School Of Basic And Applied Sciences
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Item Simple and Productive Method to Develop Highly Sensitive and Fast Infrared Photodetector Using Spray Deposited Nanocrystalline PbS Thin Film(Institute of Physics, 2023-02-16T00:00:00) Thabit, Mohammed Y. H.; Kaawash, Nabeel M. S.; Begum, Sumayya; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.This work demonstrates the development of a highly sensitive and fast infrared photodetector using a PbS thin film deposited using a simple and scalable method known as "spray pyrolysis". An aqueous precursor solution was deposited on a glass substrate at 150 �C have a cubic phase of PbS. Silver electrodes with a 1 mm gap are drawn on the film to create photo-detector devices. Low resistive contact between the silver electrode and the PbS film is revealed from the linear I-V measurements performed in the dark and under light illumination. Under the illumination of a 100-watt tungsten lamp, the photo-responsivity, sensitivity, response time, and decay time of the PbS film were measured. The Ag/PbS/Ag photodetector device has a responsivity of 70 mA/W, a sensitivity of 200 at 30 V, and the best response and decay times of 6.4 and 15.6 ms, respectively. The photodetector device produced by this simple and low-cost fabrication method has a fast response and decay time. � Published under licence by IOP Publishing Ltd.Item Synthesis and characterization of copper and silver complexes stabilized by Dithiocarbazate(Central University of Punjab, 2018) Rout, Sambit Shashanka Sekhar; Dhayal, Rajendra SinghMetal complexes of Dithiocarbazoic acid, it's esters and their Schiff bases have been considered for the potential of anticancer, antibacterial, antifungal, antiamoebic and insecticidal activities. S-methyldithiocarbazate, S-benzyldithiocarbazate and it's Schiff bases were already reported. We synthesize copper(I)/silver(I) complexes using of dithiocarbazate and it's Schiff base. We also isolated heteroatomic (copper and silver) complexes stabilized by dithiocarbazate. All the complexes are characterised by SEM (Scanning Electron Microscope), EDS (Energy dispersive X-ray Spectroscopy), Elemental mapping and NMR (Nuclear Magnetic Resonance). Further, we synthesize hetero clusters by the use of copper and silver, which can be utilized for making of nanoparticles and nanomaterials in near future.Item [Ag20{S2P(OR)2}12]: A Superatom Complex with a Chiral Metallic Core and High Potential for Isomerism(Wiley-VCH Verlag, 2016) Dhayal, R.S.; Lin, Y.-R.; Liao, J.-H.; Chen, Y.-J.; Liu, Y.-C.; Chiang, M.-H.; Kahlal, S.; Saillard, J.-Y.; Liu, C.W.The synthesis and structural determination of a silver nanocluster [Ag20{S2P(OiPr)2}12] (2), which contains an intrinsic chiral metallic core, is produced by reduction of one silver ion from the eight-electron superatom complex [Ag21{S2P(OiPr)2}12](PF6) (1) by borohydrides. Single-crystal X-ray analysis displays an Ag20core of pseudo C3symmetry comprising a silver-centered Ag13icosahedron capped by seven silver atoms. Its n-propyl derivative, [Ag20{S2P(OnPr)2}12] (3), can also be prepared by the treatment of silver(I) salts and dithiophosphates in a stoichiometric ratio in the presence of excess amount of [BH4]?. Crystal structure analyses reveal that the capping silver-atom positions relative to their icosahedral core are distinctly different in 2 and 3 and generate isomeric, chiral Ag20cores. Both Ag20clusters display an emission maximum in the near IR region. DFT calculations are consistent with a description within the superatom model of an 8-electron [Ag13]5+core protected by a [Ag7{S2P(OR)2}12]5?external shell. Two additional structural variations are predicted by DFT, showing the potential for isomerism in such [Ag20{S2P(OR)2}12] species. ? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimItem Alloyed monolayers of Cu, Ag, Au and Pt in hexagonal phase: A comprehensive first principles study(Elsevier Ltd, 2018) Kapoor, Pooja; Kumar, Arun; Sharma, Munish; Kumar, Jagdish; Kumar, Ashok; Ahluwalia, P. K.We present density functional theory (DFT) based comprehensive study of two-dimensional (2D) alloyed monolayers of noble metals (AgCu, AgPt, AgAu, AuCu, AuPt and CuPt) in hexagonal phase within numerical atomic orbitals and plane wave basis sets methods. The monolayers considered exhibit positive phonon frequencies suggesting them to be dynamically stable. The Pt containing alloyed monolayers have superior structural stability (binding energy and tensile strength) and exhibit metallic and ferromagnetic character amongst all the alloyed monolayers. Interestingly, alloying of Au monolayer with Cu and Ag show semiconducting behavior whereas alloyed AgCu monolayer posseses Dirac-cone like features at high symmetry points. These distinct features in electronic structures of alloyed 2D monolayers have been captured in STM like set up. An anisotropic behavior has been observed in dielectric spectra for all the considered structures. Tunneling characteristics show NDR region for Pt containing alloyed monolayers. The considered alloyed monolayers may potentially be useful as a building blocks for the applications in nano- and opto-electronics. ? 2017 Elsevier B.V.Item Electronic, Mechanical, and Dielectric Properties of Two-Dimensional Atomic Layers of Noble Metals(Springer New York LLC, 2017) Kapoor, Pooja; Kumar, Jagdish; Kumar, Arun; Kumar, Ashok; Ahluwalia, P. K.We present density functional theory-based electronic, mechanical, and dielectric properties of monolayers and bilayers of noble metals (Au, Ag, Cu, and Pt) taken with graphene-like hexagonal structure. The Au, Ag, and Pt bilayers stabilize in AA-stacked configuration, while the Cu bilayer favors the AB stacking pattern. The quantum ballistic conductance of the noble-metal mono- and bilayers is remarkably increased compared with their bulk counterparts. Among the studied systems, the tensile strength is found to be highest for the Pt monolayer and bilayer. The noble metals in mono- and bilayer form show distinctly different electron energy loss spectra and reflectance spectra due to the quantum confinement effect on going from bulk to the monolayer limit. Such tunability of the electronic and dielectric properties of noble metals by reducing the degrees of freedom of electrons offers promise for their use in nanoelectronics and optoelectronics applications. ? 2016, The Minerals, Metals & Materials Society.