The process used to make solar panels work in the dark is called radiative cooling.
Solar energy is the most promising route to clean energy. Unfortunately, solar panels have one major disadvantage - they cannot generate electricity in darkness. However, this may soon change as scientists from Stanford University have created a solar panel that works in the dark.
Scientists published their findings on a new type of solar panel in the journal Applied Physics Letters back in April 2022. They discovered a way to make solar panels work in the dark, and found that solar panels already installed can be modified to generate electricity at night as well, saving businesses and homes from having to switch to new panels.
The process used to make old solar panels work in the dark is called radiative cooling. When the sun goes down, the Earth cools down, releasing heat into the air. This helps create a temperature difference between the air and the surface of the panels. Scientists have reported that we can install thermoelectric generators on the panels, allowing us to utilize the energy produced by radiation cooling.
In fact, a similar idea has been floated even earlier. Back in 2020, scientists at UCLA did something similar with what they called an "anti-solar panel". Photovoltaic solar panels already utilize this radiation cooling to generate electricity after sunset, allowing these solar panels to operate in the dark.
Scientists are looking at so-called thermoradiation cells to generate electricity, as opposed to the photovoltaic cells used in familiar solar panels. Conventional solar cells are usually made of silicon, which is good at capturing light that is in the visible spectrum. The new device must be made of something that can capture light with very long wavelengths. Scientists are currently selecting mercury alloys that would be good for this purpose.
So why haven't we heard anything about it if solar panels are generating electricity even after the sun goes down? Well, it's because they're not generating the necessary electricity. Instead, by some estimates, they generate only about 25 percent of the energy that a solar panel can generate on a sunny day. But it's still pure energy that you didn't have before, so it's still worth using while you can.
