1. Journal Articles
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Item Trihydrazone functionalized cyanopyridine discoids: Synthesis, mesogenic and optical properties(2014) Ahipa, T.N.; Adhikari, A.V.A new series of trihydrazone functionalized cyanopyridine derivatives (CPTH-Dm) carrying 3,4-dialkoxyphenyl groups was designed and synthesized successfully as discotic columnar liquid crystals. These new discoid mesogens display hexagonal columnar phase with a wide mesophase range from ambient temperature to 110 C and the observed columnar assembly is due to the presence of intermolecular hydrogen bonds and ?-? interactions in them. Their optical studies reveal that the compounds are good blue light emitters and hence they are potential candidates for OLED device fabrication. � 2013 Elsevier Ltd. All rights reserved.Item Solvent-free synthesis of bis-hydrazones through 1,3-dipolar cycloaddition of sydnone and study of their optical, molecular docking, and antioxidant properties(2018) Asma; Kalluraya, B.; Manju, N.; Adhikari, A.V.; Chandra; Mahendra, M.A series of new 1-(aryl)-1H-pyrazol-3,4-bis (aryl)-3,4-dicarbohydrazones (4) was obtained by the condensation of 1-arylpyrazole-3,4-dicarbohydrazides (3) with various aryl aldehydes under solvent-free conditions. The structures of the newly synthesized hydrazones were confirmed by proton-nuclear magnetic resonance spectroscopy, infrared spectroscopy, liquid chromatography mass spectrometry, elemental analysis, and by single crystal X-ray diffraction. All the synthesized compounds were screened for their antioxidant activity, where compound 4a has shown percentage inhibition higher than the standard butylated hydroxyanisole. The molecular docking and photophysical property were also investigated. 2018 Connect Journals.Item Solvent selection for highly reproducible carbon-based mixed-cation hybrid lead halide perovskite solar cells via adduct approach(2020) Keremane, K.S.; Prathapani, S.; Haur, L.J.; Bahulayan, D.; Adhikari, A.V.; Priyadarshi, A.; Dr.; Mhaisalkar, S.G.; Prof.The major problem identified in carbon-based mixed cation perovskite solar cells (PSCs) is the selection of a suitable solvent for single-step solution-processed perovskite deposition in order to promote their scalable production. Herein we report a detailed study on the selection of appropriate solvent for the one-step deposition of cesium-formamidinium lead iodide (Cs0.1FA0.9PbI3) perovskite via Lewis acid-base adduct approach for fully printable mesoporous PSCs with mesoporous TiO2/ZrO2/C architecture. Highly reproducible Cs0.1FA0.9PbI3 solar cells were fabricated via adducts of PbI2 with eco-friendly dimethyl sulfoxide (DMSO). The best cells fabricated with the above approach yielded a photoconversion efficiency (PCE) of 12.33% for a small area device (active area: 0.09 cm2) and 10.1% for a large area device (active area 0.7cm2). The average power conversion efficiency for 62 PSCs was found to be 10.5% under an AM 1.5G illumination. Finally, the mixed cation perovskite in carbon architecture using the Lewis acid-base adduct approach is remarkably stable, with less than 1% change from the initial PCE after 1800h of storage under dark ambient conditions (25 C, 60 70% RH). 2020 International Solar Energy SocietyItem Synthesis, structural analysis and solvatochromic behaviour of 4,6-bis (4-butoxyphenyl)-2-methoxynicotinonitrile mesogen(2013) Ahipa, T.N.; Kumar, V.; Adhikari, A.V.In this communication, we report the synthesis and characterisation of a new luminescent liquid crystalline material, 4,6-bis (4-butoxyphenyl)-2-methoxynicotinonitrile (3). We have confirmed its structure by Fourier transform infrared and 1H nuclear magnetic resonance spectroscopy, elemental analysis and X-ray single crystal diffraction studies. The newly synthesised compound crystallises in a monoclinic system with the space group C2/c and its cell parameters are found to be a = 25.181(4) , b = 15.651(4) , c = 12.703(19) , V = 4880.4 (16) , Z = 8. The results indicate that the presence of weak CH... O and CH... N hydrogen bonding as short-range intermolecular interactions are responsible for the formation of its crystal assembly. The measured torsion angle shows the existence of a distorted structure for the molecule wherein 4-butoxyphenylene ring substituent at the fourth position of the central pyridine ring forms a torsion angle ?[C(4), C(3), C(10), C(19)] of 40.55 . Its liquid crystalline behaviour was investigated with the aid of polarised optical microscopy and differential scanning calorimetry. The study reveals that the compound displays a broad nematic phase in the range of 78-112 C. Further, solution phase optical studies indicate that it is a blue light emitter in different non-polar and polar organic solvents at a concentration of 10-5M. 2013 Copyright Taylor and Francis Group, LLC.Item Synthesis, electrochemical and optical studies of new cyanopyridine based conjugated polymers as potential fluorescent materials(2011) Vishnumurthy, K.A.; Sunitha, M.S.; Safakath, K.; Philip, R.; Adhikari, A.V.In this communication we describe the design and synthesis of four new conjugated polymers (P1-P4) carrying cyanopyridine in their backbone via Wittig condensation technique. Their structures were well established by FTIR, 1H NMR, elemental analysis and gel permeation chromatographic techniques. They exhibited good thermal stability with the onset decomposition temperature around 300-350 C in nitrogen atmosphere. Further, their electrochemical, linear and third-order non-linear optical properties have been investigated. The polymers showed low electrochemical band gaps in the range of 1.77-1.99 eV and displayed very good fluorescence emission property in various polar solvents. The fluorescence quantum yields of polymers P1-P4 in tetrahydrofuran (THF) were found to be 35, 42, 38 and 34%, respectively. The effective two-photon absorption coefficients (?) for the polymers were determined by Z-Scan technique and were found to be 1.34 10 -11, 1.24 10-11, 3.04 10-11 and 1.85 10-11 m/W for polymers P1-P4, respectively. 2011 Elsevier Ltd. All rights reserved.Item Synthesis, anticonvulsant and anti-inflammatory studies of new 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones(2013) Ulloora, S.; Shabaraya, R.; Ranganathan, R.; Adhikari, A.V.The present work involves design and synthesis of new substituted 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones (4a-s, 5a-h), starting from 4-hydroxybenzaldehyde. The final compounds were screened for their in vivo anticonvulsant activity by MES, scPTZ and 6 Hz methods, while their anti-inflammatory screening was performed by Carrageenan induced Paw Edema method. The results indicated that compounds carrying electron donating groups are anticonvulsant active, while most of the tested compounds exhibited significant anti-inflammatory activity. Compounds 4k, l, 4p-s, and 5c showed rapid anti-inflammatory activity within 30 min and appeared as lead compounds. Further, Neurotoxicity study revealed that all the tested compounds are non-toxic up to 300 mg/kg doses. Selected compounds were also subjected to analgesic screening following Tail immersion method and they exhibited good activity. 2013 Elsevier Masson SAS. All rights reserved.Item Synthesis and two-photon absorption property of new ? -conjugated donor-acceptor polymers carrying different heteroaromatics(2013) Sunitha, M.S.; Vishnumurthy, K.A.; Adhikari, A.V.In this communication, we report the synthesis of three newly designed fluorescent polymers P1-P3, starting from simple thiophene derivatives through precursor polyhydrazide route. The new polymers, carrying donor and acceptor heterocyclic moieties with different spacer groups were found to be thermally stable and good of nonlinear optical (NLO) materials with two photon absorption property. The structures of newly synthesized monomers and polymers were confirmed by FTIR, NMR spectral and elemental analyses. Further, polymers were characterized by GPC and TGA studies. Their linear optical and electrochemical properties were evaluated by UV-vis, fluorescence spectroscopic and cyclic voltammetric (CV) studies, respectively, whereas their NLO properties were studied by Z-scan technique using Nd: YAG laser at 532 nm with 7 ns pulse. The electrochemical band gap of P1-P3 was determined to be 1.98, 1.91 and 2.05 eV, respectively. The NLO results reveal that polymers P1-P3 show good optical limiting property with TPA coefficient values 2.9 10 - 11 m/W, 8.0 10 - 11 m/W and 1.4 10 - 11 m/W, respectively. 2013 Indian Academy of Sciences.Item Synthesis and photovoltaic performance of a novel asymmetric dual-channel co-sensitizer for dye-sensitized solar cell beyond 10% efficiency(2017) Babu, D.D.; Su, R.; Naik, P.; El-Shafei, A.; Adhikari, A.V.In this paper, we report the design and synthesis of a new bi-anchoring indole based co-sensitizer DBA-8 with A-?-D-A (acceptor-? bridge-donor-acceptor) architecture, carrying indole moiety as a donor and barbituric acid as acceptor/anchoring groups. Its photo-physical and electrochemical properties along with molecular geometries, calculated from Density Functional Theory (DFT) are employed to comprehend the effect of co-sensitizer structure on photovoltaic characteristics of DSSCs. The abovementioned organic dye (DBA-8) was employed as a co-sensitizer along with well-known ruthenium based sensitizer NCSU-10 in order to broaden the spectral responses of the co-sensitized DSSC. In the present work, for the first time we are demonstrating the profound role of a dual-anchoring co-sensitizer that can play in ameliorating the overall performance of a solar cell. The photovoltaic studies indicated that, the co-sensitizer DBA-8 succeeded in increasing the light harvesting ability in the device significantly. Notably, the device co-sensitized using 0.2 mM DBA-8 along with ruthenium based chromophore NCSU-10, showed a maximum efficiency of 10.68% (Jsc = 25.14 mAcm?2, Voc = 0.695 V, ff = 61.2%). Further, the good agreement between the theoretically and experimentally obtained ?max data vindicate that, the energy functional and basis set employed in this study can be successfully utilized for predicting the absorption spectra of new photosensitizers, with great precision before synthesis. Furthermore, all these findings showcase the vast potential of bi-anchoring molecules in improving the overall performance of the dye-sensitized solar cells. 2017 Elsevier LtdItem Synthesis and characterization of thiophene-based donor-acceptor type polyimide and polyazomethines for optical limiting applications(2013) Vishnumurthy, K.A.; Sunitha, M.S.; Adhikari, A.V.In this communication we describe the design and synthesis of four new conjugated polymers (P1-P4) based on 3,4-ditetradecyloxythiophene. The required diamine monomer was prepared by a unique catalyst-free reduction process using hydrazine hydrate. The structures of the intermediates and polymers were established by FTIR, 1H NMR spectroscopy. Molecular weights of polymers were determined by gel permeation chromatographic (GPC) method. Their electrochemical properties were investigated by cyclic voltammetry and linear optical properties were determined by UV-Visible absorption and fluorescence emission spectroscopic techniques. Further, their nonlinear optical properties were evaluated by Z-scan technique using Nd:YAG laser. These polymers showed strong optical limiting behavior with two-photon absorption (2PA) coefficients of the order of 10-10 m/W, which are comparable to that of good optical limiting materials reported in the literature. Also, it has been observed that the optical nonlinearity enhanced with the increase in donor-acceptor strength of the polymer backbone. 2012 Springer-Verlag.Item Synthesis and characterization of a new NLO-active donor-acceptor-type conjugated polymer derived from 3,4-diphenylthiophene(2010) Manjunatha, M.G.; Adhikari, A.V.; Hegde, P.K.; Suchand, Sandeep, C.S.; Philip, R.A new donor-acceptor-type conjugated polymer (P1) carrying 3,4-diphenylthiophene, 2,5-dihexyloxybenzene, and 1,3,4-oxadiazole units was synthesized through multistep reactions. The polymer was prepared using a polyhydrazide precursor route. The polymer has a well-defined structure and exhibits good thermal stability, with a decomposition onset temperature in nitrogen of 300 C. Cyclic voltammetry experiments revealed that the polymer has low-lying LUMO (-3.68 eV) and high-lying HOMO (-5.78 eV) energy levels. The electrochemical band gap was found to be 2.10 eV. The UV-visible absorption spectrum of the polymer presented a maximum at 373 nm, and it displayed bluish-green fluorescence in dilute chloroform solution. The nonlinear optical properties of the new polymer were investigated at 532 nm using the Z-scan technique with nanosecond laser pulses. The polymer exhibited strong optical limiting behavior due to excited state absorption, which was phenomenologically similar to a three-photon absorption (3PA) process. The 3PA coefficient ? was found to be 7 10-22 m3/W2. The studies show that the new polymer (P1) is a promising material for developing efficient photonic devices.