Graphenized Carbon Nanofiber: A Novel Light-Trapping and Conductive Material to Achieve an Efficiency Breakthrough in Silicon Solar Cells

摘要

The large-scale deployment of environmental friendly photovoltaic (PV) technology promises a radical and might be the only viable solution to the world energy crisis, but has been severely hindered by the slow pace of the efficiency advances achieved in the last 15 years. Nanophotonics strategies have emerged recently as an unparalleled conceptual framework to address the fundamental light-trapping issue in solar cells. Tailored nanomaterials including plasmonic nanopartides, plasmonic nanogratings, and dielectric nanoparticles have been developed and integrated with PV devices. However, the demonstrated record efficiency of nanophotonics solar cells is still significantly inferior to that of the conventional ones. The key reason is due to the often contradictory requirements from the optical and electrical considerations for the nanoma-terial design, in particular for state-of-the-art solar cells that have been optimized with little margin to further improve. For an example, although large plasmonic nanoparticles introduce stronger light scattering, the embedding of the large nanoparticles into solar cells leads to the high roughness on the cell structures. In this case, the electrical transfer among the cell layers is impeded due to some contact loss, and the fill factor reduces dramatically. Therefore to add the critical efficiency breakthrough, the development of advanced nanomaterials that have outstanding light-trapping capabilities but with ignorable optical and electrical losses holds the key.