Random pyramidal texture modelling

Rodríguez, José María Fernández

doi:10.1016/s0927-0248(96)00040-2

Cited by 40 publications

(20 citation statements)

References 3 publications

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“…Note that Lambertian structures using surfaces engraved with large motifs are widely used in the industry, for instance, anisotropically etched ͑1,0,0͒ crystals follow accurately the Lambertian behavior. 17,18 According to this concept the theoretical limit of confinement is C I =4n 2 , independently of wavelength and the illumination bundle ͑assuming all directions within the critical angle are allowed to escape͒. For the value used of n = ͱ 11, this gives C I = 44.…”

Section: Discussionmentioning

confidence: 99%

Light intensity enhancement by diffracting structures in solar cells

Tobias

Ĺuque

Martı́

2008

Journal of Applied Physics

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A simplified three-dimensional study is presented of the light confinement, that is, of the enhancement of the Poynting vector of the electromagnetic radiation of the light inside a solar cell absorbing the light weakly when diffracting structures are used. The model is based on the theory of periodic radiation arrays and is easily applied to one-and two-dimensional diffraction gratings. Realistically wide illumination bundles are considered. The extended nature of illumination severely limits the enhancement capabilities of diffraction structures. Results are compared to those of the more widely used Lambertian light confinement.

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Section: Discussionmentioning

confidence: 99%

Light intensity enhancement by diffracting structures in solar cells

Tobias

Ĺuque

Martı́

2008

Journal of Applied Physics

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“…For example, the loss mechanisms for incident solar photons include reflection, contact shadowing, a) absorption in barrier layers and by free-carriers, and transmission through the junction. Of these losses, reflection can be significantly reduced using anti-refection coatings 14 and textured surfaces, 4,15 contact shadowing can be minimized or eliminated by using transparent 16 or backside contacts, 17 and parasitic absorption can be minimized using widebandgap barriers and optimal doping profiles in the junction. Conversely, transmission losses are inherent to photovoltaic solar cells and strongly depend on the optical properties of the junction materials.…”

Section: Fundamental Loss Mechanisms In Solar Cellsmentioning

confidence: 99%

A semi-analytical model for semiconductor solar cells

Ding

Johnson

et al. 2011

Journal of Applied Physics

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A semi-analytical model is constructed for single- and multi-junction solar cells. This model incorporates the key performance aspects of practical devices, including nonradiative recombination, photon recycling within a given junction, spontaneous emission coupling between junctions, and non-step-like absorptance and emittance with below-bandgap tail absorption. Four typical planar structures with the combinations of a smooth/textured top surface and an absorbing/reflecting substrate (or backside surface) are investigated, through which the extracted power and four types of fundamental loss mechanisms, transmission, thermalization, spatial-relaxation, and recombination loss are analyzed for both single- and multi-junction solar cells. The below-bandgap tail absorption increases the short-circuit current but decreases the output and open-circuit voltage. Using a straightforward formulism this model provides the initial design parameters and the achievable efficiencies for both single- and multiple-junction solar cells over a wide range of material quality. The achievable efficiency limits calculated using the best reported materials and AM1.5 G one sun for GaAs and Si single-junction solar cells are, respectively, 27.4 and 21.1% for semiconductor slabs with a flat surface and a non-reflecting index-matched absorbing substrate, and 30.8 and 26.4% for semiconductor slabs with a textured surface and an ideal 100% reflecting backside surface. Two important design rules for both single- and multi-junction solar cells are established: i) the optimal junction thickness decreases and the optimal bandgap energy increases when nonradiative recombination increases; and ii) the optimal junction thickness increases and the optimal bandgap energy decreases for higher solar concentrations.

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“…There have been great efforts to form upright pyramid geometry, especially in Si solar cell technologies [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Viewing Angle Direction Brightness-Enhancement Optical Films using Surface Textured Silicon Wafers

Jang

Shim

Lee

et al. 2014

Journal of the Optical Society of Korea

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We demonstrate a low-cost, superbly efficient way of etching for the nano-, and micro-sized pyramid patterns on (100)-oriented Si wafer surfaces for use as a patterned master. We show a way of producing functional optical films for the viewing angle direction brightness-enhancement of Lambertian LED (light emitting diode)/OLED (organic light emitting diode) planar lighting applications. An optimally formulated KOH (Potassium hydroxide) wet etching process enabled random-positioned, and random size-distributed (within a certain size range) pyramid patterns to be developed over the entire (100) silicon wafer substrates up to 8" and a simple replication process of master patterns onto the PC (poly-carbonate) and PMMA (polymethyl methacrylate) films were performed. Haze ratio values were measured for several film samples exhibiting excellent values over 90% suitable for LED/OLED lighting purposes. Brightness was also improved by 13~14% toward the viewing angle direction. Computational simulations using LightTools™ were also carried out and turned out to be in strong agreement with experimental data. Finally, we could check the feasibility of fabricating low-cost, large area, high performance optical films for commercialization.

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Random pyramidal texture modelling

Cited by 40 publications

References 3 publications

Light intensity enhancement by diffracting structures in solar cells

Light intensity enhancement by diffracting structures in solar cells

A semi-analytical model for semiconductor solar cells

Fabrication of Viewing Angle Direction Brightness-Enhancement Optical Films using Surface Textured Silicon Wafers

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