14 Nov 2013

Organic LEDs

From Our Changing World, 9:36 pm on 14 November 2013


From left to right: a blue-emitting OLED and Rebecca Sutton (images: Baptiste Auguie and Woolf photography)

Light emitting diodes or LEDs are found in digital clocks, TVs and traffic lights -- but they are brittle. Organic LEDs use thin films instead of crystalline layers, so they are thinner and lighter and can be made to bend or flex.

Rebecca Sutton is a Masters student at Victoria University and she’s studying what happens to blue organic LEDs (OLEDs) as they degrade. She’s particularly interested in blue-emitting OLEDs because they degrade faster than other OLEDs, such as red ones. As part of her Masters project she developed a procedure for making blue-emitting OLEDs and then studied how they degrade during operation (they are sensitive to oxygen and water and so don't emit light for very long when they have been exposed to air). The technique used to do this is electron paramagnetic (=spin) resonance. This technique is similar to NMR (like that used to conduct MRI scans) but looks at the electrons rather than the nuclei. She found some evidence of chemical reactions occurring while the OLEDs was emitting light. Rebecca shows Ruth Beran how she makes OLEDs and demonstrates how they emit light.

Rebecca’s Masters project was funded by Victoria University and the MacDiarmid Institute of Advanced Materials and Nanotechnology, and her supervisors were Andy Edgar and Natalie Plank.