Deemed useful electric power generators during daylight hours, solar cells might also be configured to provide nighttime photovoltaic power. An alternative solar cell device that can supply up to 50 W/m² is under development at the University of California Davis.

A cell for nocturnal generating service advances thermoradiative photovoltaics principles and incorporates concepts from the advancing field of radiative cooling. Power is produced by transmitting heat as infrared light to the ambient environment, in contrast to conventional solar cells which absorb light. Since it is warmer than outer space, a thermoradiative cell pointed at the night sky would emit infrared light. By emitting rather than absorbing infrared photons, the device generates voltage and electric power.

Daytime operation of the nighttime photovoltaic cell might also be realized by blocking direct solar irradiation.

A conventional solar cell (left) absorbs photons of light from the sun and generates an electrical current. A thermoradiative cell (right) generates electrical current as it radiates infrared light (heat) toward the extreme cold of deep space. Source: Tristan Deppe/Jeremy Munday