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Nanophotonics, vol. 10, no. 8, 2020, pp. 2145-2156
Two-dimensional perovskites with alternating cations in the interlayer space for stable light-emitting diodes
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Lead halide perovskites have attracted tremendous attention in photovoltaics due to their impressive optoelectronic properties. However, the poor stability of perovskite-based devices remains a bottleneck for further commercial development. Two-dimensional perovskites have great potential in optoelectronic devices, as they are much more stable than their three-dimensional counterparts and rapidly catching up in performance. Herein, we demonstrate high-quality two-dimensional novel perovskite thin films with alternating cations in the interlayer space. This innovative perovskite provides highly stable semiconductor thin films for efficient near-infrared light-emitting diodes (LEDs). Highly efficient LEDs with tunable emission wavelengths from 680 to 770 nm along with excellent operational stability are demonstrated by varying the thickness of the interlayer spacer cation. Furthermore, the best-performing device exhibits an external quantum efficiency of 3.4% at a high current density (J) of 249 mA/cm(2) and remains above 2.5% for a J up to 720 mA cm(-2), leading to a high radiance of 77.5 W/Sr m(2) when driven at 6 V. The same device also shows impressive operational stability, retaining almost 80% of its initial performance after operating at 20 mA/cm(2) for 350 min. This work provides fundamental evidence that this novel alternating interlayer cation 2D perovskite can be a promising and stable photonic emitter.
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Adv. Electron. Mater. 2022, 2101388
Directed Self-Assembly for Dense Vertical III–V Nanowires on Si and Implications for Gate All-Around Deposition
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Fabrication of next generation transistors calls for new technological requirements, such as reduced size and increased density of structures. Development of cost-effective processing techniques to fabricate small-pitch vertical III-V nanowires over large areas will be an important step toward realizing dense gate all-around transistors, having high electron mobility, and low power consumption. It is demonstrated here, how arrays of III-V nanowires with a controllable number of rows, ranging from one single row up to bands of 500 nm, can be processed by directed self-assembly (DSA) of block copolymer (BCP). Furthermore, it is shown that the DSA-orientation with respect to the substrate's crystal direction affects the nanowire facet configuration, and thereby the nanowire spacing and gate all-around deposition possibilities. A high chi poly(styrene)-block-poly(4-vinylpyridine) BCP pattern directed by electron beam lithography-defined guiding lines is transferred into silicon nitride. The silicon nitride is then used as a selective area metal-organic vapor phase epitaxy mask atop an indium arsenide (InAs) buffer layer on a silicon platform to grow vertical InAs nanowires at 44-60 nm row pitch. Finally, deposition of high-kappa oxide and titanium nitride at this high pattern density is demonstrated, to further illustrate the considerations needed for next generation transistors.
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Nat. Nanotechnol. (2022)
Fast and selective reduction of nitroarenes under visible light with an earth-abundant plasmonic photocatalyst
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Reduction of nitroaromatics to the corresponding amines is a key process in the fine and bulk chemicals industry to produce polymers, pharmaceuticals, agrochemicals and dyes. However, their effective and selective reduction requires high temperatures and pressurized hydrogen and involves noble metal-based catalysts. Here we report on an earth-abundant, plasmonic nano-photocatalyst, with an excellent reaction rate towards the selective hydrogenation of nitroaromatics. With solar light as the only energy input, the chalcopyrite catalyst operates through the combined action of hot holes and photothermal effects. Ultrafast laser transient absorption and light-induced electron paramagnetic resonance spectroscopies have unveiled the energy matching of the hot holes in the valence band of the catalyst with the frontier orbitals of the hydrogen and electron donor, via a transient coordination intermediate. Consequently, the reusable and sustainable copper-iron-sulfide (CuFeS2) catalyst delivers previously unattainable turnover frequencies, even in large-scale reactions, while the cost-normalized production rate stands an order of magnitude above the state of the art.
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Deliverables view all
WP9 - VA – Virtual Access
D9.1 - Deployment of the VA service prototypes
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Virtual Access (VA) is a novel service offered in NEP. It comprises innovative online simulation services, databases, machine learning services, data and metadata services, which will be seamlessly integrated into the NEP infrastructure and provided as cloud services to authenticated users. The access will be provided by the facilities hosting the services. Each Access Provider will operate its own infrastructure, made of one or more installations. All involved Access Providers will offer identified User Access to the VA services under their own schemes based on institutional policies. Part of the online data services that will be made available as VA are currently (or will be) developed in the Joint Activity (JA) 6 on FAIR data approach. According to the NEP proposal, seven services are planned, even though scouting activities to enlarge the offer are foreseen. The services are at different stages of development, and will be gradually completed and integrated into the offer. This deliverable presents the first prototype of a VA service: the MetaRepo, a metadata repository to register and validate Metadata Schemas and Metadata Documents. The document is structured as follows: Section 1 describes the MetaRepo service, and Section 2 shows the functionalities of its Graphical User Interface (GUI). Being the purpose of this Section only demonstrative, for the sake of simplicity the functionalities of the MetaRepo GUI are shown on basic examples instead of being applied to a real NEP use case. This choice has been made to prevent the confusion which might arise due to the complexity of the Metadata Schemas. A real usage example is presented in Milestone 10. Section 3 shows how the Authorization and Authentication has been implemented for the MetaRepo. Section 4 explains how the monitoring of user accesses and actions is performed.
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WP10 - TAS - TA programme support structures: Technical Liaison Network (TLNet) and pilot User Office Network (UONet)
D10.2 - The NEP Technical Liaison Network (TLNet): implementation report
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The multidisciplinary research context requires an effective and reliable integration of different research infrastructures and academic facilities. NFFA-EUROPE is an interoperable multi-technique, multi-competence, multi-site distributed research infrastructure, offering a wide ensemble of tools for nanoscience and nanotechnology devoted to research and innovation, covering many TRLs, and therefore involving different competences. The Open Access to such a complex distributed research infrastructure is managed by a support service structure, the Technical Liaison Network (TLNet): a centralized technical authority, involving all nodes, in charge to assess the technical request/offer, and to establish the feasibility and the best work-flow for the peer-review prioritised research. The full TLNet service, i.e. a widespread network of experts, rules of engagement and well defined technical evaluation procedures, and an efficient communication system, have been implemented with the objective to be us much as possible user-friendly for both (new) providers and (new) users, by making wide use of smart front-ends, interfacing with a huge database managed with a complex back-end, for creating a common platform to share data and exchange information among providers offering different competences, and between users and providers. The TLNet has been implemented as a distributed network consisting of a Central coordinating TLNet node (at the Coordinator headquarters) and Local TLNet nodes at the providers, as established in June 2021. The network has been initially operative with a temporary IC platform hosted on the GARR network, ready for the 1st Call for proposals. Then, from the 2nd Call (technical evaluation in February 2022), a final set of online monitoring tools, directly implemented in the Single Entry Point, have been used, allowing the TLNet to reach a full perceptiveness on the access.
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WP11 - Real-time observation and control in microscopy and spectroscopy of nano-objects
D11.1 - Commissioning of HHG with enhanced properties
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During the first year of NEP project the beam line towards the generation of intense circularly polarized XUV radiation was under development and implementation. The two techniques for the generation of intense circular polarized XUV radiation were installed to the MW beamline based on the Attosecond Science and Technology (AST) Laboratory of IESL-FORTH. By applying the two-color counter rotating electric fields setup under loose focusing conditions we were able to generate highly elliptical extreme ultraviolet radiation in Ar gas as generating medium. The energy of the XUV radiation emitted per laser pulse is found to be of the order of ~100 nJ with the spectrum spanning from 17 to 26 eV (See Figure 3(b)). Preliminary results in Xe and Ne gas as generating medium are also available. Briefly, it was found in Xe that under optimal conditions the energy content of highly elliptical XUV radiation was of the order of the order of ~200 nJ with a spectrum spanning from 17 to 22 eV. On the other hand in the case of Ne as generating medium the energy content was in the order of pJ in the spectral region 17-29 eV. The current performance of high-harmonic generation sources offers a temporal resolution of a few tens of femtoseconds and an energy resolution of approximately one hundred meV. However, some of the most intriguing open problems in materials science arise from phenomena taking place at faster time-scales, in the few-femtosecond range. This includes physical processes, such as the collapse and recovery of metallic or magnetic states, electron hopping, screening phenomena, or charge transfer mechanisms. During the first year of the project, in order to access such temporal scales by means of time and angular-resolved photo-electron spectroscopy (tr-ARPES), we started to implement an optical setup, which allowed us to generate laser pulses in the sub-10 femtosecond range. The few-cycle pulses have been generated by focusing the driving laser of the CITIUS light source at Nova Gorica university into a capillary wave-guide, placed in an environment filled with noble gas. This induced a proper amount of self-phase modulation, i.e., a controlled increase of the pulse bandwidth. The latter has been then recompressed by means of “chirped” mirrors, designed to introduce a proper amount of dispersion, down to a few femtoseconds.
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Transnational Access Statistics
18 calls for access
617 proposals submitted
64% rate of acceptance
31% with Large Scale Facilities
12% with theory
12% with industry
~3 average users per proposal
58 countries applying
1840 lab sessions