Optimizing the parameters of plasmonic metal nanoparticles to maximize the energy conversion efficiency of thin-film solar cells

Photovoltaic (PV) cells are important devices that can be used to convert photons into electrical energy. However, the cost of current PV devices needs to be significantly reduced and their efficiencies need to be substantially enhanced to enable large scale implementation of PV cells as sources of clean electrical energy. Surface plasmon polaritrons (SPP) in metallic nanostructures in close proximity to a Si substrate can lead to enhanced optical absorption and improved energy conversion efficiency in amorphous silicon thin-film PV devices. Optimization of this phenomenon requires a detailed characterization and understanding of the parameters that govern the underlying physical mechanisms. This paper explores the relationship between energy conversion efficiency in thin-film Si solar cells and the type of metallic nanoparticle, the size of the metallic nanoparticles, and the distance between neighboring metallic nanoparticles in a periodic array of the metallic nanoparticles deposited on top of the Si substrate. Of the different metallic nanoparticle systems studied, it is found that silver nanoparticles with diameter of 100 nm and spaced 220 nm from neighboring nanoparticles in a periodic array of the metallic nanoparticles deposited on top of the Si substrate provides the maximum increase in the generated short circuit current density (JSC).