A Laser-Processed Silicon Solar Cell With Photovoltaic Efficiency In The Infrared

Hyperdoped and textured silicon created with a femtosecond laser in the presence of SF6 gas has a highly absorbing surface with extended spectral sensitivity in the infrared. The main drawback of this micro- and nanostructured material for photovoltaic (PV) cells is an increase in charge-carrier recombination at the surface due to the typically poor crystallinity of the surface layer. Laser annealing postprocessing of the black silicon (b-Si) surface is used to greatly reduce the crystal structure defects while maintaining sub-bandgap absorption. The back side of the cell is functionalized with spin-on doping and laser fired contacts to make an interdigitated back-contact proof-of-concept b-Si solar cell. It is shown that this cell has measurable PV efficiency in the sub-bandgap infrared, a promising step toward developing intermediate-band silicon PVs.