Surface plasmon enhanced silicon solar cells

TLDR

Thin‑film silicon solar cells can reduce photovoltaic costs, but efficient light trapping is essential to boost absorption and cell efficiency. The authors aim to assess whether localized surface plasmons on silver nanoparticles can enhance silicon solar cell absorbance. They employ silver nanoparticles to generate localized surface plasmons that increase light absorption in silicon solar cells. The plasmonic enhancement boosts the spectral response across the solar spectrum, delivering up to a 16‑fold increase at 1050 nm for 1.25 µm SOI cells, a seven‑fold boost at 1200 nm for wafer cells, and nearly 12‑fold electroluminescence enhancement in ultrathin SOI LEDs, with particle size variations further modulating the effect.

Abstract

Thin-film solar cells have the potential to significantly decrease the cost of photovoltaics. Light trapping is particularly critical in such thin-film crystalline silicon solar cells in order to increase light absorption and hence cell efficiency. In this article we investigate the suitability of localized surface plasmons on silver nanoparticles for enhancing the absorbance of silicon solar cells. We find that surface plasmons can increase the spectral response of thin-film cells over almost the entire solar spectrum. At wavelengths close to the band gap of Si we observe a significant enhancement of the absorption for both thin-film and wafer-based structures. We report a sevenfold enhancement for wafer-based cells at λ=1200 nm and up to 16-fold enhancement at λ=1050 nm for 1.25 μm thin silicon-on-insulator (SOI) cells, and compare the results with a theoretical dipole-waveguide model. We also report a close to 12-fold enhancement in the electroluminescence from ultrathin SOI light-emitting diodes and investigate the effect of varying the particle size on that enhancement.