Calcite Scientist Wins Nobel Prize in Chemistry

On October 4, the Royal Swedish Academy of Sciences unveiled the 2023 Nobel Prize in Chemistry, and three people, including American scientist Moungi G. Bawendi, were honored for their contributions to the discovery and synthesis of quantum dots.

And one of the trio, Moungi G. Bawendi, from the Massachusetts Institute of Technology (MIT) in the United States, is a true expert in chalcogenide solar cells:

• In February 2019, the efficiency of the chalcogenide solar cell he developed was certified by NREL to reach 24.2%, making it the 10th efficiency record point for chalcogenide solar cells;
• In September 2019, its development of chalcogenide solar cell efficiency was certified by NREL to reach 25.2%, making it the 11th efficiency record point for chalcogenide solar cells;
• In February 2021, Moungi G. Bawendi’s team, together with Jangwon Seo & Seong Sik Shin’s research team at the Korea Research Institute of Chemical Technology (KRICT), published their research results on improving the performance of chalcogenide solar cells through carrier management in Nature.

Quantum Dots: A New Start in Solar Cell Efficiency

Quantum dots (QDs) , also known as semiconductor nanocrystals, are semiconductor particles several nanometers in size. Due to quantum mechanics, their optical and electronic properties differ from those of larger particles. When a quantum dot is irradiated with ultraviolet light, the electrons in the quantum dot can be excited to a higher energy state. In the case of semiconductor quantum dots, this process corresponds to a jump of electrons from the valence band to the conduction band.

Quantum dots in considered to be an ideal material for use in stacked solar cells. Quantum dots of different energy levels are combined into multiple layers of light-absorbing material in a stacked cell, with each layer designed to capture a specific portion of the solar spectrum. This allows for more efficient utilization of the solar spectrum than conventional single-junction cells.

The most promising application for stacked solar cells is the chalcogenide cell. The combined application of quantum dots and chalcogenide materials can create solar cells that are more efficient than quantum dots alone. Some tandem solar cells containing quantum dots have reportedly been able to achieve photovoltaic conversion efficiencies of more than 40%.

With quantum dots, chalcogenide solar cells will undoubtedly usher in a new beginning!