A hybrid resist hemispherical-pit array layer for light trapping in thin film silicon solar cells via UV nanoimprint lithography

Micromorph tandem solar cells coated with a HP array layer were fabricated by UV NIL. The HP array layer could reduce the average reflectance of the solar cells from 7.7% to 1.8%. And a relative improvement of efficiency of up to 4.1% is observed as compared to the bare solar cells.

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Nanoimprint lithography of textures for light trapping in thin film silicon solar cells

physica status solidi (a) ◽

10.1002/pssa.201200887 ◽

2012 ◽

Vol 210 (4) ◽

pp. 707-710 ◽

Cited By ~ 13

Author(s):

Wim Soppe ◽

Maarten Dörenkämper ◽

Jean-Baptiste Notta ◽

Paul Pex ◽

Wilfried Schipper ◽

...

Keyword(s):

Thin Film ◽

Solar Cells ◽

Nanoimprint Lithography ◽

Light Trapping ◽

Silicon Solar Cells ◽

Thin Film Silicon

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Light-trapping in Thin Film Silicon Solar Cells with a Combination of Periodic and Randomly Textured Back-reflectors

MRS Proceedings ◽

10.1557/opl.2012.888 ◽

2012 ◽

Vol 1426 ◽

pp. 117-123 ◽

Cited By ~ 1

Author(s):

Sambit Pattnaik ◽

Nayan Chakravarty ◽

Rana Biswas ◽

D. Slafer ◽

Vikram Dalal

Keyword(s):

Thin Film ◽

Solar Cells ◽

Light Absorption ◽

Nanoimprint Lithography ◽

Light Trapping ◽

Silicon Solar Cells ◽

Long Wavelength ◽

Thin Film Silicon ◽

Back Reflectors ◽

Back Reflector

ABSTRACTLight trapping is essential to harvest long wavelength red and near-infrared photons in thin film silicon solar cells. Traditionally light trapping has been achieved with a randomly roughened Ag/ZnO back reflector, which scatters incoming light uniformly through all angles, and enhances currents and cell efficiencies over a flat back reflector. A new approach using periodically textured photonic-plasmonic arrays has been recently shown to be very promising for harvesting long wavelength photons, through diffraction of light and plasmonic light concentration. Here we investigate the combination of these two approaches of random scattering and plasmonic effects to increase cell performance even further. An array of periodic conical back reflectors was fabricated by nanoimprint lithography and coated with Ag. These back reflectors were systematically annealed to generate different amounts of random texture, at smaller spatial scales, superimposed on a larger scale periodic texture. nc-Si solar cells were grown on flat, periodic photonic-plasmonic substrates, and randomly roughened photonic-plasmonic substrates. There were large improvements (>20%) in the current and light absorption of the photonic-plasmonic substrates relative to flat. The additional random features introduced on the photonic-plasmonic substrates did not improve the current and light absorption further, over a large range of randomization features.

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Nanoimprint lithography of light trapping patterns in sol-gel coatings for thin film silicon solar cells

10.1117/12.781072 ◽

2008 ◽

Cited By ~ 2

Author(s):

Maurits C. R. Heijna ◽

Jochen Löffler ◽

Bas B. Van Aken ◽

Wim J. Soppe ◽

Herman Borg ◽

...

Keyword(s):

Thin Film ◽

Solar Cells ◽

Nanoimprint Lithography ◽

Light Trapping ◽

Sol Gel ◽

Silicon Solar Cells ◽

Thin Film Silicon

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Nanoimprint Lithography of Light Trapping Structures in Sol-gel Coatings for Thin Film Silicon Solar Cells

MRS Proceedings ◽

10.1557/proc-1101-kk13-05 ◽

2008 ◽

Vol 1101 ◽

Author(s):

Maurits Heijna ◽

Jochen Loffler ◽

Bas Van Aken ◽

Wim Soppe ◽

Herman Borg ◽

...

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Barrier Layer ◽

Nanoimprint Lithography ◽

Light Trapping ◽

Silicon Solar Cells ◽

Metal Foil ◽

Periodic Patterns ◽

Thin Film Silicon

AbstractFor thin-film silicon solar cells, light trapping schemes are of uppermost importance to harvest all available sunlight. Typically, superstrates with randomly textured TCO front layers are used to scatter the light diffusively in pin-cells on glass. Here, we investigate methods to texture opaque substrates with both random and periodic textures, for use in nip-cells on metal foil. We applied an electrically insulating SiOx-polymer coating on a stainless steel substrate, and textured this barrier layer by nanoimprint. On this barrier layer the back contact is deposited for further use in the solar cell stack. Replication of masters with various random and periodic sub-micron patterns was tested, and, using scanning electron microscopy, replicas were found to compare well with the originals. The embossing of the barrier layer does not diminish its electrically isolating properties, and thus adds extra functionality to this layer. Masters with U-grooves of various sub-micrometer widths have been used to investigate the optimal dimensions of regular patterns for light trapping in the silicon layers. Angular reflection distributions were measured to evaluate the light scattering properties of both periodic and random patterns. These periodic patterns, comprising diffraction gratings, show promising results in scattering the light to specific angles, enhancing the total internal reflection in the solar cell.

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