Anti-reflective coating is used in many types of solar cell on the market today. They do add a few percentages to overall performance, however, there are further improvements to be made. This is what Professor E. Fred Schubert and his team at the Rensselaer Polytechnic Institute is working on.
Recent improvements in nanotechnology have made it possible to alter the refractive index of some materials. In laymen`s terms, this means that we can change the speed of light through a material – potentially highly beneficial for photovoltaic applications. The faster light flows through a material, the higher the electrical output of a solar cell.
Air and many gases have refractive indexes close to 1.0, which is to say that they behave similarly to absolute vacuum. The fastest non-gaseous material has previously been magnesium fluoride with a refractive index of 1.39.
The team at Rensselaer Polytechnic Institute has now developed a new four-layer anti-reflective coating that is based on silicon dioxide (SiO2), indium-tin oxide (ITO), and titanium dioxide (TiO2). The refractive index of the new coating has been demonstrated to be 1.05.
Schubert states the following on the recent development of the new anti-reflective coating technology:
“The fabrication process of this coating is additive and purely physical, so it’s fully compatible with current manufacturing processes of solar cells. Our customizable approach readily lends itself to the incorporation of antireflection coating design into solar cell device structures for application-specific requirements.”
The research sure is promising, but the team has yet to release any data on how much of an improvement the new anti-reflective coating material might induce in conventional solar cells.