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2015
Águas, Hugo, Tiago Mateus, António Vicente, Diana Gaspar, Manuel J. Mendes, Wolfgang A. Schmidt, Lu{\'ıs Pereira, Elvira Fortunato, and Rodrigo Martins. "Thin film silicon photovoltaic cells on paper for flexible indoor applications." Advanced Functional Materials. 25 (2015): 3592-3598. Abstract
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Palma, A. S., Y. Liu, H. Zhang, Y. Zhang, B. V. McCleary, G. Yu, Q. Huang, L. S. Guidolin, A. E. Ciocchini, A. Torosantucci, D. Wang, AL Carvalho, C. M. Fontes, B. Mulloy, R. A. Childs, T. Feizi, and W. Chai. "Unravelling glucan recognition systems by glycome microarrays using the designer approach and mass spectrometry." Mol Cell Proteomics (2015). AbstractWebsite

Glucans are polymers of D-glucose with differing linkages in linear or branched sequences. They are constituents of microbial and plant cell-walls and involved in important bio-recognition processes including immunomodulation, anti-cancer activities, pathogen virulence and plant cell-wall biodegradation. Translational possibilities for these activities in medicine and biotechnology are considerable. High-throughput micro-methods are needed to screen proteins for recognition of specific glucan sequences as a lead to structure-function studies and their exploitation. We describe construction of a glucome microarray, the first sequence-defined glycome-scale microarray, using a designer approach from targeted ligand-bearing glucans in conjunction with a novel high-sensitivity mass spectrometric sequencing method, as a screening tool to assign glucan recognition motifs. The glucome microarray comprises 153 oligosaccharide probes with high purity, representing major sequences in glucans. The negative-ion electrospray tandem mass spectrometry with collision-induced dissociation was used for complete linkage analysis of gluco-oligosaccharides in linear homo and hetero and branched sequences. The system is validated using antibodies and carbohydrate-binding modules known to target α- or β-glucans in different biological contexts, extending knowledge on their specificities, and applied to reveal new information on glucan recognition by two signalling molecules of the immune system against pathogens: Dectin-1 and DC-SIGN. The sequencing of the glucan oligosaccharides by the MS method and their interrogation on the microarrays provides detailed information on linkage, sequence and chain length requirements of glucan-recognizing proteins, and are a sensitive means of revealing unsuspected sequences in the polysaccharides.

Palma, Angelina S., Yan Liu, Hongtao Zhang, Yibing Zhang, Barry V. McCleary, Guangli Yu, Qilin Huang, Leticia S. Guidolin, Andres E. Ciocchini, Antonella Torosantucci, Denong Wang, Ana Luisa Carvalho, Carlos M. G. A. Fontes, Barbara Mulloy, Robert A. Childs, Ten Feizi, and Wengang Chai. "Unravelling Glucan Recognition Systems by Glycome Microarrays Using the Designer Approach and Mass Spectrometry." Molecular & Cellular Proteomics. 14 (2015): 974-988. Abstract
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Silva, Teresa Pereira, João Pedro Veiga, Daniel PS Oliveira, Maria João Batista, Diogo Rosa, and Ondina M. Figueiredo. "A utilização da radiação de sincrotrão no estudo de materiais geológicos; breve abordagem sobre experiências recentes de um grupo de utilizadores." Geonovas (2015). Abstract
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Clemmensen, Lars B., Jesper Milàn, Jan Schulz Adolfssen, Eliza Jarl Estrup, Nicolai Frobøse, Nicole Klein, Octávio Mateus, and Oliver Wings. "The vertebrate-bearing Late Triassic Fleming Fjord Formation of central East Greenland revisited: stratigraphy, palaeoclimate and new palaeontological data." Geological Society, London, Special Publications. 434 (2015). AbstractWebsite

In Late Triassic (Norian–Rhaetian) times, the Jameson Land Basin lay at 40° N on the northern part of the supercontinent Pangaea. This position placed the basin in a transition zone between the relatively dry interior of the supercontinent and its more humid periphery. Sedimentation in the Jameson Land Basin took place in a lake–mudflat system and was controlled by orbitally forced variations in precipitation. Vertebrate fossils have consistently been found in these lake deposits (Fleming Fjord Formation), and include fishes, dinosaurs, amphibians, turtles, aetosaurs and pterosaurs. Furthermore, the fauna includes mammaliaform teeth and skeletal material. New vertebrate fossils were found during a joint vertebrate palaeontological and sedimentological expedition to Jameson Land in 2012. These new finds include phytosaurs, a second stem testudinatan specimen and new material of sauropodomorph dinosaurs, including osteologically immature individuals. Phytosaurs are a group of predators common in the Late Triassic, but previously unreported from Greenland. The finding includes well-preserved partial skeletons that show the occurrence of four individuals of three size classes. The new finds support a late Norian–early Rhaetian age for the Fleming Fjord Formation, and add new information on the palaeogeographical and palaeolatitudinal distribution of Late Triassic faunal provinces.

Figueiredo, Ondina M., Teresa Pereira Silva, João Pedro Veiga, Maria João Batista, and Daniel PS Oliveira. "X-ray absorption near-edge spectroscopy (XANES) applied to the speciation of tungsten in Panasqueira mine debris." 4th ENURS and ESRF-Day Meeting of Synchrotron Radiation Users from Portugal. 2015. Abstract
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Mendes, MJ, S. Morawiec, T. Mateus, A. Lyubchyk, H. Águas, I. Ferreira, E. Fortunato, R. Martins, F. Priolo, and I. Crupi. "{Broadband light trapping in thin film solar cells with self-organized plasmonic nanocolloids}." Nanotechnology. 26 (2015). Abstract

© 2015 IOP Publishing Ltd. The intense light scattered from metal nanoparticles sustaining surface plasmons makes them attractive for light trapping in photovoltaic applications. However, a strong resonant response from nanoparticle ensembles can only be obtained if the particles have monodisperse physical properties. Presently, the chemical synthesis of colloidal nanoparticles is the method that produces the highest monodispersion in geometry and material quality, with the added benefits of being low-temperature, low-cost, easily scalable and of allowing control of the surface coverage of the deposited particles. In this paper, novel plasmonic back-reflector structures were developed using spherical gold colloids with appropriate dimensions for pronounced far-field scattering. The plasmonic back reflectors are incorporated in the rear contact of thin film n-i-p nanocrystalline silicon solar cells to boost their photocurrent generation via optical path length enhancement inside the silicon layer. The quantum efficiency spectra of the devices revealed a remarkable broadband enhancement, resulting from both light scattering from the metal nanoparticles and improved light incoupling caused by the hemispherical corrugations at the cells' front surface formed from the deposition of material over the spherically shaped colloids.

Nunes, D., T. R. Calmeiro, S. Nandy, JV Pinto, A. Pimentel, P. Barquinha, P. A. Carvalho, J. C. Walmsley, E. Fortunato, and R. Martins. "{Charging effects and surface potential variations of Cu-based nanowires}." Thin Solid Films (2015): 1-9. AbstractWebsite

The presentwork reports charging effects and surface potential variations in pure copper, cuprous oxide and cu- pric oxide nanowires observed by electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). The copper nanowires were produced by wet synthesis, oxidation into cuprous oxide nanowires was achieved throughmicrowave irradiation and cupric oxide nanowireswere obtained via furnace annealing in at- mospheric conditions. Structural characterization of the nanowireswas carried out byX-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. During the EFM experiments the electrostatic field of the positive probe charged negatively the Cu-based nanowires, which in turn polarized the SiO2 dielectric substrate. Both the probe/nanowire capacitance as well as the sub- strate polarization increased with the applied bias. Cu2O and CuO nanowires behaved distinctively during the EFMmeasurements in accordancewith their band gap energies. Thework functions(WF) of the Cu-based nano- wires, obtained by KPFM measurements, yieldedWFCuO N WFCu N WFCu2O

Kololuoma, Terho, Jaakko Leppäniemi, Himadri Majumdar, Rita Branquinho, Elena Herbei-Valcu, Viorica Musat, Rodrigo Martins, Elvira Fortunato, and Ari Alastalo. "{Gravure printed sol–gel derived AlOOH hybrid nanocomposite thin films for printed electronics}." J. Mater. Chem. C. 3 (2015): 1776-1786. AbstractWebsite

We report a sol-gel approach to fabricate aluminum-oxy-hydroxide (AlOOH) -based inks for gravure printing of high-dielectric-constant nanocomposite films. By reacting 3-glycidoxypropyl- trimethoxysilane (GPTS) with aluminum-oxide-hydroxide (AlOOH) nanoparticles under constant bead milling, inks suitable for gravure printing were obtained. The calculated relative dielectric constant based on measured capacitances and film thicknesses for the gravure-printed GPTS:AlOOH nanocomposite varied between 7 and 11 at a 10 kHz frequency. The dielectric constant depended on the mixing ratio of the composite and was found to follow the Maxwell-Garnett ternary-system mixing rule indicating presence of micro/nanopores that affect the electrical properties of the fabricated films. Increasing leakage current with increasing AlOOH content was observed. High leakage current was reduced by printing two-layer films. The double-layered gravure-coated films exhibited similar capacitance density but clearly lower leakage current and less electrical breakdowns in comparison to single-layered films having comparable film compositions and film thicknesses. The best composite yielded a capacitance density of 109 ± 2 pF/mm2 at the 10 kHz frequency and a leakage current density of 60 ± 20 µA/cm2 at 0.5 MV/cm electric field as a single layer. The calculated relative dielectric constant at the 10 kHz frequency for this composition was 11.2 ± 0.5. Introduction

Alexa, A., N. Tigau, P. Alexandru, A. Pimentel, R. Branquinho, D. Salgueiro, T. Calmeiro, R. Martins, E. Fortunato, and V. Musat. "{Morphological and optical characterization of transparent thin films obtained at low temperature using ZnO nanoparticles}." Journal of Optoelectronic and Advanced Materials. 17 (2015): 1288-1295. Abstract

Transparent metal oxides thin films are a class of inorganic conductors and semiconductors with significant importance for use in portable electronics, displays, flexible electronics, multi-functional windows and solar cells. Due to the recent development of transparent and flexible electronics, there is a growing interest in depositing metal-oxide thin-film on plastic substrates that can offer flexibility, lighter weight, and potentially lead to cheaper manufacturing by allowing printing and roll- to-roll processing. The plastic substrates, however, limit device processing to below 200oC. In this context, the deposition of high-performance semiconductor thin films from dispersions of pre-prepared oxide nanoparticles at temperatures below 200oC represents a potential key route. This paper reports on the preparation of ZnO transparent thin films using solution- processed nanoparticles (NPs) precipitated from zinc acetate alcoholic solution with potassium hydroxide. The nanoparticles size distribution, microstructure and crystallinity were measured by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The thin films were deposited by spin-coating onto soda lima glass substrate, using a dispersion of 1wt{%} ZnO NPs. The morphology of the films annealed at 120 and 180oC, observed by atomic force microscopy and cross-section scanning electron microscopy, shows columnar grains with diameter ranging between 20 and 70 nm, depending on the conditions of depositions. Optical measurements indicated high transparency, between 85 and 94 {%}, in the visible range, a direct nature of band-to-band transitions and band gap values between 3,22 and 3,32 eV. The refractive index and extinction coefficient have been calculated from optical transmittance and reflectance spectra.

Lyubchyk, A., SA Filonovich, T. Mateus, MJ Mendes, A. Vicente, JP Leitão, BP Falcão, E. Fortunato, H. Águas, and R. Martins. "{Nanocrystalline thin film silicon solar cells: A deeper look into p/i interface formation}." Thin Solid Films (2015). AbstractWebsite
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Kiazadeh, Asal, Daniela Salgueiro, Rita Branquinho, Joana Pinto, Henrique L. Gomes, Pedro Barquinha, Rodrigo Martins, and Elvira Fortunato. "{Operational stability of solution based zinc tin oxide/SiO2 thin film transistors under gate bias stress}." APL Materials. 3 (2015): 062804. AbstractWebsite

In this study, we report solution-processed amorphous zinc tin oxide transistors exhibiting high operational stability under positive gate bias stress, translated by a recoverable threshold voltage shift of about 20{%} of total applied stress voltage. Under vacuum condition, the threshold voltage shift saturates showing that the gate-bias stress is limited by trap exhaustion or balance between trap filling and emptying mechanism. In ambient atmosphere, the threshold voltage shift no longer saturates, stability is degraded and the recovering process is impeded. We suggest that the trapping time during the stress and detrapping time in recovering are affected by oxygen adsorption/desorption processes. The time constants extracted from stretched exponential fitting curves are ≈106 s and 105 s in vacuum and air, respectively.

Nunes, D., A. Pimentel, JV Pinto, T. R. Calmeiro, S. Nandy, P. Barquinha, L. Pereira, P. A. Carvalho, E. Fortunato, and R. Martins. "{Photocatalytic behavior of TiO2 films synthesized by microwave irradiation}." Catalysis Today (2015). AbstractWebsite
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Vicente, Antonio, Hugo Aguas, Tiago Mateus, Andreia Araujo, Andriy Lyubchyk, Simo Siitonen, Elvira Fortunato, and Rodrigo Martins. "{Solar cells for self-sustainable intelligent packaging}." Journal of Materials Chemistry A. 3 (2015): 13226-13236. AbstractWebsite

Nowadays there is a strong demand for intelligent packaging to provide comfort, welfare and security to owners, vendors and consumers by allowing them to know the contents and interact with the goods. This is of particular relevance for low cost, fully disposable and recyclable products, such as identification tags and medical diagnostic tests, and devices for analysis and/or quality control in food and pharmaceutical industries. However, the increase of complexity and processing capacity requires continuous power and can be addressed by the combined use of a small disposable battery, charged by a disposable solar cell, which is able to work under indoor lighting. Herein, we show a proof-of-concept of the pioneering production of thin-film amorphous silicon (a-Si:H) solar cells with an efficiency of 4{%} by plasma enhanced chemical vapour deposition (PECVD) on liquid packaging cardboard (LPC), which is commonly used in the food and beverage industries. Such accomplishment put us one step closer to this revolution by providing a flexible, renewable and extremely cheap autonomous energy packaging system. Moreover, such Si thin films take advantage of their good performance at low-light levels, which also makes them highly desirable for cheap mobile indoor applications.

Santos, Lídia, Daniela Nunes, Rita Branquinho, Daniela Salgueiro, Pedro Barquinha, Rodrigo Martins, and Elvira Fortunato. "{Solvothermal Synthesis of Gallium − Indium-Zinc-Oxide Nanoparticles for Electrolyte-Gated Transistors}." ACS applied materials {&} interfaces. 7 (2015): 638-646. AbstractWebsite

Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium–indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 106, threshold voltage (VTh) of 0.3–1.9 V, and mobility up to 1 cm2/(V s), as a function of gallium–indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping.

Águas, Hugo, Tiago Mateus, António Vicente, Diana Gaspar, Manuel J. Mendes, Wolfgang A. Schmidt, LuÍs Pereira, Elvira Fortunato, and Rodrigo Martins. "{Thin Film Silicon Photovoltaic Cells on Paper for Flexible Indoor Applications}." Advanced Functional Materials. 25 (2015): 3592-3598. AbstractWebsite

The present development of non-wafer-based photovoltaics (PV) allows supporting thin film solar cells on a wide variety of low-cost recyclable and flexible substrates such as paper, thereby extending PV to a broad range of consumer-oriented disposable applications where autonomous energy harvesting is a bottleneck issue. However, their fibrous structure makes it challenging to fabricate good-performing inorganic PV devices on such substrates. The advances presented here demonstrate the viability of fabricating thin film silicon PV cells on paper coated with a hydrophilic mesoporous layer. Such layer can not only withstand the cells production temperature (150 °C), but also provide adequate paper sealing and surface finishing for the cell's layers deposition. The substances released from the paper substrate are continuously monitored during the cell deposition by mass spectrometry, which allows adapting the procedures to mitigate any contamination from the substrate. In this way, a proof-of-concept solar cell with 3.4{%} cell efficiency (41{%} fill factor, 0.82 V open-circuit voltage and 10.2 mA cm−2 short-circuit current density) is attained, opening the door to the use of paper as a reliable substrate to fabricate inorganic PV cells for a plethora of indoor applications with tremendous impact in multi-sectorial fields such as food, pharmacy and security.

Branquinho, Rita, Daniela Salgueiro, Ana Santa, Asal Kiazadeh, Pedro Barquinha, LuÍs Pereira, Rodrigo Martins, and Elvira Fortunato. "{Towards environmental friendly solution- based ZTO / AlO x TFTs}." Semicond. Sci. Technol.. 30 (2015): 024007. AbstractWebsite

Solution based deposition has been recently considered as a viable option for low-cost flexible electronics. In this context research efforts have been increasingly centred on the development of suitable solution-processed materials for oxide based transistors. Nevertheless, the majority of synthetic routes reported require the use of toxic organic solvents. In this work we report on a new environmental friendly solution combustion synthesis route, using ethanol as solvent, for the preparation of indium/gallium free amorphous zinc-tin oxide (ZTO) thin film transistors (TFTs) including AlOx gate dielectric. The decomposition of ZTO and AlOx precursor solutions, electrical characterization and stability of solution processed ZTO/AlOx TFTs under gate-bias stress, in both air and vacuum atmosphere, were investigated. The devices demonstrated low hysteresis ($Δ$V = 0.23 V), close to zero turn on voltage, low threshold voltage (VT = 0.36 V) and a saturation mobility of 0.8 cm2 V−1 s−1 at low operation voltages. Ethanol based ZTO/AlOx TFTs are a promising alternative for applications in disposable, low cost and environmental friendly electronics.

2014
Fliedel, Christophe, Gilles Schnee, Teresa Aviles, and Samuel Dagorne. "{Group 13 metal (Al, Ga, In, Tl) complexes supported by heteroatom-bonded carbene ligands}." {COORDINATION CHEMISTRY REVIEWS}. {275} (2014): {63-86}. Abstract

{The present contribution comprehensively reviews the synthesis, structural characterization and current applications of group 13 metal complexes supported by heteroatom-bonded carbene ligands. Detailed structural analysis and comparison of the structure/reactivity trends of group 13 metal carbene species constitute the primary purpose of the present contribution. The current use and applications of this class of compounds are also discussed. In general, such adducts have been thoroughly characterized (both in solution or in the solid state) and structural data, frequently supported by theoretical investigations, provided insight into the stability/reactivity of the adducts formed. While essentially dominated by Arduengo-type NHC adducts, N- and P-bonded cyclic and acyclic carbene complexes of Al, Ga and In have also been recently described, including the recent use of ``carbon(0) ligands{''}. In general, recent developments in carbene group 13 species exploit the improved stability of the resulting metal complexes for either the isolation/characterization of unprecedented structural motifs or the production of robust group 13 metal reagents subsequently used for organic substrates functionalization or in catalysis. (C) 2014 Elsevier B.V. All rights reserved.}

Fliedel, Christophe, Vitor Rosa, Carla I. M. Santos, Pablo J. Gonzalez, Rui M. Almeida, Clara S. B. Gomes, Pedro T. Gomes, Amelia M. N. D. A. Lemos, Gabriel Aullon, Richard Welter, and Teresa Aviles. "{Copper(II) complexes of bis(aryl-imino)acenaphthene ligands: synthesis, structure, DFT studies and evaluation in reverse ATRP of styrene}." {DALTON TRANSACTIONS}. {43} (2014): {13041-13054}. Abstract

{Two new Ar-BIAN Cu(II) complexes (where Ar-BIAN = bis(aryl-imino)acenaphthene) of formulations {[}CuCl2(Mes-BIAN)] (1) (Mes = 2,4,6-Me3C6H2) and {[}CuCl2(Dipp-BIAN)] (2) (Dipp = 2,6-iPr(2)C(6)H(3)) were synthesised by direct reaction of CuCl2 suspended in dichloromethane with the respective ligands Mes-BIAN (L1) and Dipp-BIAN (L2), dissolved in dichloromethane, under an argon atmosphere. Attempts to obtain these compounds by solubilising CuCl2 in methanol and adding a dichloromethane solution of the corresponding ligand, under aerobic conditions, gave also compound 1, but, in the case of L2, the Cu(I) dimer {[}CuCl(Dipp-BIAN)](2) (3) was obtained instead of compound 2. The compounds were fully characterised by elemental analyses, MALDI-TOF mass spectrometry, FT-IR, H-1 NMR and EPR spectroscopic techniques. The solid-state molecular structures of compounds 1-3 were determined by single crystal X-ray diffraction, showing the expected chelation of the Ar-BIAN ligands and two chloride ligands completing the coordination sphere of the Cu(11) centre. In the case of the complex 1, an intermediate coordination geometry around the Cu(II) centre, between square planar and tetrahedral, was revealed, while the complex 2 showed an almost square planar geometry. The structural differences and evaluation of energetic changes were rationalised by DFT calculations. Analysis of the electrochemical behaviour of complexes 1-3 was performed by cyclic voltammetry and the experimental redox potentials for Cu(II)/Cu(I) pairs have been compared with theoretical values calculated by DFT in the gas phase and in dichloromethane and methanol solutions. The complex 1 exhibited good activity in the reverse atom transfer radical polymerisation (ATRP) of styrene.}

Fliedel, Christophe, Samir Mameri, Samuel Dagorne, and Teresa Aviles. "{Controlled ring-opening polymerization of trimethylene carbonate and access to PTMC-PLA block copolymers mediated by well-defined N-heterocyclic carbene zinc alkoxides}." {APPLIED ORGANOMETALLIC CHEMISTRY}. {28} (2014): {504-511}. Abstract

{Four novel Zinc-NHC alkyl/alkoxide/chloride complexes (4, 5, 9 and 9) were readily prepared and fully characterized, including X-ray diffraction crystallography for 5 and 9. The reaction of N-methyl-N-butyl imidazolium chloride (3.HCl) with ZnEt2 (2 equiv.) afforded the corresponding {[}(CNHC)ZnCl(Et)] complex (4) via a protonolysis reaction, as deduced from NMR data. The alcoholysis of 4 with BnOH led to quantitative formation of the dinuclear Zn(II) alkoxide species {[}(CNHC)ZnCl(OBn)]2 (5), as confirmed by X-ray diffraction analysis. The NMR data are in agreement with species 5 retaining its dimeric structure in solution at room temperature. The protonolysis reaction of N-(2,6-diisopropylphenyl)-N-ethyl methyl ether imidazolium chloride (8.HCl) with ZnEt2 (2 equiv.) yielded the {[}(CNHC)ZnCl(Et)] species 9. The latter was found to be reactive with CH2Cl2 in solution and to cleanly convert to the corresponding Zn(II) dichloride {[}(CNHC)ZnCl2]2 (9), whose molecular structure was also elucidated using X-ray diffractometry. Unlike Zn(II)-NHC alkoxide species 1 and 2, which contain a NHC flanked with an additional N-functional group (i.e. thioether and ether, respectively), the Zn(II) alkoxide species 5 incorporates a monodentate NHC ligand. The Zn(II) complexes 1, 2 and 5 were tested in the ring-opening polymerization (ROP) of trimethylene carbonate (TMC). All three species are effective initiators for the controlled ROP of trimethylene carbonate, resulting in the production of narrow disperse PTMC material. Initiator 1 (incorporating a thioether moiety) was found to perform best in the ROP of TMC. Notably, the latter also readily undergoes the sequential ROP of TMC and rac-LA in the presence of a chain-transfer agent, leading to well-defined and high-molecular-weight PTMC/PLA block copolymers. Copyright (c) 2014 John Wiley & Sons, Ltd.}

Branquinho, Rita, Daniela Salgueiro, Lídia Santos, Pedro Barquinha, Luis Pereira, Rodrigo Ferrão De Paiva Martins, and Elvira Fortunato. "{Aqueous Combustion Synthesis of Aluminum Oxide Thin Films and Application as Gate Dielectric in GZTO Solution-based TFTs.}." ACS applied materials {&} interfaces. 6 (2014): 195592-9. AbstractWebsite

Solution processing has been recently considered as an option when trying to reduce the costs associated to deposition under vacuum. In this context most of the research efforts have been centered in the development of the semiconductors processes nevertheless the development of the most suitable dielectrics for oxide based transistors is as relevant as the semiconductor layer itself. In this work we explore the solution combustion synthesis and report on a completely new and green route for the preparation of amorphous aluminum oxide thin films; introducing water as solvent. Optimized dielectric layers were obtained for a water based precursor solution with 0.1 M concentration and demonstrated high capacitance, 625 nF cm-2 at 10 kHz, and a permittivity of 7.1. These thin films were successfully applied as gate dielectric in solution processed gallium-zinc-tin oxide (GZTO) thin film transistors (TFTs) yielding good electrical performance such as subthreshold slope of about 0.3 V dec-1 and mobility above 1.3 cm2 V-1 s-1.

Branquinho, Rita, Daniela Salgueiro, Lidia Santos, Pedro Barquinha, Luis Pereira, Rodrigo Martins, and Elvira Fortunato. "Aqueous Combustion Synthesis of Aluminum Oxide Thin Films and Application as Gate Dielectric in GZTO Solution-Based TFTs." Acs Applied Materials & Interfaces. 6 (2014): 19592-19599. AbstractWebsite
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Valletta, A., G. Fortunato, L. Mariucci, P. Barquinha, R. Martins, and E. Fortunato. "Contact Effects in Amorphous InGaZnO Thin Film Transistors." Journal of Display Technology. 10 (2014): 956-961. AbstractWebsite
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Branquinho, Rita, Daniela Salgueiro, L??dia Lídia Santos, Pedro Barquinha, Luís Lu??s Pereira, Rodrigo Martins, and Elvira Fortunato. "{Aqueous combustion synthesis of aluminum oxide thin films and application as gate dielectric in GZTO solution-based TFTs}." ACS Applied Materials and Interfaces. 6 (2014): 19592-19599. AbstractWebsite

Solution processing has been recently considered as an option when trying to reduce the costs associated with deposition under vacuum. In this context, most of the research efforts have been centered in the development of the semiconductors processes nevertheless the development of the most suitable dielectrics for oxide based transistors is as relevant as the semiconductor layer itself. In this work we explore the solution combustion synthesis and report on a completely new and green route for the preparation of amorphous aluminum oxide thin films; introducing water as solvent. Optimized dielectric layers were obtained for a water based precursor solution with 0.1 M concentration and demonstrated high capacitance, 625 nF cm(-2) at 10 kHz, and a permittivity of 7.1. These thin films were successfully applied as gate dielectric in solution processed gallium-zinc-tin oxide (GZTO) thin film transistors (TFTs) yielding good electrical performance such as subthreshold slope of about 0.3 V dec(-1) and mobility above 1.3 cm(2) V(-1) s(-1).

Gaspar, D., S. N. Fernandes, G. dea Oliveira, J. G. Fernandes, P. Grey, R. V. Pontes, L. Pereira, R. Martins, M. H. Godinho, and E. Fortunato. "{Nanocrystalline cellulose applied simultaneously as the gate dielectric and the substrate in flexible field effect transistors.}." Nanotechnology. 25 (2014): 094008. AbstractWebsite

Cotton-based nanocrystalline cellulose (NCC), also known as nanopaper, one of the major sources of renewable materials, is a promising substrate and component for producing low cost fully recyclable flexible paper electronic devices and systems due to its properties (lightweight, stiffness, non-toxicity, transparency, low thermal expansion, gas impermeability and improved mechanical properties).Here, we have demonstrated for the first time a thin transparent nanopaper-based field effect transistor (FET) where NCC is simultaneously used as the substrate and as the gate dielectric layer in an 'interstrate' structure, since the device is built on both sides of the NCC films; while the active channel layer is based on oxide amorphous semiconductors, the gate electrode is based on a transparent conductive oxide.Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>7 cm(2) V (-1) s(-1)), drain-source current on/off modulation ratio higher than 10(5), enhancement n-type operation and subthreshold gate voltage swing of 2.11 V/decade. The NCC film FET characteristics have been measured in air ambient conditions and present good stability, after two weeks of being processed, without any type of encapsulation or passivation layer. The results obtained are comparable to ones produced for conventional cellulose paper, marking this out as a promising approach for attaining high-performance disposable electronics such as paper displays, smart labels, smart packaging, RFID (radio-frequency identification) and point-of-care systems for self-analysis in bioscience applications, among others.