One of the most promising and new solar cell technologies has achieved significant efficiency gains. Engineers at UNIST in South Korea have created a quantum dot solar cell with a world record efficiency of 18.1%.
Quantum dots are small, round semiconductor crystals that absorb and emit light very efficiently. The color of the light it interacts with can be adjusted by changing its size in the display technology or by using it as a sensor.
However, its biggest application is in solar cells. Most commercial solar cells are made of a massive material such as a light-harvesting layer, meaning the entire surface absorbs the same wavelengths. But with quantum dots, you can have different sizes that focus on different parts of the spectrum, increasing potential efficiency. As a bonus, it's cheap and easy to prepare, and can even be made into a spray solution.
For this new study, UNIST researchers slightly modified the recipe to improve the technology. Quantum dot solar cells made from organic materials have the highest theoretical efficiency, but unfortunately have drawbacks that make them less stable in sunlight and weather: they are not ideal for devices designed to be exposed to sunlight. sun all day. To avoid this, solar cells are usually made from inorganic materials, but this limits their effectiveness, scientists say.
The UNIST team created quantum dots from organic perovskite and developed a new way of attaching them to a substrate, allowing them to be brought close together. This brought efficiency to a record high of 18.1%, up from 16.6% in 2020. This record was recognized by the National Renewable Energy Laboratory (NREL), which independently produces graphs comparing the effectiveness of different technologies.
Surprisingly, new solar panels are more stable. They remain effective for 1,200 hours under normal conditions and 300 hours at high temperatures of 80°C (176°F). After two years of storage, they work well.
Quantum dot solar cells still have a long way to go to catch up with traditionally used silicon solar cells. Silicon solar cells have been around for half a century and are rapidly approaching their maximum theoretical efficiency. Meanwhile, quantum dots have only appeared in the laboratory since 2010, when their efficiency was less than 4%. In addition to improving efficiency, easy and cheap production will help improve technology and create more types of photovoltaic surfaces.
The study was published in the journal Nature Energy .
Source: UNIST
