Electrospun Fibers in Composite Materials for Medical Applications

Sem PDF conforme Despacho. The authors acknowledge Portuguese Science and Technology Foundation (FCT-MCTES) for the financial support through the Strategic Project PEstC/CTM/LA0025/2013-14. Ana C. Baptista also acknowledges FCT-MCTES for the doctoral grant SFRH/BD/69306/2010.The development of nanoscaled materials has deserved a remarkable interest for biomedical applications. Biological tissues are essentially composite materials with particular mechanical properties that should be carefully considered during the design of innovative biomedical scaffolds. Electrospun membranes are often found in medical applications due to its high specific surface which creates a 3D porous structure that mimics the native extracellular matrix. These electrospun membranes can also be designed to have enhanced mechanical properties, biocompatibility and cellular response making them appealing and inspiring to be used in composites materials. This paper reviews the new insights in the development of advanced nanostructured composites materials based on electrospun fibers. From tissue engineering to bioelectronics, these composite materials can be found in the most promising research developments for the medical applications.publishersversionpublishe

Cellulose-Based Bioelectronic Devices

The authors work was partially supported by Portuguese Science and Technology Foundation (FCT-MCTES) through the Strategic Project PEst-C/CTM/LA0025/2011. Ana Baptista also acknowledges FCT-MCTES for the doctoral grant SFRH/BD/69306/2010.publishersversionpublishe

Large-Area Paper Batteries with Ag and Zn/Ag Screen-Printed Electrodes

This work was partially funded by H2020-ICT-2014-1, RIA, ERC-CoG-2014, and FEDER funds through the COMPETE 2020 Program and National Funds through FCT -Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2019.Large-area paper batteries have been explored in this paper, correlating electrode materials and screen printing with the electrochemical performances. The use of office paper embedded in salt solution with two electrodes performed by an easy and large-scale application technique opens doors to a new concept of energy storage. The proposed device is Li-free and uses zinc and silver powder-based screen printable pastes to deposit the electrodes. Cyclic voltammetry and charge-discharge curves reveal the performance of the produced devices using NaCl and KOH solutions in different concentrations. The simulation of electrochemical impedance spectroscopy measurements gave clue of a similar working mechanism to conventional Li-ion batteries. After charging, a single paper battery achieves 1.83 V with 60 mA/cm2 and 90.6% charge-discharge efficiency. As a proof of concept, a small paper battery and a set integrated in series and parallel were used to power a commercial red light-emitting diode.publishersversionpublishe

Broadband photocurrent enhancement in a-Si:H solar cells with plasmonic back reflectors

The authors acknowledge Francesco Ruffino for the AFM measurements. This work was funded by the EU FP7 Marie Curie Action FP7-PEOPLE-2010-ITN through the PROPHET project (Grant No. 264687), the bilateral CNR/AVCR project "Photoresponse of nanostructures for advanced photovoltaic applications", the MIUR project Energetic (Grant no. PON02_00355_3391233) and by the Portuguese Science Foundation (FCT-MEC) through the Strategic Project PEst-C/CTM/LA0025/2013-14 and the research project PTDC/CTM-ENE/2514/2012.Plasmonic light trapping in thin film silicon solar cells is a promising route to achieve high efficiency with reduced volumes of semiconductor material. In this paper, we study the enhancement in the opto-electronic performance of thin a-Si:H solar cells due to the light scattering effects of plasmonic back reflectors (PBRs), composed of self-assembled silver nanoparticles (NPs), incorporated on the cells' rear contact. The optical properties of the PBRs are investigated according to the morphology of the NPs, which can be tuned by the fabrication parameters. By analyzing sets of solar cells built on distinct PBRs we show that the photocurrent enhancement achieved in the a-Si:H light trapping window (600 - 800 nm) stays in linear relation with the PBRs diffuse reflection. The best-performing PBRs allow a pronounced broadband photocurrent enhancement in the cells which is attributed not only to the plasmon-assisted light scattering from the NPs but also to the front surface texture originated from the conformal growth of the cell material over the particles. As a result, remarkably high values of J(sc) and V-oc are achieved in comparison to those previously reported in the literature for the same type of devices. (C)2014 Optical Society of Americapublishersversionpublishe