Solar power has emerged as the biggest source of clean energy the world over. However, it has a limitation, the sun is now always out. A new technology developed in Australia is claiming to solve the problem by generating power from solar energy, even at night.
Researchers at the University of New South Wales (UNSW) Sydney have generated electricity from heat radiated as infrared light by a semiconductor device called a thermoradiative diode. This “night-time” solar power equipment is composed of materials found in night-vision goggles.
While the power generated at this stage is very small around 1,00,000 times less than that supplied by a solar panel, the team is hopeful of ramping up the capacity in the future. The research has been published in the journal ACS Photonics.
“We have made an unambiguous demonstration of electrical power from a thermoradiative diode. Using thermal imaging cameras, you can see how much radiation there is at night, but just in the infrared rather than the visible wavelengths. What we have done is make a device that can generate electrical power from the emission of infrared thermal radiation,” team lead, Associate Professor Ned Ekins-Daukes said in a statement.
A thermal imaging camera highlights the amount of heat radiating from Sydney Harbour. (Photo: UNSW)
The technology taps into the solar energy that warms up the planet during the day and radiates back into space in the form of infrared light at night. Researchers showed the heat radiating from the surface during the night using a thermal imaging camera.
Dr. Phoebe Pearce, one of the paper’s co-authors said, “Whenever there is a flow of energy, we can convert it between different forms. Photovoltaics, the direct conversion of sunlight into electricity, is an artificial process that humans have developed in order to convert solar energy into power. In that sense the thermoradiative process is similar; we are diverting energy flowing in the infrared from a warm Earth into the cold universe.”
The research team from the School of Photovoltaic and Renewable Energy Engineering believes that the technology can be used in a range of products and most importantly in equipment powered by batteries. “Down the line, this technology could potentially harvest that energy and remove the need for batteries in certain devices or help to recharge them. That isn’t something where conventional solar power would necessarily be a viable option,” Ekins-Daukes said.
The team hopes to leverage the knowledge of how to design and optimise solar cells and borrow materials from the existing mid-infrared photodetector community to ramp up the technology’s capabilities.