Scientists develop a solar cell that generates light in the dark

Scientists have created a "reverse solar cell" capable of harnessing the heat released by the earth at night to generate electric light. According to the report, most solar panels generate electricity from the sun through a physical process called photoelectric effect. Some use an alternative method – based on the temperature difference between the hot sun and the cold land to generate usable energy.

According to the Mirror website, the new device, developed by researchers at Stanford University, fundamentally reverses this method: at night, the Earth is hotter than air, which means that it emits heat , a process called radiative cooling. The device exploits this heat exchange and turns it into electricity.

Although the energy produced by the cooling of the sky is much lower than the energy obtained directly from the sun by the solar cells, it is enough to light a light bulb. LED"A large part of the world's population still lacks electricity, especially at night when photovoltaic systems do not work," the researchers wrote.".

"The ability to generate electricity at night can be important for a wide range of applications, including low-power light sensors," he said. The validation device was made from economical, basic, ready-to-use components at less than $ 30..

The cell consists of a polystyrene housing covered with aluminum mylar, surmounted by a black aluminum disc of 200 mm, suspended as a "heat emitter". Which radiates heat in the air.

The test generated 25 milliwatts per square meter of disk – enough to work LED However, the researchers say that with increased isolation and a drier climate, they will be able to provide up to 0.5 watts per square meter of disc, and with larger discs they may be able to illuminate the house permanently..

The device can also operate in the opposite direction during the day, absorbing sunlight and producing electricity from the heat transmitted by the sun to the disc. "In off-grid locations around the world, the process of generating light from the dark brings the lighting is completely negative at night".

The generated energy can also be used to power small sensors in remote areas, without the battery life being limited by batteries but by an electrothermal unit, the size of which can be longer .".