Browsing by Author "Shubham Sharma"

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An AcOH-mediated metal free approach towards the synthesis of bis-carbolines and imidazopyridoindole derivatives and assessment of their photophysical properties
(Royal Society of Chemistry, 2019) Dharmender Singh; Shubham Sharma; Mukesh Kumar; Inderpreet Kaur; Ravi Shankar; Satyendra Kumar Pandey; Virender Singh
An AcOH-mediated concise, atom-economical and environmentally sustainable tandem strategy has been formulated to access highly fluorescent (Φ F up to 40%) N-fused bis-carbolines, imidazopyrido[3,4-b]indoles and imidazo[1,5-a]pyridines via the formation of three C-N bonds in a single operation. The multicomponent character of the reaction, easy to execute reaction conditions, simple purification procedure and excellent light emitting properties of the product afforded thereof provide a huge scope. © 2019 The Royal Society of Chemistry.
Application of new natural dyes extracted from Nasturtium flowers (Tropaeolum majus) as photosensitizer in dye-sensitized solar cells
(Elsevier GmbH, 2021) Shalini Singh; Ishwar Chandra Maurya; Shubham Sharma; Shiva Prakash Singh Kushwaha; Pankaj Srivastava; Lal Bahadur
This work reported the natural dyes extracted from yellow and orange Nasturtium (Tropaeolum majus) flower petals and then used them as sensitizer in dye-sensitized solar cells (DSSCs) for the first time. The functional groups present in the dyes were identified by FTIR spectroscopy which revealed the characteristic peaks of pigments anthocyanins and carotenoids. The UV–Visible analysis of dye extracts showed absorption in the visible region and the dye loaded TiO2 exhibited broad absorption. The density functional theory (DFT) calculation was performed on Lutein, Cyanidin-3-sophoroside, Delphinidine-3-dihexoside and Pelargonidin-3-sophoroside to find out the HOMO and LUMO levels of each. The DSSCs were constructed using these natural extracts as sensitizer dye and photovoltaic performance such as conversion efficiency (η), short-circuit current density (Jsc), open-circuit voltage (Voc) and fill factor (FF) were investigated. The electrochemical impedance spectroscopy (EIS) studies were performed to analyze the charge transfer characteristics. The light-to-electricity conversion efficiency of 0.28% is achieved with Voc of 0.556 V, Jsc of 0.72 mA/cm2 and FF of 0.70 for natural sensitizer extracted from orange petals of Nasturtium flowers. © 2021 Elsevier GmbH
Base-Mediated Regioselective Synthesis of Pyrrolo[3,4-b]quinolin-1-one and Benzo[b][1,6]Naphthyridin-1(2H)-One Derivatives from o-Alkynyl Quinoline-3-carbonitriles and Their Photophysical Properties
(John Wiley and Sons Inc, 2024) Vipin Kumar; Shubham Sharma; Satyendra Kumar Pandey; Virender Singh
A KOtBu-promoted robust strategy has been described for the regioselective synthesis of pyrrolo[3,4-b]quinolin-1-one and naphthyridin-1(2H)-one derivatives from o-alkynylquinolinecarbonitriles in good to excellent yields. The reaction proceeds through in situ transformation of the nitrile moiety into an amide group followed by the selective C−N bond formation through a 5-exo-dig or 6-endo-dig annulation reaction. Among the synthesized derivatives, 6-endo-dig naphthyridin-1(2H)-ones displayed good photophysical properties. The present approach is superior to other established methodologies as it avoids use of transition metals and column chromatographic purification and affords the products in high yields. Additionally, the current methodology provides several additional advantages, such as one-pot operation, high atom economy, broad substrate scope and a step-economical process. © 2024 Wiley-VCH GmbH.
Colletotrichum gloeosporioides (endophytic fungi) mediated biosynthesis of TiO2 nanoparticles for high-performance dye-sensitized solar cell
(Elsevier B.V., 2025) Sakshi Singh; Shubham Sharma; Rajnish Bharti; Ravindra Nath Kharwar; Pankaj Kumar Srivastava
This work reports an environmentally friendly protocol for synthesizing TiO2 nanoparticles (NPs) by utilizing endophytic fungi, Colletotrichum gloeosporioides (C. gloeosporioides). The fungi isolated from Thevetia peruviana, worked as a bio-capping agent to regulate the growing TiO2 NPs morphology and agglomeration behavior. The formation of TiO2 NPs was validated by surface plasmon resonance, observed using UV–vis spectroscopy. Using XRD and HRTEM, the structure, size, and shape of the as-synthesized anatase TiO2 NPs were characterized. BET analysis was used to examine the surface area and porosity. EIS revealed the greater charge collection efficiency and enhanced electron lifetime for the TiO2 obtained with N-3 (endophytic fungal extract). The dye-sensitized solar cell (DSSC) fabricated with bio-capped TiO2 (N-3) photoanode exhibited greater light-to-current conversion efficiency, 3.50 %; much enhanced compared to 0.98 % obtained with un-capped TiO2 NPs (N-1) based cell. The study demonstrated that the endophytic fungus C.gloeosporioides played a vital role in enhancing the cell performance. © 2024 The Authors
Comparative study of natural dyes extracted from dark red and yellow Frangipani flowers (Plumeria rubra L.) as DSSC sensitizer
(Elsevier GmbH, 2024) Abhilasha Tiwari; Shubham Sharma; Nikhil Srivastav; Pankaj Srivastava
Dye-sensitized solar cells (DSSC) provide credible alternative for the inorganic solid-state photovoltaic devices. In this work, natural sensitizer extracted from Plumeria rubra L. flower (Frangipani) in ethanol has been used as the sensitizer dye. Dark red and yellow species of Frangipani flower petals extracted natural dyes have been studied for their comparative performance as sensitizer dye. FTIR revealed the presence of hydroxyl and carbonyl group in the sensitizer dye, which helped in binding with TiO2. UV-Visible analysis revealed absorption in visible region, which got broadened for dye loaded TiO2. Mass spectrometry confirmed major chemical constituents present in Plumeria rubra L. flower. For the HOMO and LUMO levels of dark red and yellow Frangipani flowers, the density functional theory (DFT) calculation was performed. Light-to-electricity conversion efficiency (ɳ%) of dark red Frangipani flowers was achieved 0.148 % with Voc 0.27 V, Jsc 0.88 mA/cm2 and FF 0.62, which was comparatively higher than yellow Frangipani flowers-based cell having ɳ% 0.128 % with Voc 0.54 V, Jsc 0.37 mA/cm2 and FF 0.64, respectively. For analyzing the charge transfer characteristics, electrochemical impedance spectroscopy (EIS) studies were carried out. The dark red species of Frangipani flower showed better result as sensitizer dye compared to the yellow species. © 2024 Elsevier GmbH
Effect of Dye Extraction Solvent on the Photovoltaic Performance of Tecoma stans-Sensitized Solar Cells
(Springer, 2020) Shalini Singh; Ishwar Chandra Maurya; Shubham Sharma; Pankaj Srivastava; Lal Bahadur
Abstract: The use of natural dyes as photosensitizers has several advantages including their easy extraction and their biodegradable, nontoxic, and environmentally friendly nature, which makes them vital for application in dye-sensitized solar cells (DSSC). In the present work, we study the effects of extraction solvent on the photovoltaic performance of a natural dye sensitizer for TiO2-based DSSC. Extracts of Tecoma stans flowers in two different solvents, ethanol and ethanol–water mixture, were used as the dye sensitizer for extending the spectral sensitivity of TiO2. The optical properties of the dye extracts were studied by their UV–visible absorption spectra. Fourier transform infrared spectra revealed the presence of anchoring groups and coloring pigments, and nuclear magnetic resonance spectroscopy and mass spectrometry were used to characterize the main constituents of the dye extract. The photovoltaic characteristics of these dye extracts coated on TiO2 were investigated by employing them as DSSC photoanodes. With the dye extracted in ethanol and coated on TiO2, an open-circuit voltage (Voc) of 0.293 V, short-circuit photocurrent density (Jsc) of 0.790 mA/cm2, fill factor (FF) of 0.46, and conversion efficiency (η) of 0.13% were obtained, whereas dye extracted in the ethanol–water mixture revealed Voc of 0.285 V, Jsc of 0.735 mA/cm2, FF of 0.37, and η of 0.09%. The photovoltaic performance of the dye extracts in the two cases underlines the greater effectiveness of ethanol as dye extraction solvent. Graphical Abstract: [Figure not available: see fulltext.] © 2020, The Minerals, Metals & Materials Society.
Enhanced conversion efficiency enabled with natural dyes extracted from Mirabilis flower and Bixa seed revealing prospects of application of co-sensitized DSSC
(Elsevier GmbH, 2024) Ishwar Chandra Maurya; Shalini Singh; Shubham Sharma; Shiva Prakash Singh Kushwaha; Pankaj Srivastava; Lal Bahadur
In this report, we present the studies on co-sensitization effects of two natural dyes extracted from Mirabilis flower and Bixa seeds on TiO2-based dye-sensitized solar cells (DSSC). The objective is to extend the spectral sensitivity and light-to-electrical energy conversion efficiency of the selected dyes. UV–visible absorption within the 480–580 nm and 400–500 nm range signify anthocyanin in Mirabilis flower and carotenoid in Bixa seed respectively. Bixa seed and Mirabilis flower extracted mixed natural dye exhibited absorption in 400–600 nm range. The study further established the co-sensitization through computational studies and electrochemical impedance spectroscopy (EIS) studies. With the use of Bixa seed and Mirabilis flower extracted dye, photovoltaic parameter short-circuit current density (Jsc) & conversion efficiency (η) were observed 0.20 mA/cm2, 0.44 mA/cm2 and 0.09 % 0.38 % respectively. The Bixa seed and Mirabilis flower extracts co-sensitized DSSC revealed enhanced Jsc 0.65 mA/cm2 and η 0.40 %. © 2024 Elsevier GmbH
Extensive enhancement in power conversion efficiency of dye-sensitized solar cell by using Mo-doped TiO2 photoanode
(Springer Science and Business Media Deutschland GmbH, 2022) Ashish Jayasawal; Shubham Sharma; Shalini Singh; Pankaj Srivastava
In this work, we have synthesized Mo-doped TiO2 nanoparticles by sol–gel method and used them as photoanode in dye-sensitized solar cells (DSSCs). Mo doping resulted in reduced TiO2 crystallite size as revealed from XRD and TEM studies, which caused enhancement in surface area and greater dye loading and hence improved current conversion efficiency of DSSC. The short-circuit current density (JSC) and efficiency (η) of the cell employing Mo-doped TiO2 photoanode have been extensively enhanced compared to the cell using un-doped TiO2. The optical bandgap (Eg) for 0.25 wt% Mo-doped TiO2 and un-doped TiO2 was obtained as 2.35 eV and 3.04 eV, respectively. The values of JSC and η for the cell employing 0.25 wt% Mo-doped TiO2 photo-anode were 8.54 mA/cm2 and 3.78%, respectively, under illumination of 100 mW/cm2 light intensity (with corresponding values for un-doped TiO2 4.01 mA/cm2 and 0.73% respectively under similar illumination condition). Electrochemical impedance spectroscopy (EIS) and Mott–Schottky analyses revealed resistivity, capacitive elements, the donor density, and flat band potential respectively for un-doped and Mo-doped TiO2. The work demonstrated that Mo-doped TiO2 can be used as a photo-anode material for developing low-cost, high-efficiency DSSC. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Natural Saccharum officinarum (sugarcane) juice assisted TiO2 nanoparticle synthesis for high performance dye-sensitized solar cell
(Elsevier B.V., 2024) Priyanshi Singh; Shubham Sharma; Pankaj Srivastava
Green chemistry technologies are perceived to be more straightforward, sustainable and cost-effective and therefore explored extensively in recent years. A range of natural reducing and capping agents, viz. proteins, enzymes, and phytochemicals have been used to synthesize TiO2 nanoparticles. The capping agents are vital in stabilizing nanoparticles, avoiding their over-growth and aggregation during synthesis. In this work, green synthesis of TiO2 has been carried out through the sol-gel method using Saccharum officinarum (sugarcane) juice as a capping agent. The optical properties, morphology, size, and porosity of the synthesized TiO2 were characterized by UV, FT-IR, XRD, TEM, and BET respectively. The XRD pattern and TEM confirmed the anatase phase and particle size, while BET revealed surface area and pore sizes. Under irradiance of 100 mWcm−2 light intensity, the photoelectric conversion efficiency using capped TiO2 sensitized with N719 dye was observed to 3.65 %, much enhanced compared to the efficiency 0.69 % observed with the un-capped TiO2. The present study successfully demonstrated that sugarcane phytochemicals have the potential to improve dye-sensitized solar cell (DSSC) efficiency via inducing capping during nucleation in TiO2 synthesis. © 2023 Elsevier B.V.
NCCP-ICS joint consensus-based clinical practice guidelines on medical thoracoscopy
(Wolters Kluwer Medknow Publications, 2024) Rakesh K. Chawla; Mahendra Kumar; Arun Madan; Raja Dhar; Richa Gupta; Dipti Gothi; Unnati Desai; Manoj Goel; Rajesh Swarankar; Amita Nene; Radha Munje; Dhruv Chaudhary; Randeep Guleria; Vijay Hadda; Vivek Nangia; Girish Sindhwani; Rajesh Chawla; Naveen Dutt; Yuvarajan; Sonia Dalal; Shailendra Nath Gaur; Subodh Katiyar; Jai Kumar Samaria; K.B. Gupta; Parvaiz A. Koul; Suryakant; D.J. Christopher; Dhrubajyoti Roy; Basant Hazarika; Shanti Kumar Luhadia; Anand Jaiswal; Karan Madan; Prem Parkash Gupta; B.N.B.M. Prashad; Nasser Yusuf; Prince James; Amit Dhamija; Veerotam Tomar; Ujjwal Parakh; Ajmal Khan; Rakesh Garg; Sheetu Singh; Vinod Joshi; Nikhil Sarangdhar; Sushmita Roy Chaudhary; Sandeep Nayar; Anand Patel; Mansi Gupta; Rama Kant Dixit; Sushil Jain; Pratibha Gogia; Manish Agarwal; Sandeep Katiyar; Aditya Chawla; Hari Kishan Gonuguntala; Ravi Dosi; Vijya Chinnamchetty; Apar Jindal; Shubham Sharma; Vaibhav Chachra; Utsav Samaria; Avinash Nair; Shruti Mohan; Gargi Maitra; Ashish Sinha; Rishabh Kochar; Ajit Yadav; Gaurav Choudhary; M. Arunachalam; Amith Rangarajan; Ganesh Sanjan
Medical Thoracoscopy (MT) is commonly performed by respiratory physicians for diagnostic as well as therapeutic purposes. The aim of the study was to provide evidence-based information regarding all aspects of MT, both as a diagnostic tool and therapeutic aid for pulmonologists across India. The consensus-based guidelines were formulated based on a multistep process using a set of 31 questions. A systematic search of published randomized controlled clinical trials, open labelled studies, case reports and guidelines from electronic databases, like PubMed, EmBase and Cochrane, was performed. The modified grade system was used (1, 2, 3 or usual practice point) to classify the quality of available evidence. Then, a multitude of factors were taken into account, such as volume of evidence, applicability and practicality for implementation to the target population and then strength of recommendation was finalized. MT helps to improve diagnosis and patient management, with reduced risk of post procedure complications. Trainees should perform at least 20 medical thoracoscopy procedures. The diagnostic yield of both rigid and semirigid techniques is comparable. Sterile-graded talc is the ideal agent for chemical pleurodesis. The consensus statement will help pulmonologists to adopt best evidence-based practices during MT for diagnostic and therapeutic purposes. © 2024 Indian Chest Society.
Thoracoscopic practices in India-a survey by Indian chest society
(Tuberculosis Association of India, 2021) Rakesh K. Chawla; D.J. Christopher; Raja Dhar; S. Yuvarajan; Kamal Chopra; J.K. Samaria; Virender singh; Neeraj Gupta; Parvaiz Kaul; Rajesh Swarankar; Arun Madan; Mahendra Kumar; Aditya K. Chawla; Shubham Sharma; Gaurav Chaudhary; Madhav k. Chawla
Background: Diagnostic thoracentesis is the initial diagnostic investigation in the workup of an undiagnosed Pleural effusion. However, a significant percentage of pleural effusions remain undiagnosed after this step and after closed pleural biopsy. Medical thoracoscopy (MT) has a high diagnostic yield in these patients. MT is now widely practised in India. This survey endeavours to study the practice of this technique by respiratory physicians in India. Methods: An electronic survey called ‘Indian Thoracoscopy survey’ was prepared and conducted under the aegis of Indian Chest Society. In all there were 63 Questions in English prepared and disseminated as a “Google Form” to conduct this survey. The subjects were recruited from the e-mail lists of the three major professional surgeries that serve the interests of the respiratory physicians. The participation in the survey was voluntary and no incentive of any sort was offered to the participants. The survey link was kept open for a 3-month period. Results: There were total 659 respondents, whose mean age was 41.5 years and majority of them were males (n = 564, 85.6%). The largest group of respondents practiced in corporate/private hospitals (n = 315, 47.8%). Only 311 (47.2%) respondents performed MT. Of these, 190 (61.1%) used flex-rigid/semi rigid thoracoscopes. Undiagnosed pleural effusions (N = 194; 62.4%) and recurrent pleural effusions (N = 117; 37.6%) were the most common indications for performing MT. Majority of the thoracoscopists (222, 71.4%) used conscious sedation and a combination of Midazolam and Fentanyl was the most preferred combination (n = 238; 76.5%). Most follow the manufacturer's recommendation for thoracoscope cleaning and disinfection and had safety check lists in place. Conclusion: Our survey captures the practice of MT in India. MT seems to be increasing in popularity with significant numbers of respiratory physicians performing the procedure. Respondents felt that MT was a valuable investigation that was underused and more of them wanted to learn. It is safe to perform MT under conscious sedation and local anaesthesia and a boon to patients who required surgical procedures for evaluation of difficult to diagnose pleural diseases. The setup cost is significant and would not justify installation in all centres. The lack of opportunities for training is something that needs to be looked in to. © 2021 Tuberculosis Association of India
Utilization of plant food waste: Sustainable approaches and innovations
(Elsevier, 2025) Shiva Bakshi; Shubham Sharma; Vishal Kumar; Kaminee Singh; Prajasattak Kanetkar; V. K. Paswan; Durga Shankar Bunkar
With the alarming rise in the global population, the issue of waste generation, particularly food waste, has reached a critical level. The urgency of this problem is underscored by the fact that reducing food waste is one of the key sustainable development goals. The plant waste includes leftover, spoiled, processed/unprocessed agricultural produce possessing the potential for manufacturing high-value compounds. However, most conventional approaches to waste utilization are either composting, animal food, or landfill, having their own demerits. Hence, at present, there is a pressing need for economical and eco-friendly techniques that can ultimately contribute toward sustainability. Valorization presents a new opportunity for the production of biofuels, fertilizers, and bioactives. This chapter provides insight into the distinctive types of food waste: fruits and vegetables, cereals and legumes, roots and tubers, spices and herbs, etc. It also comprehensively emphasizes that strategies opted for waste utilization, leading to a circular economy. Furthermore, the nutritional value and potential health benefits of derived phytoconstituents are highlighted. Nonetheless, more interdisciplinary and collaborative studies are required for the promotion of waste utilization. © 2026 Elsevier Inc. All rights reserved..