Annular hole array design as a high efficiency absorber for photovoltaic applications

Abstract

In order to benefit from thin-film solar cells cost advantage, increasingly effort is deployed to maximize their harvesting capability. In this work, we focus on improving an a-Si solar thin-film by engraving it with an Annular Hole Array (AHA). The design parameters are fashioned to maximize the absorption across the visible spectral range exploiting the 3D Finite-Difference Time-Domain method (3D−FDTD). When comparing the AHA device to an unpatterned a-Si solar cell, an important absorption enhancement of 64.2% was obtained along with a broad spectral absorption bandwidth with peaks reaching 97.7% at normal incidence over the AM1.5 solar spectrum. It turns out that a proper design optimization highlighted promising results like polarization and almost incidence insensitivity. In fact, an integrated absorption of 90.5% over the AM1.5 solar spectrum was achieved and maintained over 65% for any angle of incidence for the spectral field λ∈[300nm;1000nm]. These results are beneficial for solar energy harvesting and allow this structure to be an advantageous candidate for photovoltaic applications.