Browsing by Author "Nilanjan Basu"

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Label-Free Fluorometric Detection of Adulterant Malachite Green Using Carbon Dots Derived from the Medicinal Plant Source Ocimum tenuiflorum
(Wiley-Blackwell, 2019) Devyani Shukla; Fanindra Pati Pandey; Puja Kumari; Nilanjan Basu; Manish K. Tiwari; Jayeeta Lahiri; Ravindra N. Kharwar; Avanish S. Parmar
Food adulteration is an alarming concern in developing countries causing an increased rate of cancer incidents. This study aims to address this concern by detecting adulteration in green vegetables. A facile green one-step and cost-effective strategy to synthesize carbon quantum dots derived from a herbal source has been utilized to design a fluorescence-based sensor for detecting malachite green (MG), a toxic carcinogenic dye, commonly used as an adulterant to give a fresh green look to green vegetables. The leaf-extract of Ocimum tenuiflorum has been used to synthesize highly photostable carbon dots for detecting MG with a limit of detection (LOD) as low as 18 nM. Further, this principle has been utilized to design a prototype calorimetric sensor. The mechanism of the interaction between malachite green and carbon dots has been probed using DFT by employing the SMD solvation model. In addition, CQDs also possess strong antioxidant activity and minimal cytotoxicity enabling their utilization in many biological and sensing applications. This shows the versatility of these easily scalable carbon dots. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Large area few‐layer hexagonal boron nitride as a raman enhancement material
(MDPI AG, 2021) Nilanjan Basu; Moram Sree Satya Bharathi; Manju Sharma; Kanchan Yadav; Avanish Singh Parmar; Venugopal Rao Soma; Jayeeta Lahiri
Increasingly, two‐dimensional (2D) materials are being investigated for their potential use as surface‐enhanced Raman spectroscopy (SERS) active substrates. Hexagonal Boron Nitride (hBN), a layered 2D material analogous to graphene, is mostly used as a passivation layer/dielectric substrate for nanoelectronics application. We have investigated the SERS activity of few‐layer hBN film synthesized on copper foil using atmospheric pressure chemical vapor deposition. We have drop casted the probe molecules onto the hBN substrate and measured the enhancement effect due to the substrate using a 532 nm excitation laser. We observed an enhancement of ≈103 for malachite green and ≈104 for methylene blue and rhodamine 6G dyes, respectively. The observed enhancement factors are consistent with the theoretically calculated interaction energies of MB > R6G > MG with a single layer of hBN. We also observed that the enhancement is independent of the film thickness and surface morphology. We demonstrate that the hBN films are highly stable, and even for older hBN films prepared 7 months earlier, we were able to achieve similar enhancements when compared to freshly prepared films. Our detailed results and analyses demonstrate the versatility and durability of hBN films for SERS applications. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Substrate roughness and crystal orientation-controlled growth of ultra-thin BN films deposited on Cu foils
(Springer Science and Business Media Deutschland GmbH, 2022) Nilanjan Basu; Alapan Dutta; Ranveer Singh; Md. Bayazeed; Avanish S Parmar; Tapobrata Som; Jayeeta Lahiri
This work demonstrates the synthesis of boron nitride (BN) films by reactive radio-frequency (RF) magnetron sputtering over the copper foil. Copper foil preparation conditions determine the phase selectivity of BN films and the growth of continuous films. Discontinuous films are observed for Cu foils with high surface roughness. Deposition of BN on non-electropolished Cu foils with a predominant (100) orientation and high surface roughness, resulted in the growth of discontinuous BN islands with mixed cubic and hexagonal BN phases. On Cu foils having (100) and (110) orientations with grain sizes (100 μm) and low surface roughness, the growth of cubic BN (cBN) films is observed. While on electropolished Cu foils with (111) surface orientation, similar grain sizes, and low surface roughness (about 5 nm), we get the growth of continuous hexagonal BN films. The current–voltage (I–V) response of the hBN films showed a rectifying behavior. This work would be beneficial to researchers who are investigating the epitaxial growth of BN films metal substrates. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.