Ullaha, S, Matteis DF, Branquinho R, Fortunato E, Martins R, Davoli I.
2015.
{A combination of solution synthesis solution combustion synthesis for highly conducting and transparent Aluminum Zinc Oxide thin films}. 2015 IEEE 15th International Conference on Nanotechnology (IEEE-NANO). :144–147.
AbstractAluminum Zinc Oxide has been extensively investigated as a cheap alternative to transparent conducting tin oxide films for electronic and optoelectronic applications. Thin films of Aluminum Zinc Oxide have been developed successfully through a combination of solution combustion synthesis and solution synthesis. Zn(NO3)3·6H2O as metal source was dissolved in 2-methoxyethanol as solvent through combustion synthesis with Urea as fuel while dopant source of AlCl3·6H2O was mixed separately in solvent to avoid aluminum oxide formation in the films. Precursor solutions were obtained mixing Zn {&} Al separate solutions in 9:1, 8:2, and 7:3 ratios respectively with oxide, fuel and dopant concentrations of 0.5, 0.25, 0.1, and 0.05 M. The film stacks have been prepared through spin-coating with heating at 400°C for 10 minutes after each deposition to remove residuals and evaporate solvents. Thermal annealing in oven at 600°C for 1 hour followed by rapid thermal annealing at 500°C {&} 600°C first in vacuum and then in N2-5{%}H2 environment respectively for 10 minutes each reduced the resistivity of film stacks. Film stack with 10 layers for an average thickness of 0.5$μ$m gave the best Hall Effect resistivity of 3.2 × 10-2 $Ømega$-cm in the case of 0.5M solution with Zn:Al mixing ratio of 9:1 for RTA annealings at 600°C with an average total transparency of 80 {%} in the wavelength range of 400-1200 nm. The results show a clear trend that increasing the amount of ingredients resistivity could further be decreased.
Fernandes, M, Leones R, Costa AMS, Silva MM, Pereira S, Mano JF, Fortunato E, Rego R, {de Zea Bermudez} V.
2015.
{Electrochromic devices incorporating biohybrid electrolytes doped with a lithium salt, an ionic liquid or a mixture of both}. Electrochimica Acta. 161:226–235.: Elsevier Ltd
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Kololuoma, T, Leppäniemi J, Majumdar H, Branquinho R, Herbei-Valcu E, Musat V, Martins R, Fortunato E, Alastalo A.
2015.
{Gravure printed sol–gel derived AlOOH hybrid nanocomposite thin films for printed electronics}. J. Mater. Chem. C. 3:1776–1786., Number 8
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Wojcik, PJ, Santos L, Pereira L, Martins R, Fortunato E.
2015.
{Tailoring nanoscale properties of tungsten oxide for inkjet printed electrochromic devices}. Nanoscale. 7:1696–1708., Number 5: Royal Society of Chemistry
AbstractThis paper focuses on the engineering procedures governing the synthesis of tungsten oxide nanocrystals and the formulation of printable dispersions for electrochromic applications. By that means, we aim to stress the relevancy of a proper design strategy that results in improved physicochemical properties of nanoparticle loaded inks. In the present study inkjet printable nanostructured tungsten oxide particles were successfully synthesized via hydrothermal processes using pure or acidified aqueous sol-gel precursors. Based on the proposed scheme, the structure and morphology of the nanoparticles were tailored to ensure the desired printability and electrochromic performance. The developed nanomaterials with specified structures effectively improved the electrochemical response of printed films, resulting in 2.5 times higher optical modulation and 2 times faster coloration time when compared with pure amorphous films.
Branquinho, R, Salgueiro D, Santa A, Kiazadeh A, Barquinha P, Pereira L, Martins R, Fortunato E.
2015.
{Towards environmental friendly solution-based ZTO/AlOx TFTs}. SEMICONDUCTOR SCIENCE AND TECHNOLOGY. 30, Number 2, SI
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Nunes, D, Santos L, Duarte P, Pimentel A, Pinto JV, Barquinha P, Carvalho PA, Fortunato E, Martins R.
2015.
{Room temperature synthesis of Cu₂O nanospheres: optical properties and thermal behavior.}, feb. Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada. 21:108–19., Number 1
AbstractThe present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.
Santos, L, Wojcik P, Pinto JV, Elangovan E, Viegas J, Pereira LÍ, Martins R, Fortunato E.
2015.
{Structure and Morphologic Influence of WO 3 Nanoparticles on the Electrochromic Performance of Dual-Phase a -WO 3 /WO 3 Inkjet Printed Films}, feb. Advanced Electronic Materials. 1:n/a–n/a., Number 1-2
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Veigas, B, Fortunato E, Baptista PV.
2015.
{Field Effect Sensors for Nucleic Acid Detection: Recent Advances and Future Perspectives}, jan. Sensors. 15:10380–10398., Number 5: Multidisciplinary Digital Publishing Institute
AbstractIn the last decade the use of field-effect-based devices has become a basic structural element in a new generation of biosensors that allow label-free DNA analysis. In particular, ion sensitive field effect transistors (FET) are the basis for the development of radical new approaches for the specific detection and characterization of DNA due to FETs' greater signal-to-noise ratio, fast measurement capabilities, and possibility to be included in portable instrumentation. Reliable molecular characterization of DNA and/or RNA is vital for disease diagnostics and to follow up alterations in gene expression profiles. FET biosensors may become a relevant tool for molecular diagnostics and at point-of-care. The development of these devices and strategies should be carefully designed, as biomolecular recognition and detection events must occur within the Debye length. This limitation is sometimes considered to be fundamental for FET devices and considerable efforts have been made to develop better architectures. Herein we review the use of field effect sensors for nucleic acid detection strategies—from production and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics lab.