Browsing by Author "Thakur A."

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Morphological, optical and thermal properties of (TiO2)xembedded (PVC/PE)1?x(where X = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) blend nanocomposites
(Springer Science and Business Media, LLC, 2017) Thakur A.; Thakur P.; Yadav K.
Present study deals with the dispersion of TiO2 nanoparticles in PVC/PE blends. The prepared blend nanocomposites have been characterized using FESEM, FTIR, UV-Visible spectroscopy, TGA, and EDX to study the morphology, optical and thermal properties of prepared samples. FESEM confirms the dispersion of nanoparticles in polymer blend and formation of blend nanocomposites. Decrease in optical band gap has been observed by addition of TiO2 content. Variation in melting point is studied by TGA. Thermal stability is enhanced with increasing TiO2 content in polymer blend.
Steering the antitumor drug discovery campaign towards structurally diverse indolines
(Academic Press Inc., 2020) Thakur A.; Singh A.; Kaur N.; Ojha R.; Nepali K.
Indoline framework is often perpended as a privileged heterocycle present in medicinally valuable compounds of natural and synthetic origin. This review article presents the rational approaches/strategies employed for the design of anticancer indolines along with the structure activity relationship and mechanistic insights revealed in the in-vitro and in-vivo assays. The chemist has always been fascinated towards the indoline ring for the construction of antitumor scaffolds owing to its versatility as evidenced by its existence in scaffolds inducing antiproliferative effects via diverse mechanisms. To the delight of medicinal chemist, the applicability of indoline has also been expanded towards the design of dual inhibitors (multitargeting anticancer agents) as well as PROTACS. Overall, it can be concluded that indoline moiety is a magic bullet and the scaffolds containing this ring are foraying towards detailed preclinical and clinical stage investigations by leaps and bounds.
Study of variation in the band gap with concentration of TiO2In (LaMnO3)1-x / (TiO2)x (where x = 0.0,0.1,0.2,0.3 and 0.4) nanocomposites
(American Institute of Physics Inc., 2016) Thakur P.; Thakur A.; Yadav K.
In this paper(LaMnO3)1-x/ (TiO2) x (where x = 0.0, 0.1, 0.2, 0.3 and 0.4) nanocomposite are prepared by mixing the LaMnO3 and TiO2 (Sigma Chemicals, particle size ?21 nm) nanoparticle in appropriate ratio. These samples were characterized by using FESEM, EDS and FTIR to study the optical properties. Field Emission Scanning Electron Microscopy (FESEM) image of pure LaMnO3 sample shows that the uniform particle size distribution is observed. The average particle size of the LaMnO3 nanoparticles is 43 nm. The crystallite size increases from 16-24 nm with increasing the weight percentage of TiO2 in LaMnO3/TiO2 nanocomposite up to x = 0.4. The Fourier transform infrared spectroscopy (FTIR) spectra show that the absorption peaks appear at 450 cm-1 and 491 cm-1 which represent the Mn-O bending and Ti-O stretching mode respectively. The broadening of these peaks with increasing the concentration of TiO2 is also observed. It gives an evidence for the formation of metal oxygen bond. The absorption band at 600 cm-1 corresponds to the stretching mode, which indicates the pervoskite phase present in the sample. The values of band gap are found 2.1, 1.9, 1.5, 1.3 and 1.2 eV for the x = 0.0, 0.1, 0.2, 0.3, and 0.4 respectively. Thus, the decrease in band gap and increase in refractive index with increasing concentration of TiO2 has been observed. These prepared nanocomposites can be used in the energy applications, to make the electrical devices and as a catalyst for photocatalytic processes e.g. hydrogenation.
Superior Mechanical and Electronic Properties of Novel 2D Allotropes of As and Sb Monolayers
(American Chemical Society, 2019) Jamdagni P.; Thakur A.; Kumar A.; Ahluwalia P.K.; Pandey R.
Novel monolayer allotropes of As and Sb monolayers are predicted to be energetically and dynamically stable by calculations based on density functional theory. Remarkably, these monolayers possess superior mechanical flexibility and can withstand tensile strain as large as 58% in the armchair direction and 24% in the zigzag direction, which are higher than the strain limits of 2D materials such as graphene, MoS2, and phosphorene. The predicted mechanical flexibility is mainly due to the highly puckered nature of these monolayer structures. Tensile strain along the armchair direction expands the puckering of the structure by increasing the dihedral angle without a significant increase in the bond lengths. Moreover, the mechanical properties are found to be highly anisotropic: Young's modulus in the armchair direction is 3 times less than that in the zigzag direction. Furthermore, we show that these monolayer allotropes undergo semiconductor-to-metal transition on application of uniaxial strains and a transverse electric field. The calculated results show the possibility of wide-range tuning of the band gap of these monolayers while keeping their direct gap behavior intact, which can be useful in optoelectronic applications including light-emitting diodes and solar cells.