Shedding light on the absorption of light by titanium dioxide

EPFL scientists have uncovered the hidden properties of titanium dioxide, one of the most promising materials for light-conversion technology. Figure Caption: Lattice structure of anatase TiO₂ with a graphical representation of the 2D exciton that is generated by the absorption of light (purple wavy arrow). This 2D exciton is the lowest energy excitation of the material. Titanium dioxide (TiO₂) is one of the most promising materials for photovoltaics and photocatalysis nowadays. This material appears in different crystalline forms, but the most attractive one for applications is called "anatase". Despite decades of studies on the conversion of the absorbed light into electrical charges in anatase TiO₂, the very nature of its fundamental electronic and optical properties was still unknown. EPFL scientists, with national and international partners, have now shed light onto the problem by a combination of cutting-edge steady-state and ultrafast spectroscopic techniques, as well as theoretical calculations.