Organic nanoscale organic OLEDs

Organic nano-scale light emitting diodes (OLEDs) are interesting for a number of reasons, they offer the ability to manufacture single photon sources, which can be used in a range of potential applications, from sensitive molecular probes, to quantum cryptography.

At Sheffield researchers have managed to make test devices with LED pixel diameters as small as 100nm. They have done this using a combination of ion beam and electron lithography techniques, familiar to conventional silicon device manufacturers, plus spin coating to apply the active polymer layer.

Square arrays of pixels were prepared, with a separation of 10µm, as shown in the photomicrograph (above right). the animation below focusses on a single emitting pixel.

Above we zoom in on a single nano-LED showing the device structure. The LED modelled is 100nm in diameter, rather smaller than the spatial resolution of any optical microscope, so the light appears as an Airy disk, with a pronounced halo effect.

References

"Nanoscale Conjugated-Polymer Light-Emitting Diodes" Farhad A. Boroumand, Paul W. Fry, and David G. Lidzey, Nano Letters, 5 (2005), 67-71.

Find out more about nanoscale electronic and photonic materials on the Electronic and photonic molecular materials research group website: EPMM website.