Researchers from the University of Toronto have created the world’s most efficient colloidal quantum dot (CQD) solar cells ever. The researchers’ CQD cells have world record 7% efficiency, a 37% improvement over previous CQD cells. “Previously, quantum dot solar cells have been limited by the large internal surface areas of the nanoparticles in the film, which made extracting electricity difficult,” said Dr. Susanna Thon. The cells achieve their record efficiency due to a scheme that fills charge traps -- that block electron flow -- while simultaneously ensuring the cells were as dense as possible to absorb more light. “Our breakthrough was to use a combination of organic and inorganic chemistry to completely cover all of the exposed surfaces,” says Thon. The research is a major advance for CQD solar cells and paves the way for efficient solar cells that can be produced quickly and cheaply on flexible substrate the same way newspapers are rapidly printed in mass quantities.