Highly directional emission from a broadband organic light-emitting diode using a substrate diffractive optical element for visible light communications

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 10. for s-polarisation and 14. 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.