Ultralow Index SiO<sub>2</sub> Antireflection Coatings Produced via Magnetron Sputtering

Ruud, Christian J.; Cleri, Angela; Maria, Jon‐Paul; Giebink, Noel C.

doi:10.1021/acs.nanolett.2c01945

Cited by 19 publications

(9 citation statements)

References 22 publications

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“…Prior studies have shown that incorporating a refractive index gradient across the thickness of a film is an efficient method to produce a broadband ARC. ,, To produce such a structure, we infiltrate subsaturating amounts of PMMA into the disordered packings of hollow NPs. To control the extent of UCaRI, we define the volume fraction of PMMA in each film as ϕ PMMA = h PMMA h NP , where h PMMA and h NP are the thicknesses of the PMMA layer and hollow silica NP layer, respectively.…”

Section: Resultsmentioning

confidence: 99%

Dual Porosity-Enhanced Antireflection Coatings with Continuous Gradient

Hwang,

Nam,

Lee

2023

ACS Appl. Mater. Interfaces

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The incorporation of porous structures into films and coatings can transform their properties for applications in optics, separation, electronics, and energy generation and storage. Packing nanoparticles (NPs) is a versatile approach for fabricating nanoporous films with a tunable structure and properties. The mechanical fragility of NP packing-based films and coatings, however, significantly impedes their widespread utilization. Although infiltrating a polymer into the interstices of these NP packings has been shown to enhance their mechanical durability, this method completely eliminates the porosity of the structures, compromising their properties and functionality. This study presents a new approach to fabricate highly loaded porous nanocomposite films with a gradient in the refractive index by infiltrating subsaturating amounts of poly(methyl methacrylate) (PMMA) into disordered packings of hollow silica NPs. We demonstrate that dual porosity is a critical feature that enhances their antireflection (AR) and mechanical properties. The hollow cores of NPs prevent a substantial increase in the refractive index of the resulting films. Moreover, the interparticle voids allow for mechanical reinforcement to occur when the NP packings are infiltrated with PMMA, making them even more suitable for AR coatings. The refractive index and gradient across the nanocomposites can be tailored by adjusting the amount of PMMA infiltrated into the NP packing, the shape of hollow NPs, and the annealing time. The nanocomposite coatings with a continuous gradient in refractive index exhibit excellent AR properties and enhanced mechanical durability. Combined with the unique structural tunability afforded by the dual porosity, this approach provides a scalable and effective way to create robust and graded nanoporous structures for various applications.

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Section: Resultsmentioning

confidence: 99%

Dual Porosity-Enhanced Antireflection Coatings with Continuous Gradient

Hwang,

Nam,

Lee

2023

ACS Appl. Mater. Interfaces

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“…Compared with atomic layer deposition methods, magnetron sputtering has a faster preparation speed and larger preparation area, which is necessary for commercial applications. In addition, this process does not require a high-temperature annealing step in comparison to alternative method of producing films with low refractive index using the sputtering–annealing–etching process . This significantly reduces the cost of production and allows the process to rapidly produce ultralow refractive coatings on optical glasses with lower melting points .…”

Section: Resultsmentioning

confidence: 99%

“…In addition, this process does not require a high-temperature annealing step in comparison to alternative method of producing films with low refractive index using the sputtering−annealing−etching process. 37 This significantly reduces the cost of production and allows the process to rapidly produce ultralow refractive coatings on optical glasses with lower melting points. 38 However, similar to other methods for preparing low refractive index coatings using increased porosity, the NS coatings prepared by this process do not perform well enough in terms of mechanical properties, and the test results on the hardness of the NS films are shown in Figure S6, Supporting Information.…”

Section: ■ Introductionmentioning

confidence: 99%

Nanoporous Silicon Dioxide Films for Large Area and Low-Cost Fabrication of Ultra-Low Refractive Index Coatings

Wu,

Liu,

Zhu

et al. 2023

ACS Appl. Nano Mater.

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Ultralow refractive index films can reduce the reflection loss of light propagating between different media, which is crucial for enhancing the performance and efficiency of optical components. This work presents an approach to the production of ultralow refractive index thin films based on magnetron cosputtering and subsequent selective chemical etching, where a nanoporous silicon dioxide film with a variable refractive index is fabricated by the sacrificial method of forming random holes with a size less than 100 nm. The effective refractive index can be adjusted from 1.1 to 1.46 by simply controlling the sputtering power ratio of the silicon target to the aluminum target. The antireflection properties of ultralow refractive index films have been verified, and their process reproducibility and environmental reliability have been evaluated. The results demonstrate the efficacy of this technique as a viable solution for large-area, low-cost, and high-performance fabrication of ultralow refractive index coatings, which have great potential for the preparation of industrial-scale antireflective films.

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“…In order to overcome this problem, one can consider another light absorbing scheme, i.e., the design of graded-refractive-index (GRI) thin dielectric layers on the metallic mirror. [12,13] However, it is a great challenge to design such SMAs within a short time. Conventionally, it relies on broadband impedance matching in the entire solar spectrum, and this demands numerous experiments, optical simulations, and some classical algorithms to optimize layer thicknesses.…”

Section: Introductionmentioning

confidence: 99%

Broadband Solar Metamaterial Absorbers Empowered by Transformer‐Based Deep Learning

Chen

Gao

et al. 2023

Advanced Science

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The research of metamaterial shows great potential in the field of solar energy harvesting. In the past decade, the design of broadband solar metamaterial absorber (SMA) has attracted a surge of interest. The conventional design typically requires brute-force optimizations with a huge sampling space of structure parameters. Very recently, deep learning (DL) has provided a promising way in metamaterial design, but its application on SMA development is barely reported due to the complicated features of broadband spectrum. Here, this work develops the DL model based on metamaterial spectrum transformer (MST) for the powerful design of high-performance SMAs. The MST divides the optical spectrum of metamaterial into N patches, which overcomes the severe problem of overfitting in traditional DL and boosts the learning capability significantly. A flexible design tool based on free customer definition is developed to facilitate the real-time on-demand design of metamaterials with various optical functions. The scheme is applied to the design and fabrication of SMAs with graded-refractive-index nanostructures. They demonstrate the high average absorptance of 94% in a broad solar spectrum and exhibit exceptional advantages over many state-of-the-art counterparts. The outdoor testing implies the high-efficiency energy collection of about 1061 kW h m −2 from solar radiation annually. This work paves a way for the rapid smart design of SMA, and will also provide a real-time developing tool for many other metamaterials and metadevices.

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Ultralow Index SiO₂ Antireflection Coatings Produced via Magnetron Sputtering

Cited by 19 publications

References 22 publications

Dual Porosity-Enhanced Antireflection Coatings with Continuous Gradient

Dual Porosity-Enhanced Antireflection Coatings with Continuous Gradient

Nanoporous Silicon Dioxide Films for Large Area and Low-Cost Fabrication of Ultra-Low Refractive Index Coatings

Broadband Solar Metamaterial Absorbers Empowered by Transformer‐Based Deep Learning

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Ultralow Index SiO2 Antireflection Coatings Produced via Magnetron Sputtering

Cited by 19 publications

References 22 publications

Dual Porosity-Enhanced Antireflection Coatings with Continuous Gradient

Dual Porosity-Enhanced Antireflection Coatings with Continuous Gradient

Nanoporous Silicon Dioxide Films for Large Area and Low-Cost Fabrication of Ultra-Low Refractive Index Coatings

Broadband Solar Metamaterial Absorbers Empowered by Transformer‐Based Deep Learning

Contact Info

Product

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Ultralow Index SiO₂ Antireflection Coatings Produced via Magnetron Sputtering