Browsing by Author "Subanya, S"

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    SENSITIVITY ENHANCEMENT OF SPR SENSOR USING NI/ZNO NANOCOMPOSITE ASSISTED WITH GRAPHENE
    (Springer Link, 2021-11-20) Maheswari, P; Subanya, S; Nisha, A; Ravi, V; Rajesh, K B; Rajan, Jha
    In this paper the performance of surface plasmon resonance (SPR) biosensor in modified kretchmann configuration utilizing nanocomposite layer consisting of nickel and ZnO as plasmonic material is analyzed numerically using N-layered transfer matrix method. The performance parameters of proposed sensor are investigated in terms of sensitivity (S), detection accuracy (DA) and quality factor (QF) at the operating wavelength of 633 nm. Parameters such as the influence of refractive index of the coupling prism, the thickness of the nanocomposite layer, the constituent components of the nanocomposite layer and the number of the graphene layers over the nanocomposite layer are investigated and the optimal values are identified to achieve maximum sensitivity. The numerical results shows that upon suitable optimization of the above parameters, the proposed SPR sensor is found to exhibits sensitivity as high as 378.34°/RIU with quality factor (QF) as 39.78/RIU. Compared with existing similar type of SPR sensors, the proposed sensor exhibits higher sensitivity, lower FWHM and better quality factor which would make our design to have more applications in the field of biosensor.
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    STRUCTURAL AND OPTICAL CHARACTERIZATION OF PURE AND STARCH-CAPPED ZNO QUANTUM DOTS AND THEIR PHOTOCATALYTIC ACTIVITY
    (SpringerLink, 2015) Vidhya, K; Saravanan, M; Bhoopathi, G; Devarajan, V P; Subanya, S
    Among the different types of metal oxides, zinc oxide (ZnO) is a most commonly used metal oxide in a broad variety of applications. In the present investigation, a modified green synthesis route was used to synthesize pure and starch-capped ZnO (ZnO/starch) quantum dots (QDs) and studied their structural and optical characteristics. In this study, hexagonal crystal structure was observed in both pure and ZnO/starch QDs using X-ray diffraction technique. A spherical-shaped surface morphology was found with the size of 5–10 nm using transmission electron microscope technique. The interaction between ZnO QDs and starch molecules was proved via Fourier infra-red spectrometer technique. On the other hand, their fluorescence behaviors were investigated using photoluminescence technique, in that the ZnO/starch QDs showed an enhanced emission behavior when compared to the pure ZnO QDs. Further, the solar photocatalytic activity of both the ZnO QDs was examined with the dye Rhodamine B (RhB) at the end of 30, 60, 90, and 120 min. In this, ZnO/ starch QDs show a good and more decomposition of RhB than pure ZnO QDs. Collectively, in the present study, green synthesis route produced an efficient QDs (pure and ZnO/starch) and it will be very useful for many other QDs. The ZnO/starch QDs are suitable for decomposing the RhB and other toxic organic dyes.