Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure
Diamond properties down to the quantum-size region are still poorly understood. High-pressure high-temperature (HPHT) synthesis from chloroadamantane molecules allows precise control of nanodiamond size. Thermal stability and optical properties of nanodiamonds with sizes spanning range from <1 to...
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MDPI AG
2022-01-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/3/351 |
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| author | Evgeny Ekimov Andrey A. Shiryaev Yuriy Grigoriev Alexey Averin Ekaterina Shagieva Stepan Stehlik Mikhail Kondrin |
| author_facet | Evgeny Ekimov Andrey A. Shiryaev Yuriy Grigoriev Alexey Averin Ekaterina Shagieva Stepan Stehlik Mikhail Kondrin |
| author_sort | Evgeny Ekimov |
| collection | DOAJ |
| description | Diamond properties down to the quantum-size region are still poorly understood. High-pressure high-temperature (HPHT) synthesis from chloroadamantane molecules allows precise control of nanodiamond size. Thermal stability and optical properties of nanodiamonds with sizes spanning range from <1 to 8 nm are investigated. It is shown that the existing hypothesis about enhanced thermal stability of nanodiamonds smaller than 2 nm is incorrect. The most striking feature in IR absorption of these samples is the appearance of an enhanced transmission band near the diamond Raman mode (1332 cm<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>). Following the previously proposed explanation, we attribute this phenomenon to the Fano effect caused by resonance of the diamond Raman mode with continuum of conductive surface states. We assume that these surface states may be formed by reconstruction of broken bonds on the nanodiamond surfaces. This effect is also responsible for the observed asymmetry of Raman scattering peak. The mechanism of nanodiamond formation in HPHT synthesis is proposed, explaining peculiarities of their structure and properties. |
| first_indexed | 2024-03-09T23:25:34Z |
| format | Article |
| id | doaj.art-9fbf679db7f64c0c959fae56878725b6 |
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| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T23:25:34Z |
| publishDate | 2022-01-01 |
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| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-9fbf679db7f64c0c959fae56878725b62023-11-23T17:19:19ZengMDPI AGNanomaterials2079-49912022-01-0112335110.3390/nano12030351Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High PressureEvgeny Ekimov0Andrey A. Shiryaev1Yuriy Grigoriev2Alexey Averin3Ekaterina Shagieva4Stepan Stehlik5Mikhail Kondrin6Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, 108840 Moscow, RussiaFrumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, RussiaShubnikov Institute of Crystallography of Federal Scientific Research Centre, Crystallography and Photonics’, Russian Academy of Sciences, 119333 Moscow, RussiaFrumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, RussiaInstitute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague, Czech RepublicInstitute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague, Czech RepublicVereshchagin Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, 108840 Moscow, RussiaDiamond properties down to the quantum-size region are still poorly understood. High-pressure high-temperature (HPHT) synthesis from chloroadamantane molecules allows precise control of nanodiamond size. Thermal stability and optical properties of nanodiamonds with sizes spanning range from <1 to 8 nm are investigated. It is shown that the existing hypothesis about enhanced thermal stability of nanodiamonds smaller than 2 nm is incorrect. The most striking feature in IR absorption of these samples is the appearance of an enhanced transmission band near the diamond Raman mode (1332 cm<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>). Following the previously proposed explanation, we attribute this phenomenon to the Fano effect caused by resonance of the diamond Raman mode with continuum of conductive surface states. We assume that these surface states may be formed by reconstruction of broken bonds on the nanodiamond surfaces. This effect is also responsible for the observed asymmetry of Raman scattering peak. The mechanism of nanodiamond formation in HPHT synthesis is proposed, explaining peculiarities of their structure and properties.https://www.mdpi.com/2079-4991/12/3/351nanodiamondFourier-transformed infrared spectraRaman scatteringhigh-pressure high-temperature synthesisFano effectchloroadamantane |
| spellingShingle | Evgeny Ekimov Andrey A. Shiryaev Yuriy Grigoriev Alexey Averin Ekaterina Shagieva Stepan Stehlik Mikhail Kondrin Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure Nanomaterials nanodiamond Fourier-transformed infrared spectra Raman scattering high-pressure high-temperature synthesis Fano effect chloroadamantane |
| title | Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure |
| title_full | Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure |
| title_fullStr | Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure |
| title_full_unstemmed | Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure |
| title_short | Size-Dependent Thermal Stability and Optical Properties of Ultra-Small Nanodiamonds Synthesized under High Pressure |
| title_sort | size dependent thermal stability and optical properties of ultra small nanodiamonds synthesized under high pressure |
| topic | nanodiamond Fourier-transformed infrared spectra Raman scattering high-pressure high-temperature synthesis Fano effect chloroadamantane |
| url | https://www.mdpi.com/2079-4991/12/3/351 |
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