Self-adjusting Light Source Based on a Dual-Function GaN Light-Emitting Diode

Abstract

GaN light-emitting diodes (LED) play a vital role in modern lighting technology, and the further development of smart lighting systems capable of automatically adjusting the brightness has received extensive attention. Herein, we present a simple and elegant approach based on a single GaN LED that can self-adjust the output intensity in response to the changes in ambient intensity. The GaN LED with InGaN/GaN multi-quantum wells can operate in both luminescence and photodetection modes, and its electrical and optical performances are thoroughly investigated. Driven by a microcontroller board under pulse-width modulation, the device acts as a detector to provide photocurrent signals that reflect the ambient light intensity at the off state, and provides the desired intensity level at the on state. This work also exhibits a proof-of-concept demonstration of real-time stabilization of blue and white light irradiances at target areas despite large variations in ambient irradiance. The proposed novel self-adjusting scheme based on a dual-function LED chip without the need for external photosensors can be an alternative approach for smart lighting applications.