Highly Directional Emission from a Broadband Organic Light-Emitting Diode using a Substrate Diffractive Optical Element for Visible Light Communications
Shuyu Zhang, Graham A. Turnbull and Ifor D.W. Samuel
An important challenge for organic light-emitting diodes (OLEDs) is to control their emission pattern. Here a SuperYellow OLED was fabricated and the spatial distribution of the emission from the OLED was strongly shaped into a directional beam by using a butt-coupled diffractive optical element and a green band-pass filter. The out-coupled beam peaked at 535 nm with a fullwidth- half-maximum (FWHM) of ~20 nm and the overall FWHM divergence of the beam integrated from 500 nm to 570 nm was 10⁰ for s-polarisation and 14⁰ for p-polarisation, which shows a strong directionality, compared with the normally Lambertian emission of an OLED. Such directional emission can be used to enhance data-rates of visible light communications by using parallel data transmission and decreasing cross talk.
Keywords: OLED, diffractive optical element, nanoimprint lithography, broadband emitter, visible light communications