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The purpose of this investigation was to explore the processing parameters involved in the production of thin film superconductors by spray pyrolysis processing (SPP). The present study is an attempt to optimize the many parameters in SPP. The specific parameters studied were substrate temperature, carrier gas flow rate, substrate materials, solution stoichiometry, spray rate, concentration, starting materials, and substrate to nozzle distance. The effect of these parameters on film stoichiometry and the anticipated superconducting behavior were investigated at some length. Films were routinely produced in a spray chamber designed as a part of this research. Films were analyzed by Rutherford Backscattering Spectroscopy, X-Ray Diffraction, Scanning Electron Microscopy, and Meissner effect measurements.

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In this thesis, atomic force microscopy (AFM), transmission electron microscopy (TEM) and optical microscopy techniques were used to investigate systematically the self-assembled nanostructure behaviour of two different types of spin-cast polymer thin films: poly(isoprene-b-ethylene oxide), PI-b-PEO diblock copolymers and [poly(9,9-dioctylfluorene-co-benzothiadiazole)]:poly[9,9- dioctyfluorene-co-N-(4-butylphenyl)-diphenylamine], F8BT:TFB conjugated polymer blends. In the particular case of the polymer blend thin films, the morphology of their composites with cadmium selenide (CdSe) quantum dot (QD) nanoparticles was also investigated. For the diblock copolymer thin films, the behaviour of the nanostructures formed and the wetting behaviour on mica, varying the volume fraction of the PEO block (fPEO) and the average film thickness was explored. For the polymer blend films, the effect of the F8BT/TFB blend ratio (per weight), spin-coating parameters and solution concentration on the phase-separated nanodomains was investigated. The influence of the quantum dots on the phase separation when these were embedded in the F8BT:TFB thin films was also examined. It was found that in the case of PI-b-PEO copolymer thin films, robust nanostructures, which remained unchanged after heating/annealing and/or ageing, were obtained immediately after spin coating on hydrophilic mica substrates from aqueous solutions. The competition and coupling of the PEO crystallisation and the phase separation between the PEO and PI blocks determined the ultimate morphology of the thin films. Due to the great biocompatible properties of the PEO block (protein resistance), robust PEO-based nanostructures find important applications in the development of micro/nano patterns for biological and biomedical applications. It was also found that sub-micrometre length-scale phase-separated domains were formed in F8BT:TFB spin cast thin films. The nanophase-separated domains of F8BT-rich and TFB-rich areas were close to one order of magnitude smaller (in the lateral direction) than those reported in the literature. When the quantum dot nanoparticles were added to the blend thin films, it was found that the QDs prefer to lie in the F8BT areas alone. Furthermore, adding quantum dots to the system, purer F8BT and TFB nano-phase separated domains were obtained. Conjugated polymer blend thin films are excellent candidates for alternatives to the inorganic semiconductor materials for use in applications such as light emitting diodes and photovoltaic cells, mainly due to the ease of processing, low-cost fabrication and mechanical flexibility. The rather limited optoelectronic efficiency of the organic thin films can be significantly improved by adding inorganic semiconducting nanoparticles.

Carbon-based thin films are a vast group of materials of great technological importance. Thanks to the different bonding options for carbon, a large variety of structures (from amorphous to nanostructured) can be achieved in the process of film synthesis. The structural diversity increases even more if carbon is combined with relatively small quantities of atoms of other elements. This results in a set of materials with many different interesting properties for a wide range of technological applications. This doctoral thesis is about nanostructured carbon-based thin films. In particular, the focus is set on theoretical modeling, prediction of structural features and design of sulfo carbide (CSx) and carbon fluoride (CFx) thin films. The theoretical approach follows the synthetic growth concept (SGC) which is based on the density functional theory. The SGC departure point is the fact that the nanostructured films of interest can be modeled as assemblies of low dimensional units (e.g., finite graphene-like model systems), similarly to modeling graphite as stacks of graphene sheets. Moreover, the SGC includes a description of the groups of atoms that act as building blocks (i.e., precursors) during film deposition, as well as their interaction with the growing film. This thesis consists of two main parts: Prediction: In this work, I show that nanostructured CSx thin films can be expected for sulfur contents up to 20 atomic % with structural characteristics that go from graphite-like to fullerene-like (FL). In the case of CFx thin films, a diversity of structures are predicted depending on the fluorine concentration. Short range ordered structures, such as FL structure, can be expected for low concentrations (up to 5 atomic %). For increasing fluorine concentration, diamond-like and polymeric structures should predominate. As a special case, I also studied the ternary system CSxFy. The calculations show that CSxFy thin films with nanostructured features should be possible to synthesize at low sulfur and fluorine concentrations and the structural characteristics can be described and explained in terms of the binaries CSx and CFx. Design: The carbon-based thin films predicted in this thesis were synthesized by magnetron sputtering. The results from my calculations regarding structure and composition, and analysis of precursors (availability and role during deposition process) were successfully combined with the experimental techniques in the quest of obtaining films with desired structural features and understanding their properties.

CIVINS / Carbon nanotubes (CNTs) exhibit exceptional electrical, thermal, and mechanical properties that could potentially transform such diverse fields as composites, electronics, cooling, energy storage, and biological sensing. For the United States Navy, composites potentially provide a significant decrease in lifetime maintenance costs of ships by eliminating hull corrosion. A stronger composite could also improve naval ship survivability or increase combat payloads by reducing the hull weight of ships and submarines. Further, cooling requirements of ship borne electronics have grown exponentially and represent a significant weight penalty for advanced ship designs. Any improvement in thermal transport could significantly improve future naval ship designs. In order to realize these benefits, methods must be discovered to fully characterize CNT growth mechanisms, consistently produce CUTs in manufacturable quantities, and to integrate CUTs into macroscale structures which reflect the properties of individual CUTs. While growth of CNTs in laboratory scale chemical vapor deposition (CVD) tube furnaces has shown great promise, existing low cost tube furnace designs limit the researcher's ability to fully separate critical reaction parameter such as temperature and flow profiles and limit the rate of temperature change during the growth process. Conventional tube furnace designs also provide limited mechanical access to the growth Site and prevent optical monitoring of the growth site, removing the ability to observe and interact in situ during growth. This thesis presents the SabreTube, a low-cost desktop cvD apparatus that decouples temperature and flow variables, provides mechanical and optical access to the reaction site during growth, and provides modular fixturing to enable versatile experimentation with and characterization of CUT growth mechanisms. This thesis also presents the Nanosled, a device designed to translate a substrate through a CVD furnace. / Contract number: N62271-97-G-0026. / CIVINS

Phosphorescent organic light emitting diodes (PHOLEDs) based on efficient electrophosphorescent dopant, platinum(II)-pyridyltriazolate complex, bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp)2) have been studied and improved with respect to power efficiency, external efficiency, chromacity and efficiency roll-off. By studying the electrical and optical behavior of the doped devices and functionality of the various constituent layers, devices with a maximum EQE of 20.8±0.2 % and power efficiency of 45.1±0.9 lm/W (77lm/W with luminaries) have been engineered. This improvement compares to devices whose emission initially could only be detected by a photomultiplier tube in a darkened environment. These devices consisted of a 65 % bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp)2) doped into 4,4'-bis(carbazol-9-yl)triphenylamine (CBP) an EML layer, a hole transporting layer/electron blocker of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), an electron transport layer of 1,3,5-tris(phenyl-2-benzimidazolyl)-benzene (TPBI), and a LiF/Al cathode. These devices show the acceptable range for warm white light quadrants and qualify to be called "warm white" even w/o adding another emissive layer. Dual EML devices composed of neat Pt(ptp)2 films emitting orange and CBP: Pt(ptp)2 film emitting blue-green produced a color rendering index (CRI) of 59 and color coordinates (CIE) of (0.47,0.49) at 1000Cd/m² with power efficiency of 12.6±0.2 lm/W and EQE of 10.8±0.2 %. Devices with two blue fluorescent emission layers as singlet filters and one broad yellow emission layer from CBP: Pt(ptp)2 displayed a CRI of 78 and CIE of (0.28,0.31) at 100Cd/m² with maximum power efficiency of 6.7±0.3 lm/W and EQE of 5.7±0.2 %.

Chloride, bromide, pyridinium and quinolinium homologues of 4-(N- hexadecylpyridinium-4-ylmethylidene-amino)-2,6-dichlorophenolate have been investigated in solution, Langmuir and Langmuir-Blodgett films. Techniques including spectroscopy, surface potential measurement, quartz crystal microbalance, surface plasmon resonance, atomic force microscopy, reectometry and X-ray diffraction have been used to characterise these molecular systems. In solution, solvatochroism was observed and Benisi-Hildebrand analysis revealed dimeric aggregation. Langmuir monolayers were compressed at the air/water interface and chromophore rotation was observed by surface potential measurement. Langmuir- Blodgett monolayers showed lm-thickness dependence on the deposition-pressure. Monolayer thicknesses between 6-24Ä were measured using SPR and molecular areas between 40-l25Ä2 were measured using a quartz crystal microbalance. Both the molecular/s/area)and monolayer thicknesses were deposition-pressure dependent. The high tilt phases were visually distinguishable from the low tilt phases using atomic force microscopy, The compounds showed phase behaviour that was predominantly alike for the bromide and chloride homologues but different for the pyridinium and quinolinum homologues. Multilayer Y-type films of the merocyanine dyes were analysed using reectometry and deposition-pressure dependent thicknesses were found. Alternate layer structures of NLO-active hemicyanine amphiphiles were used to achieve homogeneous. orientation ordering using active and inactive spacer layers. Ordering was achieved but the optical efficiency was reduced by high proportions of inactive material and interlayer dipole formation. Double chained hemicyanine molecules were used to form Z-type structures and subsequent layers were found to significantly interdigitate. Different chain lengths were found to interdigitate by the length of the shortest chain. Gas detection experiments were undertaken on the quinolinium, dichloro merocyanine using three optical geometries. The absorption method showed slow switching and poor sensitivity. The Kretschmann SPR geometry showed high sensitivity and rapid switching. The grating SPR geometry showed rapid switching but was less sensitive than the ATR method. Protonation of the monolayers was investigated using hydrochloric acid gas, acetic acid vapour and stearic acid immobilised within the lm.

1 is a suitable material for thin-film gas sensors. Higher sensitivity could be achieved by platinum dopping of the layer. This work focuses on the optimalization of and thin film preparation by radio-frequency magnetron sputtering method. Subsequent analysis by means of XPS, AFM, SEM and XRD was carried out to determine physicochemical attributes of resulting layers. It appears that after the deposition, platinum within the layer is present in the metalic , as well as in the mixed chemical state. After the annealing process mixed state dominates over metalic state and after additional annealing platinum is present solely in oxidized form. Sensory response of layers for presence of hydrogen were examined on two different chip platforms (glass with chromium contacts and sapphire with platinum contacts). Contrary to expectations, the platinum dopped layers performed worse in comparison to the pure tin dioxide layers. This could be explained by the fact, that after annealing platinum within the layer was present mainly in the non-metalic form. Both and layers were more sensitive on sapphire platform, which could be associated with the crystal structure formed on its surface or with presence of metalic contacts.