Arrays of nanoparticles exploited in light scattering applications commonly only feature either a periodic or a rather random arrangement of its constituents. For the periodic case, light scattering is mostly governed by the strong spatial correlations of the arrangement, expressed by the structure factor. For the random case, structural correlations cancel each other out and light scattering is mostly governed by the scattering properties of the individual scatterer, expressed by the form factor. In contrast to these extreme cases, it is shown here that hyperuniform disorder in self‐organized large‐area arrays of high refractive index nanodisks enables both structure and form factor to impact the resulting scattering pattern, offering novel means to tailor light scattering. The scattering response from the authors’ nearly hyperuniform interfaces can be exploited in a large variety of applications and constitutes a novel class of advanced optical materials.
We show that the anti-reflection performance of nano-particle arrays on top of solar cell stacks is related to two conditions: a high enough degree of discrete rotational symmetry of the array and the ability of the system to suppress cross-talk between the two handednesses (helicities) of the electromagnetic field upon light-matter interaction.For particle-lattice systems with high enough degree of discrete rotational symmetry 2π/n for n ≥ 3), our numerical studies link the suppression of backscattering to the ability of the system to avoid the mixing between the two helicity components of the incident field. In an exemplary design, we optimize an array of TiO 2 disks placed on top of a flat heterojunction solar cell stack and obtain a three-fold reduction of the current 1 arXiv:1902.07546v3 [physics.optics] 5 Jun 2019 loss due to reflection with respect to an optimized flat reference. We numerically analyze the helicity preservation properties of the system, and also show that a hexagonal array lattice, featuring a higher degree of discrete rotational symmetry, can improve over the anti-reflection performance of a square lattice. Importantly, the disks are introduced in an electrically decoupled manner such that the passivation and electric properties of the device are not disturbed. IntroductionMinimal reflection is an obvious design goal in solar cell technology which attracts much research attention. Different approaches to anti-reflection (AR) range from chemical texturing of the silicon waver 1,2 to sophisticated AR coatings 3-7 and plasmonic structures 8-10 .Recently, the use of arrays of dielectric nano-structures is being investigated as a possible avenue to improve AR properties of solar cells [11][12][13][14][15][16] . Due to the low profiles of the patterning nanostructures, this approach is suitable for ultra thin film solar cells. Clearly, understanding the underlying physical principles behind backscattering minimization is relevant for the AR aspect of solar cell design.Much of the nanophotonics research on backscattering minimization stems from the 1983 article of Kerker et al. 17 . This early work showed that a sphere whose relative electric permittivity and magnetic permeability are equal exhibits zero backscattering under plane wave illumination, i.e., there is no energy in the specular back reflection direction, independently of the polarization of the illuminating plane wave. Since then, the theoretical and experimental works on zero backscattering have been numerous, see e.g. Refs. 18-26. On the theoretical side, the relationship between electromagnetic duality symmetry and zero backscattering 18,20,27 has provided a new point of view on Kerker's result by connecting the backscattering suppression to a fundamental symmetry in electromagnetism. A system is symmetric under duality transformations 29 if and only if its electric and magnetic responses to incident radiation are equivalent. This equivalence connects directly to Kerker's = µ
A large variety of different strategies has been proposed as alternatives to random textures to improve light coupling into solar cells. While the understanding of dedicated nanophotonic systems deepens continuously, only a few of the proposed designs are industrially accepted due to a lack of scalability. In this Article, a tailored disordered arrangement of high-index dielectric submicron-sized titanium dioxide (TiO2) disks is experimentally exploited as an antireflective Huygens’ metasurface for standard heterojunction silicon solar cells. The disordered array is fabricated using a scalable bottom-up technique based on colloidal self-assembly that is applicable virtually irrespective of material or surface morphology of the device. We observe a broadband reduction of reflectance resulting in a relative improvement of a short-circuit current by 5.1% compared to a reference cell with an optimized flat antireflective indium tin oxide (ITO) layer. A theoretical model based on Born’s first approximation is proposed that links the current increase in the arrangement of disks expressed in terms of the structure factor S(q) of the disk array. Additionally, we discuss the optical performance of the metasurface within the framework of helicity preservation, which can be achieved at specific wavelengths for an isolated disk for illumination along the symmetry axis by tuning its dimensions. By comparison to a simulated periodic metasurface, we show that this framework is applicable in the case of the structure factor approaching zero and the disks’ arrangement becoming stealthy hyperuniform.
While various nanophotonic structures applicable to relatively thin crystalline silicon-based solar cells were proposed to ensure effective light in-coupling and light trapping in the absorber, it is of great importance to evaluate their performance on the solar module level under realistic irradiation conditions. Here, we analyze the annual energy yield of relatively thin (crystalline silicon (c-Si) wafer thickness between 5 μm and 80 μm) heterojunction (HJT) solar module architectures when optimized anti-reflective and light trapping titanium dioxide (TiO2) nanodisk square arrays are applied on the front and rear cell interfaces, respectively. Our numerical study shows that upon reducing c-Si wafer thickness down to 5 μm, the relative increase of the annual energy yield can go up to 23.3 %rel and 43.0 %rel for mono- and bifacial solar modules, respectively, when compared to the reference modules with flat optimized anti-reflective coatings of HJT solar cells.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.