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Multifunctional Digital Materials Platform for Smart Integrated Applications
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High UV and sunlight photocatalytic performance of porous ZnO nanostructures synthesized by a facile and fast microwave hydrothermal method
Publication . Ferreira, Sofia Henriques; Morais, Maria; Nunes, Daniela; Oliveira, Maria João; Rovisco, Ana; Pimentel, Ana; Águas, Hugo; Fortunato, Elvira; Martins, Rodrigo; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Molecular Diversity Preservation International (MDPI)
The degradation of organic pollutants in wastewaters assisted by oxide semiconductor nanostructures has been the focus of many research groups over the last decades, along with the synthesis of these nanomaterials by simple, eco-friendly, fast, and cost-effective processes. In this work, porous zinc oxide (ZnO) nanostructures were successfully synthesized via a microwave hydrothermal process. A layered zinc hydroxide carbonate (LZHC) precursor was obtained after 15 min of synthesis and submitted to different calcination temperatures to convert it into porous ZnO nanostructures. The influence of the calcination temperature (300, 500, and 700 °C) on the morphological, structural, and optical properties of the ZnO nanostructureswas investigated. All ZnO samples were tested as photocatalysts in the degradation of rhodamine B (RhB) under UV irradiation and natural sunlight. All samples showed enhanced photocatalytic activity under both light sources, with RhB being practically degraded within 60 min in both situations. The porous ZnO obtained at 700 °C showed the greatest photocatalytic activity due to its high crystallinity, with a degradation rate of 0.091 and 0.084 min-1 for UV light and sunlight, respectively. These results are a very important step towards the use of oxide semiconductors in the degradation of water pollutants mediated by natural sunlight.
New challenges of printed high-к oxide dielectrics
Publication . Carlos, Emanuel; Branquinho, Rita; Martins, Rodrigo; Fortunato, Elvira; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; Elsevier Science B.V., Amsterdam.
High-permittivity (к) oxide dielectrics have been widely demanded concerning the Internet of Things (IoT) requirements, such as flexible large-area manufacturing, energy efficiency, low-cost processes, and sustainable electronics, especially in thin-film transistors (TFTs). From there emerged the necessity of printing energy-efficient (vacuum-free) eco-devices using low-temperature methods (e.g., combustion synthesis, post-treatments) in the production and processing of nanomaterials, thus reducing the human carbon footprint. However, currently the main deposition method used is typically spin-coating which requires higher temperatures and long annealing times, not compatible with the printing industry. Besides the concerns with process integration, the market highly demands high-к dielectrics with great stability and high yield. To surpass these challenges, some crucial parameters in the ink design need to be considered to guarantee successful upscale for large-area electronics manufacturing.
Poly(Ionic) Liquid-Enhanced Ion Dynamics in Cellulose-Derived Gel Polymer Electrolytes
Publication . Paiva, Tiago G; Klem, Maykel; Silvestre, Sara L.; Coelho, João; Alves, Neri; Fortunato, Elvira; Cabrita, Eurico J; Corvo, Marta C; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; Wiley | Wiley-VCH Verlag
Gel polymer electrolytes (GPEs) are regarded as a promising alternative to conventional electrolytes, combining the advantages of solid and liquid electrolytes. Leveraging the abundance and eco-friendliness of cellulose-based materials, GPEs were produced using methyl cellulose and incorporating various doping agents, either an ionic liquid (1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr14][TFSI]), its polymeric ionic liquid analogue (Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl)imide) [PDADMA][TFSI]), or an anionically charged backbone polymeric ionic liquid (lithium poly[(4-styrenesulfonyl)(trifluoromethyl(S-trifluoromethylsulfonylimino) sulfonyl) imide] LiP[STFSI]). The ion dynamics and molecular interactions within the GPEs were thoroughly analyzed using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Heteronuclear Overhauser Enhancement Spectroscopy (HOESY), and Pulsed-Field Gradient Nuclear Magnetic Resonance Diffusion (PFG-NMR). Li + transference numbers (t Li+) were successfully calculated. Our study found that by combining slow-diffusing polymeric ionic liquids (PILs) with fast-diffusing lithium salt, we were able to achieve transference numbers comparable to those of liquid electrolytes, especially with the anionic PIL, LiP[STFSI]. This research highlights the influence of the polymer's nature on lithium-ion transport within GPEs. Additionally, micro supercapacitor (MSC) devices assembled with these GPEs exhibited capacitive behavior. These findings suggest that further optimization of GPE composition could significantly improve their performance, thereby positioning them for application in sustainable and efficient energy storage systems.
Touch-Interactive Flexible Sustainable Energy Harvester and Self-Powered Smart Card
Publication . Ferreira, Guilherme; Goswami, Sumita; Nandy, Suman; Pereira, Luis; Martins, Rodrigo; Fortunato, Elvira; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; WILEY-V C H VERLAG GMBH
Sustainable and safe energy sources combined with cost effectiveness are major goals for society when considering the current scenario of mass production of portable and Internet of Things (IoT) devices along with the huge amount of inevitable e-waste. The conceptual design of a self-powered “eco-energy” smart card based on paper promotes green and clean energy, which will bring the zero e-waste challenge one step closer to fruition. A commercial raw filter paper is modified through a fast in situ functionalization method, resulting in a conductive cellulose fiber/polyaniline composite, which is then applied as an energy harvester based on a mechano-responsive charge transfer mechanism through a metal/conducting polymer interface. Different electrodes are studied to optimize charge transfer based on contact energy level differences. The highest power density and current density obtained from such a paper-based “eco-energy” smart card device are 1.75 W m−2 and 33.5 mA m−2 respectively. This self-powered smart energy card is also able to light up several commercial light-emitting diodes, power on electronic devices, and charge capacitors.
Porous ZnO Nanostructures Synthesized by Microwave Hydrothermal Method for Energy Harvesting Applications
Publication . Ferreira, Sofia Henriques; Rovisco, Ana; Santos, Andreia dos; Aguas, Hugo; Igreja, Rui; Barquinha, Pedro Miguel Cândido; Fortunato, Elvira; Martins, Rodrigo; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias
The ever-growing global market for smart wearable technologies and Internet of Things (IoT) has increased the demand for sustainable and multifunctional nanomaterials synthesized by low-cost and energy-efficient processing technologies. Zinc oxide (ZnO) is a key material for this purpose due to the variety of facile methods that exist to produced ZnO nanostructures with tailored sizes, morphologies, and optical and electrical properties. In particular, ZnO nanostructures with a porous structure are advantageous over other morphologies for many applications because of their high specific surface area. In this chapter, a literature review on the latest progress regarding the synthesis and applications of ZnO with a porous morphology will be provided, with special focus on the synthesis by microwave hydrothermal method of these nanomaterials and their potential for application in energy harvesting devices. Nanogenerators of a composite made by polydimethylsiloxane (PDMS) and porous ZnO nanostructures were explored and optimized, with an output voltage of (4.5 ± 0.3) V being achieved for the best conditions. The daily life applicability of these devices was demonstrated by lighting up a commercial LED, by manually stimulating the nanogenerator directly connected to the LED.
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Entidade financiadora
European Commission
Programa de financiamento
H2020
Número da atribuição
787410