28 research outputs found
Recommended from our members
Solution-based self-aligned hybrid organic/metal-oxide complementary logic with megahertz operation
We have developed a novel solution-based integration scheme featuring organic and metal-oxide semiconductors with a polymeric gate dielectric. The integration relies on a facile subtractive patterning technique for the semiconductors, which, through the selection of an appropriate etch stopper, leads to ideal transistor performance. We utilized this novel integration scheme to fabricate self-aligned transistors and logic circuits with a high-mobility p-type conjugated polymer and an n-type amorphous oxide semiconductor, along with a composite polymeric gate dielectric, all solution-deposited by spin coating. The resulting complementary logic gates are capable of rail-to-rail transitions, low-voltage operation down to a 3.5 V power supply, and ample noise margins. Thanks to the self-aligned-gate approach and the state-of-the-art balanced mobilities of the selected semiconductors, our logic gates achieve megahertz operation, thus demonstrating the strength of our hybrid integration scheme.We gratefully acknowledge Mike Hurhangee and Iain
McCulloch of Imperial College for supplying the IDT-BT conjugated
polymer. We also acknowledge financial support from the
European Commission through the POINTS project (FP7-NMP-
2010-Small-4).This is the author accepted manuscript. The final version is available via Elsevier at http://www.sciencedirect.com/science/article/pii/S1566119915000956
Recommended from our members
Lead-free halide perovskite photovoltaics: Challenges, open questions, and opportunities
In recent years, lead-free metal-halide perovskite photovoltaics has attracted ever-growing attention, in view of its potential to replicate the outstanding properties of lead-halide perovskite photovoltaics, but without the toxicity burden of the latter. Despite a research effort much smaller in scale than that pursued with lead-based perovskites, considerable progress has been achieved in lead-free perovskite photovoltaics, with the highest power conversion efficiencies now being in the region of 13%. In this Perspective, we first discuss the state of the art of lead-free perovskite photovoltaics and additionally highlight promising directions and strategies that could lead to further progress in material exploration and understanding as well as in photovoltaic efficiency. Furthermore, we point out the widespread lack of experimental data on the fundamental optoelectronic properties of lead-free halide perovskite absorbers (e.g., charge carrier mobility, defect parameters, Urbach energy, and the impact of dimensionality). All of this currently hampers a rational approach to further improving their performance and points to the need for a concerted effort that could bridge this knowledge gap. Additionally, this Perspective brings to the fore the manifold photovoltaic opportunitiesâthus far largely unexplored with lead-free perovskite absorbersâbeyond single-junction outdoor photovoltaics, which may potentially enable the realization of their full potential. The exploration of these opportunities (tandem photovoltaics, indoor photovoltaics, and building-integrated and transparent photovoltaics) could energize the investigation of existing and new classes of lead-free perovskite absorbers beyond current paradigms and toward high photovoltaic performance.</jats:p
Aging of materials at inlet and outlet fuel manifolds in a SOFC stack
Analyses performed on a stack operated for more than 4000h at 750\ub0C at high fuel utilization (80%) revealed significant differences in aging behaviour of stack components when comparing fuel inlet and fuel outlet areas. Two samples were cut from the fuel inlet and outlet manifolds of the operated SOFC stack. The glass-ceramic sealing material and the interconnect alloy were exposed to a dual atmosphere (external air and internal fuel stream). The fuel composition was dry H2/N2 (60:40 vol. %) at the inlet and H2O/H2/N2 (48:12:40 vol. %) at the outlet. The stack was operated in co-flow configuration, with a large excess of air. It was found that the interfaces between the seal and the alloy were significantly affected by the difference in fuel composition. The sealant exposed to the outgoing air was significantly polluted by chromium generated in the stack and transported by the air stream. These investigations therefore reveal that the long-term evolution of the sealing and of the metallic support depends on the local conditions in the stack, as well as on additional interactions with other degradation phenomena
Programmable logic circuits for functional integrated smart plastic systems
In this paper, we present a functional integrated plastic system. We have fabricated arrays of organic thin-film transistors (OTFTs) and printed electronic components driving an electrophoretic ink display up to 70mm by 70mm on a single flexible transparent plastic foil. Transistor arrays were quickly and reliably configured for different logic functions by an additional process step of inkjet printing conductive silver wires and poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) resistors between transistors or between logic blocks. Among the circuit functions and features demonstrated on the arrays are a 7-stage ring oscillator, a D-type ip-flop memory element, a 2:4 demultiplexer, a programmable array logic device (PAL), and printed wires and resistors. Touch input sensors were also printed, thus only external batteries were required for a complete electronic subsystem. The PAL featured 8 inputs, 8 outputs, 32 product terms, and had 1260 p-type polymer transistors in a 3-metal process using diode-load logic. To the best of our knowledge, this is the first time that a PAL concept with organic transistors has been demonstrated, and also the first time that organic transistors have been used as the control logic for a flexible display which have both been integrated on to a single plastic substrate. The versatility afforded by the additive inkjet printing process is well suited to organic programmable logic on plastic substrates, in effect, making flexible organic electronics more flexibleRCUK, OtherThis is the final published version. It is also available from Elsevier at http://www.sciencedirect.com/science/article/pii/S1566119914003607#
Programmable logic circuits for functional integrated smart plastic systems
In this paper, we present a functional integrated plastic system. We have fabricated arrays of organic thin-film transistors (OTFTs) and printed electronic components driving an electrophoretic ink display up to 70 mm by 70 mm on a single flexible transparent plastic foil. Transistor arrays were quickly and reliably configured for different logic functions by an additional process step of inkjet printing conductive silver wires and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) resistors between transistors or between logic blocks. Among the circuit functions and features demonstrated on the arrays are a 7-stage ring oscillator, a D-type flip-flop memory element, a 2:4 demultiplexer, a programmable array logic device (PAL), and printed wires and resistors. Touch input sensors were also printed, thus only external batteries were required for a complete electronic subsystem. The PAL featured 8 inputs, 8 outputs, 32 product terms, and had 1260 p-type polymer transistors in a 3-metal process using diode-load logic. To the best of our knowledge, this is the first time that a PAL concept with organic transistors has been demonstrated, and also the first time that organic transistors have been used as the control logic for a flexible display which have both been integrated on to a single plastic substrate. The versatility afforded by the additive inkjet printing process is well suited to organic programmable logic on plastic substrates, in effect, making flexible organic electronics more flexible. Crown Copyright (C) 2014 Published by Elsevier B.V.X113426Ysciescopu
In search for comparability: the PECUNIA reference unit costs for health and social care services in Europe
Improving the efficiency of mental healthcare service delivery by learning from international best-practice examples requires valid data, including robust unit costs, which currently often lack cross-country comparability. The European ProgrammE in Costing, resource use measurement and outcome valuation for Use in multi-sectoral National and International health economic evaluAtions (PECUNIA) aimed to harmonize the international unit cost development. This article presents the methodology and set of 36 externally validated, standardized reference unit costs (RUCs) for five health and social care services (general practitioner, dentist, help-line, day-care center, nursing home) in Austria, England, Germany, Hungary, The Netherlands, and Spain based on unambiguous service definitions using the extended DESDE PECUNIA coding framework. The resulting PECUNIA RUCs are largely comparable across countries, with any causes for deviations (e.g., country-specific scope of services) transparently documented. Even under standardized methods, notable limitations due to data-driven divergences in key costing parameters remain. Increased cross-country comparability by adopting a uniform methodology and definitions can advance the quality of evidence-based policy guidance derived from health economic evaluations. The PECUNIA RUCs are available free of charge and aim to significantly improve the quality and feasibility of future economic evaluations and their transferability across mental health systems
Electrolyteâgated organic fieldâeffect transistors with high operational stability and lifetime in practical electrolytes
A key component of organic bioelectronics is electrolyteâgated organic fieldâeffect transistors (EGâOFETs), which have recently been used as sensors to demonstrate labelâfree, singleâmolecule detection. However, these devices exhibit limited stability when operated in direct contact with aqueous electrolytes. Ultrahigh stability is demonstrated to be achievable through the utilization of a systematic multifactorial approach in this study. EGâOFETs with operational stability and lifetime several orders of magnitude higher than the state of the art have been fabricated by carefully controlling a set of intricate stabilityâlimiting factors, including contamination and corrosion. The indacenodithiopheneâcoâbenzothiadiazole (IDTBT) EGâOFETs exhibit operational stability that exceeds 900 min in a variety of widely used electrolytes, with an overall lifetime exceeding 2 months in ultrapure water and 1 month in various electrolytes. The devices were not affected by electrical stressâinduced trap states and can remain stable even in voltage ranges where electrochemical doping occurs. To validate the applicability of our stabilized device for biosensing applications, the reliable detection of the protein lysozyme in ultrapure water and in a physiological sodium phosphate buffer solution for 1500 min was demonstrated. The results show that polymerâbased EGâOFETs are a viable architecture not only for shortâterm but also for longâterm biosensing applications
Roadmap on printable electronic materials for next-generation sensors
The dissemination of sensors is key to realizing a sustainable, âintelligentâ world, where everyday objects and environments are equipped with sensing capabilities to advance the sustainability and quality of our livesâe.g., via smart homes, smart cities, smart healthcare, smart logistics, Industry 4.0, and precision agriculture. The realization of the full potential of these applications critically depends on the availability of easy-to-make, low-cost sensor technologies. Sensors based on printable electronic materials offer the ideal platform: they can be fabricated through simple methods (e.g., printing and coating) and are compatible with high-throughput roll-to-roll processing. Moreover, printable electronic materials often allow the fabrication of sensors on flexible/stretchable/biodegradable substrates, thereby enabling the deployment of sensors in unconventional settings. Fulfilling the promise of printable electronic materials for sensing will require materials and device innovations to enhance their ability to transduce external stimuliâlight, ionizing radiation, pressure, strain, force, temperature, gas, vapours, humidity, and other chemical and biological analytes. This Roadmap brings together the viewpoints of experts in various printable sensing materialsâand devices thereofâto provide insights into the status and outlook of the field. Alongside recent materials and device innovations, the roadmap discusses the key outstanding challenges pertaining to each printable sensing technology. Finally, the Roadmap points to promising directions to overcome these challenges and thus enable ubiquitous sensing for a sustainable, âintelligentâ world
Roadmap on energy harvesting materials
Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere
Lead-free halide perovskite photovoltaics: Challenges, open questions, and opportunities
In recent years, lead-free metal-halide perovskite photovoltaics has attracted ever-growing attention, in view of its potential to replicate the outstanding properties of lead-halide perovskite photovoltaics, but without the toxicity burden of the latter. In spite of a research effort much smaller in scale than that pursued with lead-based perovskites, considerable progress has been achieved in lead-free perovskite photovoltaics, with the highest power conversion efficiencies now being in the region of 13%. In this Perspective, we firstly discuss the state of the art of lead-free perovskite photovoltaics and additionally highlight promising directions and strategies that could lead to further progress in material exploration and understanding as well as in photovoltaic efficiency. Furthermore, we point out the widespread lack of experimental data on the fundamental optoelectronic properties of lead-free halide perovskite absorbers (e.g., charge carrier mobility, defect parameters, Urbach energy, the impact of dimensionality). All of this currently hampers a rational approach to further improving their performance and points to the need for a concerted effort that could bridge this knowledge gap. Additionally, this Perspective brings to the fore the manifold photovoltaic opportunitiesâthus far largely unexplored with lead-free perovskite absorbersâbeyond single-junction outdoor photovoltaics, which may potentially enable the realization of their full potential. The exploration of these opportunities (tandem photovoltaics, indoor photovoltaics, and building-integrated and transparent photovoltaics) could energize the investigation of existing and new classes of lead-free perovskite absorbers beyond current paradigms and toward high photovoltaic performance