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4. Environment-Driven Variability in Absolute Band Edge Positions and Work Functions of Reduced Ceria

Author

Zhang, Xingfan, primary, Blackman, Christopher, additional, Palgrave, Robert G., additional, Ashraf, Sobia, additional, Dey, Avishek, additional, Blunt, Matthew O., additional, Zhang, Xu, additional, Liu, Taifeng, additional, Sun, Shijia, additional, Zhu, Lei, additional, Guan, Jingcheng, additional, Lu, You, additional, Keal, Thomas W., additional, Buckeridge, John, additional, Catlow, C. Richard A., additional, and Sokol, Alexey A., additional

Published
2024
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6. Applications of atmospheric pressure plasma in surface engineering

Author

Dey, Avishek

Subjects
621.044
Abstract

Plasma processing of materials has grown to be a key technology for various industrial applications. Low pressure plasmas have found wide applications; they require expensive vacuum systems and need orderly maintenance. Atmospheric pressure plasma jets (APPJs) on the other hand are less technically demanding. APPJs can generate a high flux of active species and are a promising alternative to low pressure plasmas for surface treatment. For an APPJ the plasma is not confined within the dimensions of the electrodes and can be directed towards the desired region. This dissertation is aimed at three novel applications of atmospheric pressure plasmas: printing nanomaterials, functionalization of nanomaterials and deactivation of airborne microbes. For all the contributions presented in this thesis emphasis have be given on studying the effects of plasma on surfaces. A novel APPJ based printing technique is proposed and developed to address issues of material degradation in conventional printing techniques. The process involves printing using nano-colloidal ink. The novelty of this printing technique is that it can tune the electronic properties of the nanomaterials in-situ while printing. Near edge X-ray fine structure (NEXAFS) spectroscopy of the deposited copper nanoparticles confirmed that the oxidation state of copper can be reduced equally at the surface and in the bulk. Also, by varying the gas mixture in the plasma the morphology of the films can be varied from uniform to porous. The film formed from copper nanoparticles tend to be insulating but can be transformed to conductive films through use of APPJ processes. Graphene oxide (GO) has found applications in multi-junction devices as charge transport layers or transparent electrodes. This is because, the work function of GO can be tuned to the device specifications. A lower power APPJ has been used to dope GO films with nitrogen. High resolution X-ray photoelectron (XPS) and NEXAFS spectroscopy revealed that the plasma induces finite changes in the surface chemistry and also influences the electronic properties of GO. Kelvin probe microscopy on the functionalized films has shown that the work function of GO can be tuned by 120 mV. This variation has been linked to the specific nitrogen configuration in the graphitic lattice. An APPJ device has also been used for depositing graphene oxide (GO) films. Hummer’s method is widely used for the oxidative exfoliation of graphite. Due to the use of strong acids, the resultant GO suspension is highly acidic and need extensive dilution to neutralize pH. It has been demonstrated for the first time that an APPJ can in-situ reduce highly acidic graphene oxide while deposition. XPS and NEXAFS spectroscopy revealed marked differences in the oxygen containing functional groups after deposition. Both NEXAFS and Raman spectroscopy revealed the healing of sp² graphitic structure. Subsequent increase in conductivity was also observed from the electrostatic force microscopy measurements. The decontamination of airborne microbes using an atmospheric pressure dielectric barrier discharge has been demonstrated. Here, air has been used as the process gas and is found to be highly efficient in the inactivation of microbes. After interaction with the plasma, the physical structure of the microbes was found to be severely distorted and changes in surface chemical composition were also observed from NEXAFS studies. These physiochemical changes lead to the annihilation of microbes.

Published
2018
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14. Water‐Vapor Responsive Metallo‐Peptide Nanofibers.

Author

Dey, Avishek, Naranjo, Elma, Saha, Ranajit, Zhang, Sheng, Nair, Maya Narayanan, Li, Tai‐De, Chen, Xi, and Ulijn, Rein V.

Abstract

Short peptides are versatile molecules for the construction of supramolecular materials. Most reported peptide materials are hydrophobic, stiff, and show limited response to environmental conditions in the solid‐state. Herein, we describe a design strategy for minimalistic supramolecular metallo‐peptide nanofibers that, depending on their sequence, change stiffness, or reversibly assemble in the solid‐state, in response to changes in relative humidity (RH). We tested a series of histidine (H) containing dipeptides with varying hydrophobicity, XH, where X is G, A, L, Y (glycine, alanine, leucine, and tyrosine). The one‐dimensional fiber formation is supported by metal coordination and dynamic H‐bonds. Solvent conditions were identified where GH/Zn and AH/Zn formed gels that upon air‐drying gave rise to nanofibers. Upon exposure of the nanofiber networks to increasing RH, a reduction in stiffness was observed with GH/Zn fibers reversibly (dis‐)assembled at 60–70 % RH driven by a rebalancing of hydrogen bonding interactions between peptides and water. When these metallo‐peptide nanofibers were deposited on the surface of polyimide films and exposed to varying RH, peptide/water‐vapor interactions in the solid‐state mechanically transferred to the polymer film, leading to the rapid and reversible folding‐unfolding of the films, thus demonstrating RH‐responsive actuation. [ABSTRACT FROM AUTHOR]

Published
2024
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17. Exploring Bismuth Coordination Complexes as Visible-Light Absorbers: Synthesis, Characterization, and Photophysical Properties

Author

Bhatia, Harsh, primary, Guo, Junjun, additional, Savory, Christopher N., additional, Rush, Martyn, additional, James, David Ian, additional, Dey, Avishek, additional, Chen, Charles, additional, Bučar, Dejan-Krešimir, additional, Clarke, Tracey M., additional, Scanlon, David O., additional, Palgrave, Robert G., additional, and Schroeder, Bob C., additional

Published
2023
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20. Plasma jet printing induced high-capacity graphite anodes for sustainable recycling of lithium-ion batteries

Author

Bhar, Madhushri, Dey, Avishek, Ghosh, Sourav, van Spronsen, Matthijs A., Selvaraj, Vimalnath, Kaliprasad, Y., Krishnamurthy, Satheesh, and Martha, Surendra K.

Subjects
General Materials Science, General Chemistry
Abstract

Graphite is an integral part of lithium-ion batteries (LIBs). However, due to limited resources and high production cost, producing battery grade graphite to meet the increasing demands for energy storage devices is becoming a challenge. One viable approach is to recycle the spent graphite anodes from end-of-life LIBs. Importantly, recycling of spent lithium-ion batteries (LIBs) is off utmost importance to address the global challenge of electronic waste management. Herein, we present an environmentally friendly technique of graphite recycling from spent LIB by water leaching, followed by atmospheric plasma jet printing. The major advantage of this method is that it does not require any binders or conductive diluents. Plasma-printed recycled graphite showed a significantly enhanced specific capacity of 402 mAh g−1 at 500 mA g−1 at the end of the 1000th charge-discharge cycle, in comparison to water-washed recycled graphite (112 mAh g−1) and a 23.35 times faster diffusivity of Li+. A detailed experimental investigation revealed that the plasma activation of the graphitic structure resulted in the improved reversible Li+ storage. This work provides a new perspective on the recycling strategy of graphite anodes using in situ plasma functionalization, a significant step towards the sustainable future of LIBs.

Published
2022

22. Virtual screening and molecular docking study of some naturally available phytochemicals against SARS-CoV-2.

Author

Dey, Avishek, Ahmad, Iqrar, Mondal, Keshab, Jana, Rathin, Patel, Harun, and Mistri, Soumen

Subjects
*SARS disease, *SARS-CoV-2, *MOLECULAR docking, *PHYTOCHEMICALS, *PROTEIN-ligand interactions, *DRUG bioavailability
Abstract

The novel human corona virus disease 2019, also known as COVID 19 or SARS-CoV-2 have designated as severe acute respiratory syndrome coronavirus 2, first emerged in Wuhan, China at the end of 2019. Now a day, it is a great challenge to scientist in the area of biology and chemistry in order to develop anticoronaviral drugs to overcome from this disease. SARS-CoV-2 was identified as a single-stranded positive-sense RNA virus. In this study we used virtual screening and molecular docking investigation of some naturally occurring bioactive organic compounds having the various phytochemical properties to compare the potential inhibitory activity of these molecules against SARS-CoV-2 protease. Based on ADME analysis and molecular docking study, Amentoflavone, Kazinol A, Kazinol B, Berbamine, Broussoflavan A, (-)-Catechin gallate and Juglanin exhibits remarkable potentiality to bind with Mpro as compare to native ligand N3. Moreover the bioavailability radar study shows that Broussoflavan A is the only compound which is orally bioavailable among the studied compounds. A molecular dynamics simulation study of the ligand (Broussoflavan A) with protein indicates that the complex is stable. The docking study and MD simulation study indicates that in the protein-ligand complex, Broussoflavan A interact with active site of SARS-CoV-2 main protease. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Aminoethylpiperazine Based Metal Schiff Base Complexes: Catalytic and Biological Activities.

Author

Mondal, Keshab, Dey, Avishek, and Mistri, Soumen

Subjects
*SCHIFF bases, *CATALYTIC activity, *PIPERAZINE, *TRANSITION metal compounds, *ANTIFUNGAL agents, *ORGANOMETALLIC compounds, *METALWORK, *ANTIVIRAL agents
Abstract

Piperazine, a six-membered nitrogen-based heterocycle, is widely distributed in nature and also has great therapeutic efficacy due to abundant of large number of biomolecules with multiple functions. Owing to the activities, developments of piperazine-based compounds are receiving great attention among the research chemists. Nowadays, piperazine and its various homologues exhibit various biological roles such as antibiotics, anticancer, antimicrobial, antipsychotics and antidepressants. In this context, various piperazine-based metal-Schiff base complexes have been synthesized to investigate their catalytic and biological activity. In addition, a large number of Schiff base transition metal compounds have been reported which play a significant role in biology due to their potential antimicrobial, antifungal, antitumor, antiviral and antidiabetic properties. The present review encompasses the applications of various aminoethylpiperazine-based metal Schiff base complexes. Aminoethylpiperazine is one of important structural motifs which have different active sites/structural features and capable to bind with the metal ion to form chelate ring and also explore biological and catalytic properties of its Schiff base-based metal organic complexes. This review mainly focused on the catalytic and biological importance of aminoethylpiperazine-based metal organic complexes during the period of 2012–2020. [ABSTRACT FROM AUTHOR]

Published
2023
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32. Engineering work function of graphene oxide from p to n type using a low power atmospheric pressure plasma jet

Author

Dey, Avishek, Ghosh, Paheli, Bowen, James, Braithwaite, N St.J, and Krishnamurthy, Satheesh

Subjects
Materials science, Graphene, Plasma parameters, Doping, Analytical chemistry, General Physics and Astronomy, Atmospheric-pressure plasma, Heterojunction, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, law.invention, X-ray photoelectron spectroscopy, law, Work function, Physical and Theoretical Chemistry, 0210 nano-technology, Spectroscopy
Abstract

In this work, we demonstrate doping graphene oxide (GO) films using a low power atmospheric pressure plasma jet (APPJ) with subsequent tuning of the work function. The surface potential of the plasma functionalized GO films could be tuned by 120 ± 10 mV by varying plasma parameters. X-ray spectroscopy used to probe these changes in electronic structure of systematically functionalized GO films by plasma. Detailed investigation using X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure spectroscopy revealed the reactive nitrogen species in the plasma induce finite changes in the surface chemistry of the GO films, introducing additional density of states near the top of the valence band edge. Nitrogen introduced by the atmospheric pressure plasma is predominantly in a graphitic configuration with a varying concentration of pyridinic nitrogen. Additionally, evidence of gradual de-epoxidation of these GO films with increasing plasma exposure was also observed. We attribute this variation in work function values to the configuration of nitrogen in the graphitic structure as revealed by X-ray spectroscopy. With pyridinic nitrogen the electronic states of GO became electron deficient, inducing a p-type doping whereas an increase in graphitic nitrogen increased the electron density of GO leading to an n-type doping effect. Nitrogen doping was also found to decrease the resistivity from 138 MΩ sq−1 to 4 MΩ sq−1. These findings are extremely useful in fabricating heterojunction devices like sensors and optoelectronic devices where band structure alignment is key to device performance when GO is used as a charge transport layer. This technique can be extended to other known 2D systems.

Published
2020

34. Functionalization of Metallic Powder for Performance Enhancement

Author

Unnikrishnan, Rahul, primary, Gardy, Jabbar, additional, Spencer, Ben F., additional, Kurinjimala, Robin, additional, Dey, Avishek, additional, Nekouie, Vahid, additional, Irukuvarghula, Sandeep, additional, Hassanpour, Ali, additional, Eisenmenger-Sittner, Christoph, additional, Francis, John A., additional, and Preuss, Michael, additional

Published
2022
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43. Ultrafast epitaxial growth of CuO nanowires using atmospheric pressure plasma with enhanced electrocatalytic and photocatalytic activities

Author

Dey, Avishek, primary, Ghosh, Paheli, additional, Chandrabose, Gauthaman, additional, Damptey, Lois A. O., additional, Kuganathan, Navaratnarajah, additional, Sainio, Sami, additional, Nordlund, Dennis, additional, Selvaraj, Vimalnath, additional, Chroneos, Alexander, additional, St J. Braithwaite, Nicholas, additional, and Krishnamurthy, Satheesh, additional

Published
2021
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44. Tin oxide for optoelectronic, photovoltaic and energy storage devices : A review

Author

Dalapati, Goutam, Sharma, Himani, Guchhait, Asim, Chakrabarty, Nilanjan, Bamola, Priyanka, Liu, Qian Nial, Saianand, Gopalan, Sai Krishna, Ambati Mounika, Mukhopadhyay, Sabyasachi, Dey, Avishek, Wong, Terence Kin Shun, Zhuk, Siarhei, Ghosh, Siddharatha, Chakrabortty, Sabyasachi, Mahata, Chandreswar, Biring, Sajal, Kumar, Avishek, Ribeiro, Camila Silva, Ramakrishna, Seeram, Chakraborty, Amit Kumar, Krishnamurthy, Satheesh, Sonar, Prashant Murlidhar, Sharma, Mohit, Dalapati, Goutam, Sharma, Himani, Guchhait, Asim, Chakrabarty, Nilanjan, Bamola, Priyanka, Liu, Qian Nial, Saianand, Gopalan, Sai Krishna, Ambati Mounika, Mukhopadhyay, Sabyasachi, Dey, Avishek, Wong, Terence Kin Shun, Zhuk, Siarhei, Ghosh, Siddharatha, Chakrabortty, Sabyasachi, Mahata, Chandreswar, Biring, Sajal, Kumar, Avishek, Ribeiro, Camila Silva, Ramakrishna, Seeram, Chakraborty, Amit Kumar, Krishnamurthy, Satheesh, Sonar, Prashant Murlidhar, and Sharma, Mohit

Abstract

Tin dioxide (SnO 2), the most stable oxide of tin, is a metal oxide semiconductor that finds its use in a number of applications due to its interesting energy band gap that is easily tunable by doping with foreign elements or by nanostructured design such as thin film, nanowire or nanoparticle formation,etc., and its excellent thermal, mechanical and chemical stability. In particular, its earth abundance and non-toxicity make it very attractive for use in a number of technologies for sustainable development such as energy harvesting and storage. This article attempts to review the state of the art of synthesis and properties of SnO 2, focusing primarily on its application as a transparent conductive oxide (TCO) in various optoelectronic devices and second in energy harvesting and energy storage devices where it finds its use as an electron transport layer (ETL) and an electrode material, respectively. In doing so, we discuss how tin oxide meets the requirements for the above applications, the challenges associated with these applications, and how its performance can be further improved by adopting various strategies such as doping with foreign metals, functionalization with plasma,etc.The article begins with a review on the various experimental approaches to doping of SnO 2with foreign elements for its enhanced performance as a TCO as well as related computational studies. Herein, we also compare the TCO performance of doped tin oxide as a function of dopants such as fluorine (F), antimony (Sb), tantalum (Ta), tungsten (W), molybdenum (Mo), phosphorus (P), and gallium (Ga). We also discuss the properties of multilayer SnO 2/metal/SnO 2structures with respect to TCO performance. Next, we review the status of tin oxide as a TCO and an ETL in devices such as organic light emitting diodes (OLEDs), organic photovoltaics (OPV), and perovskite solar cells (including plasma treatment approaches) followed by its use i

Published
2021

46. Solution Processed Pure Sulfide CZCTS Solar Cells with Efficiency 10.8% using Ultra-Thin CuO Intermediate Layer

Author

Zhuk, Siarhei, Wong, Terence Kin Shun, Petrović, Miloš, Kymakis, Emmanuel, Hadke, Shreyash Sudhakar, Lie, Stener, Wong, Lydia Helena, Sonar, Prashant, Dey, Avishek, Krishnamurthy, Satheesh, and Dalapati, Goutam Kumar

Abstract

In this work, we demonstrate that incorporating an ultra‐thin p‐type cupric oxide (CuO) enhances performance and stability of the solution processed Cu2(Zn0.6Cd0.4)SnS4 (CZCTS)/CdS thin film solar cells. In sol‐gel CZCTS/CdS thin film solar cells, nanoscale CuO films (4 – 32 nm) were deposited on top of molybdenum (Mo) by magnetron sputtering and this was used as an intermediate layer (IL). The CuO IL thickness has a significant effect on the short‐circuit current density (JSC) in CZCTS/CdS solar cell devices. As a result, a maximum power conversion efficiency (PCE) of 10.77% has been measured for the optimized device with 4 nm CuO compared with 10.03% for the reference device without CuO layer. Furthermore, stability of the devices is enhanced significantly by incorporating CuO IL. The present work demonstrates that through proper design of the CuO intermediate layer thickness, both back interface quality and optical property of the CZCTS absorber can be tuned to enhance the device performance.

Published
2020

47. Solution-processed pure sulfide Cu2(Zn0.6Cd0.4)SnS4 solar cells with efficiency 10.8% using ultrathin CuO intermediate layer

Author

Zhuk, Siarhei, Wong, Terence Kin Shun, Petrović, Miloš, Kymakis, Emmanuel, Hadke, Shreyash Sudhakar, Lie, Stener, Wong, Lydia Helena, Sonar, Prashant, Dey, Avishek, Krishnamurthy, Satheesh, Dalapati, Goutam Kumar, Zhuk, Siarhei, Wong, Terence Kin Shun, Petrović, Miloš, Kymakis, Emmanuel, Hadke, Shreyash Sudhakar, Lie, Stener, Wong, Lydia Helena, Sonar, Prashant, Dey, Avishek, Krishnamurthy, Satheesh, and Dalapati, Goutam Kumar

Abstract

Herein, it is demonstrated that incorporating ultrathin p-type cupric oxide (CuO) enhances the performance and stability of solution-processed Cu2(Zn0.6Cd0.4)SnS4 (CZCTS)/CdS thin film solar cells. In sol–gel CZCTS/CdS thin film solar cells, nanoscale CuO films (4–32 nm) are deposited on top of molybdenum (Mo) by magnetron sputtering and this is used as an intermediate layer (IL). The CuO IL thickness has a significant effect on the short-circuit current density (JSC) in CZCTS/CdS solar cell devices. As a result, a maximum power conversion efficiency (PCE) of 10.77% is measured for the optimized device with 4 nm CuO compared with 10.03% for the reference device without a CuO layer. Furthermore, the stability of the devices is enhanced significantly by incorporating the CuO IL. This work demonstrates that through proper design of the CuO IL thickness, both the back interface quality and optical property of the CZCTS absorber can be tuned to enhance the device performance.

Published
2020

49. Tin oxide for optoelectronic, photovoltaic and energy storage devices: a review

Author

Dalapati, Goutam Kumar, primary, Sharma, Himani, additional, Guchhait, Asim, additional, Chakrabarty, Nilanjan, additional, Bamola, Priyanka, additional, Liu, Qian, additional, Saianand, Gopalan, additional, Sai Krishna, Ambati Mounika, additional, Mukhopadhyay, Sabyasachi, additional, Dey, Avishek, additional, Wong, Terence Kin Shun, additional, Zhuk, Siarhei, additional, Ghosh, Siddhartha, additional, Chakrabortty, Sabyasachi, additional, Mahata, Chandreswar, additional, Biring, Sajal, additional, Kumar, Avishek, additional, Ribeiro, Camila Silva, additional, Ramakrishna, Seeram, additional, Chakraborty, Amit K., additional, Krishnamurthy, Satheesh, additional, Sonar, Prashant, additional, and Sharma, Mohit, additional

Published
2021
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