Its cell conversion efficiency is 18.7% without light condensing and 19.4% at the time of 2x light condensing. The research group is led by Yasuhiko Arakawa and Katsuaki Tanabe, who are professor and specially-appointed associate professor, respectively, at the Institute for Nano Quantum Information Electronics, the University of Tokyo.
The 18.7% efficiency is the industry’s highest efficiency for a quantum dot-type PV battery that is not concentrating light, Arakawa said. Before the achievement was made, the highest efficiency had been 18.3% achieved by a research group at the Russian Academy of Sciences.
The latest quantum dot-type PV battery was developed by using the “intermediate band method,” in which conversion efficiency is improved by forming a superlattice structure (in which quantum dots are three-dimensionally arranged) and a miniband (intermediate band) that absorbs infrared light.