Researchers at the University of Queensland (UQ) are harnessing the properties of quantum dots (QDs) to make solar cells that capture a wider range of light for energy, are more stable in their energy production, and can be applied to curved surfaces. According to the team led by professor Lianzhou Wang, UQ has achieved a new world record for QD solar cell efficiency — going from 13.5% to 16.6%, a nearly 25% gain in efficiency.
The researchers developed a surface engineering strategy to overcome roughness and instability on the surface of QDs, which can interfere with efficiency. An oleic acid ligand-assisted cation-exchange strategy allowed controllable synthesis of a mixed cesium and formamidinium lead triiodide perovskite system in the form of QDs. The oleic acid-rich environment facilitates the cross-exchange of cations, enabling rapid formation of perovskite QDs with reduced defect density.
In addition to achieving a certified record power conversion efficiency of 16.6%, the new QD devices exhibit enhanced photostability compared with their thin-film counterparts because of suppressed phase segregation.