Procedimiento de obtención de un electrodo flexible

[EN] The present invention relates to a method for obtaining a flexible electrode of graphene oxide which comprises a step of placing a material that is transparent to visible light between the two faces of the flexible graphene oxide material prior to irradiation with visible light. The electrode obtained by this method is likely to be used in supercapacitors. Consequently, the present invention can be classified in the energy sector[ES] La presente invención se refiere a un procedimiento de obtención de un electrodo flexible de óxido de grafeno que comprende una etapa de colocación de material transparente a la luz visible entre ambas caras del material flexible de óxido de grafeno previa a la irradiación con una luz visible. El electrodo obtenido por este procedimiento es susceptible de ser utilizado en supercondensadores. Por tanto, la presente invención se puede encuadrar en el área de la energíaPeer reviewedConsejo Superior de Investigaciones Científicas (España), Universidad Babeș-BolyaiA1 Solicitud de patente con informe sobre el estado de la técnic

Procedimiento de obtención de un electrodo flexible

La presente invención se refiere a un procedimiento de obtención de un electrodo flexible de óxido de grafeno que comprende una etapa de colocación de material transparente a la luz visible entre ambas caras del material flexible de óxido de grafeno previa a la irradiación con una luz visible. El electrodo obtenido por este procedimiento es susceptible de ser utilizado en supercondensadores. Por tanto, la presente invención se puede encuadrar en el área de la energíaPeer reviewedConsejo Superior de Investigaciones Científicas (España), Universidad Babeș-BolyaiA1 Solicitud de patente con informe sobre el estado de la técnic

An experimental set-up to study the blockage problem in the flow of liquid helium (LHe) in small impedances

Resumen del trabajo presentado a la XXXVII Reunión Bienal de la Real Sociedad Española de Física celebrada en Zaragoza del 15 al 19 de julio de 2019.The presence of Hydrogen (H2) traces in LHe has disastrous consequences for some laboratory equipment such as evaporation cryostats, PPMS and MPMS. The working principle of those equipment to achieve temperatures below 4.2 K consists in pumping LHe through a capillary tube. If LHe contains H2 traces, that capillary will get blocked after some time. In order to unblock it, it is needed to heat the equipment at room temperature (RT) with the loss of liquid He and time. With the aim to solve this problem, the University of Zaragoza in collaboration with Quantum Design company developed a method to produce H2 free LHe. In this work, we present a study to determine what is the minimum H2 concentration in He gas that can generate blockages when the He gas is liquified. To carry out this proposal, we have developed an experimental setup to produce LHe contaminated with H2 in a controller manner. This setup can be divided in two stages (see figure): the first one consists in mixing the He gas (at RT and pressure larger than atmospheric) with a known H2 concentration to then be liquified (at 4.2 K and atmospheric pressure), whereas the second one consists in the detection of H2 traces present in the liquified He-H2 gas mixture by using a H2 detector developed by us, whose effectiveness has been proved in other labs around the world. This device consists of a flow microimpedance assembled to a stainless steel thin tube. The microimpedance is immersed in LHe while the other end of the tube is connected to a vacuum pump and a pressure sensor. If the tested LHe contains H2 traces (with an enough concentration to produce blockages), the pressure reading will decrease (in a few minutes) to the baseline of the vacuum pump.Peer reviewe

Arrays of suspended silicon nanowires defined by ion beam implantation: mechanical coupling and combination with CMOS technology

We present the fabrication, operation, and CMOS integration of arrays of suspended silicon nanowires (SiNWs). The functional structures are obtained by a top-down fabrication approach consisting in a resistless process based on focused ion beam irradiation, causing local gallium implantation and silicon amorphization, plus selective silicon etching by tetramethylammonium hydroxide, and a thermal annealing process in a boron rich atmosphere. The last step enables the electrical functionality of the irradiated material. Doubly clamped silicon beams are fabricated by this method. The electrical readout of their mechanical response can be addressed by a frequency down-mixing detection technique thanks to an enhanced piezoresistive transduction mechanism. Three specific aspects are discussed: i) the engineering of mechanically coupled SiNWs, by making use of the nanometer scale overhang that it is inherently-generated with this fabrication process, ii) the statistical distribution of patterned lateral dimensions when fabricating large arrays of identical devices, and iii) the compatibility of the patterning methodology with CMOS circuits. Our results suggest that the application of this method to the integration of large arrays of suspended SiNWs with CMOS circuitry is interesting in view of applications such as advanced radio frequency band pass filters and ultra-high-sensitivity mass sensors.SNM (FP7-ICT-2011-8)) and Nanointegra (TEC2015-69864-R)Peer reviewe

Reactive laser synthesis of nitrogen-doped hybrid graphene-based electrodes for energy storage

A versatile method based on the matrix assisted pulsed laser evaporation (MAPLE) technique was used for the fabrication of graphene-based electrodes for application in supercapacitors. The simultaneous deposition and chemical transformation of graphene oxide (GO) and GO–NiO nanoparticles was attained by including nitrogen-containing chemically reactive compounds (ammonia, urea and melamine) in aqueous MAPLE targets. Morphological analyses reveal the formation of hundreds of nanometres to tens of micrometres thick porous films on both plastic and metallic flexible substrates. Structural and compositional studies, carried out by transmission electron microscopy, and Raman and X-ray photoelectron spectroscopies, disclose significant deoxidation and nitrogen doping of the GO material. The electrodes reveal remarkable electrochemical performance, showing a maximum volumetric capacitance of 350 F cm 3 (9 mF cm 2 areal capacitance) in aqueous electrolyte. Symmetric supercapacitors fabricated with these electrodes reveal excellent long-term stability at high specific intensities. From the obtained results, it can be asserted that the reactive inverse MAPLE method stands out as a promising technology not only for the adaptable fabrication of flexible graphene-based composite electrodes but also for a wide variety of advanced functional materials for diverse applications.The authors are thankful for the nancial support of the Spanish Ministry of Economy, Industry and Competitiveness under project ENE2017-89210-C2-1-R, and support from AGAUR of Generalitat de Catalunya through project 2017 SGR 1086. ICMAB acknowledges nancial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015- 0496).Peer reviewe

New fabrication method for producing reduced graphene oxide flexible electrodes by using a low-power visible laser diode engraving system

The fabrication of bendable electronic devices is a scientific-technological area of very rapid advance in which new materials and fabrication techniques are being continuously developed. In these kinds of devices, the fabrication of flexible conductive electrodes adherent to the substrate is a key factor. Further, eco-friendliness, low cost and fast production are essential requirements for the successful progress of new technologies. In this work, a novel method for obtaining graphene-based flexible electrodes is presented. Conductive films were obtained by means of the visible laser irradiation of graphene oxide layers deposited on polyethylene terephthalate substrates and self-standing membranes sandwiched between glass slides. Despite the low power of the laser system, the numerical simulations indicate the development of temperatures over 1000 K throughout the irradiated material. The laser-induced spatially confined heating leads to the reduction of the graphene oxide material, whereas the glass-based sandwich assembly avoids reoxidation from the surrounding air. By scanning and pixelated modes, reduced graphene oxide electrodes, up to 100 μm in thickness, and with a resistivity as low as 6 × 10−4 Ωm, were obtained in an easy and versatile way. Proof-of-concept microsupercapacitors and electrochemical sensors were fabricated with this technique, showing promising performance.The authors are grateful for the financial support of the Spanish Ministry of Economy, Industry and Competitiveness under the project ENE2017-89210-C2-1-R, and support from AGAUR of Generalitat de Catalunya through projects 2017 SGR 1086 and 2017 SGR 1771. ICMAB acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the 'Severo Ochoa' Programme for Centres of Excellence in R&D (SEV- 2015-0496). Also, this work was supported by a grant of the Romanian Ministry of Research and Innovation, CCCDI—UEFISCDI, project number PN-III-P1-1.2-PCCDI-2017-0350/01.03.2018 (Graphene4Life), within PNCDI III.Peer reviewe