UV-nanoimprint lithography and large area roll-to-roll texturization with hyperbranched polymer nanocomposites for light-trapping applications

Lazo, Marina A. González; Teuscher, R.; Leterrier, Y.; Månson, Jan‐Anders E.; Calderone, Caroline; Hessler-Wyser, Aïcha; Couty, Philippe; Ziegler, Y.; Fischer, D.

doi:10.1016/j.solmat.2012.04.034

Cited by 45 publications

(20 citation statements)

References 46 publications

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“…The hybrid approach is indeed versatile and enables to produce a broad composition range with low viscosities, suited for low‐pressure replication processes, [ 23 ] which was confirmed by the present investigation. The present printing technology and hybrid formulation are both compatible with cost‐effective, roll‐to‐roll processes, that is, with good potential to increase the efficiency of solar cells at a very low cost 19b…”

Section: Resultsmentioning

confidence: 99%

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Superhard, Antireflective Texturized Coatings Based on Hyperbranched Polymer Composite Hybrids for Thin‐Film Solar Cell Encapsulation

et al. 2015

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In this study, we demonstrate by simulation and experiment the antireflective (AR) performance of hyperbranched polymer (HBP) nanocomposites textures replicated from a moth-eye pattern using UV nanoimprint lithography. A UV-curable acrylated HBP and a hybrid composite of the HBP with silica nanoparticles and an organometal precursor were used. Using effective medium theory (EMT) simulations, optimal patterns were found to be arrays of paraboloids with stable AR performance over a large range of geometries. A good agreement was found between the simulated and measured optical behavior of such AR arrays with a normal reflectance within the visible range of around 4% when using a glass substrate. The photocurrent of AR coated a-Si:H solar cells was found to be 2% higher than the reference value of an uncoated cell whereas for AR coated tandem thin film Si cells the increase was 3% for the top a-Si:H cell and 2% for the bottom microcrystalline Si cell.Antireflective hardcoats: Synthetic moth eye textures eliminate light reflection in the front encapsulation of solar cells, leading to a 5% photocurrent increase in thin film tandem a-Si:H and µc-Si devices. The sub-micron antireflective textures are optimized using optical simulations and replicated in a low shrinkage and superhard hyperbranched polymer nanocomposite hybrid by means of a UV nanoimprint lithography process.

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Section: Resultsmentioning

confidence: 99%

“…AR textures were replicated into the HBP and hybrid materials from a template using a UVNIL tool as detailed in a previous work 19b. The template was a 20 mm×20 mm square nickel foil with an hexagonal array of 300 nm high moth‐eye based structures (NIL Technology, Denmark).…”

Section: Methodsmentioning

confidence: 99%

Superhard, Antireflective Texturized Coatings Based on Hyperbranched Polymer Composite Hybrids for Thin‐Film Solar Cell Encapsulation

et al. 2015

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“…13 Acrylated HBPs were used to fabricate polymer micro-and nano-structures with high accuracy. 14,15 The HBP used in this study was a polyester acrylate oligomer (Sartomer) with functionality of 16 and a glass transition temperature in cured state equal to 155°C. The photoinitiator was Esacure TPO (Lamberti) at a concentration of 6 wt%.…”

Section: Ultraviolet Nanoimprint Lithography Replicationmentioning

confidence: 99%

“…15,16 This tool consist of a cylindrical steel mould equipped with a UV-transparent quartz window. Pressure was applied using a pressure-controlled pneumatic movable stamp to which the master was attached.…”

Section: Ultraviolet Nanoimprint Lithography Replicationmentioning

confidence: 99%

Embedded microstructures for daylighting and seasonal thermal control

et al. 2012

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A novel concept for an advanced fenestration system was studied and samples were produced to demonstrate the feasibility. The resulting novel glazing will combine the functions of daylighting, glare protection, and seasonal thermal control. Coated microstructures provide redirection of the incident solar radiation, thus simultaneously reducing glare and projecting daylight deep into the room in the same manner as an anidolic mirror-based system. The solar gains are reduced for chosen angles corresponding to aestival elevations of the sun, thereby minimising heating loads in winter and cooling loads in summer.A ray-tracing program developed especially for the study of laminar structures was used for the optimisation of structures with the above mentioned goals. The chosen solution is based on reflective surfaces embedded in a polymer film that can be combined with a standard doubled glazed window. The fabrication of such structures required several steps. The fabrication of a metallic mould with a relative high aspect ratio and mirror polished surfaces is followed by the production of an intermediate Polydimethylsiloxane moulds that was subsequently used to replicate the structure with a UV curable polymer. Selected facets of these samples were then coated with a thin film of highly reflective material in a physical vapour deposition process. Finally, the structures were filled with the same polymer to integrated the mirrors.The samples were characterised using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), confocal microscopy and laser profilometry. A miniature goniophotometer was built to assess the performance of the structured glazing. The daylighting behaviour was successfully demonstrated.

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“…The desired light trapping can be achieved either via plasmonic effects [8][9][10] or via light scattering with random [11][12][13] and periodic [14][15][16] structures. Owing to its deposition sequence, the n-i-p configuration opens the route for direct depositions on opaque substrates like commercial ceramic tiles [17], flexible stainless steel [18,19] and plastic foils [20][21][22]. An additional advantage is that a large choice of light-scattering patterns covered with a silver (Ag) layer can be used to optimize light trapping in the bottom cell.…”

Section: Introductionmentioning

confidence: 99%

New progress in the fabrication of n–i–p micromorph solar cells for opaque substrates

Biron

Hänni

Boccard

et al. 2013

Solar Energy Materials and Solar Cells

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a b s t r a c tIn this paper, we investigate tandem amorphous/microcrystalline silicon solar cells with asymmetric intermediate reflectors grown in the n-i-p substrate configuration. We compare different types of substrates with respect to their light-trapping properties as well as their influence on the growth of single-junction microcrystalline cells. Our most promising back reflector combines a textured zinc oxide film grown by low-pressure chemical vapor deposition, a silver film for reflection, and a zinc oxide buffer layer. Grown on this substrate, microcrystalline cells exhibit excellent response in the infrared while keeping high open-circuit voltage and fill factor, leading to efficiencies of up to 10.0%. After optimizing the morphology of the asymmetric intermediate reflector, we achieve an n-i-p micromorph solar cell stabilized efficiency of 11.6%, using 270 nm and 1.7 mm of silicon for the absorber layer of the amorphous top cell and the microcrystalline bottom cell, respectively. Using this original device architecture, we reach efficiencies close to those of state-of-the-art n-i-p and p-i-n micromorph devices, demonstrating a promising route to deposit high-efficiency thin-film silicon solar cells on opaque substrates.

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UV-nanoimprint lithography and large area roll-to-roll texturization with hyperbranched polymer nanocomposites for light-trapping applications

Cited by 45 publications

References 46 publications

Superhard, Antireflective Texturized Coatings Based on Hyperbranched Polymer Composite Hybrids for Thin‐Film Solar Cell Encapsulation

Superhard, Antireflective Texturized Coatings Based on Hyperbranched Polymer Composite Hybrids for Thin‐Film Solar Cell Encapsulation

Embedded microstructures for daylighting and seasonal thermal control

New progress in the fabrication of n–i–p micromorph solar cells for opaque substrates

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