University of Toronto has successfully made the first layered solar cell that absorbs both visible and infrared solar energy. At the core of the technology is Colloidal Quantum Dots (CQD). The CQDs are used as the cells photovoltaic material.
A quantum dot is a bit of semiconductor matter with electrical characteristics that are closely related to the size/shape of the crystals they are grown in. The smaller the crystal, the larger the band gap of energy, or the difference between the highest electron valence band and the lowest conduction band. The band gap is then tunable for the energy levels targeted. In straight single band efficiency, CQD solar cells have been proven to be at 5.1%. Silicon cells are at 17%.
The U of T "Tandem cells" uses what they dubbed the "Graded Recombination Layer" with a infrared harvester top, and visible harvester underneath linked together efficiently. Their manufacturing is simple, the layers are a nano-particle paint that is able to be applied to a sub straight in a thin film form at room temperature. The perfect tandem solar cell has a theoretical 42% efficiency. This is a stark difference from today's thin film solar at 12% max or silicon at 18% max efficiency.
Although this is an amazing achievement, Professor Ted Sargent mentioned 3 layer solar. I would assume he is suggestion the collection of the ? If so, power output will increase by a factor of 6 over current solar technology. As Sargent said, coating the outside of an EV car would go a long way.