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Diffractive Interference Design Using Front and Rear Surface Metal and Dielectric Nanoparticle Arrays for Photocurrent Enhancement in Thin Crystalline Silicon Solar Cells

2014; American Chemical Society; Volume: 1; Issue: 9 Linguagem: Inglês

10.1021/ph5001567

2330-4022

Enrico Massa, Vincenzo Giannini, Nicholas P. Hylton, Nicholas J. Ekins‐Daukes, Samarth Jain, Ounsi El Daïf, Stefan A. Maier,

Silicon and Solar Cell Technologies

Using an interference design model we were able to quickly optimize the nanophotonic control afforded by metal and dielectric nanoparticle arrays to enhance the absorption and photocurrent in a thin crystalline silicon solar cell, which were simulated via full field electromagnetic FEM calculations. Fabry–Perot interference fringes introduced by placing structures on the front and rear surfaces are shown to lead to significant enhanced light trapping in the absorbing silicon layer. We report a 46.7% increase in the estimated short-circuit photocurrent over the solar spectrum (AM 1.5G) range of 300–1100 nm for a 1 μm thick crystalline silicon solar cell with metal and dielectric nanoparticle arrays designed using interference modeling. The enhancement was achieved by placing nanoparticle arrays on the front and rear surface of the cell, where the particles on the front surface are dielectric (Si) and those on the rear surface are metal (Al). Additionally, an estimated photocurrent enhancement of 29.4% was obtained with just the aluminum nanoparticle array on the rear surface of the cell. Our study of nanoparticle arrays of metal (aluminum) and dielectrics (silicon, titanium oxide, aluminum oxide, and silicon nitride) involved different radius, pitch, and position on the front and rear surface of silicon solar cells with antireflection coatings. Improved light trapping and absorption thanks to the arrays are unambiguously shown. The rear surface array is shown to broadly reduce the reflectance of the cell via multiple Fabry–Perot resonances due to the interference of the incident and diffracted field from the array of particles. The front surface array broadly reduces the reflectance due to the excitation of local resonances and preferential scattering into the substrate. Together with local resonance excitation, these two combined effects are significant for the design of thin-film solar cells with light-trapping properties to increase the absorption and improve cell performance.