Research shows new light-harvesting potential

Researchers at Australia’s Griffith University have discovered significant new potentials for light harvesting through narrowing the bandgap of titania (TiO2) and graphene quantum dots.

According to a report by IDTechEx’s online Energy Harvesting Journal, the researchers for the first time have found a quantum-confined bandgap-narrowing mechanism where ultraviolet absorption of grapheme quantum dots and TiO2 nanoparticles can easily be extended into the visible light range. Such a mechanism may allow the design of new composite materials for light harvesting and optoelectronics.

Dr Qin Li of the university’s Environmental Engineering and Queensland Micro- and Nanotechnology Centre, says such applications would offer high-efficiency paintable solar cells and water purification using sun light. Visible light makes up 43 percent of solar energy compared to only 5 percent possessed by UV light. Major efforts have been made to improve titania’s absorption of visible light or develop visible-light-sensitive materials in general.

Methods used for titania—including metal ion doping, carbon doping, nitrogen doping and hydrogenation—usually require stringent conditions to obtain the modified (TiO2) such as elevated temperature or high pressure, the report notes.

The research was published in Chemical Communications, a Royal Society of Chemistry journal.