University Develops Nanodisk Formation Technology for Highly Efficient Quantum-Dot Solar Cells

A research group led by Professor Seiji Samukawa of Tohoku University has developed a high-density quantum-dot solar cell manufacturing technology, which produces quantum-dot solar cells with an expected energy conversion efficiency of 45 percent or more, it was announced on June 15, 2011 by the Institute of Fluid Science, Tohoku University.

Theoretically, the maximum conversion efficiency of currently available thin-film silicon solar batteries cannot exceed 30 percent. The group has fabricated the quantum dots by developing highly practical and unique technologies, when compared to conventional ones, such as a mask generation technology using iron-containing protein and an ultra-high precision etching technology. The team has succeeded in fabricating 10-nanometer quantum nanodisk array structures by making a trillion 10-nanometer-diameter quantum dots per one square centimeter of a silicon substrate.

Furthermore, by embedding such silicon quantum nano array structures on silicon carbide (Sic), minibands were successfully formed, which is indispensable for highly efficient quantum-dot solar cells, resulting in improved optical absorption efficiency, the team confirmed. This improvement makes it possible for the solar light absorption efficiency to be 1.5 or 2 times higher than usual - theoretically enabling an energy conversion efficiency of 45 percent or more.

Quantum-dot solar cells are expected to be a next-generation version of solar cells. Professor Samukawa's group intends to experimentally manufacture solar cells using this structure in about three years and to put them into practical use around 2020.

Posted: 2011/11/05 06:00:15 AM