Author(s): Bermel P, Luo C, Zeng L, Kimerling LC, Joannopoulos JD
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Abstract Most photovoltaic (solar) cells are made from crystalline silicon (c-Si), which has an indirect band gap. This gives rise to weak absorption of one-third of usable solar photons. Therefore, improved light trapping schemes are needed, particularly for c-Si thin film solar cells. Here, a photonic crystal-based light-trapping approach is analyzed and compared to previous approaches. For a solar cell made of a 2 mum thin film of c-Si and a 6 bilayer distributed Bragg reflector (DBR) in the back, power generation can be enhanced by a relative amount of 24.0\% by adding a 1D grating, 26.3\% by replacing the DBR with a six-period triangular photonic crystal made of air holes in silicon, 31.3\% by a DBR plus 2D grating, and 26.5\% by replacing it with an eight-period inverse opal photonic crystal.
This article was published in Opt Express
and referenced in Journal of Lasers, Optics & Photonics