Browsing by Author "Naik, P."

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A simple D-A-?-A configured carbazole based dye as an active photo-sensitizer: A comparative investigation on different parameters of cell
(Elsevier B.V., 2020) Babu, D.D.; Naik, P.; Keremane, K.S.
An organic photosensitizer (DP-1) with D-A-?-A architecture was systematically analyzed along with our previously reported dye N1. In the design, the dyes carry carbazole as donor, thiophene acetonitrile as ?-spacer connected to varied acceptor/anchoring unit i.e., cyanoacrylic acid (N1) and 4-aminobenzoic acid (DP-1). Generally, cyanoacrylic acid and carboxyl groups have been investigated extensively as effective electron acceptor/anchoring unit for the design of the sensitizer for dye-sensitized solar cells (DSSC) application and displayed superior photon conversion efficiency. In the present work, both the dyes were taken up for various studies focusing on photophysical, electrochemical, theoretical and photovoltaic investigation in the corresponding solar cells. From the photophysical and electrochemical studies it was established that, the both dyes show upright thermodynamic feasibility for electrochemical processes in the cell i.e., both electron and dye regeneration. Also, the DFT studies appends the existence of feasible HOMO-LUMO charge distribution. Finally, the devices fabricated by employing these dyes as sensitizer with 10 mM DCA as co-adsorbent. The device based on N1 displayed improved photon conversion efficiency compared to the cell sensitized using DP-1. This work may provide a new strategy for designing efficient photosensitizers to further ameliorate the DSSCs performance. © 2020 Elsevier B.V.
An Efficient Aniline-Based Co-Sensitizer for High Performance N3-Sensitized Solar Cells
(Wiley-Blackwell info@wiley.com, 2018) Naik, P.; Abdellah, I.M.; Abdel-Shakour, M.; Acharaya, M.; Pilicode, N.; El-Shafei, A.; Vasudeva Adhikari, A.V.
In this work, we report a comprehensive photovoltaic investigation of a structurally simple Donor-Acceptor (D?A) configured organic dye, N,N-PABA as an active co-sensitizer in DSSCs sensitized with well-known Ru (II) based N3 dye. This effective co-sensitizer (N,N-PABA) comprises N,N-dimethylaniline system as a donor scaffold linked with 4-aminobenzoic acid as an electron withdrawing functionality. In the present study, we have demonstrated the profound effect of concentration of sensitizer, i. e. N3 based dye as well as co-sensitizer, i. e. N,N-PABA on the photovoltaic performance characteristics of solar cells. Interestingly, the best photovoltaic performance was obtained for the co-sensitized device fabricated using 0.2 mM of N,N-PABA along with 0.3 mM of N3 sensitizer, in presence of 20 mM of CDCA. It displayed power conversion efficiency (PCE) of 5.82% with JSC of 14.35 mA.cm?2, VOC of 0.626 V and FF of 64.85%. Here, the N,N-PABA effectively filled the absorption valley, avoided the dye aggregation and reduced the charge recombination in the co-sensitized devices. Thus, the results ameliorate the role of efficient co-sensitizers to yield DSSC with improved performance by the selection of a matchable co-sensitizer at an appropriate concentration. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Carbazole based organic dyes as effective photosensitizers: A comprehensive analysis of their structure-property relationships
(John Wiley and Sons Inc, 2022) Naik, P.; Keremane, K.S.; Elmorsy, M.R.; El-Shafei, A.; Vasudeva Adhikari, A.V.
The present work describes the effect of structural modification of carbazole-based photosensitizers carrying carboxylic acid as a common anchoring functionality, on the photovoltaic parameters of newly fabricated DSSCs. In this study, we have selected our previously reported three carbazole-based derivatives, viz. S1-3 having different structural designs, that is, D-π-A (S1), D-D-π-A (S2), and A-π-D-π-A (S3) with different donor units and π-spacers, but an identical cyanoacetic acid anchoring unit. We have evaluated their optical, electrochemical, and photovoltaic behaviors in order to explore their structure-property relationships. Also, the theoretical investigations were performed to obtain a deeper understanding of their HOMO-LUMO levels, charge distribution in FMOs, directional flow of electrons within the push-pull type sensitizers, and optical behavior. Finally, the DSSCs were constructed by employing these dyes as sensitizers without any co-absorbents and the performance of the devices was evaluated by using illuminated current-voltage characteristics. Among the tested dyes, di-anchoring S3 exhibited improved PCE of 3.77 % due to its strong adsorption on the TiO2 surface that resulted in superior VOC of the cell. While the S2 containing electron-releasing anisole as an auxiliary donor exhibited better JSC value leading to the optimum PCE of 3.73 % which is comparable to that of S3. Obviously, these results validate the role of the π-spacer and additional donor of the sensitizers on the overall performance of the DSSCs. © 2021 The Authors. Electrochemical Science Advances published by Wiley-VCH GmbH.
Carbon-carbon composites by preformed yarn method
(2011) Naik, P.; Neelakantha, N.V.; Surendranathan, A.O.; Jayaraju, T.
The conventional techniques of manufacturing carbon-carbon(C/C) composites have reportedly encountered problems because the resulting C/C composites exhibit non-uniform properties such as bending strength and density. A novel method of manufacturing C/C composites by preformed yarns (PY) is used. The matrix powder consists of coke powders and the binder. The preformed yarn contains the matrix powders inside the carbon fiber bundle and coated on circumference with nylon-6 polymer. This preformed yarn is then chopped and hot pressed at about 600°C to get bars and pellets. These are again heat treated at 1500°C and further impregnated by one more pitch cycle, again heat treated at 2200°C. The tests for hardness, compression strength, Creep strength, resistance to oxidation, and fracture toughness are conducted on these pellets and bars. The micostructural analysis in SEM is done. These tests reveal that the properties obtained from PY method are superior to the properties obtained from any other conventional method.
Determination of fracture toughness and fatigue crack growth rate using circumferentially cracked round bar specimens of Al2014T651
(Elsevier Masson SAS infos@masson.fr 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2015) Neelakantha, V.L.; Jayaraju, T.; Naik, P.; Kumar K, D.; Rajashekhar, C.R.; Kumar, M.
Fracture toughness (KIC) and fatigue crack growth rate (FCGR) are the important material properties in fracture mechanics. ASTM-E399 and ASTM-E647 are the standards for determination of KIC and FCGR of metallic materials. These standards recommend the use of compact tension (CT) or single edge notched bend (SENB) test specimens. Literature review indicates that CT or SENB specimens are complex in nature, difficult to manufacture, require typical fixtures for loading during experimentation and the test procedures using CT or SENB are time consuming and cumbersome. An alternate specimen geometry which can overcome the above said drawbacks is needed by the industry which can be used as standard test specimen geometry. This research work explains use of circumferentially cracked round bar (CCRB) specimens of high strength Al2014T651 alloy for determination of KIC and FCGR.The pre-cracked round bar specimen was loaded in tensile in a universal testing machine and pulled till failure. Using suitable stress intensity factor equations the fracture toughness can be calculated. In case of crack growth test, the pre-cracked round bar specimen is allowed to rotate under fatigue load. The ratio of length of crack propagated to the number of cycles to failure was the crack growth rate. The SEM analysis of fractured surfaces was also done.The results are comparable with the values reported in the literature obtained by using standard test specimens. There are numerous advantages of using round bar specimen in KIC and FCGR tests. It is concluded that, the methodology of determination of fracture toughness and fatigue crack growth rate using CCRB specimens is relatively simple, reliable, fast and economical. CCRB specimen may be recommended as a standard test specimen for fracture toughness as well as crack growth tests. © 2015 Elsevier Masson SAS. All rights reserved.
Effect of 1,2,3benzotriazole on the corrosion of aged 18Ni250 grade Maraging steel in Phosphoric acid solution
(2018) Naik, P.; Nayak, J.; Girish, L.V.; Somashekhar, T.M.; Bhanuprakash, S.H.; Rahul, S.
The 18 Ni 250 grade maraging steel is a potential high strength steel for advanced technologies such as aerospace, nuclear, and sporting goods. Phosphoric acid and Nitric acid solutions are used in pickling of delicate and precision items where re-rusting after pickling has to be avoided. The present work addresses the study of corrosion behaviour and inhibition using 1,2,3 benzotriazole of aged 18 Ni 250 grade maraging steel in phosphoric acid medium at higher concentration by Potentiodynamic Polarization Technique. The corrosion rates were determined in 1M, 1.5M and 2M by Tafel extrapolation technique in the temperature range 300C-500C with different concentrations of inhibitor. The results indicate that the corrosion rate increases with increase in acid concentration and temperature.Inhibition efficiency of 1,2,3benzotriazolewas found to increase with the increase in 1,2,3 benzotriazole concentration and decrease with the increase in temperature.The activation energy Ea and other thermodynamic parameters (?G,?H# and?S#) have been evaluated and discussed. The standard free energy of adsorption?Gads values indicates that the adsorption is of mixed type. Scanning electron microscopy (SEM) study confirmed the formation of an adsorbed protective film on the metal surface. � Published under licence by IOP Publishing Ltd.
Effect of 1,2,3benzotriazole on the corrosion of aged 18Ni250 grade Maraging steel in Phosphoric acid solution
(Institute of Physics Publishing helen.craven@iop.org, 2018) Naik, P.; Nayak, J.; Girish, L.V.; Somashekhar, T.M.; Bhanuprakash, S.H.; Rahul, S.
The 18 Ni 250 grade maraging steel is a potential high strength steel for advanced technologies such as aerospace, nuclear, and sporting goods. Phosphoric acid and Nitric acid solutions are used in pickling of delicate and precision items where re-rusting after pickling has to be avoided. The present work addresses the study of corrosion behaviour and inhibition using 1,2,3 benzotriazole of aged 18 Ni 250 grade maraging steel in phosphoric acid medium at higher concentration by Potentiodynamic Polarization Technique. The corrosion rates were determined in 1M, 1.5M and 2M by Tafel extrapolation technique in the temperature range 300C-500C with different concentrations of inhibitor. The results indicate that the corrosion rate increases with increase in acid concentration and temperature.Inhibition efficiency of 1,2,3benzotriazolewas found to increase with the increase in 1,2,3 benzotriazole concentration and decrease with the increase in temperature.The activation energy Ea and other thermodynamic parameters (Î”G,Î”H# andÎ”S#) have been evaluated and discussed. The standard free energy of adsorptionÎ”Gads values indicates that the adsorption is of mixed type. Scanning electron microscopy (SEM) study confirmed the formation of an adsorbed protective film on the metal surface. Â© Published under licence by IOP Publishing Ltd.
Enhancing photovoltaic performance of DSSCs sensitized with Ru-II complexes by D-?-A configured carbazole based co-sensitizers
(Royal Society of Chemistry, 2018) Naik, P.; Elmorsy, M.R.; Su, R.; El-Shafei, A.; Vasudeva Adhikari, A.
Herein, we report the photovoltaic performance studies of four D-?-A configured carbazole based co-sensitizers, P1-4, in DSSCs sensitized with Ru-II complexes, i.e.NCSU-10/N3. The organic co-sensitizers (P1-4) comprise carbazole as a donor scaffold, a phenylene ring as a ?-spacer and electron withdrawing functional groups, viz. cyanoacetic acid (P1), rhodanine-3-acetic acid (P1-2), barbituric acid (P3), and thiobarbituric acid (P4) as acceptor/anchoring units. From the results, it is evident that the device fabricated using co-sensitizer P1 carrying cyanoacetic acid, at the concentration of 0.2 mM NCSU-10, exhibited an enhanced photon conversion efficiency (PCE) of 9.19% with a JSC of 21.20 mA cm-2, VOC of 0.658 V and FF of 65.85%, while P3 containing barbituric acid displayed a PCE of 8.75% with a JSC of 22.23 mA cm-2, VOC of 0.671 V and FF of 58.64%, whereas NCSU-10 (0.2 mM) alone displayed a PCE of 8.28% with a JSC of 20.38 mA cm-2, VOC of 0.665 V and FF of 61.09%, but the dyes P2 carrying rhodanine-3-acetic acid and P4 containing thiobarbituric acid showed considerably lower performance. The co-sensitized devices of N3 with P1-4 displayed inferior photovoltaic performance compared to N3 itself, probably due to inefficient suppression of back current. The observed results have thrown new light upon the selection of appropriate and matchable co-sensitizers for improving photovoltaic performance of Ru-II based sensitizers. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Enhancing the Photoelectrochemical Performance of Ru(II)-Sensitized Dye-Sensitized Solar Cells Using Cyanopyridine-Based Cosensitizers
(John Wiley and Sons Inc, 2025) Naik, P.; Abdellah, I.M.; Abdel-Shakour, M.; Keremane, K.S.; Vasudeva Adhikari, A.V.
The cosensitization approach is one of the widely adopted strategies for systematically enhancing photovoltaic performance of dye-sensitized solar cells (DSSCs) by utilizing two or more dyes with distinct absorption spectra. This method achieves panchromatic absorption, improves intramolecular charge transfer performance, prevents dye aggregation, and increases dye loading capability. In this study, we investigated four previously reported push–pull-type dianchored chromophores (CP1–4) featuring a cyanopyridine scaffold as cosensitizer to enhance the performance of Ru(II)-based N3-sensitized DSSCs. Both the co-sensitized devices (N3 + CP1–4) and the N3-only devices were fabricated using a fixed dye concentration of 0.2 mM for each sensitizer/cosensitizers, while the coadsorbent chenodeoxycholic acid (CDCA) was systematically varied between 0 and 20 mM. This systematic variation of CDCA concentration was designed to examine its role in suppressing dye aggregation and modulating interfacial charge dynamics. Among the Series, CP4, carrying a thiobarbituric acid anchoring/acceptor group, demonstrated superior performance at all CDCA concentrations, achieving power conversion efficiency of 6.67%, 6.79%, and 5.74%, compared to 6.02%, 6.10%, and 5.44% for devices sensitized with N3 alone. Further, electrochemical impedance spectroscopy measurements confirmed the improved charge transport and reduced recombination in these devices. These findings highlight the potential of rationally engineered cosensitizers and optimized coadsorbent concentrations for enhancing the performance of metal-based sensitizers in DSSCs. © 2025 Wiley-VCH GmbH.
Exploring the application of new carbazole based dyes as effective p-type photosensitizers in dye-sensitized solar cells
(Elsevier Ltd, 2017) Naik, P.; Planchat, A.; Pellegrin, Y.; Odobel, F.; Vasudeva Adhikari, A.V.
Herein, we report the design and the synthesis of three new D-A type metal-free carbazole based dyes (C1–3) as effective photosensitizers for p-type DSSCs. In this new design, the electron rich carboxy substituted carbazole unit has been attached to three different electron withdrawing species, viz. N,N-dimethyl barbituric acid, N,N-diethyl thiobarbituric acid and N-ethyl rhodanine. They were well-characterized by spectral, photophysical and electrochemical analyses. Further, their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of structures of C1–3 on their photovoltaic performances. Further, the photovoltaic performance of C1–3 was determined along with the standard dye P1 and their PCE values were found to be in the order of P1 (0.047%) > C2 (0.040%) > C1 (0.016%) > C3 (0.001%). Interestingly, the NiO based p-type DSSC fabricated with C2 carrying electron withdrawing N,N-diethyl thiobarbituric acid displayed VOC as 59 ± 4 mV and FF as 29 ± 1%, which are higher than that of benchmark reference P1. This is attributed to the highest light harvesting ability, the greatest regeneration driving force and the lowest interfacial charge recombination of C2 among the tested dyes. Conclusively, the results showcase the potential of carbazole based D-A type sensitizers in the development of efficient p-type DSSCs. © 2017 Elsevier Ltd
Framework for Lightweight Deep Learning Model Using YOLOv5 for Arecanut Grade Assessment
(Springer, 2024) Naik, P.; Rudra, B.
Arecanut grading using Machine Learning (ML) approaches can be less ideal in real-world scenarios that require real-time operations due to the need for rapid processing and adaptation to varying conditions. This paper proposes an efficient and lightweight deep learning model for real-time Arecanut detection suitable for industrial applications. We introduce a novel Arecanut image dataset and explore the YOLOv5 architecture to achieve a lightweight and efficient model for both grading and detection. Our investigation reveals that a hybrid model utilizing GhostNet in Darknet-53 convolutions and a Feature Pyramid Network (FPN) in the YOLOv5 neck structure achieves optimal performance. This model achieves the best mean Average Precision (mAP) of 98.85% while maintaining a compact model size of only 1.9 MB. We compared our design with the latest YOLO models, and ours performed better in detecting Arecanuts. This accurate and cost-effective solution empowers Arecanut producers with the ability to identify top-grade Arecanuts, leading to economic benefits and mitigating health concerns associated with manual grading processes. Finally, we propose a framework for integrating this model into the agro-industry for future real-world implementation. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2024.
Friction and dry sliding wear of bismaleimide filled with carbon nanotubes
(Taylor and Francis Ltd. maney@maney.co.uk, 2016) Kurahatti, R.V.; Surendranathan, A.O.; Mordina, B.; Naik, P.; Auradi, V.
Three types of bismaleimide–carbon nanotubes (CNTs) nanocomposites were fabricated using two types of original multiwalled CNTs with different diameters and one amide functionalized CNTs. The influence of diameter, content and functionalization of CNTs on the flexural and dry sliding wear behaviour were measured with universal testing machine and pin-on-disc wear apparatus. The experimental results indicated that at 1.5 wt-%, the bismaleimide-functionalized MWCNTs exhibited highest flexural strength of 156 MPa which is increased by 164% as compared to the neat matrix, and lowest specific wear rate of 1.8 × 10?4 mm3 N?1 m?1 which is decreased by 90% as compared to the neat matrix. This was attributed to the dispersion of CNTs in the matrix and the filler-matrix adhesion and internal strength of the composite. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
Highly efficient carbazole based co-sensitizers carrying electron deficient barbituric acid for NCSU-10 sensitized DSSCs
(Elsevier Ltd, 2018) Naik, P.; Keremane, K.S.; Elmorsy, M.R.; Su, R.; El-Shafei, A.; Vasudeva Adhikari, A.V.
Herein, we report a comparative study of four interesting metal-free carbazole based organic dyes with different structural configurations, carrying electron deficient barbituric acid (C1-4), as effective co-sensitizers in DSSCs sensitized with NCSU-10 dye. The new entities comprise different structural architectures, viz. D-A (C1), D-?-A (C2), D-D-?-A (C3) and D-A-?-A (C4) configurations with same accepting/anchoring moiety. They consist of carbazole as donor scaffold linked to barbituric acid as an acceptor/anchoring unit via different ?-spacers. This paper describes the study of all the four co-sensitizers with regard to their structural, photophysical, electrochemical, theoretical and photovoltaic investigations. Also, it includes their structure-performance correlation study in detail. The devices co-sensitized with C1-4 displayed the superior photovoltaic performance when compared to NCSU-10 alone. The results ameliorate the role of efficient co-sensitizers to yield DSSC with improved performance. © 2018 Elsevier Ltd
Improved photovoltaic performances of Ru (II) complex sensitized DSSCs by co-sensitization of carbazole based chromophores
(Elsevier B.V., 2017) Naik, P.; Su, R.; El-Shafei, A.; Vasudeva Adhikari, A.
Herein, we report photovoltaic performance studies of three carbazole based dyes (N1–3) derived from (Z)-3-(9-hexyl-9H-carbazol-3-yl)-2-(thiophen-2-yl)acrylonitrile scaffold as effective co-sensitizers in Ru (II) complex, i.e. NCSU-10 sensitized DSSCs. From the results it is evident that, the device fabricated using co-sensitizer N3 with 0.2 mM of NCSU-10 exhibited improved photon conversion efficiency (PCE) of 8.73% with JSC of 19.87 mA·cm? 2, VOC of 0.655 V and FF of 67.0%, while N1 displayed PCE of 8.29% with JSC of 19.75 mA·cm? 2, VOC of 0.671 V and FF of 62.6%, whereas NCSU-10 (0.2 mM) alone displayed PCE of 8.25% with JSC of 20.41 mA·cm? 2, VOC of 0.667 V and FF of 60.6%. However, their EIS studies confirm that, N1, showing higher VOC is efficient in suppressing the undesired charge recombination in DSSCs through enhanced surface coverage on TiO2 and thereby resulting in longer electron lifetime than that of NCSU-10 dye alone. Here, the higher PCE of N3 can be attributed to its improved light harvesting efficiency, which is due to the presence of highly electron withdrawing barbituric acid in its structure. Conclusively, the results showcase the potential of simple carbazole based dyes as co-sensitizers in improving efficiency of DSSCs. © 2017
Improvement in performance of N3 sensitized DSSCs with structurally simple aniline based organic co-sensitizers
(Elsevier Ltd, 2018) Naik, P.; Abdellah, I.M.; Abdel-Shakour, M.; Su, R.; Keremane, K.S.; El-Shafei, A.; Vasudeva Adhikari, A.V.
In this work, we report comprehensive photovoltaic investigation of four structurally simple D-A configured organic dyes, A1-4 as active co-sensitizers in DSSCs sensitized with well-known Ru (II) based N3 dye. These effective co-sensitizers (A1-4) comprise N,N-dimethylaniline ring as donor scaffold linked with electron withdrawing functionalities, viz. barbituric acid (A1), N,N-dimethyl barbituric acid (A2), thiobarbituric acid (A3), and N,N-diethyl thiobarbituric acid (A4) as acceptor/anchoring units. In the present study, for the first time we have demonstrated the profound role of various simple organic molecules carrying different heterocyclic anchoring units on the photovoltaic parameters of the N3 sensitized devices. Also, the effect of concentration of sensitizer/co-sensitizers on the device performance characteristics has been investigated in depth. From the results, it is evident that, the device fabricated using co-sensitizer A2 carrying N,N-dimethyl barbituric acid along with sensitizer N3 in all concentrations outperformed when compared to N3 alone or other co-sensitizers. Interestingly, the best photovoltaic performance was obtained for the co-sensitized device fabricated using 0.3 mM co-sensitizer A2 along with 0.2 mM of N3 sensitizer. It displayed PCE of 7.02% with JSC of 15.27 mA·cm?2, VOC of 0.671 V and FF of 68.47%. Thus, the observed results have thrown new light upon the device optimization to yield DSSCs with improved performance by the selection of matchable co-sensitizers at appropriate concentrations. © 2018 Elsevier Ltd
Investigation of new carbazole based metal-free dyes as active photo-sensitizers/co-sensitizers for DSSCs
(Elsevier Ltd, 2018) Naik, P.; Su, R.; Elmorsy, M.R.; El-Shafei, A.; Vasudeva Adhikari, A.V.
Herein, we report the molecular design, synthesis and characterization of three new D-D-?-A configured metal-free chromophores D1-3 for their application in DSSCs as sensitizers as well as co-sensitizers. The new entities comprise carbazole as donor scaffold, 4-methoxyphenyl group as auxiliary donor and three different units, viz. cyanoacetic acid, 2, 4-thiazolidinedione and barbituric acid as acceptor/anchoring groups. Their photochemical, electrochemical and theoretical studies were carried out in order to assess their feasibility as active sensitizers. Further, D1-3 were exploited as co-sensitizers along with NCSU-10 dye. Their photoelectrochemical performances and charge transport properties in fabricated DSSCs were studied. The results revealed that D1 sensitizer displayed the highest PCE of 2.20% among the three dyes. D3 when co-sensitized with NCSU-10 displayed an improved PCE of 8.32% (JSC = 19.25 mA.cm?2, VOC = 0.680 V, FF = 63.7%) while NCSU-10 alone exhibited PCE of 8.25% (JSC = 20.41 mA.cm?2, VOC = 0.667 V, FF = 60.6%). © 2017 Elsevier Ltd
Molecular design and theoretical investigation of new metal-free heteroaromatic dyes with D-?-A architecture as photosensitizers for DSSC application
(Elsevier B.V., 2017) Naik, P.; Su, R.; Elmorsy, M.R.; Babu, D.D.; El-Shafei, A.; Vasudeva Adhikari, A.
Herein, we report design, synthesis and photovoltaic performance of four new metal-free heteroaromatic dyes (P1-4) with D-?-A architecture carrying electron donating carbazole core connected to four different electron withdrawing/anchoring groups, viz. cyanoacetic acid, rhodanine-3-acetic acid, barbituric acid and thiobarbituric acid and phenylene ring as a ?-spacer. The newly designed P1-4 were synthesized from carbazole derivative using Suzuki cross coupling approach followed by Knoevenagel condensation reaction. Their structures were confirmed by FTIR, NMR, Mass spectral and elemental analyses. The dyes were subjected to optical and electrochemical studies in order to investigate their absorption/emission behavior as well as HOMO/LUMO energies. The UV–vis spectral studies reveal that the P1-4 showed ?max at 412, 439, 458 and 489 nm, respectively. Their optical band-gap is in the range of 2.17 to 2.61 eV and fluorescence quantum yield is in the order of 44–70%. From energy level diagram, it is clear that all the dyes possess good thermodynamic feasibility for electron injection into CB edge of TiO2 as well as their regeneration from electrolyte system. The photovoltaic performance studies indicate that among the tested dyes, P1 anchored with cyanoacetic acid displayed the highest IPCE (32%), resulting in improved PCE (1.94%), JSC (4.68 mA cm?2), VOC (0.588 V) and FF (70.3%) values, when compared to other dyes. Finally, DFT studies were performed using Turbomole 7.1 V software to investigate their electron cloud delocalization in HOMO/LUMO levels and theoretical absorption spectral data. The results reveal that the dye P1 showed effective charge separation in its FMO levels, which has reflected in its ICT behavior and hence P1 displayed the improved photovoltaic performance. © 2017 Elsevier B.V.
Molecular Engineering of a New Organic Chromophore with D-?-A Architecture for Dye-Sensitized Solar Cells
(2018) Naik, P.; Vasudeva, Adhikari, A.
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 ?-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.
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 Ï€-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. Â© 2018 Elsevier Ltd. All rights reserved.
New blue light emitting cyanopyridine based conjugated polymers: From molecular engineering to PLED applications
(Elsevier B.V., 2019) Pilicode, N.; K M, N.K.; Acharya, M.; Naik, P.; N, S.M.; Vasudeva Adhikari, A.V.
In this work, we report the design of three new cyanopyridine scaffold based polymers, viz. TPy 1-3 as potential blue light emitters for PLED applications. The new polymer design comprise, a cyanopyridine core as an electron accepting entity, thiophene as an electron donating unit with different auxiliary donors, viz. phenylene (TPy 1 ), biphenyl (TPy 2 ), and fluorene (TPy 3 ), and have been synthesized, following standard synthetic protocols including Suzuki-cross coupling polymerization reaction. Further, in order to assess all the prerequisites to act as an active emitter, the polymers TPy 1-3, were subjected to structural, thermal, linear optical, electrochemical and computational studies. The results revealed that, all the polymers were thermally stable up to 300 ?C and their estimated optical band-gaps were found to be 2.59–2.80 eV. Finally, new polymer light emitting diode (PLED) were fabricated by employing the polymers TPy 1-3, as active emissive material with a configuration of ITO/PEDOT: PSS/Polymer/Al. Interestingly, all the fabricated devices, exhibited an intense blue electroluminescence at 12 V with low threshold voltages of 4.2–4.8 V, signifying an effective injection of electron in the device. © 2019 Elsevier B.V.