Hafnia-plugged microcavities for thermal stability of selective emitters

Lee, Heon-Ju; Smyth, Katherine; Bathurst, Stephen; Chou, Jeffrey B.; Ghebrebrhan, Michael; Joannopoulos, John D.; Saka, Nannaji; Kim, Sung Hoon

doi:10.1063/1.4811703

Cited by 34 publications

(31 citation statements)

References 20 publications

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“…[21] An approximate ≈8% drop in absorption is observed at higher frequencies above 3 eV due to the surface diffusion of the structure. The homologous temperatures of the furnace test for ruthenium, HfO 2 , and Al 2 O 3 are , , and , respectively, where diffusion effects are typically expected to be observed.…”

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confidence: 99%

“…[30] The same MDPhC sample measured in Figure 3(a) was then placed in a furnace at 1000°C for 24 hours in a 95% Ar and 5% H 2 environment and re-measured again as shown in Figure 3(c) where the cut-off absorption peaks remain high, thus demonstrating the high temperature structural robustness of the MDPhC. [21] An approximate ≈8% drop in absorption is observed at higher frequencies above 3 eV due to the surface diffusion of the structure. The homologous temperatures of the furnace test for ruthenium, HfO 2 , and Al 2 O 3 are , , and , respectively, where diffusion effects are typically expected to be observed.…”

mentioning

confidence: 99%

“…Furnace tests at 1000°C for 24 hours show a robust optical performance due to its fully encapsulated design which helps to retain the metal cavity shapes at high temperatures. [21] Finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA) based simulations indicate that the broadband absorption is due to a high density of hybrid cavity and surface plasmon modes overlaped with an anti-reflection coating (ARC).…”

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confidence: 99%

“…[21] Furthur study of possible adhesion layers, such as TiN, is underway to prevent delamination at higher temperatures and to test the suppressed surface diffusion. [14] Despite the surface diffusion of Ru, the HfO 2 , and Al 2 O 3 act as a mold to retain the shape of the metallic cavities during the diffusion process.…”

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confidence: 99%

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Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Chou¹,

Yeng²,

Lee³

et al. 2014

Advanced Materials

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128

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The selective absorption of sunlight plays a critical role in solar-thermophotovoltaic (STPV) energy conversion by tailoring both the absorption and emission spectrums for efficient solar-thermal-electrical energy conversion. [1][2][3][4][5][6][7] By selectively absorbing solar energy while suppressing long wavelength emission, optimal solar-thermal energy conversion can be achieved. In practical STPV systems, selective absorbers must simultaneously contain optical, manufacturing, and reliability properties. Previous efforts have typically focused only on a subset of these requirements. In this communication, we present our solution which contains all of the ideal properties of a selective absorber for large-scale and efficient solar energy conversion.The effective absorption of solar energy requires selective absorption across the solar spectrum, high temperature reliability, omnidirectional absorption, and wafer-scale fabrication 2 for mass scalability. Recent developments of metal based selective absorbers have demonstrated 1D, 2D, and 3D metallic photonic crystal structures capable of tailoring the absorption spectrum. [2,[8][9][10][11][12][13][14] One dimensional metal dielectric stacks have demonstrated promising solar absorbing properties but are unstable at temperatures greater than approximately 600°C. [13] In particular, two-dimensional metallic air photonic crystals (MAPhC) have been shown to selectively absorb light in the near-IR via cavity modes and withstand high temperatures greater than 1000°C; however, the acceptance angle is limited to ±30°, and the absorption in the visible spectrum is limited due to diffraction. [2,11,15] Metamaterial and plasmonic based absorbers have demonstrated wide angle absorption due to their subwavelength periodic structures; however high temperature stability and wafer-scalefabrication have yet to be shown. [1,3,[16][17][18][19] Here we present our 2D metallic dielectric photonic crystal (MDPhC) structure, which simultaneously demonstrates broadband (visible to near-IR) absorption, omnidirectional absorption, wafer-scale fabrication, and high temperature robustness.[20] The wafer-scale fabricated MDPhC has a measured absorption of 85% for photon energies and an absorption below 10% for . Angled measurements show existence of the cavity modes for angles up to 70° from normal. Furnace tests at 1000°C for 24 hours show a robust optical performance due to its fully encapsulated design which helps to retain the metal cavity shapes at high temperatures. [21] Finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA) based simulations indicate that the broadband absorption is due to a high density of hybrid cavity and surface plasmon modes overlaped with an anti-reflection coating (ARC).A schematic image of the MDPhC is shown in Figure 1(a) and (b). The MDPhC utilizes cut-off frequencies of cavity modes to tailor the absorption. Since the cut-off frequency is dependent on the geometry of the cavities, the absorption spectrum can be tuned by simply modif...

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Chou¹,

Yeng²,

Lee³

et al. 2014

Advanced Materials

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128

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“…All-metallic nanostructures can degrade at temperatures much lower than the bulk metal melting point. Experiments have shown that nano-and microstructures degrade under high temperature exposure for long times [148][149][150][151]. Different mechanisms can lead to such degradation, including chemical reactions [33,70,150], recrystallization [34,148] and surface diffusion [152,153].…”

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confidence: 99%

Solar thermophotovoltaics: reshaping the solar spectrum

et al. 2016

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Abstract:Recently, there has been increasing interest in utilizing solar thermophotovoltaics (STPV) to convert sunlight into electricity, given their potential to exceed the Shockley-Queisser limit. Encouragingly, there have also been several recent demonstrations of improved systemlevel efficiency as high as 6.2%. In this work, we review prior work in the field, with particular emphasis on the role of several key principles in their experimental operation, performance, and reliability. In particular, for the problem of designing selective solar absorbers, we consider the trade-off between solar absorption and thermal losses, particularly radiative and convective mechanisms. For the selective thermal emitters, we consider the tradeoff between emission at critical wavelengths and parasitic losses. Then for the thermophotovoltaic (TPV) diodes, we consider the trade-off between increasing the potential short-circuit current, and maintaining a reasonable opencircuit voltage. This treatment parallels the historic development of the field, but also connects early insights with recent developments in adjacent fields. With these various components connecting in multiple ways, a system-level end-to-end modeling approach is necessary for a comprehensive understanding and appropriate improvement of STPV systems. This approach will ultimately allow researchers to design STPV systems capable of exceeding recently demonstrated efficiency values.

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Thermoplasmonics in Solar Energy Conversion: Materials, Nanostructured Designs, and Applications

Yang

Wang

et al. 2022

Advanced Materials

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The indispensable requirement for sustainable development of human society has forced almost all countries to seek highly efficient and cost‐effective ways to harvest and convert solar energy. Though continuous progress has advanced, it remains a daunting challenge to achieve full‐spectrum solar absorption and maximize the conversion efficiency of sunlight. Recently, thermoplasmonics has emerged as a promising solution, which involves several beneficial effects including enhanced light absorption and scattering, generation and relaxation of hot carriers, as well as localized/collective heating, offering tremendous opportunities for optimized energy conversion. Besides, all these functionalities can be tailored via elaborated designs of materials and nanostructures. Here, first the fundamental physics governing thermoplasmonics is presented and then the strategies for both material selection and nanostructured designs toward more efficient energy conversion are summarized. Based on this, recent progress in thermoplasmonic applications including solar evaporation, photothermal chemistry, and thermophotovoltaic is reviewed. Finally, the corresponding challenges and prospects are discussed.

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Hafnia-plugged microcavities for thermal stability of selective emitters

Cited by 34 publications

References 20 publications

Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Solar thermophotovoltaics: reshaping the solar spectrum

Thermoplasmonics in Solar Energy Conversion: Materials, Nanostructured Designs, and Applications

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