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8. Cost-effective Green Synthesis of Boron rich Carbide Coatings for IR Windows and Night Vision OpticsMohanachandran Nair Sindhu Swapna, 2020, izvirni znanstveni članek Opis: The increasing demand for infrared (IR) window materials for various applications in optical imaging systems necessitates the development of cost-effective green techniques. Herein, the synthesis of refractory boron carbide (BC) using castor oil, as carbon precursor, and the preparation of IR transparent films by thermal vapor deposition technique is reported. Films are prepared with 1:3, 1:4, and 1:5 ratios of boric acid and castor oil, respectively. The X-ray diffraction (XRD) and Fourier-transform IR (FTIR) analyses reveal the structure of films prepared to be BC. The morphology of the films is analyzed by the atomic force microscopy (AFM) technique, and its dependence on precursor’s ratio is also studied. The spectroscopic characterization by the ultraviolet–visible–near IR (UV–vis–NIR) transmittance study reveals the potential of the films for IR window applications. The bandgap energy of the BC films determined from the Tauc plot yields a value of 2.33 eV. The absorption coefficient, extinction coefficient, refractive index, dissipation factor, and optical conductivity are also studied from the reflectance and transmittance data.
Ključne besede: Green Synthesis, Boron rich Carbide, coatings, IR Windows
Objavljeno v RUNG: 05.07.2022; Ogledov: 1063; Prenosov: 0
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9. Boron carbide Nanowires from castor oil for optronic applications: A low-temperature greener approachMohanachandran Nair Sindhu Swapna, 2021, izvirni znanstveni članek Opis: The development of one-dimensional nanostructures has revolutionized electronic and photonic industries because of their unique properties. The present paper reports the low-temperature green synthesis of boron carbide nanowires, of diameter 14 nm and length 2 lm, by the condensation method using castor oil as the carbon precursor. The nanowires synthesized exhibit beaded chain morphology, and bandgap energy of 2.08 eV revealed through the Tauc plot analysis. The structure of boron carbide nanowires is revealed by micro-Raman, Fourier transform infrared spectroscopic, and X-ray diffraction analyses. The thermogravimetric analysis of the sample reveals the excellent thermal stability. The photoluminescence study reveals the nanowire’s blue light emission capability under ultraviolet excitation, which is substantiated by the CIE plot suggesting its potential in photonic applications.
Ključne besede: Boron carbide, Nanowires, castor oil, green synthesis
Objavljeno v RUNG: 04.07.2022; Ogledov: 1063; Prenosov: 0
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10. RF sputtered boron carbide thin film for UVB and UVC shielding: A greener approachMohanachandran Nair Sindhu Swapna, 2022, izvirni znanstveni članek Opis: The paper reports the development of RF sputtered boron carbide coatings as refractory and UV-shielder for high-temperature goggles and spacecraft applications. The advancement in the design and fabrication of machinery and UV optics necessitates the development of low-cost, eco-friendly preparation of wear-resistant refractory coatings with strong absorption in the UV region.
Boron carbide coatings have proven their potential as abrasives besides their electronic applications. In the present work, boron carbide coatings are prepared by RF sputtering technique using the target prepared by low-temperature hydrothermal synthesis using cotton as carbon precursor. The sample synthesized and the film prepared are subjected to structure, morphological, and optical characterizations. The X-ray diffraction, Fourier transform infrared,
micro-Raman and X-ray photoelectron studies confirm the formation of boron-rich boron carbide with the thermal stability of 87% at 800 C, revealed through the thermogravimetric analysis. The Tauc plot analysis gives the bandgap energy of the boron carbide target and film as 2.66 eV and 2.70 eV, respectively. The UV–Vis spectroscopic study also reveals the potential of the sample and the
film in blocking UVB and UVC. The CIE plot from the photoluminescence study suggests the sample to be a blue light emitter.
Ključne besede: Boron carbide, RF sputtering, uv shielding, thin films
Objavljeno v RUNG: 30.06.2022; Ogledov: 1088; Prenosov: 0
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