Researchers at Lund University have developed a new type of light-emitting diode based on thin, branched nanowires that could offer significantly higher efficiency and lower production costs than current technology. By controlling where in the structure the light is generated, the researchers have reduced the losses that would otherwise limit the amount of light that can be used. Their study is published in the journal Nano Research.

In materials used for conventional light-emitting diodes—such as the LED bulbs found in most households—a large proportion of the light is trapped inside the material because of what is known as total internal reflection. This phenomenon means that only a small proportion of the light comes out, even though it is generated inside the material.

The new design aims to overcome this problem. The method is based on the fact that light is emitted from very thin side branches that extend from a central nanowire. If the structures are made thin enough—thinner than the wavelength of light—the light cannot be trapped inside the material in the same way.