Organic Light‐Emitting Nanofibers by Solvent‐Resistant Nanofluidics

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Soft Nanopatterning on Light‐Emitting Inorganic‐Organic Composites

In this work we demonstrate the nanopatterning of nanocomposites made by luminescent zinc oxide nanoparticles and light-emitting conjugated polymers by means of soft molding lithography. Vertical nanofluidics is exploited to overcome the polymer transport difficulties intrinsic in materials incorporating nanocrystals, and the rheology, fluorescence, absolute quantum yield, and emission directionality of the nanostructured composites are investigated. We study the effect of patterned gratings on the directionality of light emitted from the nanocomposites, finding evidence of the enhancement of forward emitted light, due to the printed wavelength-scale periodicity. These results open new possibilities for the realization of nanopatterned devices based on hybrid organic-inorganic systems

Imprinting strategies for 100 nm lithography on polyfluorene and poly(phenylenevinylene) derivatives and their blends

Abstract We report on the use of nanoimprint lithography at room temperature (RT-NIL) for the direct structuring of polyfluorene and poly(phenylenevinylene) derivatives and of their blends without the degradation of the emissive characteristics of the active molecules. We apply RT-NIL for the fabrication of periodic one- and two-dimensional gratings with feature width that varies from 100 to 500 nm. Moreover, we analysed the effects that a superimposed periodic corrugation induces on the emitted light in terms of spectral properties and luminescence efficiency, thus ruling out any degradation of the emission. In particular, the combination of nanopatterning and active blends opens new perspectives for the control of the emitted colour from conjugated polymer films

From classical to quantum machine learning: survey on routing optimization in 6G software defined networking

The sixth generation (6G) of mobile networks will adopt on-demand self-reconfiguration to fulfill simultaneously stringent key performance indicators and overall optimization of usage of network resources. Such dynamic and flexible network management is made possible by Software Defined Networking (SDN) with a global view of the network, centralized control, and adaptable forwarding rules. Because of the complexity of 6G networks, Artificial Intelligence and its integration with SDN and Quantum Computing are considered prospective solutions to hard problems such as optimized routing in highly dynamic and complex networks. The main contribution of this survey is to present an in-depth study and analysis of recent research on the application of Reinforcement Learning (RL), Deep Reinforcement Learning (DRL), and Quantum Machine Learning (QML) techniques to address SDN routing challenges in 6G networks. Furthermore, the paper identifies and discusses open research questions in this domain. In summary, we conclude that there is a significant shift toward employing RL/DRL-based routing strategies in SDN networks, particularly over the past 3 years. Moreover, there is a huge interest in integrating QML techniques to tackle the complexity of routing in 6G networks. However, considerable work remains to be done in both approaches in order to accomplish thorough comparisons and synergies among various approaches and conduct meaningful evaluations using open datasets and different topologies

Collagen-functionalised electrospun polymer fibers for bioengineering applications

Polymer electrospun fibers are gaining increasing importance in nanobiotechnology, due to their intrinsic three-dimensional topography and biochemical flexibility. Here we present an in-depth study of protein functionalisation for polymethylmethacrylate fibers. We compare different coating approaches for type I collagen, including physisorption and covalent binding methods relying on functional linkers. The biofunctionalised fibers are investigated by scanning electron and confocal laser scanning microscopy, wettability measurements, Fourier-transform infrared spectroscopy, and protein quantification assays. We demonstrate that the largest amount of proteins adsorbed on fibers does not determine the best performance in terms of cell attachment and proliferation in vitro, which is instead related to the type of linking and the relevant role played by adsorption of serum biomolecules on the three-dimensional nanostructures. This study is relevant for designing and engineering novel biomaterials and scaffold architectures based on electrospun nanofibers

Nanoparticle image velocimetry at topologically structured surfaces

Nanoparticle image velocimetry ͑nano-PIV͒, based on total internal reflection fluorescent microscopy, is very useful to investigate fluid flows within ϳ100 nm from a surface; but so far it has only been applied to flow over smooth surfaces. Here we show that it can also be applied to flow over a topologically structured surface, provided that the surface structures can be carefully configured not to disrupt the evanescent-wave illumination. We apply nano-PIV to quantify the flow velocity distribution over a polydimethylsiloxane surface, with a periodic gratinglike structure ͑with 215 nm height and 2 m period͒ fabricated using our customized multilevel lithography method. The measured tracer displacement data are in good agreement with the computed theoretical values. These results demonstrate new possibilities to study the interactions between fluid flow and topologically structured surfaces

Patterning of light-emitting conjugated polymer nanofibres.

Organic materials have revolutionized optoelectronics by their processability, flexibility and low cost, with application to light-emitting devices for full-colour screens, solar cells and lasers. Some low-dimensional organic semiconductor structures exhibit properties resembling those of inorganics, such as polarized emission and enhanced electroluminescence. One-dimensional metallic, III-V and II-VI nanostructures have also been the subject of intense investigation as building blocks for nanoelectronics and photonics. Given that one-dimensional polymer nanostructures, such as polymer nanofibres, are compatible with sub-micrometre patterning capability and electromagnetic confinement within subwavelength volumes, they can offer the benefits of organic light sources to nanoscale optics. Here we report on the optical properties of fully conjugated, electrospun polymer nanofibres. We assess their waveguiding performance and emission tuneability in the whole visible range. We demonstrate the enhancement of the fibre forward emission through imprinting periodic nanostructures using room-temperature nanoimprint lithography, and investigate the angular dispersion of differently polarized emitted light

Towards Large-Scale Fast Reprogrammable SOA-Based Photonic Integrated Switch Circuits

Due to the exponentially increasing connectivity and bandwidth demand from the Internet, the most advanced examples of medium-scale fast reconfigurable photonic integrated switch circuits are offered by research carried out for data- and computer-communication applications, where network flexibility at a high speed and high connectivity are provided to suit network demand. Recently we have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip for high connectivity. In this paper, the current status of fast reconfigurable medium-scale indium phosphide (InP) integrated photonic switch matrices based on the use of semiconductor optical amplifier (SOA) gates is reviewed, focusing on broadband and cross-connecting monolithic implementations, granting a connectivity of up to sixteen input ports, sixteen output ports, and sixty-four channels, respectively. The opportunities for increasing connectivity, enabling nanosecond order reconfigurability, and introducing distributed optical power monitoring at the physical layer are highlighted. Complementary architecture based on resonant switching elements on the same material platform are also discussed for power efficient switching. Performance projections related to the physical layer are presented and strategies for improvements are discussed in view of opening a route towards large-scale power efficient fast reprogrammable photonic integrated switching circuits