From source to sink: the path to efficient energy harvesting with LEDs and displays

In the last three decades, light emitting diodes (LEDs) have represented a breakthrough innovation for optoelectronic applications. From optical communication to lighting and compact displays, LEDs are nowadays the device of choice in all those fields where high fluence, low power consumption and high pixel density are required. While LEDs are usually designed to maximize their performance in terms of light emission, they share the same materials and basic structure with solar cells. This similarity suggests to exploit LEDs in photovoltaic mode to be operated for harvesting energy from light in the environment. Despite the apparent simplicity of this approach, only a few examples to this extent are available in literature and several technical aspects of the corresponding implementation of LEDs as energy harvesters remain unexplored. Hereby, we report on recent progress in employing LEDs in the photovoltaic mode for energy harvesting and discuss future research directions, advocating increased efforts towards the exploitation of LEDs and LED-displays for the reduction of the energy footprint of portable appliances and electronic devices.