Comparison between Periodicity and Randomness from an Effective Refractive Index Point of View; Applicable to thin-film Solar Cells

In this paper, embedding plasmonic nanoparticles inside the solar cell’s active layer both in a periodic and a random manner is extensively investigated. The reason behind this study is to investigate optical mechanisms inside the active layer as a consequence of nanoparticle inclusion as well as comparing periodicity versus randomness in such structures, where the intended maximization of the ultra-broadband absorption renders the analysis complicated. To perform such study, an effective refractive index analysis is employed to simultaneously covering of the influential parameters. The results show that although fully periodic structures are more desirable in narrow-band applications such as e.g. grating-assisted waveguide coupling; random inclusions of plasmonic nanoparticles in the solar cell’s active layer yield a much higher optical absorption. Furthermore, random inclusions of nanoparticles are easier and much cheaper relative to periodic inclusion to implement in solar cell fabrication.