Recent results on enhanced light outcoupling from OLEDs on corrugated plastic substrates

We report strongly enhanced light outcoupling from phosphorescent OLEDs (PhOLEDs) fabricated on patterned polycarbonate (PC) and polyethylene terephthalate (PET) substrates. The patterns range from shallow (height h<200 nm) to deep (h~500 nm) convex PC patterns with period a ~750 vs ~400 nm, and concave PET/CAB (cellulose acetate butyrate) patterns with large m-size periods – a new promising approach. Bottom-emitting PhOLEDs on such substrates enhance the external quantum efficiency EQE ~2.4x to 2.8x vs devices on glass/ITO; the EQE of green and blue patterned PC/PEDOT:PSS OLEDs reached 56.5% and ~43%, respectively. The corrugated substrates (refractive index ~1.6) are fabricated by direct molding, amenable to R2R transfer, at room temperature. Surprisingly, OLEDs on substrates with narrower a and relatively low h show significant outcoupling enhancement despite h reduction across the OLED stack. OLEDS on substrates with a2 m (and large a/h) showed significant enhancement with fully