Our paper presents a detailed numerical simulation and experimental study of the efficiency enhancement gained by optimizing metal nanocubes incorporated on the surface of silicon solar cells. We investigate the effects of nanoparticle size, surface coverage and spacer layer thickness on solar absorption and cell efficiency. The fabrication of nanocubes on solar cells is also presented, with the trends observed in simulation verified through experimental data. Testing reveals that nanocubes show worse performance than nanospheres when sitting directly on the silicon substrate; however, enhancement exceeds that of nanospheres when particles are placed on an optimized spacer layer of SiO2, for reasonable surface coverages of up to 25%. Our analysis shows that for a large range of particle sizes, 60 - 100nm, enhancement in light absorption remains at a high level, near the optimum. This suggests a high level of fabrication tolerance which is important due to the chemical growth mechanism used for nanocube synthesis, as it consistently produces nanocubes in that range. Further, we note that efficiency enhancement by nanocubes is influenced by particle size, surface coverage, and spacer layer thickness much differently than that for a spherical geometry, thus our study focuses on the optimization of the nanocube parameters. We show that 80nm nanocubes on a 25nm SiO2spacer layer realize ~ 24% enhancement in light absorption compared to an identical particle-free cell. Finally, we present both the numerical and experimental results for silicon solar cells coated with nanocube arrays.
We present a design of implementing plasmonic nanoparticles made from silver onto the surface of amorphous silicon based solar cells. When adding these silver nanoparticles we expect to see enhancements to the solar cells due to the plasmonic effects induced by the metal nanoparticles. The nanoparticles are used as subwavelength scattering elements to couple and trap light within the cell. In addition, the excited surface plasmon-polaritons promote a strong localized field enhancement which increases the cells ability to absorb light. Our choice of geometry of the nanoparticle is cubic rather than the traditional spherical geometry. We expect to see the cell perform better with the cubic shape due to the larger surface area it spans. We investigate the effects of these particles on to the performance of the solar cells, as well as introduce an intrinsic layer between the active p and n region creating a p-i-n solar cell configuration. We report the use of an FDTD simulator to characterize the optical performance of the solar cell. Both cubical and spherical nanoparticles made from silver were studied. Our simulations predict an overall increase of 67% (from 7.5% to 12.5) based on the p-i-n configuration with inclusion of the plasmonic particles onto the surface of the cells. Experimentally we verified the results by first fabricating a crystalline silicon-based solar cell with a p-n configuration and then placing the silver nanocubes onto the surface of the cell. An overall increase of about 28% was experimentally demonstrated (from 3.97% to 5.081%). We anticipate further increases with the p-i-n configuration.
We report a novel plasmonic solar cell design implemented on an amorphous silicon platform. The enhancement of
the scattering and trapping of the light is achieved by embedding nano-metallic cubic particles within the cell’s
junction. Amorphous silicon cell with a thickness of 1200nm is used. The spectral absorption of the silicon cell is
limited to wavelengths larger than 1.1 u. Our proposed solar cell has a p-i-n configuration, with the amorphous
silicon as the photo-active layer. Silver cubic nanoparticles are embedded at different locations within the photoactive
layers of the solar cell. With the use of an FDTD simulator, we are able to characterize the optical
performance of the solar cell. Our results show that the plasmonic properties of the cubic nanoparticles are more
attractive for sensing applications compared to the traditional spherical configuration. The geometry of the cubic
nanoparticles enables control over plasmon resonances both in the resonant wavelength and the degree of field
enhancement. This is done by improving the refractive-index sensitivity on a thin silicon film, as well as increasing
the scattering and trapping of light. Our simulations predict that the silver metallic nanoparticles will enhance the
solar cell efficiency, by optimizing the plasmonic properties of the silver nanocube monolayer. We have achieved a
67% increase (from 7.5% to 12.5%) in the cell’s efficiency by adding plasmonics to traditional amorphous p-i-n