Night Time Solar Cell

Researchers may have found a way to balance availability of solar power over the day-night cycle using a specially designed solar cell that can generate power at night.

A conventional solar cell absorbs energy in the form of sunlight because it is cool in comparison to the sun. This energy generates a voltage across the cell through which current can flow. Another type of device – known as a thermoradiative cell – works just the opposite. When pointed toward the night sky, it will radiate energy in the form of heat because it is cooler than space. This flow of energy creates a voltage and current in the opposite direction, but still generates power.

The recently developed photovoltaic cell can generate up to 50 watts per square meter, which is about one-fourth of the power that is generated by a solar panel during the day. The principal can also be applied to drawing heat away from buildings during the hot summer months or to capture waste heat from engines.