Graphene layers to improve solar energy capture
doi:10.1038/nindia.2013.62 Published online 9 May 2013
Researchers have devised a new technique to synthesize graphene monolayers that can be used as anti-reflection coatings on the surfaces of silicon materials used in solar cells. Such coatings reduce the reflection of incident solar radiation, enabling more solar energy to be captured and hence potentially enhancing the performance of solar cells.
Graphene shows remarkable electronic, electrical, mechanical and optical properties. Recent studies have shown that it transmits radiation at ultraviolet (UV) and visible wavelengths. This property makes graphene an excellent anti-reflective material for solar cells.
To explore this potential of graphene, the researchers produced two types of graphene monolayers — one by chemically reducing a single layer of graphene oxide and the other by heating a plasma of a carbon-based gas and an inert gas using microwaves. They then coated each type of graphene layer on polished and textured silicon surfaces.
Both types of graphene layers reduced the reflection of incident UV and visible radiation from silicon surfaces. The low reflectance of graphene-deposited samples in the UV region make graphene coatings promising for use on nanoscale UV photodetectors and other UV-sensitive photoelectric devices.
The inert nature of a single atomic sheet of graphene is an additional potential advantage for surface-coating applications. "The key aspect of this research is that anti-reflection properties can be achieved by just depositing monolayer graphene onto silicon solar-cell surfaces," says B. R. Mehta, a co-author of the study.
The authors of this work are from: Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas and Department of Physics and Astrophysics, University of Delhi, Delhi, India