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Hyperdoped and textured silicon created with a femtosecond laser in the presence of SF6 gas has a highly absorbing surface with extended spectral sensitivity in the infrared. The main drawback of this micro‐ and nanostructured material for photovoltaic (PV) cells is an increase in charge‐carrier recombination at the surface due to the typically poor crystallinity of the surface layer. Laser annealing postprocessing of the black silicon (b‐Si) surface is used to greatly reduce the crystal structure defects while maintaining sub‐bandgap absorption. The back side of the cell is functionalized with spin‐on doping and laser fired contacts to make an interdigitated back‐contact proof‐of‐concept b‐Si solar cell. It is shown that this cell has measurable PV efficiency in the sub‐bandgap infrared, a promising step toward developing intermediate‐band silicon PVs. [ABSTRACT FROM AUTHOR]

Presents a parametric study of three different modes of magnetic-spiker circuits, the switch, diode and overshoot modes. Operation of the spikier-sustainer circuits with magnetic isolation; Comparison of the three modes; Discussion on laser head and corona preionization; Influence of the spiker circuit on laser performance.

Western France is at the crossroads of the migratory routes of two subspecies of black-tailed godwit, Limosa limosa. After leaving Iceland, the godwit L.l. islandica Icelandic black-tailed godwit (IBTG) winters on the coast of western Europe, while the continental black-tailed godwit (CBTG) L.l. limosa can stop in France when migrating between Iberia or Africa and their main breeding grounds in the Netherlands. In this study, we analysed δ15N and δ13C from flight feathers and whole blood throughout the non-breeding period to trace variations in habitat use for both subspecies on the western French coast. Adults and juveniles of IBTG adopt the same feeding habitats as soon as they arrive in the study area, progressively losing the Icelandic freshwater habitat signal, and becoming clearly restricted to marine habitats in winter. Some individuals begin to move locally to freshwater habitats, joining CBTG in a stopover at the end of the wintering period in preparation for northward migration. [ABSTRACT FROM AUTHOR]

Among the additive manufacturing techniques, laser-induced forward transfer addresses the challenges of printing thin films in solid phase or small volume droplets in liquid phase with very high resolution. This paper reviews the physics of this process and explores the pros and cons of this technology versus other digital printing technologies. The main field of applications are printed electronics, organic electronics and tissue engineering, and the most promising short terms ones concern digital laser printing of sensors and conductive tracks. Future directions and emerging areas of interest are discussed such as printing solid from a liquid phase and 3D digital nanomanufacturing. [ABSTRACT FROM AUTHOR]

We produce and characterize high-angle femtosecond Bessel beams at 1300-nm wavelength leading to nonlinearly ionized plasma micro-channels in both glass and silicon. With microjoule pulse energy, we demonstrate controlled through-modifications in 150-μm glass substrates. In silicon, strong two-photon absorption leads to larger damages at the front surface but also a clamping of the intensity inside the bulk at a level of ≈4 × 1011 W cm-2 which is below the threshold for volume and rear surface modification. We show that the intensity clamping is associated with a strong degradation of the Bessel-like profile. The observations highlight that the inherent limitation to ultrafast energy deposition inside semiconductors with Gaussian focusing [Mouskeftaras et al., Appl. Phys. Lett. 105, 191103 (2014)] applies also for high-angle Bessel beams. [ABSTRACT FROM AUTHOR]

We present the results of a review of the bird species historically observed in Niokolo-Koba National Park, a World Heritage Site and 913 000 ha natural protected area in southeastern Senegal. In carrying out this work we consulted both formal and informal literature, and contacted the original observers whenever possible to try to verify unusual observations. We conclude that there is sufficient evidence to support the historical presence of 400 bird species in or just outside the park, although two species can be considered as locally extinct. We also list 19 additional bird species whose presence can be considered as possible or probable. The historical patterns of the observations are briefly discussed. If only those species observed after 1992 are counted, 333 bird species would be considered as present in Niokolo-Koba National Park. [ABSTRACT FROM AUTHOR]

Molecular absorption measurements have been made across the tube radius and with respect to time in a Cu-HBr laser media. CuBr and CuH relative densities in their fundamental levels are found from spectra around 428 and 434 nm. CuBr density decreases from the wall to zero absorption on the axis with a steep gradient at 15 mm from the axis. Inversely, CuH is present on the axis and its absorption decreases toward the wall. Dissociation of the CuH molecules in different excited levels can explain the temporal and radial increase of the copper ground-state density in our operating conditions in a Cu-HBr laser. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Migration patterns in birds vary in space and time. Spatial patterns include chain, leapfrog and telescopic migration. Temporal patterns such as migration duration, number, and duration of stopovers may vary according to breeding latitude, sex, and season. This study aimed to verify these patterns in a long‐distance migrant, the Eurasian curlew Numenius arquata arquata, and to provide a synopsis of spatio‐temporal migration patterns in this species of concern throughout the East Atlantic Flyway. We tagged 85 adults with GPS‐data loggers in Germany, Poland, France and Estonia between 2013 and 2019. We computed the distance flown, linear loxodromic distance, duration, stopover number, total stopover duration, mean stopover duration, departure time and arrival time for 177 out of 187 tracks. On average (± standard deviation), spring migration occurred from 4 to 14 April (10.2 ± 8.4 days), curlews flew 3.623 ± 1.366 km, and had 5.8 ± 3.6 stopovers, with a duration of 29.4 ± 38.2 h per stopover, while autumn migration occurred from 18 to 29 June (10.9 ± 9.9 days), curlews flew 3.362 ± 1.351 km, and had 5.4 ± 4.0 stopovers, with 31.8 ± 32.3 h per stopover. Curlews displayed chain migration because wintering curlews maintained the latitudinal sequence to their breeding sites. Southern curlews had a longer nesting period due to their earlier arrivals. While spring arrival at breeding sites did not differ between the sexes, in autumn females departed earlier than males. Migration duration and distance, as well as stopover number and duration, showed a significant increase with breeding site latitude but did not differ between the sexes or between spring and autumn migrations, suggesting that curlews took a comparable amount of time migrating during both seasons. The high site faithfulness in curlews suggests that rapid autumn migration allows them to return to defend their winter foraging areas. [ABSTRACT FROM AUTHOR]

Thin solid pixels made of Ag/PMMA stacks have been fabricated by laser-induced forward transfer (LIFT), to be tested as thin film microcapacitors in organic electronics applications. The square-shaped laser-printed pixels have a lateral size of ∼350 μm, and the thickness of the dielectric film was varied between 100 and 1500 nm. The pixels were deposited on electrode structures made by LIFT printing of silver nanoparticles ink and paste. Optimal printing conditions led to the fabrication of microcapacitors with typical capacitance in the pF range, tuned by changing the properties of the multilayered structure (e.g. pixel size and/or thickness of the dielectric). Their stability was also investigated over time. We discuss on the morphological and electrical properties of such laser-printed structures, with respect to the impact resistance of the polymer and its suitability for the LIFT process. [ABSTRACT FROM AUTHOR]

Highlights: [•] We studied the laser-induced forward transfer of thin layers of semiconducting PQT-12. [•] PEDOT:PSS was laser-printed to act as conductor in the transistor configuration. [•] Optimization by reducing the background pressure and increasing the films thickness. [•] We fabricated polymeric thin-film transistors devices using the LIFT technique. [•] Transistor performances with mobilities up to 0.02cm2 V−1 s−1 were obtained. [ABSTRACT FROM AUTHOR]

Abstract: Because of the short penetration depth of ultraviolet (UV) in semiconductor, the realization of UV sensors requires the reduction of the junction thickness. Excimer laser annealing (ELA) is a new annealing technical allowing to achieve a thin layer (<30nm) heavily boron doped (R sq <350Ω/sq) on n-type silicon substrate together with a good profile abruptness (<3nm/dec). The small size of the laser beam requires a scanning procedure for processing large surfaces. That could generate non-homogeneities resulting in defect growth. In order to investigate these phenomena, we developed a Light Beam Induced Current (LBIC) measurement set-up. LBIC analyses consist in the measurement of the photocurrent generated by a localized irradiation of the sample. The presence of defects in the irradiated zone leads to a local decrease of the photo-current. Moreover, thanks to different probe beams with wavelengths ranging from 193nm to 800nm, we can control the depth of photo-carriers generation. Thus, we are able to perform a 3D-localization of the defects which helps in understanding their origins. We have developed and validated this detection method of defects generated in the ultra-thin junctions, down to thirty nanometers, with a spatial resolution of ten micrometers at the surface of the sample. First experimental results demonstrate that most of the defects are localized at the edge of the irradiated zone within the first ten nanometers from the surface. [Copyright &y& Elsevier]

Abstract: Today, the collection of generated charges is a limiting problem for the realization of UV sensors. Indeed, the native silicon oxide of the surface acts as a region of recombination centers . Then, the sensors exhibit a low sensitivity in the UV wavelengths. An approach to overcome this drawback is the realization of a few nanometers thick passivation layer at the surface by creating an ultra-shallow junction (USJ) with a high activation level. The realization of such junctions requires two steps: first, the implantation of dopants which consists in introducing impurities at the surface of the substrate, then the thermal activation of these dopants to obtain the electrical characteristics of the junction. The Plasma Immersion Ion Implantation (PIII) process allows us to implant dopants in a very thin layer (10–20nm) into the silicon substrate . These impurities are located in interstitial sites in the silicon, and need an activation process to modify the electrical properties of the layer. The step is performed by means of an excimer laser annealing process (ELA) to melt a very thin layer of the silicon substrate and then activate the dopants without diffusion. In the framework of the ALDIP project (Laser Activation of Dopants implanted by Plasma Immersion), IBS Company has developed with its partners a cluster to realize these two steps with industrial production rates and cleanliness. Four-point probe measurements and SIMS analyzes have been used to characterize the junctions realized with this process. We have reached a sheet resistance lower than 500Ω/sq for a junction depth of 29nm and an abruptness of 3nm/dec. Nevertheless, electrical measurements on diodes have revealed a significant leakage current of around 10−5 A/cm2, revealing the presence of defects inside the junction. Light Beam Induced Current (LBIC) characterization has shown that these defects are localized at the edge of the laser beam. [Copyright &y& Elsevier]

Abstract: Today, the main challenges for the realization of the source/drain extensions concern the ultra-low energy implantation and the activation of the maximum amount of dopants with a minimized diffusion. Among the different annealing processes, one solution is the laser thermal annealing. Many studies [F. Torregrosa, C. Laviron, F. Milesi, M. Hernandez, H. Faik, J. Venturini, Proc. 14th International Conference on Ion Implant Technology, 2004; M. Hernandez, J. Venturini, D. Zahorski, J. Boulmer, D. Débarre, G. Kerrien, T. Sarnet, C. Laviron, M.N Semeria, D. Camel, J.L Santailler, Appl. Surf. Sci. 208–209 (2003) 345–351] have shown that the association of Plasma Immersion Ion Implantation (PIII) and Laser Thermal Process (LTP) allows to obtain junctions of a few nanometers with a high electrical activation. All the wafers studied have been implanted by PULSION® (PIII implanter developed by Ion Beam Services) with an acceleration voltage of 1kV and a dose of 6×1015 at./cm2. In this paper, we compare the annealing process achieved with three excimer lasers: ArF, KrF and XeCl with a wavelength of respectively 193, 248 and 308nm. We analyse the results in terms of boron activation and junction depth. To complete this study, we have observed the effect of pre-amorphization implantation (PAI) before PIII process on boron implantation and boron activation. We show that Ge PAI implanted by classical beam line allows a decrease of the junction depth from 20 down to 12nm in the as-implanted condition. Transmission Electron Microscopy (TEM) analyses were performed in order to study the structure of pre-amorphized silicon and to estimate the thickness of the amorphous layer. In order to determine the sheet resistance (R s ) and the junction depth (X j ), we have used the four-point probe technique (4PP) and secondary ion mass spectrometry (SIMS) analysis. To complete the electrical characterizations some samples have been analyzed by non-contact optical measurements. All the results are presented as a function of the laser fluence and the laser wavelength. [Copyright &y& Elsevier]

Abstract: This paper deals with transfer induced by laser of thin layers of a conducting polymer, the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), for applications in plastic electronics. This relatively simple technique of direct writing offers the ability to make surface micro-patterning by localized deposits of material. The study of the various mechanisms (ablation, transfer and deposit) has been carried out according to different conditions of irradiation: wavelength (from ultraviolet to infrared radiation), pulse duration (nanosecond and sub-nanosecond) and fluence. The morphology of the transferred patterns has been analyzed by optical microscopy and scanning electronic microscopy. Our objective is to understand the different mechanisms involved in the process in order to optimize it in terms of geometrical resolution while preserving the properties of the transferred material. [Copyright &y& Elsevier]

Habitat selection is an important process in birds that influences individual survival and fitness, and ultimately shapes population dynamics. As a consequence, strong selective pressures apply to favor strategies allowing individuals to choose high-quality habitat for foraging while reducing predation risk and competition. In long-distance migratory birds, such as shorebirds, the non-breeding period is considered as a key period of their annual cycle with reported effects on individual survival and subsequent reproduction. Site selection by non-breeding shorebirds should depend on habitat quality for them to ensure survival until the next breeding season. More specifically, birds should distribute in space and time according to their resource availability and specialize on feeding habitats or/and prey to reduce intraspecific competition. To test this hypothesis, we studied Bar-tailed Godwits (Limosa lapponica) at one of their main non-breeding sites along the French coast. We first used GPS tracking to investigate their foraging and roosting home ranges as well as core sampling to define the diversity of available habitats and their quality as feeding resources. We then compared individual habitat selection in relation to feeding home range sizes and benthic macrofauna abundances. Our results provide the first fine scale definition of shorebird movements and distribution along the non-breeding period. We found that godwits showed an extreme fidelity to restricted feeding areas (about 3.4 km2) during winter, with low overlap between individual feeding home ranges. Each bird appeared to mainly use 4–6 of the 11 available foraging habitats, with a specialization on 1 to 2 main habitats and their associated prey. However, our results did not emphasize a clear relationship between home range sizes and the quality of bird feeding sites. This study thus demonstrates the high specialization of individual non-breeding Bar-tailed godwits relying on specific foraging grounds and habitats, with important implications for the conservation of this species. [ABSTRACT FROM AUTHOR]

Highlights • A laser-induced forward transfer (LIFT) strategy combining quasi-continuous (QCW) and femtosecond (fs) lasers is successfully applied for high resolution printing from a 1 µm copper donor film. • Influences of copper film temperature, and especially diameter of the melted metal area, on the printing dynamics are revealed. • By simply adjusting the synchronization between the QCW and fs pulses, droplets with different shapes are printed. The reproducibility is demonstrated by printing two-dimensional arrays. • Double-pulse LIFT prints debris-free microstructures with controllable dimensions. Abstract Laser induced forward transfer process can be implemented in a double-pulse scheme where a solid thin film deposited on a transparent donor substrate is irradiated by two synchronized lasers. In a recently demonstrated methodology, a long pulse is first applied to melt the film and an appropriately delayed ultrashort laser pulse initiates material transfer in the liquid phase toward a receiver substrate. This provides a versatile method to print high-resolution (<2 µm) patterns with a long working distance (>40 µm). In this paper we focus on the study of the dynamical aspects associated with these printing performances. The temperature evolution of the thin copper film during irradiation with a quasi-continuous wave (QCW) pulse is calculated. By combining the calculations with time-resolved imaging experiments, we reveal the influence of the copper film temperature and molten metal diameter on the ejection dynamics. Characterization of the transferred materials shows that the delay between the two laser pulses is a control parameter for the shape and volume of the printed structures. This is finally exploited to demonstrate high-precision printing of different debris-free microstructures onto a Si receiver substrate set as far as 60 µm away from the donor film. [ABSTRACT FROM AUTHOR]

We present an experimental study of double-pulse laser-induced forward transfer (LIFT) and jet formation from different metal donor films. The dynamics of the jet formation and propagation have been investigated by time-resolved shadowgraphy studies. The morphologies of the irradiated films have been studied by means of scanning electron microscopy analysis. The experiments have been performed with copper, gold and nickel-copper double-layer films and the results point out the ability of double-pulse LIFT method to form long liquid metal jets and to print micro-droplets with a limited dependence on the metal properties. [ABSTRACT FROM AUTHOR]

We show that high-quality pentacene (P5) thin films of high crystallinity and low surface roughness can be produced by pulsed laser deposition (PLD) without inducing chemical degradation of the molecules. By using Raman spectroscopy and X-ray diffraction measurements, we also demonstrate that the deposition of P5 on Au layers result in highly disordered P5 thin films. While the P5 molecules arrange within the well-documented 1.54-nm thin-film phase on high-purity fused silica substrates, this ordering is indeed destroyed upon introducing an Au interlayer. This observation may be one explanation for the low electrical performances measured in P5-based organic thin film transistors (OTFTs) deposited by laser-induced forward transfer (LIFT). [ABSTRACT FROM AUTHOR]

Carbon nanowalls (CNW) are two-dimensional interconnected graphitic nanostructures that have a few μm in length and height, reaching typical thicknesses of a few tens of nm. We present results on such layers synthesized in a low pressure argon plasma jet, injected with acetylene and hydrogen, on transparent substrates (quartz) heated at 600 °C, without catalyst. Thermogravimetric analysis reveals that the CNW are stable up to 420 °C in air, and Raman spectroscopy investigations highlight their graphene-like structure. Finally, using a pulsed Nd:YAG laser device (355 nm, 50 ps), we show that 2D-arrays of CNW (pixels and lines) can be printed by laser-induced forward transfer (LIFT), preserving their architecture and structure. Electrical measurements on 1 μm thick CNW demonstrate typical values in the range of 357.5–358.4 Ω for the samples grown on Au/Cr electrodes, and in the range of 450.1–474.7 Ω for the LIFT printed lines (under positive, negative, and neutral polarization; 1 kHz–5 MHz frequency range; 500 mV and 1 V, respectively). Their morphology is highlighted by means of optical and electronic microscopy. Such structures have potential applications as soft conductive lines, in sensor development and/or embedding purposes. [ABSTRACT FROM AUTHOR]

Following the standard Sonogashira cross-coupling conditions, the reaction between 1,4-diiodo-2,5-bis(octyloxy)benzene with 2.2 equiv. of 1-ethynylpyrene afforded a yellowish bis -pyrene derivative, namely 1,4-bis(octyloxy)-2,5-bis(ethynylpyrene)benzene , that exhibits typical fluorescence and semiconducting properties. Thermal analysis studies are discussed, with emphasis made on the oxidative decomposition and thermal effects. Further on, thin films have been grown by vacuum thermal evaporation, on silicon and quartz substrates. The temperature's influence on the thin film's morphology and electrical properties is investigated. Finally, top-contact thin film transistor configurations are presented and the influence of substrate temperature is discussed with respect to the semiconducting properties. [ABSTRACT FROM AUTHOR]

Understanding environmental factors underlying animal foraging distribution is of major importance in defining priority conservation actions. During their wintering stage, most shorebirds depend on intertidal areas, as foraging grounds, and on supratidal areas, as high tide roosts. The accessibility of foraging areas and food resources is thus limited, and most wintering shorebirds have to forage whenever mudflats are available, both day and night, to fulfil their daily energetic demands. However, current knowledge of shorebirds' spatio-temporal use of foraging habitats is often restricted to the daylight period. In that context, we investigated the spatial distribution and habitat selection of wintering black-tailed godwits Limosa limosa islandica , during both the day and night, and in relation to the environmental characteristics. We equipped wintering black-tailed godwits at two different sites on the Pertuis Charentais (Atlantic French coast) with miniaturised GPS loggers. We then tested the hypothesis that godwits feed both during day and night, and show contrasting foraging behaviours and distribution in response to different visual capacities, prey availability, predation risks and human activities. The selection of feeding areas was highly variable according to nycthemeral periodicities, with little change in the habitat types selected. The estimated nocturnal surface of feeding areas were two times smaller than daytime ones, and located closer to the coastline. Moreover, birds largely foraged inside protected areas during the daytime, while most of them foraged outside at night. Finally, godwits with the smallest feeding home ranges stayed inside the Nature Reserves, during both day and night, while the others prospected outside the protected areas more often, preferentially at night. • Few studies examined behaviour of Shorebird at fine spatiotemporal scale. • Our results highlighted nocturnal feeding areas two times smaller than daytime ones, and located closer to the coastline. • Birds largely foraged inside protected areas during the daytime, while most of them foraged outside at night. [ABSTRACT FROM AUTHOR]

The use of laser-based processing is presented here for the transfer of azo-derivatives, for optoelectronics assembly applications. Laser-printing techniques are also adequate tools for rapid prototyping of diverse materials, since they avoid the usage of solutions, moulds, lithography masks, etc. Here, we present a study on the laser-induced forward transfer (LIFT) and printing of micrometric-sized pixels (350 μm × 350 μm), by using matrix-assisted pulsed laser evaporation (MAPLE) deposited thin film donors. Due to their particular optical properties, i.e. second harmonic generation, optical limiting and all-optical poling, and with applications in optoelectronics and sensor development, azo-dyes have been intensively studied in bulk or as thin films. The influence of a metallic dynamic release layer (DRL) during LIFT is investigated. [ABSTRACT FROM AUTHOR]

We present results on a newly synthesized bis -pyrene compound that, besides the typical fluorescence, also exhibits semiconducting properties. Thin films have been grown by vacuum thermal evaporation on oxidized silicon and on transparent quartz substrates. Micrometric-sized pixels have subsequently been printed by laser-induced forward transfer (LIFT), in air and at low pressure (90 mbar), by using a Nd:YAG laser source (355 nm, 50 ps pulse duration) to produce functional organic thin film transistors (o-TFTs). Top-contact (TC) configurations are emphasized, and the influence of the pressure and laser fluence during the LIFT procedure is discussed. [ABSTRACT FROM AUTHOR]

The printing of multilayered pixels using single picosecond laser pulses is investigated by using an improved laser-induced forward transfer (LIFT) technique. Micrometric low-k dielectric capacitors of hybrid organic polymer (parylene-C) and silver thin films have been transferred on laser-printed pads of annealed silver nanoparticles (AgNP) paste. This printing technique allows to design and print directly on virtually any substrate, in order to make the capacitors directly interface with other components, such as transducers or sensing devices, and which are further used for improving or complementing the characteristics of these devices. This study focuses on the use of the optimized LIFT technique using a double mask setup, i.e. smart beam shaping (SBS) in the picosecond laser pulse regime. The purpose is to optimize the energy repartition of the Gaussian beam on the thick multilayer donor by using a beam profile with increased intensity at the edges and low intensity in the center. This allows to keep the incoming irradiation fluence on the donor layer as low as possible in the centre area, and thus preventing the multilayer pixels from damage induced by laser irradiation. Electrical investigations of the SBS-LIFT printed micro-capacitors demonstrate that they are fully functional and stable over time, with capacities in the pF range. [ABSTRACT FROM AUTHOR]

Laser-induced forward transfer (LIFT) has been investigated for the transfer of a polymeric material. This study focuses on the comparison of the printing process using conventional LIFT printing with a simple square mask and an optimized LIFT technique using a double mask setup, i.e. smart beam shaping (SBS). The purpose is to optimize the energy repartition on the donor layer using a beam profile with over-intensities at the edges and low intensities in the center. This allows the incoming irradiation fluence on the donor layer to be kept as low as possible in the central area, thus preventing the organic pixels being damaged by laser irradiation. The influence of the film's thickness on the SBS efficiency is discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] A silver-nanoparticles ink is transferred by laser using LIFT at high speed. [•] Multi-jet formation is investigated with a time-resolved imaging technique. [•] Laser pulses separated by 2μs and 25μm lead to stable jets. [•] Well-defined, 16μm droplets are printed at a rate of 500,000 droplets/s. [Copyright &y& Elsevier]

Highlights: [•] Copolymers were cross-linked with formation of azo bonds and release of gaseous N2. [•] Azo groups act as chromophores upon irradiation with a 248nm KrF nanosecond laser. [•] The amount of initial copolymer crosslinking determines extent of LIPSS formation. [ABSTRACT FROM AUTHOR]

Abstract: Organic thin-film transistor (OTFT) devices were achieved using the laser-induced forward transfer technique. As p-type organic semiconductor, distyryl-quaterthiophene (DS4T) was vacuum-deposited on a donor substrate and transferred with picosecond laser pulses on Si/SiO2-based receiver substrates to form an organic active layer. To avoid laser damage of the organic thin film, a UV-sensitive aryltriazene polymer as a sacrificial layer was used. The polymer layer, deposited on the donor substrate prior to the organic layer deposition, has high absorption at the laser wavelength and does not contaminate the printed pixels. The DS4T pixels printed on receiver substrates have well defined morphological properties as shown by atomic force microscopy and scanning electronic microscopy. OTFT devices were characterized in top- and bottom-contact configurations using thermally evaporated gold lines as source-drain electrodes. DS4T pixels printed as active layer for charge transport not only issue mobility values comparable to DS4T layers prepared by vacuum evaporation but also a relative electrical stability over time. [Copyright &y& Elsevier]

In western Europe, the coasts of Vendée and Charente-Maritime on the central Atlantic shoreline of France constitute the most southern wintering site for the Red Knot Calidris canutus islandica, welcoming around 37,000 individuals each winter, and also represent a key stopover area for C. c. canutus (up to 60,000 individuals) between Africa and the Wadden Sea in spring. Nevertheless, the origin of the birds in France arriving in the autumn is unclear, considering that the first islandica start to appear for wintering while canutus could use the same sites as a stopover on their migration route to Africa. We used biometric data from birds caught between 1983 and 2008 to assess the origin of Red Knot staging and wintering in France, and we also investigated the age structure of Red Knot groups during three distinctive periods of their biological cycle: autumn migration, wintering and spring migration. This first assessment was completed by data analysis of ring recoveries over a period of 44 years and isotopic ratio signatures of feathers. The obtained results were in conformity with the general patterns of distribution throughout the year and the timing of migration of both subspecies in Europe as described in previous reviews. Nevertheless, this study highlights two unknown features for both subspecies in this part of their European area distributions. First, a very large predominance of juveniles was recorded at the expense of an extreme rarity of adults in autumn and early winter. We prove the presence of canutus-knots among these juveniles, even with staging later in the autumn and the possibility of wintering there for some of them. Although the Atlantic coast of France welcomes only 9% of the population of islandica-knots wintering in Europe, this network of estuarine bays could represent a crucial strategic area for juveniles. The place could constitute a liberated area for islandica juveniles coming later than adults already settled in northern sites. It offers the possibility for canutus to migrate south on distance-limited stages in order to experiment with the flyway and refuel to join the traditional African wintering grounds. [ABSTRACT FROM AUTHOR]

Abstract: Functional laser printed Organic Thin Film Transistors (OTFTs) have been achieved from multilayer substrates composed with semiconductor and electrodes. The p-type copper phthalocyanine (CuPc) was used to form the active layer. Different kinds of metallic materials were used for source and drain electrodes. Multilayer donor substrates were prepared by the successive depositions of materials by either thermal evaporation under vacuum or laser printing. The materials were transferred together in a single step onto a receiver substrate by laser pulses in the picosecond regime. The latter substrate formed the gate and the dielectric of the transistor. The results are compared with the step-by-step laser printing process, where electrodes and organic layer were successively printed from two different donor substrates. The multilayer laser printing reveals an improvement of the performances of the OTFT devices. [Copyright &y& Elsevier]

Abstract: Laser-induced forward transfer (LIFT) has been used to deposit pixels of an organic semiconductor, distyryl-quaterthiophenes (DS4T). The dynamics of the process have been investigated by shadowgraphic imaging for the nanosecond (ns) and picosecond (ps) regime on a time-scale from the laser iradiation to 1.5μs. The morphology of the deposit has been studied for different conditions. Intermediate sacrificial layer of gold or triazene polymer has been used to trap the incident radiation. Its role is to protect the layer to be transferred from direct irradiation and to provide a mechanical impulse strong enough to eject the material. [Copyright &y& Elsevier]

Abstract: The laser-induced forward transfer technique has been performed on thin layers of conducting organic materials for applications in plastic micro-electronics. This process is a promising alternative for fabrication of organic electronic components on flexible supports when usual techniques, such like ink-jet printing, cannot be considered. For example, when the organic material has no solubility properties or when complex architectures are needed. Experiments on the influence of pulse duration (nanosecond and picosecond) and wavelength on a large range of fluences have been proceeded using different lasers. An optimization of the process has been carried out by inserting a thin layer of absorbing metallic material between the substrate and the organic film. The advantage of this technique is to preserve organic layers from being damaged by thermal and photochemical effects during the interaction. The morphology and thickness of the deposit have been investigated by optical and scanning electronic microscopy. This experimental study is supplemented by electrical characterization of the deposits. [Copyright &y& Elsevier]

Driven by flexibility, precision, repeatability and eco-friendliness, laser-based technologies have attracted great interest to engineer or to analyze materials in various fields including energy, environment, biology and medicine. A major advantage of laser processing relies on the ability to directly structure matter at different scales and to prepare novel materials with unique physical and chemical properties. It is also a contact-free approach that makes it possible to work in inert or reactive liquid or gaseous environment. This leads today to a unique opportunity for designing, fabricating and even analyzing novel complex bio-systems. To illustrate this potential, in this paper, we gather our recent research on four types of laser-based methods relevant for nano-/micro-scale applications. First, we present and discuss pulsed laser ablation in liquid, exploited today for synthetizing ultraclean "bare" nanoparticles attractive for medicine and tissue engineering applications. Second, we discuss robust methods for rapid surface and bulk machining (subtractive manufacturing) at different scales by laser ablation. Among them, the microsphere-assisted laser surface engineering is detailed for its appropriateness to design structured substrates with hierarchically periodic patterns at nano-/micro-scale without chemical treatments. Third, we address the laser-induced forward transfer, a technology based on direct laser printing, to transfer and assemble a multitude of materials (additive structuring), including biological moiety without alteration of functionality. Finally, the fourth method is about chemical analysis: we present the potential of laser-induced breakdown spectroscopy, providing a unique tool for contact-free and space-resolved elemental analysis of organic materials. Overall, we present and discuss the prospect and complementarity of emerging reliable laser technologies, to address challenges in materials' preparation relevant for the development of innovative multi-scale and multi-material platforms for bio-applications. [ABSTRACT FROM AUTHOR]

Organic thin-film transistors have been fabricated using laser-induced forward transfer as spatially resolved laser-printing method. Using this technique, source and drain electrodes were deposited from silver nanoparticle ink and the copper phthalocyanine (CuPc) was used to form the active layer. Both kinds of materials were transferred from a donor substrate onto a receiver substrate upon irradiation with laser pulses in the picosecond regime. The latter substrate formed the gate and the dielectric of the transistor. Electrical characterizations showed that the transistors are fully operative, showing well-defined linear and saturation regimes in the I-V curves. [ABSTRACT FROM AUTHOR]

Tungsten was chosen as a wall component to interact with the plasma generated by the International Thermonuclear Experimental fusion Reactor (ITER). Nevertheless, during plasma operation tritiated tungsten nanoparticles (W-NPs) will be formed and potentially released into the environment following a Loss-Of-Vacuum-Accident, causing occupational or accidental exposure. We therefore investigated, in the bronchial human-derived BEAS-2B cell line, the cytotoxic and epigenotoxic effects of two types of ITER-like W-NPs (plasma sputtering or laser ablation), in their pristine, hydrogenated, and tritiated forms. Long exposures (24 h) induced significant cytotoxicity, especially for the hydrogenated ones. Plasma W-NPs impaired cytostasis more severely than the laser ones and both types and forms of W-NPs induced significant micronuclei formation, as shown by cytokinesis-block micronucleus assay. Single DNA strand breaks, potentially triggered by oxidative stress, occurred upon exposure to W-NPs and independently of their form, as observed by alkaline comet assay. After 24 h it was shown that more than 50% of W was dissolved via oxidative dissolution. Overall, our results indicate that W-NPs can affect the in vitro viability of BEAS-2B cells and induce epigenotoxic alterations. We could not observe significant differences between plasma and laser W-NPs so their toxicity might not be triggered by the synthesis method. [ABSTRACT FROM AUTHOR]