
Electronics and Information Systems Department, Ghent University, Gent, Belgium. Saso.Mladenovski@elis.ugent.be
Neyts
Kristiaan
K
Pavicic
Domagoj
D
Werner
Ansgar
A
Rothe
Carsten
C
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008029:Lighting / Q000295:instrumentation*; D009930:Organic Chemicals / Q000737:chemistry*; D012031:Refractometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D009930:Organic Chemicals