Indirect X-ray detectors based on inkjet-printed photodetectors with a screen-printed scintillator layer

Organic photodetectors (PDs) based on printing technologies will allow to expand the current field of PD applications toward large-area and flexible applications in areas such as medical imaging, security, and quality control, among others. Inkjet printing is a powerful digital tool for the deposition of smart and functional materials on various substrates, allowing the development of electronic devices such as PDs on various substrates. In this work, inkjet-printed PD arrays, based on the organic thin-film transistor architecture, have been developed and applied for the indirect detection of X-ray radiation using a scintillator ink as an X-ray absorber. The >90% increase of the photocurrent of the PDs under X-ray radiation, from about 53 nA without the scintillator film to about 102 nA with the scintillator located on top of the PD, proves the suitability of the developed printed device for X-ray detection applicationsThe authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT-Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013 and projects PTDC/EEI-SII/5582/2014, PTDC/CTM-ENE/5387/2014 and in the framework of EuroNanoMed 2016 call, Project LungChek ENMed/0049/2016. J.O. and V.C. thank the FCT for the SFRH/BD/98219/2013 and SFRH/BPD/97739/2013 grants, respectively. The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R. Financial support from the Basque Government Industry Department under the ELKARTEK program is also acknowledged. The authors thank Iain McCulloch and Martin Heeney from Flexink for providing the OSC. Dirk Rittrich (Department Layer Deposition at Fraunhofer ENAS) is acknowledged for the FIB/SEM analysis and the sample preparation. R.D.R acknowledges the DFG Unit FOR1317 SMINT, the Cluster of Excellence, and the Tomsk Polytechnic University Competitiveness Enhancement Program grant TPU CEP_IHTP_73\2017. This work was performed in the context of the European COST Action MP1302 Nanospectroscopy.info:eu-repo/semantics/publishedVersio

Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites

Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196°C, temperature-programmed desorption and determination of pH at the point of zero charge. CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%. It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response

Piezoresistive sensors for force mapping of hip-prostheses

The success of artificial prosthetic replacements depends on the fixation of the artificial prosthetic component after being implanted in the thighbone. The materials for fixation are subject to mechanical stresses, which originate permanent deformations, incipient cracks and even fatigue fractures. This work shows the possibility of monitoring the mechanical stress over time in prosthesis. In this way, highly sensitive silicon thin-film piezoresistive sensors were developed attached to prosthesis and their results compared with commercial strain gauge sensors. Mechanical stress-strain experiments were performed in compressive mode, during 10,000 cycles. Experimental data was acquired at mechanical vibration frequencies of 0.5 Hz, 1 Hz and 5 Hz, and sent to a computer by means of a wireless link. The results show that there is a decrease in sensitivity of the thin-film silicon piezoresistive sensors when they are attached to the prosthesis, but this decrease does not compromise its monitoring performance. The sensitivity, compared to that of commercial strain gauges, is much larger due to their higher gauge factors (-23.5), when compared to the GFs of commercial sensors (2).This work is funded by FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE" and by national funds arranged by FCT- Fundação para a Ciência e a Tecnologia, project references NANO/NMed-SD/0156/2007, PTDC/CTM/73030/2006 and PTDC/CTM/69316/2006. The authors also thank support from the COST Action MP1003, 2010 ‘European Scientific Network for Artificial Muscles’. VS, VC and MSM thank the FCT for the SFRH/BPD/63148/2009, SFRH/BD/48708/2008 and SFRH/BD/60713/2009 grants, respectively. CR thanks the IINL for a financial support via a PhD

Dielectric relaxation and ferromagnetic resonance in magnetoelectric (Polyvinylidene-fluoride)/ferrite composites

In this work the dielectric properties and ferromagnetic resonance of Polyvinylidene- uoride embedded with 10 wt. % of NiFe2O4 or Ni0.5Zn0.5Fe2O4 nanoparticles are presented. The mechanisms of the dielectric relaxation in these two composites do not differ from each other. For more precise characterization of the dielectric relaxation, a two dimensional distribution of relaxation times was calculated from the temperature dependencies of the complex dielectric permittivity. The results obtained from the 2D distribution and the mean relaxation time are found to be consistent. The dynamics of the dielectric permittivity is described by the Arrhenius law. The energy and attempt time of the dielectric relaxators lie in a narrow energy and time region thus proving that the single type chains of polymer are responsible for a dispersion. The magnetic properties of the composites were investigated using the fer- romagnetic resonance. A single resonance line was observed for both samples. From the temperature dependence (100 K - 310 K) of the resonance eld and linewidth, the origin of the observed line was attributed to the NiFe2O4 and Ni0.5Zn0.5Fe2O4 superparamagnetic nanoparticles. By measuring lms at dif- ferent orientations with respect to the external magnetic eld, the angular dependence of the resonance was observed, indicating the magnetic dipolar in-plane interactions.This work was supported by Lithuanian Research Council under the project MIP-068/2012 and by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011, project PTDC/CTM-NAN/121038/2010 and the project MateproOptimizing Materials and Processes, ref. NORTE-07 − 0124-FEDER-000037, cofunded by the Programa Operacional Regional do Norte (ON.2 O Novo Norte), under the Quadro de Referncia Estratgico Nacional (QREN), through the Fundo Europeu de Desenvolvimento Regional (FEDER). P. Martins thanks the FCT for the grant FCT-DFRH SFRH/BPD/96227/2013

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

Roadmap on energy harvesting materials

Abstract 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

Roadmap on energy harvesting materials

Funder: Fundação para a Ciência e TecnologiaFunder: BIDEKO ProjectFunder: MCIN/AEIFunder: Spanish State Research Agency (AEI)Funder: Basic Science Research ProgramFunder: Ministry of Education; doi: http://dx.doi.org/10.13039/501100002701Funder: Swedish Knowledge FoundationFunder: University of Calgary; doi: http://dx.doi.org/10.13039/100008459Funder: National Renewable Energy Laboratory; doi: http://dx.doi.org/10.13039/100006233Funder: Fonds de recherche du Québec – Nature et technologies; doi: http://dx.doi.org/10.13039/501100003151Funder: Canada Research Chairs programFunder: EUFunder: National Research Foundation of Korea; doi: http://dx.doi.org/10.13039/501100003725Funder: NRFFunder: Priority Research Centers ProgramFunder: European regional development fund (ERDF)Funder: European Research Council (ERC)Funder: ERCFunder: Alliance for Sustainable Energy, LLCFunder: MIURFunder: Italian MinistryFunder: the Cardiff University, Engineering and Physical Sciences Research CouncilFunder: JST Mirai ProgramFunder: Agence Nationale de la Recherche (ANR)Funder: A*STARFunder: JSTFunder: PRESTOFunder: Aerospace ProgrammeFunder: EBFunder: U.S. Department of Commerce, National Institute of Standards and TechnologyFunder: Laboratory-Directed Research and Development (LDRD)Funder: Sandia, LLCFunder: the Office of Science, Office of Basic Energy SciencesFunder: United States GovernmentFunder: Honeywell International Inc.Funder: The Leverhulme TrustFunder: Royal Academy of Engineering; doi: http://dx.doi.org/10.13039/501100000287Funder: Office of the Chief Science Adviser for National SecurityFunder: Henry Samueli School of Engineering & Applied ScienceFunder: Department of Bioengineering at the University of California, Los AngelesFunder: CRESTFunder: Beijing Forestry University; doi: http://dx.doi.org/10.13039/501100012138Funder: Japan Science and Technology Agency (JST)Funder: the Australian Research Council, QUTFunder: Center for Hierarchical Materials DesignFunder: Austrian Christian Doppler Laboratory for ThermoelectricityFunder: HBIS-UQ Innovation Centre for Sustainable SteelAmbient 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