Solar panels operating around the clock and generating electricity even at night is not a far-fetched idea anymore. According to a new study published in the journal ACS Photonics, it is possible to design solar panels that can produce energy at night.
A traditional solar cell generates electricity when it absorbs photons of light from the sun, and produces a voltage across the device from the current to flow. The new design approach involves specially designed photovoltaic cells, where light is instead emitted to generate current and voltage, which work in the opposite direction and still produce energy. However, the drawback of these anti-solar cells (or thermoradiative cells) is that the electricity produced is much lower than the power generated by the conventional solar cells.
According to the research team at the University of California (UC), Davis, the photovoltaic cells could generate up to 50 watts of power per square meter under ideal conditions at night, which is around a quarter of what conventional solar panels can generate during the day.
Jeremy Munday, a professor in the Department of Electrical and Computer Engineering at UC Davis states that an object that is hot compared to its surroundings will radiate heat as infrared light. He further explains that as the space is cold, a warm object when pointed at the sky would radiate heat toward it. Munday pointed out that the thermoradiative cells, when pointed at the night sky, would emit infrared light as it was warmer than outer space.
According to the new study, the device would work during the day as well, if steps were taken to block sunlight or point it away from the sun. The process would allow the new type of solar cell to operate around the clock and provide an intriguing option to balance the power grid over the day-night cycle.