Optics in Thin-film Silicon Solar Cells with Integrated Lamellar Gratings

2009 ◽  
Vol 1153 ◽  
Author(s):  
Rahul Dewan ◽  
Darin Madzharov ◽  
Andrey Raykov ◽  
Dietmar Knipp
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Incident Light ◽  
Short Circuit Current ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
Diffracted Waves ◽  
Difference Time

AbstractLight trapping in microcrystalline silicon thin-film solar cells with integrated lamellar gratings was investigated. The influence of the grating dimensions on the short circuit current and quantum efficiency was investigated by numerical simulation of Maxwell’s equations by a Finite Difference Time Domain approach. For the red and infrared part of the optical spectrum, the grating structure leads to scattering and higher order diffraction resulting in an increased absorption of the incident light in the silicon thin-film solar cell. By studying the diffracted waves arising from lamellar gratings, simple design rules for optimal grating dimensions were derived.

scholarly journals Light Scattering and Current Enhancement for Microcrystalline Silicon Thin-Film Solar Cells on Aluminium-Induced Texture Glass Superstrates with Double Texture

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yunfeng Yin ◽  
Nasim Sahraei ◽  
Selvaraj Venkataraj ◽  
Sonya Calnan ◽  
Sven Ring ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Optical Scattering ◽  
Thin Film Solar Cells ◽  
Surface Topology ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
Wide Range

Microcrystalline silicon (μc-Si:H) thin-film solar cells are processed on glass superstrates having both micro- and nanoscale surface textures. The microscale texture is realised at the glass surface, using the aluminium-induced texturing (AIT) method, which is an industrially feasible process enabling a wide range of surface feature sizes (i.e., 700 nm–3 μm) of the textured glass. The nanoscale texture is made by conventional acid etching of the sputter-deposited transparent conductive oxide (TCO). The influence of the resulting “double texture” on the optical scattering is investigated by means of atomic force microscopy (AFM) (studying the surface topology), haze measurements (studying scattering into air), and short-circuit current enhancement measurements (studying scattering into silicon). A predicted enhanced optical scattering efficiency is experimentally proven by a short-circuit current enhancementΔIscof up to 1.6 mA/cm2(7.7% relative increase) compared to solar cells fabricated on a standard superstrate, that is, planar glass covered with nanotextured TCO. Enhancing the autocorrelation length (or feature size) of the AIT superstrates might have the large potential to improve theμc-Si:H thin-film solar cell efficiency, by reducing the shunting probability of the device while maintaining a high optical scattering performance.

scholarly journals Optical developments for silicon thin film solar cells in the substrate configuration

2008 ◽  
Vol 1101 ◽  
Author(s):  
Thomas Soderstrom ◽  
Franz-Joseph Haug ◽  
Xavier Niquille ◽  
Oscar Cubero ◽  
Stéphanie Perregaux ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Series Resistance ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Back Contact ◽  
Silicon Thin Film ◽  
Optical Behavior

AbstractIn the nip or substrate configuration thin film silicon solar cells, the choice of front TCO contact is critical because there is a trade off between its transparency which influences the current in the solar cell and its conductivity which influences the series resistance. Here, we investigate the optical behavior of two different TCO front contacts, either a 70 nm thick, nominally flat ITO or a 2 μm thick rough LPCVD ZnO. The back contact consists of LP-CVD ZnO with random texture. First we investigate the influence of the rough and flat front TCOs in μc-Si:H and a-Si:H solar cells. With the back contact geometries used in this work, the antireflection properties of ITO are effective at providing as much light trapping as the rough LP-CVD ZnO. In the second part, we demonstrate that total of 25 to 26 mA/cm2is achievable in nip micromorph tandem cells and show short circuit current up to 11.7 mA/cm2 using an SIO based intermediate reflector.

Light Trapping in μc-Si:H Thin-film Solar Cells by Back Surface Reflector with Grating Structure Fabricated by Self-ordering Process

2008 ◽  
Vol 1101 ◽  
Author(s):  
Hitoshi Sai ◽  
Hiroyuki Fujiwara ◽  
Michio Kondo
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Incident Light ◽  
Short Circuit Current ◽  
Back Surface ◽  
Diffraction Effect ◽  
Grating Structure ◽  
Reflection Measurement

AbstractBack surface reflectors (BSRs) with grating structures have been developed to enhance light trapping in thin-film microcrystalline Si (μc-Si:H) solar cells. As a grating structure, a periodic honeycomb-like dimple pattern with periods of 100 ˜ 450 nm has been fabricated on Al substrates by a self-ordering process using anodic oxidation of Al. A clear diffraction effect by the grating structure has been confirmed on the patterned Al using angle-dependent reflection measurement. From quantum efficiency measurements, we found that the periodically patterned BSR can confine the incident light effectively, especially at longer wavelengths. Nevertheless, short circuit current densities obtained from the patterned BSRs are rather comparable to that obtained from the random textured substrate. For further improvement of the light-trapping effect by the grating structure, it is necessary to realize higher diffraction efficiencies while maintaining high total reflectivity on the BSR structure.

Nanoimprint Photonic Crystal Film Enhanced Light-Trapping in a-Si Thin Film Solar Cells

2011 ◽  
Vol 110-116 ◽  
pp. 497-502
Author(s):  
Wei Ping Chu ◽  
Fuh Shyang Juang ◽  
Jian Shian Lin ◽  
Tien Chai Lin ◽  
Chen Wei Kuo
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Photonic Crystals ◽  
Current Density ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Thin Film Solar Cells ◽  
Uv Lamp

We utilize photonic crystals to enhanced lighttrapping in a-Si:H thin film solar cells. The photonic crystals effectively increase Haze ratio of glass and decrease reflectance of a-Si:H solar cells. Therefore, increase the photon path length to obtain maximum absorption of the absorber layer. The photonic crystals can effective in harvesting weakly absorbing photons with energies just above the band edge. We were spin coated UV glue on the glass, and then nanoimprint of photonic crystals pattern. Finally, used UV lamp was curing of UV glue on the glass. When the 45∘composite photonic crystals structures, the haze was increase to 87.9 %, resulting the short circuit current density and efficiency increasing to 13.96 mA/cm2 and 7.39 %, respectively. Because 45∘composite photonic crystals easy to focus on the point of light lead to the effect of scattering can’t achieve. So, we designs 90∘V-shaped photonic crystals structures to increase scattering. When the 90∘V-shaped photonic crystals structures, the Haze was increase to 93.9 %. Therefore, the short circuit current density and Efficiency increasing to 15.62 mA/cm2 and 8.09 %, respectively. We observed ~35 % enhancement of the short-circuit current density and ~31 % enhancement of the conversion efficiency.

Analysis of short circuit current gains by an anti-reflective textured cover on silicon thin film solar cells

2012 ◽  
Vol 21 (8) ◽  
pp. 1672-1681 ◽  
Author(s):  
Carolin Ulbrich ◽  
Andreas Gerber ◽  
Ko Hermans ◽  
Andreas Lambertz ◽  
Uwe Rau
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Thin Film Solar Cells ◽  
Silicon Thin Film

Thermodynamic limits of nanophotonic light trapping in thin film silicon solar cells

2014 ◽  
Vol 92 (7/8) ◽  
pp. 909-912 ◽  
Author(s):  
Brian R. Maynard ◽  
E.A. Schiff
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Thin Film Silicon ◽  
Solar Tracking ◽  
Current Densities ◽  
Thermodynamic Limits

We have extended an earlier thermodynamic treatment of light-trapping in lattice-textured solar cells to higher absorptances. This treatment is used to calculate the quantum efficiency spectra and short-circuit current densities JSC for thin-film silicon solar cells with ideal lattice textures. An optimal triangular lattice period of 900 nm yields a calculated JSC that is 2 mA/cm2 larger than for ideal random textures in a 1000 nm thick cell. We compare the calculations to recent experiments with periodically textured cells. While the experimental cells give JSC values that are comparable to the best cells with conventional textures, they do not show the features associated with the prediction of higher JSC. We discuss the role of imperfections in the periodic texturing, and suggest that cells used with solar tracking may realize the predicted JSC improvement.

scholarly journals Enhanced Light Trapping in Thin Film Solar Cells Using a Plasmonic Fishnet Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Sayan Seal ◽  
Vinay Budhraja ◽  
Liming Ji ◽  
Vasundara V. Varadan
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Wire Mesh ◽  
Thin Film Solar Cells ◽  
Plasmonic Structures ◽  
Spacer Layer ◽  
High Absorption

Incorporating plasmonic structures into the back spacer layer of thin film solar cells (TFSCs) is an efficient way to improve their performance. The fishnet structure is used to enhance light trapping. Unlike other previously suggested discrete plasmonic particles, the fishnet is an electrically connected wire mesh that does not result in light field localization, which leads to high absorption losses. The design was verified experimentally. A silver fishnet structure was fabricated using electron beam lithography (EBL) and thermal evaporation. The final fabricated structure optically resembles a TFSC. The results predicted by numerical simulations were reproduced experimentally on a fabricated sample. We show that light absorption in the a-Si absorber layer is enhanced by a factor of 10.6 at the design wavelength of 690 nm due to the presence of the fishnet structure. Furthermore, the total absorption over all wavelengths was increased by a factor of 3.2. The short-circuit current of the TFSC was increased by 30% as a result of including the fishnet.

Light Management Using Periodic Textures for Enhancing Photocurrent and Conversion Efficiency in Thin-Film Silicon Solar Cells

2013 ◽  
Vol 1536 ◽  
pp. 3-15 ◽  
Author(s):  
Hitoshi Sai ◽  
Takuya Matsui ◽  
Adrien Bidiville ◽  
Takashi Koida ◽  
Yuji Yoshida ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Aspect Ratio ◽  
Light Trapping ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Area Efficiency ◽  
Cell Thickness

ABSTRACTPeriodically textured back reflectors with hexagonal dimple arrays are applied to thin-film microcrystalline silicon (μc-Si:H) solar cells for enhancing light trapping. The period and aspect ratio of the honeycomb textures have a big impact on the photovoltaic performance. When the textures have a moderate aspect ratio, the optimum period for obtaining a high short circuit current density (JSC) is found to be equal to or slightly larger than the cell thickness. If the cell thickness exceeds the texture period, the cell surface tends to be flattened and texture-induced defects are generated, which constrain the improvement in JSC. Based on these findings, we have fabricated optimized μc-Si:H cells achieving a high active-area efficiency exceeding 11% and a JSC of 30 mA/cm2.

scholarly journals Advances in Evaporated Solid-Phase-Crystallized Poly-Si Thin-Film Solar Cells on Glass (EVA)

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
O. Kunz ◽  
Z. Ouyang ◽  
J. Wong ◽  
A. G. Aberle
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solid Phase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Device Fabrication ◽  
Thin Film Solar Cells ◽  
Large Area ◽  
Silicon Thin Film ◽  
Numerical Device

Polycrystalline silicon thin-film solar cells on glass obtained by solid-phase crystallization (SPC) of PECVD-deposited a-Si precursor diodes are capable of producing large-area devices with respectable photovoltaic efficiency. This has not yet been shown for equivalent devices made from evaporated Si precursor diodes (“EVA” solar cells). We demonstrate that there are two main problems for the metallization of EVA solar cells: (i) shunting of the p-n junction when the air-side metal contact is deposited; (ii) formation of the glass-side contact with low contact resistance and without shunting. We present a working metallization scheme and first current-voltage and quantum efficiency results of 2 cm2 EVA solar cells. The best planar EVA solar cells produced so far achieved fill factors up to 64%, series resistance values in the range of 4-5 Ωcm2, short-circuit current densities of up to 15.6 mA/cm2, and efficiencies of up to 4.25%. Using numerical device simulation, a diffusion length of about 4 μm is demonstrated for such devices. These promising results confirm that the device fabrication scheme presented in this paper is well suited for the metallization of EVA solar cells and that the electronic properties of evaporated SPC poly-Si materials are sufficient for PV applications.

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