On the possibility of using plasmonic metal nanoparticles embedded within the silicon substrate to enhance the energy conversion efficiency of silicon thin-film solar cells

Abstract

While photovoltaic cells have become increasingly available commercially over the last few decades, their relatively low efficiencies leave much room for improvement. Plasmonic nanostructures have been used to enhance the optical and electrical activity within PV cells. However, while plasmonic nanostructures have been placed above the surface of the cell, the effect that nanostructures embedded within the cell can have on its energy conversion has not been extensively studied. This study analyzes the effect of plasmonic nanostructures embedded within a thin-film amorphous Si solar cell on the efficiency of the solar cell, and hopes to provide a relationship between the physical parameters of the nanostructures and the optical and electrical enhancement within the solar cell. The parameters considered were the size of the nanoparticles and the distance between neighboring nanoparticles. The metal chosen for the nanospheres is silver (Ag). The analyses performed were — plasmon resonance analyses, absorption enhancement, short circuit current density and near field enhancement imaging. Through this study, it was found that although there is no linear increase in optical and electrical activity with respect to particle size, the largest particle (diameter of 500nm) studied resulted in the highest enhancement. Furthermore, the closer the particles were, the greater the enhancements obtained.