The researchers used a tiny pen to draw patterns with a solvent on a thin film of polymer semiconductor. The solvent changes the shape of a selection of chain segments from a disordered state to ordered rigid strands. This change in structure alters the way in which the material interacts with light, changing its refractive index as well as the colour of light emitted.
Professor Donal Bradley, director of the Centre for Plastic Electronics at Imperial College London, said: "Usually we use lenses or mirrors to change the direction of light. This method lets us manipulate a light source itself to tightly control the direction of light that it emits. The material adopts the desired structure naturally – it just requires a little encouragement to do so."
The approach is said to allow scientists to alter these properties on a much smaller scale than they could before – over distances shorter than the wavelength of light. The researchers expect this will make it possible to build a variety of novel structures leading to new and more efficient devices.
