Faculty Publications

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    Effect of pressure on the band structure of BC3
    (American Institute of Physics Inc. subs@aip.org, 2016) Manju, M.S.; Harikrishnan, H.; Ajith, A.; Valsakumar, M.C.
    Density functional theory (DFT) calculations were carried out to study the effect of pressure on the band structure of two dimensional BC3 sheet. BC3 is a semiconductor at ambient conditions having a band gap of ~0.3 eV. Electronic structure calculations are carried out on BC3 at pressures of 5, 20, 50 and 100 GPa. The system shows a semiconductor - metal transition by the application of pressure without any structural transition. © 2016 Author(s).
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    Synthesis, Characterization and Performance Studies of a New Metal-Free Organic Sensitizer for DSSC application
    (Elsevier Ltd, 2018) Naik, P.; Babu, D.D.; Su, R.; El-Shafei, A.; Vasudeva Adhikari, A.V.
    In this present work we report, design, synthesis and performance studies of a new metal-free organic dye (N, N'-PABA) based on N,N-dimethyl-4-vinyl aniline carrying 4-amino benzoic acid as acceptor, as sensitizers for sensitizing photoanode (TiO2). In the sensitizers, N,N-dimethylaniline ring acts as anelectron donorwhile para amino benzoic acid function as electron acceptor/anchoring units. It was synthesized via condensation reaction starting from simple 4-(N,N-dimethyl amino)benzaldehyde and their structures were confirmed using spectral techniques like FTIR, 1HNMR, 13CNMR, MS and elemental analysis. Further, it was subjected to electrochemical and optical characterization in order to evaluate their band gap and absorption/emission behavior. Further, DFT studies were performed using turbo mole V6.6 software package to evaluate their optimized geometry and FMO levels. Finally, DSSC devices were fabricated using this dye under simulated solar radiation AM1.5G and result revealed that it shows a conversion efficiency of 1%. © 2018 Elsevier Ltd.
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    Molecular Engineering of a New Organic Chromophore with D-Ï€-A Architecture for Dye-Sensitized Solar Cells
    (Elsevier Ltd, 2018) Naik, P.; Vasudeva Adhikari, A.V.
    Herein, we report design and synthesis of a new metal-free organic dye N1 derived from (Z)-3-(9-hexyl-9H-carbazol-3-yl)-2-(thiophen-2-yl) acrylonitrile scaffold. In this design, the electron rich carbazole unit is connected to rhodanine-3-acetic acid via cyano vinyl thiophene as π-spacer. Its molecular structure was confirmed by FTIR, NMR, Mass spectral and elemental analyses. The dye was subjected to optical and electrochemical studies in order to investigate their absorption/emission behaviour as well as HOMO/LUMO energies. The DFT studies were performed using Turbomole 7.1V software and the results indicated the existence of proper charge separation between its HOMO and LUMO energy levels. © 2018 Elsevier Ltd. All rights reserved.
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    Study of Electronic and Optical Properties of Bulk and Monolayer Vanadium Di-Sulfide for Energy Storage Devices
    (Institute of Electrical and Electronics Engineers Inc., 2023) Yadav, A.K.; Jasil, T.K.; Pandey, S.K.
    In this study, the WIEN2k code implementation of the density functional theory (DFT) approach was used to examine the structural, electronic, and optical characteristics of bulk and monolayer VS2 material. For both bulk and monolayer VS2 material, we calculated the various properties including density of states, band-structure, and dielectric functions using the generalised gradient approximation (GGA). This method gives better results for the structural parameters and shows that monolayer VS2 is more favorable for energy storage devices. Additionally, we report the growth of the bulk and monolayer VS2 crystals using a chemical vapor deposition system. It was also found the crystal growth of monolayer VS2 started at the growth temperature of 690 °C. Bulk VS2 crystal growth also performed in this study. Raman spectroscopy shows a peak intensity started at 385 cm-1 for monolayer VS2 growth crystal at 690 °C. These observations show monolayer VS2 material is more suitable for energy storage devices. © 2023 IEEE.
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    An Online technique for estimation of the C and ESR of DC link capacitor in a boost converter based on multiple harmonic injection
    (Institute of Electrical and Electronics Engineers Inc., 2023) Muhammad Ramees, M.K.P.; Waseem Ahmad, M.
    Aluminium Electrolytic capacitors (AEC) are widely used in DC-DC converters. Health of the capacitor can be monitored using the capacitance and equivalent series resistance (ESR) as the ageing will decrease the capacitance and increase the ESR. Hence the estimation of these parameters is essential for the diagnosis of AEC. So, in this paper a method for the estimation of the capacitance and ESR are proposed. This method is based on the injection of low frequency current harmonics into the converter by modifying the duty ratio. A group of harmonic currents are injected, and corresponding voltage and current ripples are obtained using DFT analysis which is used to calculate the impedance at each frequency. From these impedances the capacitance and ESR are estimated using Least Mean Square (LMS) algorithm. Detailed simulation is carried out using MATLAB/Simulink and results are included in this paper. © 2023 IEEE.
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    Computational materials discovery and development for Li and non-Li advanced battery chemistries
    (International Association of Physical Chemists, 2023) Sharma, H.; Nazir, A.; Kasbe, A.; Kekarjawlekar, P.; Chatterjee, K.; Motevalian, S.; Claus, A.; Prakash, V.; Acharya, S.; Sahu, K.K.
    Since the discovery of batteries in the 1800s, their fascinating physical and chemical properties have led to much research on their synthesis and manufacturing. Though lithium-ion batteries have been crucial for civilization, they can still not meet all the growing demands for energy storage because of the geographical distribution of lithium resources and the intrinsic limitations in the cell energy density, performance, and reliability issues. As a result, non-Li-ion batteries are becoming increasingly popular alternatives. Designing novel materials with desired properties is crucial for a quicker transition to the green energy ecosystem. Na, K, Mg, Zn, Al ion, etc. batteries are considered the most alluring and promising. This article covers all these Li, non-Li, and metal-air cell chemistries. Recently, computational screening has proven to be an effective tool to accelerate the discovery of active materials for all these cell types. First-principles methods such as density functional theory, molecular dynamics, and Monte Carlo simulations have become established techniques for the preliminary, theoretical analysis of battery systems. These computational methods generate a wealth of data that might be immensely useful in the training and validating of artificial intelligence and machine learning techniques to reduce the time and capital expenditure needed for discovering advanced materials and final product development. This review aims to summarize the application of these techniques and the recent developments in computational methods to discover and develop advanced battery chemistries. © 2023 by the authors; licensee IAPC, Zagreb, Croatia.
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    An overview of the density functional theory on antioxidant bioactivity predictive feasibilities: Insights from natural antioxidant products
    (Elsevier B.V., 2024) Shaker, L.M.; A Al-Amiery, A.A.; Abed, T.K.; Khalid Al-Azzawi, W.K.; Kadhum, A.A.H.; Sulaiman, G.M.; Mohammed, H.A.; Khan, M.; Khan, R.A.
    Antioxidants play a crucial role in protecting biological systems from oxidative stress, which is implicated in a wide range of diseases. Computational methods have become increasingly valuable in studying the mechanisms of antioxidants, with density functional theory (DFT) being a popular approach. This review provides an overview of the theoretical basis of DFT and its application to molecular systems. It discusses the advantages and limitations of using DFT for studying antioxidants and explores the relationship between antioxidant activity and molecular structure. The paper also highlights the importance of solvation effects in determining antioxidant efficacy and suggests DFT-based methods for incorporating solvation effects into calculations. Case studies of specific antioxidants are presented to illustrate the role of the solvent environment in determining the antioxidant efficacy. Finally, it discusses the relationship between antioxidant activity and certain DFT parameters, and suggests future directions for research. Overall, this review provides valuable insights into the use of DFT in studying antioxidants, and sheds light on the future of computational studies in this field. © 2023
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    New D-?-A type indole based chromogens for DSSC: Design, synthesis and performance studies
    (Elsevier Ltd, 2015) Babu, D.D.; Gachumale, S.R.; Anandan, S.; Vasudeva Adhikari, A.V.
    Three new Donor-?-Acceptor type dyes D1-3 carrying 3-(1-hexyl-1H-indol-3-yl)-2-(thiophen-2-yl)acrylonitrile as backbone with three different acceptor units were designed and synthesized as promising sensitizers for solar cell application. The new dyes were characterized using various spectral and elemental analyses. Their optical and electrochemical properties were investigated using spectrophotometry and cyclic voltammetry respectively, while their photovoltaic performance was evaluated by a device fabrication study. The devices were subjected to electrochemical impedance spectroscopy to gain an insight into the interfacial charge transfer and recombination process while in use. Further, density functional theory study was carried out to investigate their Frontier Molecular Orbital energy states. The study reveals that the dye carrying 4-aminobenzoic acid as an acceptor showed the highest photovoltaic efficiency among the three dyes. This can be attributed to the longer electron lifetime and lower recombination rates. Additionally, a Single crystal X-ray diffraction study confirmed the structure of a key intermediate. © 2014 Elsevier Ltd. All rights reserved.
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    Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications
    (Beilstein-Institut Zur Forderung der Chemischen Wissenschaften info@beilstein-institut.de, 2017) Pangannaya, S.; Purayil, N.P.; Dabhi, S.; Mankad, V.; Jha, P.K.; Shinde, S.; Trivedi, D.R.
    New colorimetric receptors R1 and R2 with varied positional substitution of a cyano and nitro signaling unit having a hydroxy functionality as the hydrogen bond donor site have been designed, synthesized and characterized by FTIR, 1H NMR spectroscopy and mass spectrometry. The receptors R1 and R2 exhibit prominent visual response for F- and AcO- ions allowing the real time analysis of these ions in aqueous media. The formation of the receptor-anion complexes has been supported by UV-vis titration studies and confirmed through binding constant calculations. The anion binding process follows a first order rate equation and the calculated rate constants reveal a higher order of reactivity for AcO- ions. The 1H NMR titration and TDDFT studies provide full support of the binding mechanism. The Hg2+ and F- ion sensing property of receptor R1 has been utilized to arrive at "AND" and "INHIBIT" molecular logic gate applications. © 2017 Pangannaya et al.; licensee Beilstein-Institut.
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    Efficient non-doped bluish-green organic light emitting devices based on N1 functionalized star-shaped phenanthroimidazole fluorophores
    (Elsevier B.V., 2018) Tagare, J.; Ulla, H.; Satyanarayan, M.N.; Sivakumar, S.
    In this paper, two star-shaped fluorescent phenanthroimidazole fluorophores, tris(4-(1-(3-(trifluoromethyl)phenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amine (PIMCFTPA) and tris(4-(1-(4-(trifluoromethyl)phenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amine (PIPCFTPA) with a D–?–A structure were designed and synthesized by attaching a hole-transporting triphenylamine and an electron transporting phenanthroimidazole moiety. A detailed photophysical, thermal, electrochemical and related properties were systematically studied. Furthermore, theoretical investigations (DFT) were performed to get a better understanding of the electronic structures. In particular, PIMCFTPA shows blue shifted emission due to the most twisted conformation and reduced intermolecular interaction as compared with PIPCFTPA. Both the fluorophores exhibit high glass transition temperatures and high thermal stabilities with decomposition temperatures up to 377 °C. The excellent stability renders them promising materials in electroluminescent devices. Non-doped organic light-emitting devices (OLEDs) using these fluorophores as emissive materials display bluish green emissions with high efficiency (6.58 cdA?1, 5.91 lmW?1, 3.62% at 100 cdm?2), low turn-on voltages (2.83 V) (PIMCFTPA) and excellent spectral stability. Our results suggest that the molecular design strategy of integrating TPA with phenthroimdazole play an important role in the device performance. © 2017 Elsevier B.V.