Dual-interface gratings for broadband absorption enhancement in thin-film solar cells

Abass, Aimi; Le, Khai Q.; Alù, Andrea; Burgelman, Marc; Maes, Björn

doi:10.1103/physrevb.85.115449

Cited by 96 publications

(65 citation statements)

References 35 publications

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“…Much research was done on dual interface grating structures, which have front and back gratings in a single solar cell structure. [17][18][19][20] We previously demonstrated that the two gratings can complement each other in enabling access to different photonic phenomena. 18 Martins et al showed how superposing gratings with different phases at one interface can lead to more absorption enhancement, by increasing higher order diffraction while suppressing the lower order processes.…”

Section: Introductionmentioning

confidence: 99%

“…[17][18][19][20] We previously demonstrated that the two gratings can complement each other in enabling access to different photonic phenomena. 18 Martins et al showed how superposing gratings with different phases at one interface can lead to more absorption enhancement, by increasing higher order diffraction while suppressing the lower order processes. 21 These supercell gratings can be interpreted as a compromise between rough diffusers and periodic grating structures, due to the length of one supercell period and the resulting complex geometry.…”

Section: Introductionmentioning

confidence: 99%

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Modeling combined coherent and incoherent scattering structures for light trapping in solar cells

Abass

Trompoukis

Leyre

et al. 2013

Journal of Applied Physics

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Current structures for solar cells or LEDs often incorporate layers of various optical regimes, with a mixture of coherent, partially coherent or incoherent behavior. We developed a simple and efficient calculation method to study such combined solar cell structures with both wave and ray optics sections. These One-Pass Coherent calculations take wave effects into account where they matter the most, while avoiding a large computational domain to model rough structures. The method simulates a general diffuser by working directly with the reflected wavefronts, instead of using its geometry. We utilize this method to study thin film silicon solar cell structures with a grating on the front and a diffuser at the back. More absorption is obtained with the combined light trapping scheme of appropriate characteristics, compared with grating-only or diffuser-only counterparts. Finally, we report a significant effect of incoherence on the absorption of fairly thin ($10 lm) cells. We demonstrate that partially incoherent light can be more efficiently absorbed than fully coherent light on average over a broad wavelength range. It turns out that the scarcity of guided modes for fully coherent light can hinder the grating enhancement, leading to a consistently better performance when light coherence is limited or lost. V C 2013 AIP Publishing LLC.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling combined coherent and incoherent scattering structures for light trapping in solar cells

Abass

Trompoukis

Leyre

et al. 2013

Journal of Applied Physics

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“…In order to enhance light absorption, this type of solar cell employs nanostructures to couple light into the quasi-guided modes of its thin absorbing film 1,13,14,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] . The quasi-guided modes are usually excited by wavelength-scale periodic structures such as nano-wires 30,31 , photonic crystals [20][21][22][23][24][25][26][27][28][29] or metallic gratings 32,34 . The excitation of a quasi-guided mode results in strong resonant absorption enhancement, but only over a narrow bandwidth.…”

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confidence: 99%

Deterministic quasi-random nanostructures for photon control

et al. 2013

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Controlling the flux of photons is crucial in many areas of science and technology. Artificial materials with nano-scale modulation of the refractive index, such as photonic crystals, are able to exercise such control and have opened exciting new possibilities for light manipulation. An interesting alternative to such periodic structures is the class of materials known as quasi-crystals, which offer unique advantages such as richer Fourier spectra. Here we introduce a novel approach for designing such richer Fourier spectra, by using a periodic structure that allows us to control its Fourier components almost at will. Our approach is based on binary gratings, which makes the structures easy to replicate and to tailor towards specific applications. As an example, we show how these structures can be employed to achieve highly efficient broad-band light trapping in thin films that approach the theoretical (Lambertian) limit, a problem of crucial importance for photovoltaics.

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“…In this way each grating interacts in an optimal way with the mode offering the largest field-profile overlap, leading to stronger absorption peaks ( Fig. 1(b)) [3]. We rigorously simulate these effects using the frequency domain finite element software COMSOL.…”

Section: Descriptionmentioning

confidence: 99%

Tailored and tapered metallic gratings for enhanced absorption or transmission

Shen

Abass

Maes

2012

2012 14th International Conference on Transparent Optical Networks (ICTON)

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Plasmonic structures, such as metallic gratings and apertures, provide unusual abilities to modify the absorption or the transmission of thin-layered devices. In order to optimize the absorption in thin-film solar cells, we introduce complex grating geometries, implementing multiple periodicities and blazing. These gratings optimize the diffraction efficiency and increase the number of accessible modes. On the other hand, in order to achieve enhanced transmission at infrared wavelengths, we propose tapered apertures. The non-resonant funnelling phenomena provide for broadband and wide-angle focusing opportunities. Keywords: photovoltaics, plasmonics, gratings. DESCRIPTIONThin-film devices such as solar cells and LEDs can profit from the strong scattering effects provided by dielectric and metallic gratings [1,2]. To enhance the absorption we have optimized an amorphous silicon solar cell design in multiple ways ( Fig. 1(a)). In this design we couple efficiently to the two main types of guided modes: the 'photonic' modes (mainly localized in the silicon) and the plasmonic modes (localized at the metallic back-contact). We adjust the periodicity of the front (ITO/Si) grating to couple best to the photonic modes, and we lower the period of the back (Si/Ag) grating to diffract into plasmonic modes. In this way each grating interacts in an optimal way with the mode offering the largest field-profile overlap, leading to stronger absorption peaks ( Fig. 1(b)) [3]. We rigorously simulate these effects using the frequency domain finite element software COMSOL. In addition, for optimal plasmonic electrode designs we explore tapered, funnel-like shapes, in order to have large transmission over a broadband and wide-angle range. The tapering allows a smooth transition of the impedance, leading to non-resonant designs, which are not dominated by a few strong Fabry-Perot peaks as in more traditional structures. ACKNOWLEDGEMENTSWe acknowledge IWT-SBO "Silasol" and IAP "photonics@be". REFERENCES [1] H

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Dual-interface gratings for broadband absorption enhancement in thin-film solar cells

Cited by 96 publications

References 35 publications

Modeling combined coherent and incoherent scattering structures for light trapping in solar cells

Modeling combined coherent and incoherent scattering structures for light trapping in solar cells

Deterministic quasi-random nanostructures for photon control

Tailored and tapered metallic gratings for enhanced absorption or transmission

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