Empirical Comparison of Random and Periodic Surface Light‐Trapping Structures for Ultrathin Silicon Photovoltaics

Branham, Matthew S.; Hsu, Wen-Jing; Yerci, Selçuk; Loomis, James; Boriskina, Svetlana V.; Hoard, Brittany R.; Han, Sang Eon; Ebong, Abasifreke; Chen, Gang

doi:10.1002/adom.201500667

Cited by 29 publications

(23 citation statements)

References 44 publications

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“…A numerical mesh-based FDTD formalism ( Lumerical Solutions, Inc., 2017 ) was used to model the 3D electric field distribution produced in the two types of structures shown in Figure 1 . This is a widely employed method to calculate the optical response of thin-film solar cells with photonic structures, having arbitrary materials and geometries ( Grandidier et al., 2011 , Brongersma et al., 2014 , Branham et al., 2016 , Mendes et al., 2016 , Sanchez-Sobrado et al., 2017 ). The details of the computational method are given in Section S1 of Supplemental Information .…”

Section: Resultsmentioning

confidence: 99%

“…Optimized texturing has shown absorption enhancements in crystalline silicon (c-Si) wafers close to the fundamental 4n 2 LT limit of geometrical optics ( Ingenito et al., 2014 ). However, when applied in thin-film cells, the textures' size must be reduced along with the absorber thickness, which lowers their LT effects ( Haug and Ballif, 2015 , Branham et al., 2016 ). Nonetheless, the main drawback of texturing is that it increases the roughness (hence surface area) and defect density in the PV material, which deteriorate the cells' electrical transport via the increase of charge carrier trapping and recombination.…”

Section: Introductionmentioning

confidence: 99%

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Optimal-Enhanced Solar Cell Ultra-thinning with Broadband Nanophotonic Light Capture

et al. 2018

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SummaryRecent trends in photovoltaics demand ever-thin solar cells to allow deployment in consumer-oriented products requiring low-cost and mechanically flexible devices. For this, nanophotonic elements in the wave-optics regime are highly promising, as they capture and trap light in the cells' absorber, enabling its thickness reduction while improving its efficiency. Here, novel wavelength-sized photonic structures were computationally optimized toward maximum broadband light absorption. Thin-film silicon cells were the test bed to determine the best performing parameters and study their optical effects. Pronounced photocurrent enhancements, up to 37%, 27%, and 48%, respectively, in ultra-thin (100- and 300-nm-thick) amorphous, and thin (1.5-μm) crystalline silicon cells are demonstrated with honeycomb arrays of semi-spheroidal dome or void-like elements patterned on the cells' front. Also importantly, key advantages in the electrical performance are anticipated, since the photonic nano/micro-nanostructures do not increase the cell roughness, therefore not contributing to recombination, which is a crucial drawback in state-of-the-art light-trapping approaches.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal-Enhanced Solar Cell Ultra-thinning with Broadband Nanophotonic Light Capture

et al. 2018

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“…16,[18][19][20] Additionally, recent studies have shown that triangular, pyramidal, or conical gratings exhibit higher absorption due to the impedance match from air to silicon. [15][16][17][18][19][20][21][22]28,30,39 To improve light trapping even further, the inclusion of a back grating structure has been studied as a means to better scatter near-infrared light into guided resonances. [12][13][14]17,[27][28]33 By combining a front and back grating, recent studies have demonstrated enhancement to light trapping that outperforms absorbers that are textured only on one side.…”

Section: Introductionmentioning

confidence: 99%

“…[12][13][14]17,[27][28]33 By combining a front and back grating, recent studies have demonstrated enhancement to light trapping that outperforms absorbers that are textured only on one side. [27][28][29][30][31][32][33][34][35][36][37][38][39] Further improvements for these double grating structures have included the introduction of a phase shift through misalignment of two gratings and the use of blazed gratings to break symmetry. 30,[38][39][40] To optimize the double grating structure, a general design strategy was proposed in which the front grating is treated as an anti-reflection layer to couple incident light while the back grating diffracts light into guided modes to trap it within the thin film.…”

Section: Introductionmentioning

confidence: 99%

“…[27][28][29][30][31][32][33][34][35][36][37][38][39] Further improvements for these double grating structures have included the introduction of a phase shift through misalignment of two gratings and the use of blazed gratings to break symmetry. 30,[38][39][40] To optimize the double grating structure, a general design strategy was proposed in which the front grating is treated as an anti-reflection layer to couple incident light while the back grating diffracts light into guided modes to trap it within the thin film. 28,33 The periodicities of both the front and back grating are therefore crucial to the overall performance.…”

Section: Introductionmentioning

confidence: 99%

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Mismatched front and back gratings for optimum light trapping in ultra-thin crystalline silicon solar cells

Hsu

Tong

Branham

et al. 2016

Optics Communications

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The implementation of a front and back grating in ultra-thin photovoltaic cells is a promising approach towards improving light trapping. A simple design rule was developed using the least common multiple (LCM) of the front and back grating periods. From this design rule, several optimal period combinations can be found, providing greater design flexibility for absorbers of indirect band gap materials. Using numerical simulations, the photo-generated current (J ph) for a 10-μm-thick crystalline silicon absorber was predicted to be as high as 38 mA/cm 2 , which is 11.74% higher than that of a single front grating (J ph =34 mA/cm 2).

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Quasi‐Omnidirectional Ultrathin Silicon Solar Cells Realized by Industrially Compatible Processes

Zhong

Zhuang

et al. 2019

Adv Elect Materials

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Ultrathin crystalline silicon (c‐Si) solar cells provide advantages in reducing the use of c‐Si material and being flexible, but there are several challenges that need to be conquered, such as limited optical absorption, high sensitivity to surface recombination, and complicated fabrication issues. Here, all‐solution‐processed Si nanopyramids (SiNPs) are proposed as the surface texture for ultrathin c‐Si solar cells to solve the light absorption issue, whose preparation process is simple, low‐cost, and industrially compatible. Combining the SiNPs texture with good passivation technique, an efficiency of 15.1% with an open circuit voltage approaching 700 mV is realized on a 37 µm thick c‐Si solar cell. Moreover, both experimental and simulation investigation reveal that the SiNP‐textured ultrathin solar cells have quasi‐omnidirectional light absorption characteristic, showing a potential to produce higher all‐day output power compared with the Si micropyramids textured counterpart. To further reduce the cost of ultrathin c‐Si solar cells, a direct copper metallization is also investigated in replacement of silver metallization, which can result in a comparable efficiency. The present work demonstrates the conventional industrial processes for achieving low‐cost ultrathin c‐Si solar cells.

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Empirical Comparison of Random and Periodic Surface Light‐Trapping Structures for Ultrathin Silicon Photovoltaics

Cited by 29 publications

References 44 publications

Optimal-Enhanced Solar Cell Ultra-thinning with Broadband Nanophotonic Light Capture

Optimal-Enhanced Solar Cell Ultra-thinning with Broadband Nanophotonic Light Capture

Mismatched front and back gratings for optimum light trapping in ultra-thin crystalline silicon solar cells

Quasi‐Omnidirectional Ultrathin Silicon Solar Cells Realized by Industrially Compatible Processes

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