A numerical study of Bi-periodic binary diffraction gratings for solar cell applications

Mellor, A.; Tobias, Irwin; Martı́, Antonio; Ĺuque, A.

doi:10.1016/j.solmat.2011.08.017

Cited by 51 publications

(28 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…maximum current in thin cells is 650 nm, which indicates that for thin cells, both light trapping and reduced reflectance were important, in agreement with Chong et al [2]. At the optimized aspect ratio for nanotubs (0.69) for finite thickness, high absorptance and low reflectance were obtained where λ∕d 1, similar to Mellor et al where for circular pillars the region 0.9 < λ∕d < 1.1 μm had the best light trapping configuration for gratings [4].…”

Section: B Frontal Surface Reflectance Transmittance and Current Pesupporting

confidence: 86%

“…Current was obtained by integrating the absorptance over the solar photon flux (assuming all generated electron-hole pairs are collected), yielding J sc [4],…”

Section: A Simulationmentioning

confidence: 99%

“…Symmetrical textured structures of pyramids, pillars, and checkerboard grids have been assessed by Chong et al and Mellor et al, identifying optimized structures for current performance and highlighting square pyramids as superior to others [2,4]. Sai et al and Abouelsaood et al assessed square pyramids similarly, with an increased emphasis on the effects of aspect ratios, sizing, shape, and packing density on reflectance [5,6].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Three-dimensional nanotub submicrometer diffraction gratings for solar cells

McKeon

Macdonald

et al. 2014

Appl. Opt.

View full text Add to dashboard Cite

Diffraction gratings are a promising approach for reducing reflection and achieving light-trapping in solar cells. Using square lattices as a base structure, we investigate a novel bi-periodic nanotub three-dimensional grating structure and compare it with established textured structures for thin-film and wafer applications. For wafer application, simulations show that optimal AR coated nanotubs demonstrated solar weighted reflectance (SWR) of 2% compared to AR coated square pyramids with values 1.9%. Nanotubs also show SWR below 8% for polar angles to 60°. Simulated short-circuit current thin-film cells with nanotubs using smaller dimensions show higher yields (3-6 mA∕cm 2 average) compared to square pyramids. For periods greater than 700 nm at aspect ratios of 0.7 and greater, nanotubs have reduced current attributed to the increased planar surface area of the nanotub base, and evident in increased SWR. A simple nanoimprint lithography process was employed in experiments to define a square array of circular holes, utilizing a polydimethylsiloxane (PDMS) stamp applied onto a sol-gel imprint resist. The underlying silicon was then wet etched to produce the nanotub textures of 200 nm height and 513 nm period. AR coated nanotub wafers were produced via plasma enhanced chemical vapor deposition (PECVD), with an experimental and theoretical SWR of 6.4% and 5.4%, respectively.

show abstract

Section: B Frontal Surface Reflectance Transmittance and Current Pesupporting

confidence: 86%

“…Current was obtained by integrating the absorptance over the solar photon flux (assuming all generated electron-hole pairs are collected), yielding J sc [4],…”

Section: A Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Three-dimensional nanotub submicrometer diffraction gratings for solar cells

McKeon

Macdonald

et al. 2014

Appl. Opt.

View full text Add to dashboard Cite

show abstract

“…For both the line and crossed gratings, a period of 1 µm was chosen, this having been predicted as the optimum period for 40 µm thick c-Si cells using numerical calculations [10,16]. The grating depth was 300 nm for the line grating and 200 nm for the crossed grating.…”

Section: Nano-texturing Of the Wafer Rear Sidementioning

confidence: 99%

Nanoimprinted diffraction gratings for crystalline silicon solar cells: implementation, characterization and simulation

Mellor¹,

Hauser²,

Wellens³

et al. 2013

Opt. Express

View full text Add to dashboard Cite

Light trapping is becoming of increasing importance in crystalline silicon solar cells as thinner wafers are used to reduce costs. In this work, we report on light trapping by rear-side diffraction gratings produced by nano-imprint lithography using interference lithography as the mastering technology. Gratings fabricated on crystalline silicon wafers are shown to provide significant absorption enhancements. Through a combination of optical measurement and simulation, it is shown that the crossed grating provides better absorption enhancement than the linear grating, and that the parasitic reflector absorption is reduced by planarizing the rear reflector, leading to an increase in the useful absorption in the silicon. Finally, electrooptical simulations are performed of solar cells employing the fabricated grating structures to estimate efficiency enhancement potential.

show abstract

“…It can be seen that the desired binary profile and close to 50% duty cycle has been achieved in the silicon. A period of 1 urn was chosen for the diffraction gratings, this having been found to be optimum for 40 urn thick c-Si solar cells in previous numerical studies [10,11]. The grating depth was 300 nm for the line grating and 200 nm for the crossed grating.…”

Section: Fabrication Of Rear Textured Solar Cell Precursors By Nano-imentioning

confidence: 99%

Nano-imprinted rear-side diffraction gratings for absorption enhancement in solar cells

et al. 2012

View full text Add to dashboard Cite

As wafer-based solar cells become thinner, light-trapping textures for absorption enhancement will gain in importance. In this work, crystalline silicon wafers were textured with wavelength-scale diffraction grating surface textures by nanoimprint lithography using interference lithography as a mastering technology. This technique allows fine-tailored nanostructures to be realized on large areas with high throughput. Solar cell precursors were fabricated, with the surface textures on the rear side, for optical absorption measurements. Large absorption enhancements are observed in the wavelength range in which the silicon wafer absorbs weakly. It is shown experimentally that bi-periodic crossed gratings perform better than uni-periodic linear gratings. Optical simulations have been made of the fabricated structures, allowing the total absorption to be decomposed into useful absorption in the silicon and parasitic absorption in the rear reflector. Using the calculated silicon absorption, promising absorbed photocurrent density enhancements have been calculated for solar cells employing the nano-textures. Finally, first results are presented of a passivation layer deposition technique that planarizes the rear reflector for the purpose of reducing the parasitic absorption.

show abstract

A numerical study of Bi-periodic binary diffraction gratings for solar cell applications

Cited by 51 publications

References 24 publications

Three-dimensional nanotub submicrometer diffraction gratings for solar cells

Three-dimensional nanotub submicrometer diffraction gratings for solar cells

Nanoimprinted diffraction gratings for crystalline silicon solar cells: implementation, characterization and simulation

Nano-imprinted rear-side diffraction gratings for absorption enhancement in solar cells

Contact Info

Product

Resources

About