The detection of heavy metals in subsurface strata currently requires tedious sampling procedures followed by laboratory analysis using techniques such as atomic absorption spectroscopy (AAS) or inductively couple plasma atomic emission spectroscopy (ICP-AES). These techniques are extremely accurate and capable of detecting very low concentrations of metal ions. The main drawback of these techniques is that they are time consuming, expensive to perform and not portable. A portable sensor capable of detecting metals ion in solution is highly desirable. Anodic Stripping Voltammetry (ASV) can be utilized as a reliable method for the trace detection of metal ions in water. In order to improve the sensitivity of the electrochemical sensor, conjugated polymer films can be coated on the surface of the glassy carbon working electrodes. Stable films of poly (3,4 ethylenedioxythiophene) [PEDOT] and polythiophene copolymer [PTCPTA] were electrochemically synthesized on the surface of a glassy carbon electrode. These polymer modified electrodes were utilized for the detection of cadmium in water. The sensors are capable of detecting trace concentrations of cadmium approaching the maximum contamination limits imposed by the Environment Protection Agency (EPA).

Centrifuge enforced precipitation was used to disperse PbS quantum dots (diameter 4.7 nm) on polyethylene terephthalate. By employing double frequency Fourier transform spectroscopy, we studied the emission properties of the sample. Gaussian shaped emission spectra from cryogenic temperatures up to room temperatures were observed, demonstrating the potential of PbS quantum dots to be used as light emitters in combination with organic matrices. One interesting feature is that the linewidth of the emission spectrum does not follow the expected thermal broadening.

In this work, we report the effects of curing time on properties of SiO2 films produced from Spin-On Glass (SOG) diluted with H2O and cured at 200°C. The electrical characterization showed that the insulator breakdown field for the films produced from SOG diluted with H2O with 1 Hr of curing time was approximately 5 MV/cm while for 6.5 Hrs of curing time the breakdown field was 21 MV/cm. Also, the refractive index and surface roughness were improved with longer curing time.

Effect of high-pressure water vapor (HPV) annealing is discussed from density of state (DOS) by capacitance–voltage (C–V) method and ΔVFB by the cyclic C–V measurement. The DOS of HPV samples were smaller than that of conventional atmosphere (AT) annealing around conduction band minimum (Ec). The ΔVFB of HPV samples were also smaller than that of AT. This suggests that HPV annealing is an effective method to decrease electron trap density as compared with AT condition. Especially, HPV 0.5 MPa sample was lower electron trap density and more stable than the other pressure HPV samples. Therefore, it is considered that the HPV in 0.5 MPa is the most promising condition. In addition, we succeeded in demonstrating the analysis of trap density in thin film by C–V method and cyclic C–V measurement.

In this paper we report on the fabrication of n-doped ZnO and semiconducting n-ZnO at room temperature by a new ablation deposition technology that makes use of electron/plasma ablation sources named Pulsed Plasma Deposition (PPD) developed by Organic Spintronics Srl.

The oxygen vacancies n-doped ZnO PPD grown thin film is deposited on PET and shows a resistivity of 3 x 10-4ohm cm. The n-ZnO TCO is compact, smooth and highly transparent in the UV-VIS (better than 90 T%) as well as in the near IR spectral range and it is remarkably temperature stable. Typical ZnO deposition rate of the PPD is 500 nm/min.

The RT deposited semiconductor ZnO shows a very large Hall electron mobility up to 1000 cm2/Vs approaching that of the single crystal. Preliminary results of Si/SiO2 based bottom gate and contact FET test pattern structures with a 50 nm overlaying ZnO thin film shows an ON/OFF ratio of 50000 and a FET mobility of 1 cm2/Vs. Further implementation on appropriate FET design will be performed to explore the possibility to achieve a larger FET mobility. The PPD proves to be an enabling technology that makes it possible the advent of flexible OLED displays.

A high molecular weight, photocurable inorganic-organic hybrid based on ladder-like poly(phenyl6-co-methacrylate4)silsesquioxanes (LPPMA64) was investigated as a flexible display substrate. Photocured free standing films with 40μm thickness showed high transparency (>95%), excellent thermal stability (Td >450°C), and low coefficient of thermal expansion (38ppm/K) without the use of reinforced glass fibers. Furthermore, these ladder-like structured materials did not require any thermal treatment processes due to the negligible amounts of uncondensed groups, thus simplifying manufacturing processing. These novel hybrid films present an alternative to organic plastics as flexible electronic device substrates due to their excellent optical and thermal properties.

We investigated the anisotropic g tensors of nine kinds of organic semiconductor molecules in the cationic state by density functional theory (DFT) calculations. Large anisotropy was obtained in sulfur-containing molecules because of the large spin-orbit coupling at the sulfur atoms. The calculated g values were validated by electron spin resonance (ESR) experiments for the cation radicals in solution.

We have explored materials for organic field-effect transistors (OFETs) from the viewpoint of theoretical calculations. The herringbone structure, which realizes two-dimensional conduction, is investigated in detail. Transfer integrals (t) are calculated systematically as a function of the dihedral angle between the molecular planes (θ) and the displacement along the molecular long axis (D). Acenes, oligothiophenes, thienoacenes and tetrathiafulvalenes are investigated, and are discussed from the molecular orbital (MO) symmetry. Thienoacenes (nTAs) are particularly examined as a candidate of OFET materials from the calculations of transfer integrals and reorganization energies (λ) based on the energy levels and the MO symmetry. LUMO of nTAs have MO symmetry suitable for conduction, but these orbitals are usually not related to the conduction. We have investigated the electronic properties of the derivatives with dicarboximide moiety. nTA-tetracarboxydiimide is expected to show the herringbone structure and exhibit n-type transport from the properties of LUMO.

A new nano-fabrication process, utilizing protein supramolecules, biomineralization, and nano-etching was proposed, which was named Bio Nano Process (BNP). The main processes of the BNP include the nanoparticle (NP) or nanowire (NW) synthesis utilizing bio-template (biomineralization) and nanostructure fabrication utilizing self-organization of protein supramolecules. Proteins are so designed to produce the final structures. The space where nano functional structures are fabricated is named an “Active Bio-field”. It was proven that the process has vast potential to be applied to a wide range of quantum effect base nano-devices and thin film devices.

The purpose of this research is to develop a fabrication technique of microstructures on nonplanar substrates, investigating so called, optical softlithography. In addition, PDMS roller stamps were duplicated from these structures on curved substrates as the mold, roll micro contact printing was performed successfully.

Micro structuring on nonplanar substrates has not been fully established yet, although several fabrication methods, such as laser direct writing and modified photolithography, were proposed. Moreover, those techniques require still expensive and complex processes. To overcome those drawbacks, optical softlithography using flexible photomasks was developed [1]. Firstly, SU-8 micro structures were fabricated on concave substrates by optical softlithography using PDMS flexible photomasks. As a result, SU-8 structures with 2.5 μm line width and high aspect ratio over 7.9 were fabricated on a concave substrate. Also, experimental parameters for optical softlithography were investigated and established for further fabrications and applications. In addition, the tilting structures were confirmed due to the vertical UV exposure method.

Next, Based on these novel 3D patterning technologies, PDMS roller stamps were fabricated and roll micro contact printing was performed. The roll micro contact printing was investigated by using the customized roll micro contact printing apparatus and the flexible pressure sensor system. We expect this technique can provide various sized roller stamps with various micro patterns for μCP process as well as roll micro contact printing process.

A simple method is proposed for the chemical modification of carbon nanotubes (CNT) thin film counter electrodes (CE) for the replacement of fluorine-doped tin oxide (FTO) and platinum catalyst (Pt) while retaining light transparency. In order to decrease the sheet resistance, CNT thin films underwent various concentrations (≤10 M) and durations of HNO3 treatment prior to cell fabrication, and the effect on thin film properties was analyzed. P-doping was observed, and the maximum change in work function was found to be +0.35 eV with 4 M HNO3. Optimum sheet resistance reduction (50%) and work function increment were achieved after 1 h treatment with 4 M HNO3. Changes in optical transmittances for all samples were negligible (± 5%). Pristine and HNO3 treated films on plastic substrates were tested as CE in flexible bifacial dye sensitized solar cells (DSSC). Most significant improvements in conversion efficiencies were obtained when CNT on plastic substrates were pretreated with 8 M HNO3 (from 1.18% to 1.40% under roomlight, from 0.19% to 0.26% under 1 Sun).

Often, silver nanoparticles (AgNps) are looked at in the realm of their plasmonic effects that are characterized by unique absorptional bands in the visible spectrum. Herein, the kinetics of a simple gravity mediated sedimentation process of AgNps, in aqueous suspensions. The surface energy mismatch between the AgNps and the receiver substrate allow for the formation of irregularly shaped AgNp microclusters with interconnected microchannels with dimensions and particle density controlled by the distance between the exposed substrate surface and the water/suspension interface. An investigation of the interplay between these properties and the films’ nanoparticle density is presented.