Browsing by Author "Dipanjan Banerjee"

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Structural characterization of AlCuFe icosahedral quasicrystal nanoparticles synthesized using femtosecond laser ablation
(Springer, 2025) Bibek Kumar Singh; Dipanjan Banerjee; Akkanaboina Mangababu; Yagnesh Shadangi; Nilay Krishna Mukhopadhyay; Rajesh Rawat; Anand Prakash Pathak; Venugopal Rao Soma; Archana Tiwari; Ajay Tripathi
The AlCuFe icosahedral quasicrystal (IQC) targets prepared using two different methods- (1) vacuum induction melting followed by annealing, and (2) spray forming, have been subjected to femtosecond laser ablation in deionized water (DI water) for 54 min. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) pattern analysis of the synthesized nanoparticles (NPs) revealed the presence of IQC phases. NPs obtained from the induction-melted IQC target contained Al13Fe4 and β-Al(Fe,Cu) phases along with the IQC phase, reflecting the phase composition of the bulk target. In contrast, NPs from the spray-formed target exhibited only the IQC phase. Both samples also showed the presence of CuO and amorphous Al2O3. The ablated region of the target surface showed the formation of grooves and bumps. In addition, the formation of liquid vortices during the ablation process was ascertained by the presence of macropores in the ablated region of the target’s surface. I-V plots obtained from the ablated region and the non-ablated region of the target’s surface revealed an increase in the resistance post-ablation. This increase is attributed to the presence of defects and surface oxidation that incurred during the laser irradiation. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Surface enhanced Raman scattering-based sensing and ultrafast nonlinear optical properties of silver-hexagonal boron nitride nanocomposites achieved by femtosecond laser ablation
(Elsevier B.V., 2024) Kousik Bera; Sree Satya Bharati Moram; Dipanjan Banerjee; Jayeeta Lahiri; Venugopal Rao Soma
This study investigated the surface-enhanced Raman spectroscopy (SERS) properties and nonlinear optical (NLO) behavior of silver nanoparticles (Ag NPs) decorated hexagonal boron nitride (hBN) nanocomposites. Although Ag NPs are known for their excellent plasmonic properties, their susceptibility to oxidation in ambient conditions significantly reduces SERS activity. To overcome this, a femtosecond laser-assisted single-step novel approach is developed for synthesizing hybrid Ag-hBN nanocomposites via ablating Ag target in a solution of exfoliated hBN nanosheets, forming uniformly embedded Ag NPs on hBN nanosheets. The morphological characteristics and elemental compositions were validated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). TEM analysis revealed that Ag NPs averaged 15 nm in size, while hBN nanosheets had lateral dimensions of approximately 250 nm. The SERS activity of the prepared nanocomposites was investigated using dye and explosive molecules, achieving detection sensitivities of 1 μM and 100 μM, respectively, with high reproducibility. These detection sensitivities are significant as they demonstrate the potential of the Ag-hBN nanocomposites for sensitive and reliable detection of trace amounts of analytes. Notably, the Ag-hBN nanocomposites showed enhanced SERS activity compared to pure Ag NPs, with a 2.5-fold improvement for Nile blue, 3.6-fold for methylene blue, and 2.4-fold for RDX. The current study also demonstrates that hBN prevents Ag NPs’ oxidation and preserves the SERS functionality even at elevated temperatures. Furthermore, the NLO properties of the nanocomposites were investigated using the standard Z-scan technique, revealing two-photon and three-photon absorption coefficients of 3 × 10−4 cm/GW and 6.5 × 10−5 cm3/GW2, respectively. The findings highlight the potential of Ag-hBN nanocomposites to enhance SERS and NLO devices, enabling future applications in sensing and photonics. © 2024 Elsevier B.V.
Ultra-short pulsed laser ablation of decagonal AlCoNi and AlCoCuNi quasicrystals
(Elsevier Ltd, 2023) Bibek Kumar Singh; Dipanjan Banerjee; A. Mangababu; Yagnesh Shadangi; N.K. Mukhopadhyay; Rajesh Rawat; A.P. Pathak; S. Venugopal Rao; Archana Tiwari; A. Tripathi
Al70Co20Ni10 and Al70Co15Cu10Ni5 (at%) decagonal quasicrystals (DQCs) were subjected to femtosecond laser ablation at a laser wavelength of 800 nm, in deionized water (DI). The generated nanoparticles (NPs) confined within the liquid medium were studied for optical and structural properties. The structural analysis revealed the retention of the targets phase in the NPs. In case of Al70Co20Ni10, formation of Al3Ni2 phase was confirmed through the SAED patterns and HRTEM micrographs. Contrary to this, the formation of Al-Ni phase was not observed in Al70Co15Cu10Ni5. This is attributed to the presence of Cu in the latter sample, which restricts the mixing of Ni with Al. The HRTEM micrographs in both cases showed that Al2O3 was present at the edges of the NPs. The optical analysis confirmed the formation of Al2O3 in both cases. However, in the case of Al70Co15Cu10Ni5, a very weak signal corresponding to CuO was detected. This is attributed to the diffusion of Cu along with Al at the edge. The ablated region of the target's surface was studied for the formation of laser-induced periodic surface structures (LIPSS) also known as ripples, and the type of ripples formed was identified. © 2023 Elsevier B.V.