Random versus periodic: Determining light trapping of randomly textured thin film solar cells by the superposition of periodic surface textures

Dewan, Rahul; Shrestha, Shailesh; Jovanov, Vladislav; Hüpkes, J.; Bittkau, Karsten; Knipp, Dietmar

doi:10.1016/j.solmat.2015.06.014

Cited by 31 publications

(27 citation statements)

References 36 publications

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“…However, it is important to distinguish between nanowires with diameters significantly larger than the optical wavelength and nanowires with diameters smaller than the optical wavelengths. For randomly arranged nanowires with large diameters, the quantum efficiency can be approximated by the superposition of periodic structures with different period [5]. Small changes of the diameter of the nanowires have only a small effect on the quantum efficiency.…”

Section: Solar Cells With Textured Silicon Absorbersmentioning

confidence: 99%

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Comparison of Light Trapping in Silicon Nanowire and Surface Textured Thin-Film Solar Cells

et al. 2017

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Abstract:The optics of axial silicon nanowire solar cells is investigated and compared to silicon thin-film solar cells with textured contact layers. The quantum efficiency and short circuit current density are calculated taking a device geometry into account, which can be fabricated by using standard semiconductor processing. The solar cells with textured absorber and textured contact layers provide a gain of short circuit current density of 4.4 mA/cm 2 and 6.1 mA/cm 2 compared to a solar cell on a flat substrate, respectively. The influence of the device dimensions on the quantum efficiency and short circuit current density will be discussed.

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Section: Solar Cells With Textured Silicon Absorbersmentioning

confidence: 99%

“…Experimentally, high conversion efficiencies have been achieved by texturing the contact layers of silicon solar cells [2][3][4][5][6][7][8][9]. The nanotextured contact layers reduce reflection losses and enhance the scattering and diffraction of light within the solar cells.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Light Trapping in Silicon Nanowire and Surface Textured Thin-Film Solar Cells

et al. 2017

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“…Periodic arrays of micro-cone textures were achieved by patterning sapphire substrates (PSS) [53] using a well-known thermally-reflowed photoresist and dry etching method in the lightemitting diode (LED) industry [44,45], as described in Section 3.1.1. Micro-cone textured P3H1.5 PSS, as shown in Figure 15 and described in Section 3.1.2, was used in this section with a fixed lateral period of 3 μm, a fixed height of 1.5 μm and thus a constant aspect ratio (H/P) of 0.5.…”

Section: Methodsmentioning

confidence: 99%

“…If both the periodic nanoscale and microscale structures have the same total diffraction efficiency, the nanoscale structures can provide higher diffraction efficiency at the high diffraction order than the microscale ones due to its lower number of diffraction orders. It is assumed that the randomly nanotextured surface can be approximated by the superposition of periodically sinusoidal/cosinusoidal nanotextured surfaces, which represent the Fourier decomposition of the surface [53]. In this case, a series of continuous diffraction peaks can be observed at each diffraction order for the randomly nanotextured BR, finally resulting in a smooth EQE curve in the relative solar cells.…”

Section: Mcps Brs For A-sige:h Solar Cellsmentioning

confidence: 99%

“…By the improvement of the extra light-trapping effect aroused by the random nanotexture, the absorption and EQE of the QCS/AZO-based solar cell were much enhanced. It is assumed that the randomly nanotextured surface can be approximated by periodically superposing sinusoidal/cosinusoidal nanotextured surfaces, which represent the Fourier decomposition of the surface [53]. From this point of view, the QCS can provide more guided mode resonances than the MCS or the randomly nanotextured sample for each wavelength, thus resulting in an enhanced absorption of the solar cells.…”

Section: Qcs Brs For A-sige:h Solar Cellsmentioning

confidence: 99%

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Photonic Structures for Light Trapping in Thin Film Silicon Solar Cells: Design and Experiment

et al. 2017

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Abstract:One of the foremost challenges in designing thin-film silicon solar cells (TFSC) is devising efficient light-trapping schemes due to the short optical path length imposed by the thin absorber thickness. The strategy relies on a combination of a high-performance back reflector and an optimized texture surface, which are commonly used to reflect and scatter light effectively within the absorption layer, respectively. In this paper, highly promising light-trapping structures based on a photonic crystal (PC) for TFSCs were investigated via simulation and experiment. Firstly, a highly-reflective one-dimensional photonic crystal (1D-PC) was designed and fabricated. Then, two types of 1D-PC-based back reflectors (BRs) were proposed: Flat 1D-PC with random-textured aluminum-doped zinc oxide (AZO) or random-textured 1D-PC with AZO. These two newly-designed BRs demonstrated not only high reflectivity and sufficient conductivity, but also a strong light scattering property, which made them efficient candidates as the electrical contact and back reflector since the intrinsic losses due to the surface plasmon modes of the rough metal BRs can be avoided. Secondly, conical two-dimensional photonic crystal (2D-PC)-based BRs were investigated and optimized for amorphous a-SiGe:H solar cells. The maximal absorption value can be obtained with an aspect ratio of 1/2 and a period of 0.75 µm. To improve the full-spectral optical properties of solar cells, a periodically-modulated PC back reflector was proposed and experimentally demonstrated in the a-SiGe:H solar cell. This periodically-modulated PC back reflector, also called the quasi-crystal structure (QCS), consists of a large periodic conical PC and a randomly-textured Ag layer with a feature size of 500-1000 nm. The large periodic conical PC enables conformal growth of the layer, while the small feature size of Ag can further enhance the light scattering. In summary, a comprehensive study of the design, simulation and fabrication of 1D-PC-and 2D-PC-based back reflectors for TFSCs was carried out. Total absorption and device performance enhancement were achieved with the novel PC light-trapping systems because of their high reflectivity or high scattering property. Further research is necessary to illuminate the optimal structure design of PC-based back reflectors and high solar cell efficiency.

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

Branham

Hsu

Yerci

et al. 2016

Advanced Optical Materials

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Random versus periodic: Determining light trapping of randomly textured thin film solar cells by the superposition of periodic surface textures

Cited by 31 publications

References 36 publications

Comparison of Light Trapping in Silicon Nanowire and Surface Textured Thin-Film Solar Cells

Comparison of Light Trapping in Silicon Nanowire and Surface Textured Thin-Film Solar Cells

Photonic Structures for Light Trapping in Thin Film Silicon Solar Cells: Design and Experiment

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

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