Matrix formalism for light propagation and absorption in thick textured optical sheets

Eisenlohr, Johannes; Tucher, Nico; Höhn, Oliver; Hauser, Hubert; Peters, Ian Marius; Kiefel, Peter; Goldschmidt, Jan Christoph; Bläsi, Bénédikt

doi:10.1364/oe.23.00a502

Cited by 40 publications

(26 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Assuming a sphere grating rear side, the current of the Si bottom cell can be increased by 1.1 mA/cm 2 . The current density increase here is slightly lower due to the higher cell thickness and was estimated by simulations using a matrix based formalism that includes a wave optical description of the sphere grating [31]. Thus the silicon bottom cell would not limit the current anymore and the efficiency of the total device would be increased from 25.2% to 27.6% (2.4% absolute), demonstrating again the potential benefit of near infrared light trapping in Si-based tandem devices.…”

Section: Iii/v On Siliconmentioning

confidence: 75%

Rear side sphere gratings for improved light trapping in crystalline silicon single junction and silicon-based tandem solar cells

Eisenlohr

Lee

Benick

et al. 2015

Solar Energy Materials and Solar Cells

Self Cite

View full text Add to dashboard Cite

Rear side hexagonal sphere gratings are demonstrated as diffractive structures that enhance the light path length in the near infrared, where crystalline silicon solar cells suffer from weak absorption. Moreover, the rear side sphere grating can be added behind a solar cell with flat rear surface, giving an “electrically flat but optically rough” device with high efficiency potential. Here, a thin passivating tunnel-contact layer electrically separates the sphere grating from the cell's base. Solar cells with the rear side sphere grating have obtained a VOC of up to 710 mV and a FF of up to 81.9%. External quantum efficiency measurements show a current density gain of 1.4 mA/cm2 due to the sphere grating. This leads to an overall efficiency of up to 22.1% for the solar cells with planar front side and rear side sphere grating. Estimates for perovskite–silicon and III/V-silicon tandem devices show that the efficiency of tandems can be enhanced by up to 2.4% absolute with a sphere grating on the rear side. Thus, sphere gratings could improve Si-based tandem devices that are limited due to a low current in the Si bottom cell

show abstract

Section: Iii/v On Siliconmentioning

confidence: 75%

Rear side sphere gratings for improved light trapping in crystalline silicon single junction and silicon-based tandem solar cells

Eisenlohr

Lee

Benick

et al. 2015

Solar Energy Materials and Solar Cells

Self Cite

View full text Add to dashboard Cite

show abstract

“…Currently, the authors are working on a theoretical approach that allows to efficiently simulate combinations of textures in the range of several microns with ones lying in the wave optical regime and thus estimate the efficiency potential of such concepts. 21 Furthermore, this study combined photolithography with NIL processes in order to integrate multiple features into the etching mask design. In this context, master structures containing periodic features for the honeycomb texturing as well as contact grid geometries were realized and these features were replicated via NIL and transferred into silicon using plasma etching.…”

Section: Discussionmentioning

confidence: 99%

Development of nanoimprint processes for photovoltaic applications

Hauser

Tucher

Tokai

et al. 2015

J. Micro/Nanolith. MEMS MOEMS

Self Cite

View full text Add to dashboard Cite

Abstract. Due to its high resolution and applicability for large area patterning, nanoimprint lithography (NIL) is a promising technology for photovoltaic (PV) applications. However, a successful industrial application of NIL processes is only possible if large-area processing on thin, brittle, and potentially rough substrates can be achieved in a high-throughput process. The development of NIL processes using the SmartNIL technology from EV Group with a focus on PV applications is described. The authors applied this tooling to realize a honeycomb texture (8 μm period) on the front side of multicrystalline silicon solar cells, leading to an improvement in optical efficiency of 7% relative and a total efficiency gain of 0.5% absolute compared to the industrial standard texture (isotexture). On the rear side of monocrystalline silicon solar cells, the authors realized diffraction gratings to make use of light trapping effects. An absorption enhancement of up to 35% absolute at a wavelength of 1100 nm is demonstrated. Furthermore, photolithography was combined with NIL processes to introduce features for metal contacts into honeycomb master structures, which were initially realized using interference lithography. As a final application, the authors investigated the realization of very fine contact fingers with prismatic shape in order to minimize reflection losses.

show abstract

“…A matrix formalism is employed in analogy to the computation of scattering on stacks of clear layers [22]. Forward and backward reflection and transmission R f f , T f b , T b f , R bb form the four components of the BSDF (Table 1) and are each represented as a matrix of m incident and n outgoing directions [23,24]. Table 1.…”

Section: Computational Combination Of Bidirectional Scattering Distrimentioning

confidence: 99%

Computational Combination of the Optical Properties of Fenestration Layers at High Directional Resolution

Grobe

2017

Buildings

View full text Add to dashboard Cite

Abstract:Complex fenestration systems typically comprise co-planar, clear and scattering layers. As there are many ways to combine layers in fenestration systems, a common approach in building simulation is to store optical properties separate for each layer. System properties are then computed employing a fast matrix formalism, often based on a directional basis devised by JHKlems comprising 145 incident and 145 outgoing directions. While this low directional resolution is found sufficient to predict illuminance and solar gains, it is too coarse to replicate the effects of directionality in the generation of imagery. For increased accuracy, a modification of the matrix formalism is proposed. The tensor-tree format of RADIANCE, employing an algorithm subdividing the hemisphere at variable resolutions, replaces the directional basis. The utilization of the tensor-tree with interfaces to simulation software allows sharing and re-use of data. The light scattering properties of two exemplary fenestration systems as computed employing the matrix formalism at variable resolution show good accordance with the results of ray-tracing. Computation times are reduced to 0.4% to 2.5% compared to ray-tracing through co-planar layers. Imagery computed employing the method illustrates the effect of directional resolution. The method is supposed to foster research in the field of daylighting, as well as applications in planning and design.

show abstract

Matrix formalism for light propagation and absorption in thick textured optical sheets

Cited by 40 publications

References 17 publications

Rear side sphere gratings for improved light trapping in crystalline silicon single junction and silicon-based tandem solar cells

Rear side sphere gratings for improved light trapping in crystalline silicon single junction and silicon-based tandem solar cells

Development of nanoimprint processes for photovoltaic applications

Computational Combination of the Optical Properties of Fenestration Layers at High Directional Resolution

Contact Info

Product

Resources

About