A carregar...
Projeto de investigação
SYmbiosis for eNERGY harversting concepts for smart platforms on foils
Financiador
Autores
Publicações
Printed and drawn flexible electronics based on cellulose nanocomposites
Publication . Cunha, Inês Isabel Fortuna Neves Fernandes da; Pereira, Luís; Martins, Rodrigo
Sustainability, flexibility, and low-power consumption are key features to meet the growing re-
quirements of simplicity and multifunctionality of low-cost, disposable/recyclable smart electronic
-of- -based composites hold po-
tential to fulfill such demands when explored as substrate and/or electrolyte-gate, or as active
channel layer on printed transistors and integrated circuits based on ionic responses (iontronics).
In this work, a new generation of reusable, healable and recyclable regenerated cellulose hydro-
gels with high ionic conductivity and conformability, capable of being provided in the form of stick-
ers, are demonstrated. These hydrogels are obtained from a simple, fast, low-cost, and environ-
mental-friendly aqueous alkali salt/urea dissolution method of native cellulose, combined with
eration and simultaneous ion incorporation with acetic acid. Their electrochemical properties can
be also merged with the mechanical robustness, thermal resistance, transparency, and smooth-
-
strate.
Beyond gate dielectrics, a water-based screen-printable ink, composed of CMC binder and com-
mercial zinc oxide (ZnO) semiconducting nanoparticles, was formulated. The ink enables the
printing of relatively smooth and densely packed films on office paper with semiconducting func-
tionality at room temperature. The rather use of porous ZnO nanoplates is beneficial to form per-
colative pathways at lower contents of functional material, at the cost of rougher surfaces.
The engineered cellulose composites are successfully integrated into flexible, recyclable, low-
voltage (<3.5 V), printed electrolyte-gated
office paper or on the ionically modified nanopaper. Ubiquitous calligraphy accessories are used
-the-
out on the target substrate, where are already printed the devices. Such concept paves the way
for a worldwide boom of creativity, where we can freely create personal electronic kits, while
having fun at it and without generating waste.
Next-Generation Solar-Powering
Publication . Santos, Ivan M.; Alexandre, Miguel; Vicente, António T.; Teixeira, Cristina; Almeida, Eva; Fortunato, Elvira; Martins, Rodrigo; Águas, Hugo; Mendes, Manuel J.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Wiley
Escalating environmental and energy supply concerns, coupled with an increasing interest in space exploration, are driving the development of advanced energy harvesting systems and the adoption of cutting-edge photovoltaic (PV) technologies. Photonics allows precise light manipulation in a multitude of ways, empowering PV with the means to tackle the multifaceted challenges inherent to the harsh space environment, with great potential to concomitantly spin off to on-Earth systems, prioritizing efficiency and reliability. This review thus synthesizes the key insights from the latest experimental and simulation R&D outcomes to inform the design and implementation of advanced photonic strategies for various PV applications. The state-of-the-art performance and foreground of photonic-managed thick- (single-junction crystalline silicon, c-Si, and perovskite-on-silicon tandem) and thin-film (hydrogenated amorphous silicon, a-Si:H, and perovskite) PV devices are assessed by comparison with theoretical ideal light-trapping scenarios (single-, double-pass, and Lambertian absorption models), looking also at the potential of photonic coolers as an emergent platform for effective thermal management. Finally, this work examines novel photonic approaches for spectrum modification, emphasizing the relevance of illumination-tailoring for outer space systems.
Determination of Mechanical Properties of Thin Film Materials Used in Oxide TFTs Toward Advanced Material Models
Publication . Bentes, Carolina Alves; Martins, Rodrigo; Zlotnikov, Igor; Clausner, André
With an increasing demand for improvement and innovation in the field of microelectronics, flexible electronics,
driven by applications that range from displays to medical devices, has gained much relevance in recent
years. Thin film transistors (TFTs) are the main building block for flexible microelectronic systems, but a
better understanding of the mechanical properties of the constituent thin film materials is necessary to design
more reliable microelectronic devices to be used in mechanically harsh environments. This work aims to extract
a set of mechanical properties of thin film materials used in flexible oxide TFTs and based on that, parameterize
material models for Finite Elements Analysis (FEA).
To acquire data for these material models, films from different materials are fabricated on silicon substrates.
For assessing the impact of thickness and annealing process on the mechanical properties of the thin
films, several samples of the same material are fabricated with distinct specifications. This study is divided
into two workflows for extracting two distinct sets of parameters. For films composed of metals (Mo), semiconductors
(IGZO) and dielectrics (Ta2O5 and Ta2O5/SiO2), the hardness and, as the main parameter, Young´s
modulus, are determined by nanoindentation for describing linear elasticity. For the polymeric films (PI), timedependent
parameters such as storage modulus, loss modulus and phase angle, which are necessary to describe
viscoelasticity, are determined by nanoscale Dynamic Mechanical Analysis (nano-DMA).
Based on these experimental results, the linear elastic and viscoelastic material models are parameterized
for the Finite Element Method (FEM). Based on these FEM models, now relevant geometries could be
simulated. Beyond that, following the methodology of the dissertation, further thin films used in oxide TFTs
could be characterized which paves the way for the acquisition of data from other relevant materials and the
obtaining of a complete description of the device for product development.
Flexible nanostructured TiO2-based gas and UV sensors
Publication . Nunes, Daniela; Fortunato, Elvira; Martins, Rodrigo; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Discover
Flexible sensors have been attracting an ever-growing attention over the last years due to their outstanding characteristics, that include their lightweight and cost-effective characteristics, high stretchability, biocompatibility, and conformability. Moreover, the pursue of such devices has exponentially raised, with the IoT (Internet of Things) technology and the integration of several kinds of sensor devices that allow exchanging information on the internet, as well as remotely operating devices and collecting data. In fact, IoT is bringing sensor usage to a new level, where gas and ultraviolet (UV) sensors are largely integrated, guaranteeing the well-being and safety of people, with the immediate detection and response to changes in an environment. Gas and UV sensors based on titanium dioxide (TiO2) have been largely reported, where numerous efforts have been devoted to improving its sensing performance, especially when employing TiO2 at the nanoscale. TiO2 has the advantage of being chemical stable, non-toxic, inexpensive, and compatible with low-cost wet-chemical synthesis routes. This review outlines the current state of flexible gas and UV sensor technologies having TiO2 as the sensing layer and the impact of this nanostructured material on the field.
Tailoring the synaptic properties of a-IGZO memristors for artificial deep neural networks
Publication . Pereira, Maria Elias; Deuermeier, Jonas; Freitas, Pedro; Barquinha, Pedro; Zhang, Weidong; Martins, Rodrigo; Fortunato, Elvira; Kiazadeh, Asal; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias
Neuromorphic computation based on resistive switching devices represents a relevant hardware alternative for artificial deep neural networks. For the highest accuracies on pattern recognition tasks, an analog, linear, and symmetric synaptic weight is essential. Moreover, the resistive switching devices should be integrated with the supporting electronics, such as thin-film transistors (TFTs), to solve crosstalk issues on the crossbar arrays. Here, an a-Indium-gallium-zinc-oxide (IGZO) memristor is proposed, with Mo and Ti/Mo as bottom and top contacts, with forming-free analog switching ability for an upcoming integration on crossbar arrays with a-IGZO TFTs for neuromorphic hardware systems. The development of a TFT compatible fabrication process is accomplished, which results in an a-IGZO memristor with a high stability and low cycle-to-cycle variability. The synaptic behavior through potentiation and depression tests using an identical spiking scheme is presented, and the modulation of the plasticity characteristics by applying non-identical spiking schemes is also demonstrated. The pattern recognition accuracy, using MNIST handwritten digits dataset, reveals a maximum of 91.82% accuracy, which is a promising result for crossbar implementation. The results displayed here reveal the potential of Mo/a-IGZO/Ti/Mo memristors for neuromorphic hardware.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
European Commission
Programa de financiamento
H2020
Número da atribuição
952169