Use of plasmonic metal nanoparticles to increase the light absorption efficiency of thin-film solar cells

Thin-film photovoltaic (PV) cell technology has been of keen interest over the last decade or so due to its lower cost of production, wide applicability and lower diffusion length for minority carriers. However, the conversion efficiencies of thin-film PV cells is much lower than that of conventional crystalline Si PV cells. Nanostructures have therefore been designed and implemented with such cells to improve optical and electrical efficiency of the cell, and plasmonic solar cells is among them. This study investigates how the optimization of the physical parameters of metal nanoparticles dispersed periodically over a 2μm a-Si substrate affect the enhancement in optical and electrical activity of a plasmonic solar cell. The study found that periodic arrays of Ag nanoparticles with a diameter of 100nm dispersed at a pitch of 220nm provided the highest enhancement. This conclusion was verified by analyzing absorption enhancement, short circuit current density and near-field images of all the different nanoparticle configurations studied.