Brighter LEDs with low polarization resist ‘efficiency droop’

Light-emitting diodes (LEDs) are ubiquitous, from smartphones to home lighting. However, today’s LEDs have a major limitation: when the operator tries to make them brighter by increasing their power, they become less efficient. 

Now, a team of researchers at Nagoya University in Japan has found a way to make LEDs brighter while maintaining their efficiency. Their research promises to reduce the cost and environmental impact of LED production while improving performance in applications such as visible light communication and virtual reality (VR) glasses. A study describing this development appears in Laser & Photonics Review.

InGaN LEDs represent the most efficient light source globally, although they typically operate at low power levels. To obtain brighter light, it is necessary to increase their power. However, an increase in power supplied to the LED results in a decrease in its efficiency, a phenomenon known as efficiency droop.

One way to overcome efficiency droop is to increase the area of the LED, which increases light output, but it also requires a larger chip. As a result, fewer LEDs can be obtained from a wafer, the thin piece of semiconductor material made from InGaN that serves as the base for the fabrication of LED devices. This results in higher production costs and greater environmental impact, according to the Nagoya announcement.