PhD Theses (Nanotechnology)

Browse

Now showing 1 - 20 of 44

Autonomous Motion Driven by Catalytic Nanoparticles
(2011) Dey, Krishna Kanti
Attainment of incisively directed autonomous motion of nano and microscale objects holds promise towards deterministic transportation of materials at smaller length scales. Controlled manipulation of dynamics of such objects not only opens possibilities for targeted delivery of useful biomolecules but also excavates smarter scopes for biosensing, fluidics and minimally invasive surgeries. The very first attempt towards controlled autonomous transport was to harness the self propelling ability of natural biomolecular motors, which naturally evolve and carry things within the cell with extraordinary efficiency. The approach had been to couple these proteins with inorganic structures and then to allow them to move along the cytoskeleton in a directed manner. Applications of these bio-integrated motors were, nevertheless, found to be limited not only for the need of defined environment for protein activation but also for their quick natural degradation. The challenge, therefore, lies in the fabrication of inorganic or organic micro/nano structures exhibiting two and three dimensional autonomous movements, preferably in a liquid, whose motion can be precisely steered inside the medium as desired. These structures must offer flexibility in terms of ease of synthesis and degree of scalability. Attainment of such self-propulsion would not only ensure correct understanding of small scale particle dynamics but also would find importance in targeted transport of materials at the submicronscale. Autonomous motion of micron scale objects was realized in our laboratory with polymer microstructures coated with metal nanoparticles - immersed in dilute hydrogen liquid with finite speed. Control over the motion of these objects was achieved by tuning the properties of the composite as well as that of the medium in which the particles moved. With an aim to attain controlled self-propulsion of an DallD inorganic catalytic object, we used palladium (Pd) nanoparticles incorporated cobalt ferrite (CoFe2O4) micro particles in dilute H2O2 solution. This essentially allowed observation of self propelled motion at smaller length scales, where the Brownian fluctuations were yet to dominate the dynamics. It also established the fabrication of stable magnetic microstructures capable of moving autonomously in a highly reactive medium like H2O2, for a considerably longer period of time. With Pd nanoparticles coated polymer microstructures, we finally demonstrated the first ever example of inorganic pH taxis in a liquid, where the particles were seen to migrate spontaneously from a region of low pH to a higher one. The observation not only established the fabrication of structures that mimic the bacterial behavior across a pH gradient but also marked the development of a novel, quick and efficient pH sensing method. All our observations were theoretically modeled using laws of classical physics. The calculations aided in quantifying the observations - providing estimates on the possible controls achievable over the dynamics of these objects, by manipulating different external and internal parameters. peroxide (H2O2) solution. The nanoparticles (of palladium, nickel and gold) deposited over the polymer surface were capable of decomposing H2O2 catalytically under specific conditions. This essentially generated bubbles of oxygen (O2) that remained tethered to the polymer surface after they were forme......
Cancer Theranostics With Nano-Enabled Bacterial Bots
(2023) Debasmita, Debashree
The contemporary cancer therapeutics are being strategically designed to obtain improved outcomes as compared to the conventional methods. The primary challenges faced by the conventional mode of therapies such as surgeries, radiation therapies, and later chemotherapy are difficulty in tumor accessibility, undesirable impact on normal cells, ineffectiveness towards cancer stem cells, missing the targets, rapid drug release prior to reaching the targets, poor pharmacokinetics of drugs, and resistance development to the therapy. In order to focus on the improvements, target specificity through small molecules, aptamers, antibodies, nucleic acid, stimuli sensitive polymers have been developed. Coating of the drug with polymers and loading the drugs on nano-carriers for enhanced bioavailability, slower release and safety from immune attacks have also been introduced. Developing methods for immunotherapy are also being practiced. Gradually the newer methods such as gene therapy, immunotherapy, and combined therapies have overtaken the conventional methods. Although these methods have shown improved results in comparison to the previous methods but the threat imposed by the cancer stem cells and drug resistance are still continuing. The advent of bacteria-mediated therapy has shown some light towards a path of developing a resistance – free cancer therapy. Since, the anaerobic bacteria preferably colonize in the hypoxic areas of the tumor and act on the core of the tumor, hence, there is a better opportunity for the bacteria to eradicate the stem cells and prevent relapse of cancer. The attenuated strains achieved through genetic engineering and over-expression of endotoxins and therapeutic genes have generated hopes for a better future of cancer therapeutics. The commonly used strains are Salmonella, Bifidobacterium, Clostridium, E. coli and Lactic acid bacteria (LAB). The bacteria-based therapy can have two usages, first as a therapeutic entity and second as a delivery vehicle. The anti-cancer effects of the bacteria can be inherent or can be inculcated through genetic modifications of endotoxin gene, pro-drug activating enzymes, siRNA, shRNA based silencing, and immune system evoking via over-expression of cytokines specifically activating T-cells and macrophages. The anti-biotic susceptibility, suitability for genetic manipulation, and low immunogenicity are required criteria for bacteria to be a therapeutic agent. The risk factor associated with the bacteria-mediated therapy is controlling the growth and number of bacteria after the therapeutic regimen is over. A few studies have been reported on these aspects and a lot more is yet to be explored. In order to avoid the adversities of using a pathogenic strain, the shift can be made towards opting for safer strains that do not require genetic manipulation and have inherent anticancer effects. The safest option is to use human gut friendly bacteria. The gut bacteria play a pivotal role in drug actions, resistance and overall health of an individual. The gut microbes, which have inherent anti-cancer properties are Streptococcus pyrogenes, Mycobacterium bovis, Serratia marcescens, Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus acidophilus, Salmonella, Clostritidium, Bifidobacterium and E. coli. Out of this vast range of bacterial strains the, Lactobacillus are among the safest strains as they are non-pathogenic. This could solve the safety issues of using attenuated pathogenic strains. The Lactobacillus strains are anti-tumorigenic naturally and are antibiotic susceptible, making them suitable as an anti-cancer agent and also as a carrier. The current dissertation work was up-taken to explore the potential of wild type Lactobacillus rhamnosus as a living bacbot that could function as a theranostic agent having anti-cancer effects mediated by an anti-cancer drug methotrexate and their inherent abilities in annihilating cancer tumour
Copper based nanomaterials for potential biomedical applications
(2019) Das, Madhumita
The current thesis work emphasizes on fabrication of different nanoscale dimensions of copper and manipulating them with different materials for diverse biomedical applications. As a relatively safe material with wide functionality; copper was chosen as a primary platform to fabricate some therapeutic tools. The present thesis is divided into six chapters.Chapter 1 of the thesis describes about nanoscience and nanotechnology. It also provides information about nanomaterials along with their synthesis and multi-dimensional applications. Salient features of this current thesis work have been mentioned in brief.Chapter 2 explains a facile process of fabrication of a luminescent bovine serum albumin (BSA)-copper nanocluster (BSA-Cu NCs) customized ibuprofen nanodrug (BSA-Cu NC-Ibf) for in vivo cancer therapy as malignancy has covered a major portion of the health ailments of our society. The as synthesized BSA-Cu NC-Ibf exhibited incomparable chemotherapeutic efficiency on Daltons lymphoma ascites (DLA) bearing Swiss albino mice with significant reduction of tumour growth. It also inhibited metastasis of the cancer cells and thus enhances the life expectancy of mice.
Density functional theory based analyses of 4d transition metal doped graphene and its interaction with small molecules
(2019) Kumar, Jitendra
Two-dimensional materials are being widely investigated for the development of futuristic electronic devices and creating new opportunities in electronic industries. Graphene having a hexagonal honeycomb planar structure of sp2-hybridized carbon atoms has shown extraordinary electronic, mechanical and thermal properties and is considered as a potential material for use in future electronic devices. Several computational methodologies using first principles methods are providing results close to the experimental observations. Complex quantum mechanical calculations are successful in computing equilibrium in interacting materials, optical spectra, energies, electronic properties, and catalytic properties of atoms, molecules and atomic/molecular systems.This thesis mainly focuses on the research work carried out using density functional theory (DFT) based modelling to analyze electronic properties of graphene doped with 4d-transition metal atoms, interaction of niobium-doped graphene with small molecules, spin transport properties of niobium-doped AGNR, interaction of graphene with niobium and niobium compounds, and graphene-heptahelicene interface. DMoL3 code is employed to investigate single and double vacancy graphene doped with 4d-transition metal atoms and calculate their binding energies, band structures, magnetic properties, the density of states (DOS), atom projected density of states (PDOS), and charge transfer.
Design and development of high performance polymer light emitting diode for solid state lighting
(2017) Das, Dipjyoti
The thesis entitled “Design and Development of High Performance Polymer Light Emitting Diode for Solid State Lighting” deals with fabrication of Polymer Light Emitting Diode (PLED), especially which emits white light, using different approaches such as physical doping, electroplex formation and phosphor sensitized system. The effect of processing conditions on the device performance has also been investigated. The electron transport property of polyfluorene was enhanced by incorporating strong electron acceptor moiety 1, 8-naphthalimide into polyfluorene main chain and efficient blue and white PLEDs were fabricated using this newly synthesized copolymer as emissive layer. A detailed study on the effect of electron injection barrier and the electron transport property of the widely used poly(9-vinylcarbazole) (PVK) on the device parameters such as current density, brightness and electroluminescent spectra, especially the electroplex formation of PVK based PLED is also carried out. White light was successfully obtained utilizing the concept of electroplex formation in such devices by device optimization. The effect of the device processing condition such as annealing temperature and the effect of mixed host were studied and by optimizing the annealing temperature and doping ration of the mixed host, highly efficient green PLEDs were fabricated. Furthermore, by utilizing FIrpic as the blue emitter and the bridge of energy transfer and Rubrene and DCJTB as orange/red dopant, white PLEDs utilizing the concept of phosphor sensitized system was realized.
Design and fabrication of rylene diimide based active materials, devices and applications
(2017) Kalita, Anamika
The thesis entitled “Design and Fabrication of Rylene Diimide Based Active Materials, Devices and Applications” deals with synthesis of various Rylene Diimide based derivatives following a simple one step condensation reaction route. The derivatives N, N'-bis(cyclohexyl)naphthalene diimide (NDI-CY2) and N, N'-bis(methylcyclohexane)naphthalene diimide (NMeCy2) were successfully employed for the OFETs application using simple, cost effective fabrication techniques and demonstrating the influence of various combinations of inorganic/polymeric dielectric layers on device performances. The conjugated perylene diimide derivative appended with histidine side group, PDI-HIS was utilized for the detection of ammonia (NH3) vapors via fabricating a simple two terminal sensor device. A new derivative of cationic naphthalene diimide, N, N′-bis(3-imidazolium-1-ylpropyl)-naphthalenediimide diiodide (NDMI) was developed for its application in detection of nitroexplosive picric acid (PA) both in aqueous and vapor phase. Furthermore, an economical and portable electronic prototype was established for visual and on-site detection of PA vapors under exceptionally realistic conditions.
Design and synthesis of novel conjugated organic semiconducting materials for organic light emitting diodes
(2017) Gopikrishna, P
Highly efficient materials (monomers & polymers) are developed as emissive layer for organic light emitting diode by utilizing the donor-acceptor monomers and AIE active compounds. The 1,8-naphthalimide is inserted as acceptor into the donor polyfluorene and polycarbazole main chain. The well charge balanced or efficient materials are established by varying the feed ratios of acceptor mol % in the donor polymers. Moreover, the emission colors of the copolymers are tuned from blue to green and blue to red in case of polyfluorene and polycarbazole, respectively. The PLEDs are fabricated with these new materials that exhibited excellent device properties. The AIEE active monomers are synthesized based on the mono-substituted dibenzofulvene (M-DBF) derivatives and their photophysical properties are further investigated. White light emitting polymers are synthesized by incorporating AIEE active monomers as orange or red emitting dopants into polyfluorene host. The newly developed materials showed high solubility, which is very important parameter to obtain better film forming properties during the device fabrication. In addition, to the incorporation of the AIEE active monomers into the polymer host, the voltage independent EL spectra is easily achieved. This can be attributed to the non-planarity of the AIEE active molecules which can effectively reduce the intermolecular interactions in the condense state. Another set of AIEE active monomers are synthesized based donor and acceptor units by changing the bridge (Thiophene & Phenyl) between donor and acceptor. The thiophene substituted monomers displayed the AIEE active nature and remaining phenyl substituted monomers exhibited weak or AIE inactive nature. Also, the heavy atom effect is successfully studied. The detailed theoretical studies are performed to support the experimental results. Overall new organic materials with improved optical properties are developed and utilized for OLED applications as well as AIE properties.
Design, development and fabrication of thiophene and benzothiadiazole based conjugated polymers for photovoltaics
(2018) Ratha, Radhakrishna
The content of this synopsis report entitled "Design, development and fabrication of thiophene and benzothiadiazole based conjugated polymers for photovoltaics" is divided into five chapters. In chapter 1 the respective research area, where design synthesis and fabrication of conjugated polymers, along with the scope and significance of the subsequent chapters are discussed. In chapter 2 photostability enhancement of P3HT-PCBM by using appropriate ratio of MWCNT in ambient conditions have been discussed. Chapter 3 discusses about synthesis of poly(ortho-arylene-vinylene) type of polymer alternating at 5,6-position of BT namely PI and P2 in the polymer main chain. Chapter 4 demonstrates that on functionalization of methyl acetate group at 5,6-positions of BT red-shift absorbance, lowered the LUMOOptical improves phase separation in active layer of PSC and hence improves solar cell performance compared to its methyl counterpart. Chapter 5 results in synthesis of newer napthothiadiazole (NT) based D-A polymer and their BHJ solar cell performance.
Developing gold nanocluster based cancer theranostics
(2018) Chatterjee, Bandhan
Nanotheranostic, a combination of diagnostic and therapeutic modalities at a nanoscale range offers a promising prospect in cancer therapeutics. Besides having the edges offered by the nanomaterials, it further refutes the need of separate units for individual modalities. The current thesis work is to develop novel nanoscale theranostic materials as potential candidates for their further clinical translation. The thesis is organised in six chapters. The first Chapter (Chapter 1) provides a holistic but comprehensive description about the need and basics of theranostics and current state of cancer theranostics. It also provides a comprehensive introduction of nanoclusters as majority of theranostic developed here are nanocluster based. The chapter also provides the background and objectives of the thesis. Chapter 2 describes the development of DNA (plasmid DNA) based smart theranostics for cancer therapy. The chapter entails the development of the DNA templated Au NCs and their further use in conjugation with cisplatin (anti-cancer drug) for developing composite NPs. Further these composite NPs were thoroughly characterized with various analytical instruments. The composite NPs were stable and had bright fluorescent with decent quantum yield. The composite NPs were readily taken up the HeLa cells and inflicted augmented cytotoxicity on the host cells while bioimaging them simultaneously. The composite NPs also have on demand loading capacity and pH dependent release profile. Chapter 3 deals with the synthesis of fluorescent gold nanocluster on dGTP, a small molecule. It should be borne here that whereas the previous work has gold nanocluster templated on DNA (have myriad of bases in it), this work is about stabilizing the gold nanocluster on a nucleotides (dGTP) rather the polymer of it. The dGTP templated Au NCs displayed impressive physical characteristics deemed of an imaging moiety and was further interacted with cisplatin to form theranostic composite NPs, which were further coated with PEG to provide a space for surface functionalization.The composite NPs were successful in the shuttling the drug efficiently into the treated cells while concurrently bioimaging it. Chapter 4 describes the development of a single unit theranostic. Here MTX (methotrexate), a commercial clinical drug is used as a template to synthesise gold nanoclusters. These single unit theranostics were extremely stable both in PBS and blood serum. They were brightly fluorescent, photostable and were efficiently taken by the cells. They inflicted highly augmented cytotoxicity on the host cells, also enabling the concurrent bioimaging the host cells. Chapter 5 entails the formation of a folic acid conjugated chitosan NP on which these MTX NCs were loaded. The purpose of the chapter is to study the feasibility of replacing the free drug with MTX NCs which have higher cytotoxicity and additional fluorescent properties in a drug delivery vehicle. The NPs were efficiently taken up by the cells and bioimaged it. The host cells also displayed an almost two-fold reduction in IC50 value of the drug when subjected to NPs in MTX NCs form. This augurs well for the further development of such single unit theranostics. Chapter 6 provides a comprehensive summary of the thesis and provides insight into the potential prospects of the thesis work
Device Engineering of organic field effect transistors for sensing applications
(2017) Dey, Anamika
Considering the demand of future technology, the thesis entitled “Device Engineering of Organic Field Effect Transistors for Sensing Applications” introduces important methodologies which have been developed for improving the performances of OFET. The thesis mainly focuses to modify the gate dielectric layer to reduce the operational voltage of both p-type and n-type OFETs and use them for various sensing applications. By modulating gate dielectric layer with the combinations of a high-k inorganic and two low-k organic dielectric materials, the operational voltage of OFET was effectively reduced from 50 V to 7 V, which was later used for photo-sensing application. Again, by using the combination of two inorganic and one organic dielectric material layer, the operational voltage of OFET was further successfully reduced from 7 V to 2 V and the same device architecture was used for bio-sensing application. This thesis mainly described very simple, unique and robust methodologies for lowering the operational voltage of OFETs up to 2 V, which can be further used as very effective and stable platforms in the next generation of portable electronics.
Electric Field Induced Patterning of Thin Polymer Film
(2021) Roy, Pritam
Considering the present era of miniaturization, the demand for soft patterning in micro/nanoscale is an important and relevant topic for research. In this direction, the thesis of Mr. Pritam Roy titled “Electric Field Induced Patterning of Thin Polymer Film” provides important advancement of the existing know-how and describes a novel approach capable of modulating features, reducing time scale of deformation, and most importantly template-less patterning and e-writing. We reported the development of template-less electrohydrodynamic-contact-line-lithography (ECLL) to generate micropatterns on PDMS-liquid crystal interface. The novelty of this work lies in the use of a thin film of liquid crystals. Previous work mainly focused on the interface between air and polymer or between two polymer films. The unique properties of liquid crystals (high dielectric constants and low interfacial tension) and rheological properties of the polymer film bring new insights in the so-called electrohydrodynamic patterning. New types off patterns (micropillars vs. microwells) were found, and the time scale of pattern formation was shortened by orders of magnitude. This is an extension of the previously developed electric-field induced lithography (EFL) with some novel aspects. In addition, we discovered that the rapid spreading of the 5CB layer on PDMS surface leads to the three-phase contact line movement that triggers the formation of ordered microwell arrays. This discovery is quite exciting and new. In this thesis the fabrication technique of multilength scale hierarchical patterning was also explored in the combination of various soft lithographic techniques such as breath figures, microcontact printing, and modulated electric field-induced lithography. The observations and methodologies reported in the present thesis will be helpful in the future exploration of microfabrication using an electric field with a thin polymer film.
Engineering devices with functional nanomaterials
(2016) Kumar, Sailapu Sunil
It is a commendable journey of human race to the 'age of super computers' from calculators, which were once regarded as 'big thing'. One cannot debate over 'integration of novel materials and techniques’ being a significant factor in achieving such a giant technological leap. In the contemporary age, sublime developments in science and technology are contributing to the staggering growth of innovations. There are great endeavours for generating novel materials and methods to construct devices of potential use. Prudent interest is judiciously invested towards 'small' dimension materials to achieve ‘the next big thing' in the world of devices. This may well be said as materials at the nanoscale dimensions are promising due to their versatile at the same time unique physical and chemical properties. The essence of nanotechnology is to utilize the fundamental knowledge associated with the intriguing properties prevailing at these dimensions. Hence, through effective design strategies properties at these 'small' dimensions prove to be vital in development and transformation of next generation devices and systems. The current dissertation has been directed towards engineering devices through effective integration of nanomaterials and thereby, use of their physico-chemical attributes. In particular, salient features like catalytic, magnetic, plasmonic and luminescence nature of nanoscale materials developed through bottom-up approach of chemical synthetic routes were availed to accomplish devices with on-board intelligence and clinical importance. A device with the ability to generate electrical energy from autonomous motion of microbots was engineered. Intelligent systems capable of decision making in the liquid media were developed. For disease diagnostics, a bench top device was constructed to perform polymerase chain reaction and array based gene and protein analyses. Another device for photodynamic therapy and optical based detection was achieved. These nanotechnology oriented devices indicate greater prospects and encourage further investigations to achieve other major technological leaps.
Engineering Organic and Perovskite based Solar Cells
(2022) Gupta, Ritesh Kant
It has become utmost necessary to address the energy crisis and reduce the carbon emission simultaneously. Therefore, exploration of various renewable energy sources is now the need of the hour. Among all the renewable energy sources, solar energy is considered to be the most sustainable owing to its ample availability on the surface of earth. The first and second generations of solar cell has been already commercialized and is being utilized to reduce the load on the current method of energy production through fossil fuels. However, to further consolidate the efforts, commercial utilization of the third and fourth generations of solution processable solar cells are also important. The organic solar cell (OSC) and perovskite solar cell (PSC) are the front runners among all the solution processed photovoltaic technology owing to its various advantages and PCE reaching beyond 18% and 25% respectively. Further, both these solar cells offers ease of fabrication with low-cost and abundant materials ensuring that they can be significant contributor to commercial photovoltaic technology in the near future. This thesis is broadly organized into two parts. The first part (comprising of one chapter) and second part (comprising of three chapters) focuses on fabrication of OSC and PSC, respectively. Two techniques have been employed in this thesis work for the fabrication of solar cells: (i) hot-casting technique in the first two working chapters, and (ii) room temperature anti-solvent method in the remaining two working chapters. At first, hot-casting technique is used to develop OSC through regulation of morphology and thickness. Highest power conversion efficiency (PCE) of 9.13% was obtained for a thick active layer film. Thereafter, hot-casting technique is again implemented to fabricated mixed-halide PSC by varying the ration of methyl ammonium bromide in the precursor solution. The modified PSC resulted in PCE of 18.08% which also displayed large micrometer sized grain and reduced nanometer sized grain boundaries to minimize the recombination of the photo-generated charges. Further, trifluoro acetic acid is used as additive in perovskite solution to regulate the crystallization, minimize ion migration and charge recombination in PSC. As a result, champion 20.10% PCE was obtained in the modified device. Finally, ptoluene sulphonic acid is utilized to control the crystallization kinetics of the perovskite bulk and also passivate the traps. Simultaneously, polystyrene is used to increase the moisture resistance and reduce the surface defects of the perovskite films. This dual-passivation strategy resulted in champion PCE of 20.62% with superior ambient stability. The efforts made in this thesis highlights the usefulness of various device engineering to develop OSCs and PSCs to regulate the morphology and crystallization of the photo-active layer to achieve highly efficient, stable and repeatable solar cells. The thesis provides the basis for facilitating the commercialization of OSC and PSC in the near future.
Engineering Solution Processable Organic Field Effect Transistor for Opto-electronic Applications
(2022) Choudhury, Anwesha
Electronic devices have made people’s life easier, and in today’s modern lifestyle electronic devices have become one of the basic requirements of human beings. Inorganic material are used extensively in electronic devices but the requirement of energy efficient, low-cost and flexible devices can be easily fulfilled by the organic solution processable materials. Organic field effect transistors (OFET) will enable easy implementation of large scale and flexible applications. Organic materials also have the advantage of easy tunability of the optoelectronic properties. OFETs have numerous applications like various sensors, smart card, e-skin etc. Some of the organic electronic devices like OLED, solar cell is already available in market, but low mobility and stability is a road block for organic transistors to be commercialized in high end applications.
Fabrication and Characterization of CVD Graphene Based Hybrid Nanostructures for Photoconductive and Photocatalytic Applications
(2016) Kumar, Biroju Ravi
Achieving large area wafer scale single layer graphene onto dielectric substrates without having any structural defects and layer non uniformity is still challenging. There is a lack of in-depth understanding on the role of defects in the interactions between graphene and foreign atoms and molecules. Investigating the various in-plane and edge defects including functional groups on the graphene using resonance Raman spectroscopy and HRTEM will provide the rich physics behind its electronic and optoelectronic applications. Physical and chemical functionalization of graphene preserving its sp2 crystallinity can reveal the change in the electronic structure due to covalent and noncovalent foreign material interaction with graphene. It is anticipated that a proper understanding on the interaction of noble metal with defective graphene would pave the way for controlled functionalization of graphene for cutting edge applications. Functionalized graphene and its exploitation in integrated optoelectronics is least explored in the literature. Further, origin of solid state PL from CDG is not understood well with the help of controlled environments. Fabrication and characterization of graphene based semiconducting hybrid NSs for enhanced photodetection applications is imperative to develop various optoelectronic devices. Visible light photocatalysis of graphene and functionalized graphene incorporating TM plasmonic hybrids are little explored. Graphene based TM plasmonic hybrid NSs for SERS and mechanism of SERS are still challenging. Unlimited possibility of exploiting graphene based hybrid NSs for photoconductive, photocatalytic and SERS applications still remains. This thesis focuses on the controlled growth of large area defect free graphene using CVD technique and synthesis of CDG functional materials. Extensive investigations on number of graphene layers, uniformity, functionalization and defects were probed using microRaman spectroscopy and HRTEM. Next, the fabrication of grapheneplasmonic hybrids with TM NPs such as Au, Ag, Cu and organic molecules as well as the graphene ZnO hybrid NSs and their SERS, photocatalytic and photoconductive applications were investigated.
Fabrication and Characterization of Highly Environmental Sustainable Organic Field-Effect Transistors with Tri-Layer Gate Dielectrics
(2015) Subbarao, Nimmakayala V V
Abstract not available
Fabrication of Polyaniline-Based Nano Materials for the Application in Energy Harvesting and Sensing Devices
(2020) Palsaniya, Shatrudhan
PANI nanomaterials strongly depend on the distribution of nanofillers for property enhancement. Based upon these nanomaterials, a brief introduction of energy storage and sensing devices have been included in Chapter-1. Chapter-2 describes binary and ternary nanocomposites of PANI, G and MoS2. Among them, PANI-G-MoS2 ternary nanocomposite exhibits excellent electrochemical activity and enhanced cyclic stability. Chapter-3 describes GO, RGO, and α‒MnO2 based PANI functionalized binary and ternary nanocomposites. Herein, PANI-RGO-MnO2 has appeared an excellent candidate for high‒density energy storage material with superior dielectric strength. Chapter-4 presents a comparative study of binary and ternary nanocomposites of PA6, rGO, and PANI components. We have observed that PA6-rGO-PANI 1:2 shows an excellent electrochemical performance with improved cyclic stability, as compared to other composites. Further, fabricated symmetric supercapacitor devices also have demonstrated outstanding performance. Chapter 5 unveils ZnO (transition metal oxide), and RGO based PANI functionalized nanocomposites. In particular, PANI-RGO-ZnO 2:1 composite reveals a superior performance as an electrode material. Chapter-6 describes preparation of PANI-ES and PANI-EB thin film, deposited on glass and n-type Si wafer substrates using a vacuum evaporation technique. We have observed that deposition of PANI-EB is relatively easier than PANI-ES. Contrary to PANI-EB, PANI-ES thin-film shows better electrical conductivity. Hence, fabricated thin-film capacitors also have shown remarkable current density and energy density with the high percolation threshold. Chapter-7 presents a hierarchical mesostructure of PANI nanorods by incorporating SDS and F127 as structure-directing agents (SDAs). The PANI-SDS-F127 1:1 composition has shown higher glucose sensitivity with a lower detection limit, attributed to the synergistic effect of available organic components. Chapter 8 summarizes the thesis work, with an outlook for future study.
Field effect transistor based biosensor for detection of glutathione
(2019) Barman, Ujjwol
Design, fabrication and characterization of a novel device based electrochemical detection method of glutathione is the prime focus of this thesis. The device is a FET device, channel material of which consists of a conjugation of ZnO nanoparticles and purified recombinant GST protein. The novel concept of incorporating a protein in a channel material is reported here for the first time. The device successfully and selectively detects and quantifies glutathione as compound and as well as a human cell component. The device was also tested successfully with cultured HeLa and MCF-7 cancer cells and HEK (Human Embryonic Kidney) normal cells and it was found that the device could detect enhanced concentration of glutathione in cancerous cells, which indeed is the first step towards detecting certain types of acute cancer diseases. The device can be further improved upon by keeping primary working principle the same, in order to meet the requirements to make a deliverable product for marketization.
Fluorescent nanomaterials for biological applications
(2013) Jaiswal, Amit
Nanoparticles are always accompanied with the appearance of novel properties irrespective of the metallic or semiconductor origin. Evolution of the unique physical, chemical and electronic properties at the nanoscale forms the essence of the various applications of nanoscience and nanotechnology. ....
Implications of Nanoparticle-Polymer Composites as Probes and Therapeutic Agents
(2010) Sanpui, Pallab
Abstract not available

Browse

Browsing PhD Theses (Nanotechnology) by Title

Results Per Page

Sort Options