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Deterministic Nanopatterning of Graphene Using an Ion BeamBruce, Henrik January 2022 (has links)
Graphene features a unique combination of exceptional properties and has emerged as one of the most promising nanomaterials for a variety of applications. The ability to structurally modify graphene with nanoscale precision enables the properties to be further extended. By introducing nanopores in the graphene lattice, nanoporous graphene can be used in high-performance electronic devices or as selective membranes for efficient molecular filtering. Although methods for deterministic nanopatterning already exists, key for the implementation of nanoporous graphene is the development of a scalable and customisable method of patterning graphene that does not require any lithographic mask that is introducing defects. In this project, a novel approach using a nanoporous mask and a broad beam of 20 keV Ar ions has been investigated. Masks with 60-600 nm circular pores have been fabricated, and by irradiating suspended graphene membranes grown by chemical vapor deposition (CVD) through the mask, nanoporous graphene has been deterministically generated. The masks are fabricated using electron beam lithography, and the pattern is highly customisable regarding pore size, pore distribution and areal coverage. In addition to perforating the graphene, the ion beam is also observed to significantly reduce the level of contamination on the graphene membrane. The proposed mechanism is the combination of electronic sputtering of surface contaminants and the random diffusion that follows, with a low nuclear sputtering yield and to-site pinning of contaminants. An extension of this study could include a more comprehensive characterization of the nanoporous graphene obtained as well as further studies on the dependency of beam parameters.
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Evaluating PEDOT:PSS Electrodes Dispersed With Silver Nanowires For Indoor Organic Photovoltaic DevicesRaihle, Lucas January 2022 (has links)
Indoor photovoltaics is an emerging technology that could power the Internet of Things (IoT)devices with low energy requirements. The conventional silicon-based photovoltaics is notsuitable for indoor lighting conditions, opening the door for organic photovoltaics (OPV).When fabricating OPV devices, a transparent and conductive electrode is needed. Indium tinoxide is a common transparent for research, but it is expensive and difficult to use in roll-toroll (R2R) production. PEDOT:PSS is a cheap conductive polymer compatible with R2Rprocessing, but its relatively low conductivity limits cell size and geometric fill factor. Addingsilver nanowires to the PEDOT:PSS solution could improve conductivity but raises the risk ofshort-circuiting the devices. In this thesis, organic photovoltaic devices have been fabricatedusing electrodes based on a commercially available solution of PEDOT:PSS dispersed withsilver nanowires to test its viability. Devices utilizing the novel electrode demonstrated aforward current density of 2,905 mA/cm2, dark current density of -1,25E-05 mA/cm2, shortcircuit current density of 0,037 mA/cm2, open-circuit voltage of 0,630 V, and fill factor of76,6%. Performance for devices with the a reference electrode of pure PEDOT:PSS was aforward current density of 0,94 mA/cm2, dark current density of -2,35E-05 mA/cm2, shortcircuit current density of 0,0341 mA/cm2, open-circuit voltage of 0,630 V, and fill factor of76%. However, the resistance in the novel electrode appears to degrade faster than in thereference electrode, even in an inert atmosphere, which motivates further studies ondegradation mode and methods to prevent it.
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Fluorescent quantum dots and graphene-based sensors for forensic applicationsJussi, Johnny January 2019 (has links)
A key emerging concept within the forensic sciences today areportable measurementdevices, where a much more efficient usage of the resources involved with crime-solving is possible if confirmatory measurements can be realised directly at a crimescene with such devices. Today, the majority of the presently used methods duringcriminal investigation at a crime scene involves measurements of a presumptivenature, which is a vital tool as it enables the screening of samples. In this thesis,the overarching goal is the development of tool kits for the analysis of biosampleson-site at a crime scene. This is mainly investigated through two routes: theusage of Quantum Dots (QDs) as a recognition element in sensory applications andfabrication of a graphene-based device for the detection of illicit drugs.The investigations conducted for the studies presented in this thesis focuses onsensory applications with a forensic detection scheme in mind: study I reveals in-trinsic properties of QDs to better understand sensing mechanisms upon bindinginteractions; study II demonstrates the fabrication of a graphene-based device forthe detection of illicit drugs; study III showcases the functionalised and bioconju-gated of QDs for a specific investigation into a biological process; study IV furtherthe investigation into the possible side-effects of QDs on biological specimens.In study I we numerically and experimentally investigate the intrinsic blinkingcharacteristics of CdSe-CdS/ZnS QDs. This includes a thorough examination of theexperimental parameters of the measurement setup: the bin time and excitationpower. Different mechanisms between the off- and on-state probability distributionsare found, wherein the on-state follows the random telegraph signal theory and theoff-state follows the inverse power law distribution.In study II, the detection of illicit drugs (amphetamine and cocaine) is achievedthrough graphene-based sensors processed to contain metal electrodes with superioradhesion and low contact resistance. The construction of a microfluidic system isfurther realised for a detection of molecules based on non-covalent interactions.With this system, a wavelength-dependent photoactivity for amphetamine and arange of its chemical analogs is demonstrated. A molecule dependent interactionwith the graphene surface is shown of the graphene surface either in the form ofp-doping (cocaine) or n-doping (amphetamine).Study III investigates the endocytic pathway of the vascular cell adhesionmolecule 1 (VCAM1) in Human Umbilical Vein Endothelial Cells (HUVECs) in-iiiivABSTRACTduced by Tumor Necrosis Factorα(TNFα) with the usage of 3-Mercaptopropionicacid coated (3MPA)-QDs and 5-Carboxyfluorescein (5FAM) functionalised and la-belled with VCAM1 binding peptides, respectively. Internalisation of the VCAM1molecules into lysosomes is shown with light microscopy through observations ofdifferent pathways of the 5FAM labelled peptides and functionalised QDs.In study IV we investigate the adverse effects of 3MPA-QDs on the humanairway epithelium by an examination of the calcium response in lung cells upon astimulation with QDs. The cellular response to the deposition of QDs is observedwith light microscopy and electrical measurements as a global increase of Ca2+in the epithelial layers and a transient decrease in the electrical response. Theseobservations imply that the influx of calcium caused by the QD deposition is inducedby mechanical stressIn an additional ongoing study, the age determination of dried blood spotsare investigated with the usage of protein markers commonly found in the blood.Human serum (HS) is spiked with a marker of interest to mimic those of normallevels in adult human males. After which the HS is allowed to undergo an ageingprocess in a 96 well plate and further analysed in terms of the enzymatic activitywith commercially available kits. The preliminary test results show that there is ameasurable change of activity dependenton the utilised marker that may act as abasis for the age determination of dried blod spots / <p>Examinator: Professor Björn Önfelt</p>
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Nanoteknik i textilier : För framtidens arbetskläder i hemtjänsten / Nanotechnology in textiles : For future workwear in homecareNilsson, Malin, Munkbo, Sanna January 2011 (has links)
Det har blivit allt vanligare att sjukvården i Sverige flyttas ut till vårdtagarnas hem. De kan med hjälp av hemtjänst få bo kvar i sina egna hus längre men samtidigt få den hjälp de behöver. År 2007 använde sig totalt 153 723 personer av dessa tjänster runt om i Sverige. De plagg som personalen bär utsätts för många olika typer av yttre påfrestningar vid hembesök hos vårdtagarna. Smittspridning inom vården sker främst via personalens händer och kläder.Nanoteknologi är en framväxande teknik som gått på högvarv inom många olika områden under det senaste årtiondet. Forskning pågår som involverar nanoteknologi för att förbättra egenskaper eller för att skapa funktionella textilier som kan få egenskaper som antibakteriella, lättrengörliga, vatten- och fläckavvisande samt luktfria. Syftet är att underska om nanoteknik kan användas i det textila materialet i arbetskläder inom hemtjänsten för att bättre stå emot yttre påfrestningar. Det finns idag många problem inom området arbetskläder och hygien, vi vill därför undersöka om denna teknik kan vara en av lösningarna.Nanoteknik för textilier har två inriktningar. Den ena strävar främst efter att använda nanostorleken för att skapa nanostrukturer under själva tillverkningsprocessen, medan den andra är inriktad mot ytbehandlingsprocesser. I rapporten ligger fokus på beläggningsmetoden och de självrengörande och antibakteriella egenskaperna som kan skapas hos ett material.Vi kom fram till att det bästa alternativet för dessa typer av plagg skulle vara att tillföra antibakteriella egenskaper. De kan då beläggas med antingen titandioxid, zinkoxid eller silver då det är väl beprövade ämnen som är bevisade att fungera och ger just dessa egenskaper.Med hjälp av empiriska undersökningar kunde vi ge svar på vad arbetskläder utsätts för under en arbetsdag. Utifrån dessa resultat kunde vi rikta in vår teoretiska referensram på de områden som skulle kunna vara intressanta för att uppnå syftet. Tillslut kom vi fram till att nanoteknik kan bidra till att skapa kläder som bättre står emot yttre påfrestningar och ger bättre hygieniska förhållandeIt is increasingly common for healthcare in Sweden to move out to the residents' homes. They can use homecare to continue living in their own house, but at the same time get the help they need. In 2007 the total of 153 723 people were in use of these services across Sweden.The garments that the staff is wearing get exposed to many different types of external shocks on home visits. Spread of infection in health care is primarily through the staff's hands and clothes.Nanotechnology is an emerging technology that has been booming in many areas over the past decade. Research is underway involving nanotechnology to improve properties or to create functional fabrics that can have antibacterial properties, easy to clean, water- and stain resistant and odor-free. The aim is to investigate whether nanotechnology can be used in the textile material in assisted living to better withstand external shocks. Today there are many problems in the field of workwear and hygiene, we therefore wish to consider whether this technology can be one of the solutions. Nanotechnology for textiles has two directions. On one striving primarily for the use of nanosize to create nanostructures during the manufacturing process, while the other is focused on finishing processes. The report focuses on the coating method and the self-cleaning and antibacterial properties that can be created in a material.We concluded that the best thing for these types of garments would be that they had antibacterial properties. They are then coated with either titaniumdioxide, zincoxide or silver when it is proven substances which are proven to work and provide these same qualities. With help from our empirical studies, we could provide answers to what the clothes get exposed to during a day of work. Based on these results, we could focus our theoretical framework in the areas that could be relevant to the objectives. Eventually, we concluded that nanotechnology could help to create cloths that better withstand external shocks and improves the hygienic conditions. / Program: Textil produktutveckling med entreprenörs- och affärsinriktning
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Nanotechnology Start-ups - Intellectual Property for Generating ValueHellström, Amanda, Nilsson, Sara January 2018 (has links)
Purpose – The purpose of this thesis was to increase the understanding of how formal and informal intellectual property may affect value generation of strategic and financial values within the nanotechnology start-up sector. Method – This study had an inductive approach through a qualitative multi-case study. The data collection was carried out through 23 interviews, including four exploratory interviews and 19 semi-structured interviews. The collected data was continuously analyzed in order to identify concepts, themes and aggregated dimensions. The collected data was analyzed through two categories, namely type of intellectual property and prioritized type of value desired. Findings – Through protecting innovations nanotechnology start-ups seek both strategic and financial values. The findings show nanotechnology start-ups seek strategic values in the form of trustworthiness through qualified recognition, ability to increase in market share, and having a competitive presence on the market. The findings further show nanotechnology start-ups seek financial values in the form of effective resource allocation, direct income from market transactions, and ability to attain investors. Furthermore, the findings suggest that for nanotechnology start-ups to effectively generate strategic and financial values it can be beneficial to combine formal and informal IP where a combination of trade secrets and patents can be valuable. Theoretical contributions – The analysis resulted in a grounded theory articulation in the form of a conceptual framework describing the relationships between the type of IP and how it may affect value generation for nanotechnology start-ups. This study adds to previous research that aspects fulfilling market demands can be effectively protected by patents, and aspects difficult to reverse engineer can be effectively protected by trade secrets in order to generate strategic and financial value. This study also adds to theory by identifying enablers describing how nanotechnology start-ups can generate strategic and financial values, and which type of IP is associated with each enabler. Practical implications – This study provide managers within the nanotechnology start-up sector with a framework suggesting how to generate different values from protecting innovations. The study further concludes that there are six important aspects to consider in creating effective IP strategies within the nanotechnology start-up sector. These aspects include; mapping the technological environment and the commercial market, determining which actual strategic and financial values are important for the start-up, protecting different aspects of an innovation with different types of IP, having trade secrets on aspects of an innovation that are hard to reverse engineer, to formally protect aspects of an innovation that fulfills market demand, and making a plan for how the rights attained can generate value.
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Självsanerande ytbeläggning i nanostruktur : Är det möjligt att applicera på elektrooptiska sensorer och till vilken nytta?Berg, Magnus January 2009 (has links)
Då marina enheter numera deltar i internationella missioner, kommer den nya miljön som enheterna opererar i att påverka bland annat deras sensorer. Den här studien avhandlar några av de nu framtagna självsanerande ytbeläggningarna och ger en presentation av hur de fungerar på några marina elektrooptiska sensorers yttersta linser. Studien försöker ge svar på ytbeläggningarnas transmittans och hur effektivt de kan sanera bort oönskade saltlager tillsammans med andra nedsmutsande partiklar från sensorlinserna samt den militära nyttan av att använda självsanerande ytbeläggning. / This study deals with now developed self-cleaning coatings and gives a presentation of how they work on some electro-optical sensor lenses used in the navy. The study also examines the coatings transmittance and how efficient they can clean the sensor lenses from undesired salt layers and other soiling particles. After the introduction the study presents basic facts of the chosen sensors, nanotechnology, surface wettability and also salts and salinity. Thereafter the study describes current nano-research on self-cleaning coatings and possible results there of, when the coatings are applied on the different sensors. In the study I give my opinion of the military benefit of using self-cleaning coatings, which from a general point of view is that there mostly are positive effects using such a coating, in a technical perspective. The study ends with conclusions that there are self-cleaning coatings based on TiO2-nanoparticles which can transmit within the visual spectra and also can clean undesired soiling particles. But can not confirm that these coatings have the desired effect on salt crystals, or transmit within wavelengths spectrum for IR-detectors and lasers. / ChpT 08-10
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Nanostrukturell ytbeläggning på utsatta delar av marina drivlinorBerg, Magnus January 2010 (has links)
Nowadays naval units are participating in international missions, where new and in many cases tougher conditions will affect their propulsion. This essay deals with some of the now developed nanostructure coatings and gives a presentation of how the coatings could function on some exposed parts of the naval powertrain. The essay investigates the possibility that the coatings can be used as a protective layer that will reduce or prevent wear on selected parts of the naval powertrains. As a basis for the essay, nanotechnology is described, as well as different reasons that wear occurs and application techniques for coatings The conclusion is that nanostructured coatings can be applied and provide a much better result on hardness and wear resistance as of naval powertrains compared to micro-structural coatings, both for manufacturing and renovation. The essay presents a few examples of the military utility of the nanostructure coatings as well as suggestions for further research. / Då marina enheter numera deltar i internationella missioner, kommer den nya och i många fall tuffare miljön som enheterna opererar i att påverka bland annat deras framdrivning. Den här studien avhandlar några av de nu framtagna nanostrukturella ytbeläggningarna och ger en presentation av hur de kan fungera på några marina drivlinors utsatta delar. Studien undersöker ytbeläggningarnas möjliga förmåga att utgöra ett skyddande lager som ska minska eller i bästa fall förhindra slitaget på valda delar av marina drivlinor. Som underlag till studien beskrivs i allmänna termer nanoteknik, olika anledningar till att slitaget uppstår samt något om hur ytbeläggningen kan appliceras. Studiens slutsats är att det med all sannolikhet går att applicera nanostrukturella ytbeläggningar och få ett mycket bättre resultat avseende hårdhet samt nötnings- och reptålighet jämfört med mikrostrukturella ytbeläggningar. Detta gäller såväl vid nytillverkning som renovering av de studerade delarna av drivlinor. Studien ger exempel på den militära nyttan med denna ytbeläggning samt ger förslag på fortsatt forskning.
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Magnetic fluids under applied field studied by light scattering and microscopyBraesch-Andersen, Anna January 2017 (has links)
The optical response of several magnetic nanoparticle dispersions is studied by angle resolved transmittance at wavelength of 600 nm in zero-field and under an applied magnetic field of 0.1 T, with the purpose of exploring to what extent this could be used as a method of monitoring the colloidal dispersions. In an external magnetic field, magnetic particles will start to order into needle-like structures aligned with the field, which was observed by microscopy. This will change the light scattering caused by the particles. Results showed a clear effect from applying the magnetic field by a dip in the transmitted intensity at angles around 3-5 degrees. The scattering is compared to that of a homogeneous infinite cylinder and theoretical explanations to the effect are discussed. Spectrophotometry at wavelengths between 300-1100 nm is performed and compared with calculations from Kubelka-Munk approximation to give a first characterization of the particle dispersions. Particles used in this project are magnetite, Fe3O4, and maghemite, gamma-Fe2O3, nanoparticles with sizes ranging from 5-250 nm.
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InP/Si Template for Photonic ApplicationLarsson, Niklas January 2015 (has links)
In this work an epitaxial layer of Indium Phosphide (InP) has been grown on top of a silicon substrate using the Corrugated Epitaxial Lateral Overgrowth (CELOG) technique. The grown InP CELOG top layer typically has a poor surface roughness and planarity. Before this surface can be used for any processing it has to be smooth and planarized. For this purpose a two-step Chemical Mechanical Polishing (CMP) technique has been investigated and developed. In the first step commercially available Chemlox has been used to planarize the sample. In the second step Citric Acid (CA) and sodium hypochlorite (NaClO) has been mixed together to form abrasive-free polishing slurry. The second step has been developed to remove defects introduced by the first step. This surface is prepared to demonstrate that a photonic device such as a quantum well can be realized in a Photonic Integrated Circuit (PIC). A quantum well was grown on the polished CELOG InP/Si sample and measured with Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Photoluminescence (PL). The roughness was improved with CMP from 33.2 nm to 12.4 nm. However the quantum well did not give any response in the PL measurements. / I detta arbete har ett epitaxiellt lager indiumfosfid (InP) blivit växt på ett kiselsubstrat med hjälp av en korrugerad epitaxial lateral överväxt (CELOG) teknik. Det översta lagret av den CELOG växta ytan har ofta en väldigt ojämn yta. Innan denna yta kan användas till någon fortsatt utveckling måste den vara slät och plan. Det översta lagret har polerats med hjälp av en två-stegs kemisk mekanisk polerings (CMP) teknik. I det första steget har komersiellt tillgänglig Chemlox använts för att planarisera ytan. I det andra steget har citronsyra (CA) och natrium hypoklorit (NaClO) blandats samman för att bilda ett partikelfritt polermedel. Det andra steget har tagits fram för att ta bort defekter introducerade I det första steget. Ytan är preparerad för att demonstrera att en fotonisk enhet, t.ex. en kvantbrunn kan realiseras I en fotonisk integrerad krets (PIC). En kvantbrunn växtes fram på det polerade CELOG InP/Si provet och mattes med hjälp av atomkraftsmikroskop (AFM), scanning electron mikroskopi (SEM), röntgendiffraktion (XRD) och fotoluminisens (PL). Ytojämnheten förbättrades med hjälp av CMP från 33.2 nm till 12.4 nm. Dock så gav ej kvantbrunnen någon respons I PL-mätningarna.
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Design of Multi-function Polymeric Nanoparticles for Theranostic Application / Design av multifunktionella polymera nanopartiklar för teranostisk tillämpningYamani, Zuhoor January 2019 (has links)
Block copolymer nanoparticles (NPs) have gained great attention among researcher for various medical application mainly due to their extraordinary optical, chemical, and biological properties. The current thesis presents design of multifunctional polymeric NPs for imaging and drug delivery system (DDS) with an in-vitro study of their participation in drug release and cell viability. The NPs were synthesized using reversible addition chain fragmentation transfer (RAFT)-mediated emulsion polymerization via polymerization induce self-assembly (PISA) approach. The environment-friendly emulsion polymerization process of n-buytl acrylate (n-BA) in water is highly efficient. The process produced uniform NPs which would have control over the particle size and molecular weight of the compound. Herein we report a novel simultaneous encapsulation of camptothecin (CPT) and Nile red (NR) into poly(ethylene glycol) methyl ether methacrylate-co-N-hydroxyethyl acrylamide-b-poly n-buytlacrylate (PEGA-co-HEAA)-b-P(n-BA) during the particles formation with a small particle size of 66 nm, high conversion ~80% and encapsulation efficiency of ~50%. The In vitro drug release of the CPT from the NPs exhibited an initial burst (70-80%) within 6h. cell viability was evaluated for the NPs against RAW 264.7 cell line, which indicated the designed NPs are biocompatible and not toxic.
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