“Quantum dots” solar panel breaks efficiency record

Mar 05, 2020 | 1242 views

Researchers at the University of Queensland, Australia, developed a technique that optimizes the efficiency of solar cells from quantum dots, reaching values ​​close to that obtained by traditional silicon cells: 16.4%, against the typical 20%.

Solar cells, through the photovoltaic effect, convert energy from the sun into electrical energy. Among the existing varieties (one of them works, including, through bacteria), one has been gaining attention from the scientific community for its potential, called the quantum dot solar cell. This is an opportunity to generate electricity at low cost.

Quantum dots are semiconductor particles already known to receive electricity and transform it into light with great efficiency. However, what was revealed by the study was that the reverse process is also possible, that is, that light can be transformed into electricity through the technique without such significant energy losses.

Professor Lianzhou Wang celebrates the success of the research carried out with his colleagues, since the improvement of almost 25% in efficiency achieved in relation to the previous world record indicates that the economic viability of a wider application of the novelty is not such a distant dream. "It is precisely the difference between being just a wonderful possibility and being something commercially viable", he says.

The technique behind the conquest
Applying surface engineering techniques, Lianzhou Wang and his team managed to reduce the instability and roughness of the surface of quantum dots, characteristics responsible for limiting the conversion of solar energy into electrical current. The solution found was to test a cation exchange chemistry based on oleic acid.

Although quantum dots are solid nanoparticles, they are contained in liquid solutions. The great news is that, when obtained from solar cells, they eliminate a major problem generated by the use of liquid electrolytes, which can generate leakage in the cells and even oxidize the light-absorbing materials.

The variety of applications is still unknown, but encouraging. Wang, for example, envisions a scenario for powering cars, planes, homes and dressing technologies. Because of the possibility that such cells could be part of flexible panels, such resources could coat vehicles and even windows and other surfaces. The goal is now to break new records.

"Eventually, [the quantum solar cell] could play an important role in meeting the United Nations' goal of increasing the share of renewable energy in the global energy mix," he concludes.