Browsing by Author "Biplab Mondal"

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A and B site engineered doping of the Bi2O3 to tune the structural and optical properties of lead-free BCZT ceramic
(Elsevier Ltd, 2024) Biplab Mondal; Sushmita Seth; Satyendra Prakash Pal
This work reports the different solid-state synthesis routes to tune between the A-site and B-site incorporation of the Bi2O3 additive element in the lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramic. The structural and optical properties of the synthesized samples were systematically investigated by utilizing XRD, FT-IR spectroscopy, Raman Spectroscopy, UV–visible, and Photoluminescence spectroscopy. The shifting of the XRD peaks towards higher angles and the decrement of the O–Ba–O bond length in the FT-IR spectra of the doped sample confirmed the A-site incorporation of the Bi3+ ion. Whereas, B-site substituted samples have shown the lower angle shifting of the XRD peaks and increased value of the O–Ti–O bond length in FT-IR spectra. The presence of co-existing multi-phases in all prepared ceramics structures were verified by the splitting of XRD peaks and Raman Spectroscopy data analysis. A significant decrement in the value of the energy band gap and higher emission intensity for the A-site doped sample was observed from the UV–visible and PL spectra respectively. These observations made from the optical properties indicate that the A-site substituted ceramics can greatly enhance the electrical and optical properties of the pure material concerning the B-site substituted ceramics. © 2023 Elsevier B.V.
An Amino Acid-Based Self-Shrinking Supramolecular Bioactive Hydrogel - A Sustainable Platform for Wastewater Treatment and Water Purification
(John Wiley and Sons Inc, 2025) Swaraj Ganesh Gaonkar; Pandey Priya Arun; S. Daisy Precilla; Hirak Kumar Basak; Meenakshi Singh; B. Agiesh Kumar; Sudipta Bhowmik; Biswarup Chakraborty; Mayank Varshney; Biplab Mondal; Subhasish Roy
This study investigates the unique syneresis (self-shrinking) behavior of N-Terminally Fmoc-protected amino acid, Fmoc-hPhe-OH (Fmoc-homo-L-phenylalanine, abbreviated in this work as hF)-based hydrogel, and its potential in environmental remediation applications. Fmoc-hPhe-OH (hF) forms a hydrogel in 50 mM phosphate buffer (PB) of pH 7.4. Interestingly, hF-based hydrogel shows syneresis behavior with controlled release of residual water from the hydrogel matrix. Moreover, this hydrogelator can form co-assembled hydrogels with various dyes, including Congo Red and Rhodamine B; natural water samples, including natural mud water and sea water; and heavy metal ions aqueous solutions, including CdII, PbII, and HgII separately in 50 mM PB of pH 7.4. Interestingly, after 2 to 3 hours for shake gel and 5–6 hours for nonshake gel, the released waters have been tested and it has been found that these co-assembled hydrogels are capable of retaining almost all the contaminants within the shrink hydrogels matrix and releasing almost pure water along with the presence of hydrogel nanofibers. Syneresis is augmented to purify the contaminated water with dyes, mud, dissolved salts, and toxic heavy metal ions. These co-assembled hydrogels, leading to distinct structural and functional changes, which have been characterized by using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Field Emission Scanning Electron Microscopy (FE-SEM), suggesting various supramolecular interactions including π-π stacking, hydrogen bonding, and electrostatic interactions are responsible for stable hydrogelations. The rheological study evaluates the hydrogel's mechanical and thixotropic properties and spectroscopic techniques, including UV-visible spectroscopy and fluorescence spectroscopy, to monitor structural transition. This novel class of amino acid-based hydrogel shows antibacterial activity against both Gram-positive and Gram-negative bacteria, likely through membrane-disruptive mechanisms, and also shows promising antioxidant properties. The native hF hydrogel is biocompatible and shows anticancer activity toward the pancreatic cancer cell line. The research finding bestows the biomedically relevant hydrogel's potential use in green and sustainable environmental remediation. © 2025 Wiley-VCH GmbH.
Effect of different synthesis parameters on the structural, morphological and optical properties of hydrothermally synthesized tungsten diselenide (WSe2) nanostructures: Experimental and theoretical validation
(Elsevier Ltd, 2025) Sushmita Seth; Biplab Mondal; Monalisha Nayak; Satyendra Prakash Pal
In this study, tungsten diselenide (WSe2) nanostructures were synthesized via a hydrothermal route using sodium tungstate dihydrate (Na2WO4.2H2O) and selenium (Se) powder as precursors. Particular attention was given to the influence of synthesis parameters, namely reaction temperature and growth duration, as these play a decisive role in crystallite size, morphology, and the presence of impurities. To systematically evaluate their impact, WSe2 samples were prepared under different conditions and examined for structural, morphological, and optical variations. The as-synthesized samples were characterized by using X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Analysis (EDAX), High Resolution Transmission Electron Microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Ultraviolet-Visible (UV-Vis) spectroscopy and Photoluminescence (PL) spectroscopy. The bonding structure and the vibrational modes of Raman spectrum were validated by Density Functional Theory (DFT) calculation using the B3LYP/LANL2DZ mode. The XRD and Raman spectroscopy measurements confirmed the formation of the hexagonal phase (2H-WSe2). The morphology transitioned from aggregated particles to flake-like nanostructures with increasing temperature, while reaction time influenced the crystal refinement and stacking. A significant decrement in the value of the energy band gap for most pure exfoliated WSe2 was observed from the UV-Vis absorption spectra. PL spectra revealed indirect and excitonic transitions with emission peaks in the near-IR region (∼1.3 and ∼1.5 eV). Further, the PL spectra of exfoliated bulk WSe2 exhibited a clear blue-shift of the emission peak, indicating effective material thinning from multilayered to few-layered WSe2. These optical properties indicate a possible optoelectronic potential of WSe2. © 2025 Elsevier Ltd
Energy storage properties of Bi2O3-doped lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramic and its switching and scaling behavior
(Elsevier Ltd, 2025) Biplab Mondal; Vijayeta Pal; Satyendra Prakash Pal
In this work, the intriguing crystal-structured Bi2O3 additive was doped into the lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramic with different molar percentages (0.1 mol% to 1.0 mol %) to investigate its energy storage capability. The XRD data analysis confirmed the formation of a pure Perovskite phase without any presence of secondary phases in all samples. The presence of co-existing multi-phases in all prepared ceramics structures were verified by the Rietveld refinement of XRD and Raman Spectroscopy data analysis. The maximum value of the Orthorhombic (O) ⁄Tetragonal (T) phase ratio was obtained for the 0.4 mol% Bi2O3-doped sample. FESEM micrographs revealed that the smallest average grain size and the highest percentage of porosity were found for the 0.4 mol% incorporation of Bi2O3. The temperature-dependent dielectric study demonstrated that the BCZT-04Bi sample exhibited the strongest dielectric diffuse phase transition behaviour. The modelling of P-E loop analyzed the different intrinsic properties such as ferroelectricity, and switching behavior. From P-E loop measurement it was observed that among all samples, the 0.4 mol% Bi2O3-doped sample exhibited the highest room temperature energy storage efficiency of ∼67.4 % which is 18 % more than that of the pure sample. The sample also exhibited highest recovered energy density value of 117.11 mJ/cm3 at 35 kV/cm applied electric field. The scaling behavior demonstrates that the BCZT-04Bi sample exhibits outstanding frequency stability as a relaxor-ferroelectric material, with a highly sustainable recovered energy storage density. These properties make it a promising candidate for advanced electronic applications, including sensors, actuators, and frequency-pulsed capacitors. © 2025 Elsevier Ltd and Techna Group S.r.l.
Fmoc-Appended Redox Active Aromatic Amino Acids Capped Nanoparticles Embodied Sustainable Antibacterial Catalytic Hydrogels for the Production of Value-Added Chemical
(John Wiley and Sons Inc, 2025) Swaraj Ganesh Gaonkar; Ritu Raj Patel; Meenakshi Singh; Biplab Mondal; Sunil Kumar Meena; Subhasish Roy
In this study, the hydrogelations of Fmoc-Tyr-OH (Fmoc-Y) and Fmoc-Trp-OH (Fmoc-W) have been investigated in 50 mm phosphate buffer (saline) of pH 7.4. Gold and silver nanoparticles have been synthesized in situ within these hydrogels under physiological conditions without using any toxic reducing agents to achieve hybrid hydrogels formation successfully. The nanoparticles formation kinetics have been monitored through UV-vis spectroscopy. Native and hybrid hydrogels have been characterized by using UV-vis, fluorescence, FTIR, XRD, FE-SEM, and HR-TEM analyses. Rheological measurements revealed their mechanical strength and thixotropic behaviour. Moreover, both native and hybrid hydrogels show potent antibacterial activities against both Gram-positive and Gram-negative bacteria. Interestingly, these as-synthesized gold nanoparticles containing hybrid hydrogels and their xerogels exhibited excellent catalytic activities for the reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP), monitored through time-dependent UV-vis spectroscopy. These catalysts retained their activities over multiple cycles, highlighting their reusability and stability. To the best of our literature knowledge, this is a green, sustainable, fastest, economical and effective reduction reaction of hazardous p-NP using amino acids-stabilized gold nanoparticles containing xerogels in water ever reported to produce value-added chemical precursor p-AP for the syntheses of various drug molecules. This is a minimalistic approach to device biomaterials-based advanced sustainable system for environmental remediation and value-added chemical production. © 2025 Wiley-VCH GmbH.