Fig. 4
The performance of organic light-emitting diodes (OLEDs) fabricated on large substrates. a The measured external quantum efficiencies (EQEs) vs. scatterance (S) of OLEDs with SiO2-based (asymmetry parameter (g) = 0.91) and TiO2-based (g = 0.68) scattering layers. The color-matched dotted lines indicate LightTools simulation results that reflect the actual geometry (Type A) used for EQE-S trend study. b Device test structures used to mimic a large-area device with a small, lab-scale active area. Type A uses a small substrate so that one can make several samples at the same time for studying the overall trend over certain variables. Type B uses a large substrate to explore the ultimate light extraction achievable via external scattering. Photographs of OLEDs (Type B) are also shown for both SiO2-based (S = 7.1) and TiO2-based (S = 2.0) OLEDs (scale bar: 5 mm). c−e Device characteristics of Type B champion OLEDs
