An auxetic conductive cardiac patch (AuxCP) for the treatment of myocardial infarction (MI) is introduced. The auxetic design gives the patch a negative Poisson’s ratio, providing it with the ability to conform to the demanding mechanics of the heart. The conductivity allows the patch to interface with electroresponsive tissues such as the heart. Excimer laser microablation is used to micropattern a re-entrant honeycomb (bow-tie) design into a chitosan-polyaniline composite. It is shown that the bow-tie design can produce patches with a wide range in mechanical strength and anisotropy, which can be tuned to match native heart tissue. Further, the auxetic patches are conductive and cytocompatible with murine neonatal cardiomyocytes in vitro. Ex vivo studies demonstrate that the auxetic patches have no detrimental effect on the electrophysiology of both healthy and MI rat hearts and conform better to native heart movements than unpatterned patches of the same material. Finally, the AuxCP applied in a rat MI model results in no detrimental effect on cardiac function and negligible fibrotic response after two weeks in vivo. This approach represents a versatile and robust platform for cardiac biomaterial design and could therefore lead to a promising treatment for MI.
(1 of 37)high mobility (µ) (even in amorphous phase), wide bandgap (transparent in the visible range), and the ability to be controllably doped. Importantly, they can be grown into thin films and various nanostructures with different scalable deposition techniques, including vacuum-based methods such as physical vapor deposition (PVD) [7,8] and chemical vapor deposition (CVD) [9] as well as solution-based processes such as spray [10] and spin coating. [11] Moreover, the resulting layers can be easily patterned using standard fabrication procedures and as such can be integrated into state-of-the-art processes for (opto)electronic applications. The above-mentioned capabilities have led to a plethora of applications such as switching backplanes for displays, transparent and flexible electronics, integrated circuits (ICs), photovoltaics (PVs), organic light-emitting diodes (OLEDs), capacitors, batteries, photocatalytic devices, electrochromics and memory devices, to name but a few. [8,[12][13][14] Because of their ability to be doped, their electronic properties can be tuned from dielectrics to semiconductors and conductors. This characteristic versatility has recently been exploited to stretch the range of their applications to new technological sectors, such as plasmonics in the near infrared and midinfrared spectral ranges. [12,15] One of the driving applications of metal oxides is in thinfilm transistors (TFTs) for large area electronics such as current driven optical displays and ICs. Following the early demonstrations, [16] most effort focused on the fabrication and processing of metal oxides TFTs paying particular attention to the device performance and applications. [1,5,6,17] Especially when processed over large areas, as in the case for display applications, the complexity to precisely control the device reliability and reproducibility becomes a challenging aspect of any TFT technology. To that respect, solution-based techniques progressed rapidly due to their lower cost and higher throughput compared to vacuum-based techniques. In both cases, the metal-oxide deposition has so far been limited to high processing temperatures (>250 °C) (Figure 1a) which renders the technology incompatible with inexpensive, temperature-sensitive substrates such as polymers, the material class of choice for various high throughput manufacturing techniques such as roll-to-roll (R2R) and sheet-to-sheet (S2S)Over the past few decades, significant progress has been made in the field of photonic processing of electronic materials using a variety of light sources. Several of these technologies have now been exploited in conjunction with emerging electronic materials as alternatives to conventional hightemperature thermal annealing, offering rapid manufacturing times and compatibility with temperature-sensitive substrate materials among other potential advantages. Herein, recent advances in photonic processing paradigms of metal-oxide thin-film transistors (TFTs) are presented with particular emphasis on the use of various light sour...
The photosensitivity of nanocomposite AlN films with embedded silver nanospheres is reported. It stems from localized surface plasmon resonances (LSPR) whose modulation is photoinduced by laser annealing that induces a combined effect of metallic nanoparticle enlargement and dielectric matrix recrystallization; the photoindunced changes of the refractive index of the matrix result in strong spectral shift of LSPR. We demonstrate the utilization of this process for spectrally selective optical encoding into hard, durable, and chemically inert films.
Nano-structuring of metals is one of the greatest challenges for the future of plasmonic and photonic devices. Such a technological challenge calls for the development of ultra-fast, high-throughput and low-cost fabrication techniques. Laser processing, accounts for the aforementioned properties, representing an unrivalled tool towards the anticipated arrival of modules based in metallic nanostructures, with an extra advantage: the ease of scalability. In the present work we take advantage of the ability to tune the laser wavelength to either match the absorption spectral profile of the metal or to be resonant with the plasma oscillation frequency, and demonstrate the utilization of different optical absorption mechanisms that are size-selective and enable the fabrication of pre-determined patterns of metal nanostructures. Thus, we overcome the greatest challenge of Laser Induced Self Assembly by combining simultaneously large-scale character with atomic-scale precision. The proposed process can serve as a platform that will stimulate further progress towards the engineering of plasmonic devices.
Abstract:Tin doped indium oxide (ITO) has been directly deposited onto a variety of flexible materials by a reactive sputtering technique that utilises a remotely generated, high density plasma. This technique, known as high target utilisation sputtering (HiTUS), allows for the high rate deposition of good quality ITO films onto polymeric materials with no substrate heating or post deposition annealing. Coatings with a resistivity of 3.8 ×10−4 Ωcm and an average visible transmission of greater than 90% have been deposited onto PEN and PET substrate materials at a deposition rate of 70 nm/min. The electrical and optical properties are retained when the coatings are flexed through a 1.0 cm bend radius, making them of interest for flexible display applications.
Abstract. An investigation into the modification of low temperature deposited ZnO thin films by different annealing processes has been undertaken using laser, thermal and rapid thermal annealing of 60nm ZnO films deposited by Hi-Target-Utilization-Sputtering. Single pulse laser annealing using a KrF excimer laser ( A = 248nm) over a range of fluences up to 315 mJ/cm 2 demonstrates controlled indepth modification of internal film microstructure and luminescence properties without the film degradation produced by high temperature thermal and RTA processes. Photoluminescence properties show that the ratio of defect related deep level emission (DLE, 450nm -750nm, 2.76eV-1.65eV) to excitonic near band-edge emission (NBE at 381nm, 3.26eV) is directly correlated to processing parameters. Thermal and rapid thermal processing results in the evolution of a strong visible orange/red DLE photoluminescence (with peaks at 590nm, 2.10eV and 670nm, 1.85eV) dominated by defects related to excess oxygen. At higher temperatures, the appearance of a green/yellow emission (530nm, 2.34eV) indicates a transition of the dominant radiative transfer mechanism. In contrast, laser processing removes defect related DLE and produces films with intense NBE luminescence, correlated to the observed formation of large grains (25-40nm IntroductionThin films of ZnO are of interest across a range of optoelectronic and sensor device applications due to ZnO being a wide gap (>3 eV) n-type semiconductor with a high exciton binding energy [1] and a piezoelectric response [2]. Poly crystalline thin films of ZnO are deposited by a variety of physical and chemical vapour methods, with sputtering [1] being a preferred choice for low cost and scalability. However, to achieve the desired thin film properties, particularly for low temperature deposited films, it is critical to control grain microstructure, surface morphology, and internal defects [3]. Techniques that have been previously reported to improve these properties of ZnO thin films include post deposition thermal annealing [4,5], rapid thermal annealing [6,7], and laser annealing [8,9,10]. In this paper we present the results from a comparative study of the effect of all three of these annealing processes on the microstructure, crystallinity and associated intrinsic photoluminescence properties of low temperature sputter deposited ZnO thin films. The results demonstrate that pulsed laser annealing is a powerful tool for the controlled modification of low temperature deposited thin films. In particular, the work presented here explores the effect of a more comprehensive range of laser processing parameters on low temperature ZnO thin films than previously reported. The results
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