Dual-color emissive OLED with orthogonal polarization modes

Abstract

Linearly polarized organic light-emitting diodes (LP-OLEDs) have become an appealing functional expansion in polarization optics and optoelectronic applications. However, this current LP-OLED generally presents comprehensively lower polarization performance, cost-prohibitive process and monochromatic modulation limit. Herein, a switchable dual-color OLED with orthogonal linearly polarization modes based on a dielectric/metal (D/M) nanograting-waveguide hybrid-microcavity geometry was first proposed, via the cost-efficient laser interference lithography and vacuum thermal evaporation methods. This acquired LP-OLED presented a reported transverse-electric/transverse-magnetic (TE/TM) polarization extinction ratio of 15.8 dB with a divergence angle of ± 30°, an excellent external quantum efficiency of 2.25%, and an orthogonal polarized colors from green to sky-blue. Detailed theoretical model illustrated that the rasterization of D/M-cathode further satisfied the momentum matching between waveguide and air mode. This diffracts both the targeted TE waveguide of sky-blue light that was localized furthest by modulating electron transport layer thickness and the off-confined green TM polarization light. Thereby, a polarization-encrypted colorful optical image was theoretically proposed. This work represents a significant step toward the low-cost LP-OLED with excellent polarization performance and toward the electrically-inspired polarization encryption for color images.