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This paper gathers the studies of the effects introduced when Nitrogen and Silicon were implanted in policarbonates used in optical applications. Different Nitrogen and Silicon doses were implanted for finding out the roles of this parameter in the mechanical and optical modifications. Several mechanical tests were carried out, like Microindentation, Nanoindentation and AFM. IR and UV-VIS optical tests were also carried out. Results show harder surfaces for the high Nitrogen implanted doses, and great changes in the UV-VIS spectrums.En el presente trabajo se estudian los efectos introducidos por la implantación de Nitrógeno atómico y Silicio sobre probetas de policarbonato empleadas para usos ópticos. Distintas dosis de Nitrógeno y Silicio fueron implantadas de cara a poner de manifiesto el efecto de la dosis sobre las propiedades ópticas y mecánicas. Se llevaron a cabo ensayos mecánicos de microdureza, nanodureza, y AFM, así como ensayos ópticos de Reflexión-absorción IR y Transmitancia UV-VIS. Los resultados muestran un endurecimiento superficial para las implantaciones a dosis altas de Nitrógeno, así como cambios considerables en los espectros de transmitancia.

Currently, there is a great demand for non‐toxic lead‐free halide perovskites as active materials for solar cells, light‐emitting diodes and other optoelectronic devices. Although an essential progress has been made using tin(II) halide perovskites, still greater efforts are needed to improve their stability and manufacture films and devices under a scalable technology. The first goal of the work is to achieve suitable physical properties of 2D Sn(II) polycrystalline perovskite films obtained by the industrially scalable inkjet printing deposition technique. In the present work, inks of 2D tin(II) halide perovskite 2‐thiopheneethylammonium tin(II) iodide, TEA2SnI4, have been successfully formulated in DMF (toxic) and DMSO (non‐toxic) solutions and using appropriate additives (SnF2 and reducing agents) for improving the stability of the inks and the resulting films. Room‐ and low‐temperature excitonic photoluminescence (PL), charge carrier recombination dynamics and µ‐PL is used to explain the observed two excitonic bands, which are associated to the bulk and edges of perovskite grains nanoplatelet‐like composing the polycrystalline films. Promising electro‐optical properties are also obtained in the TEA2SnI4 films inkjet‐printed from DMSO formulations onto ITO‐interdigitated electrodes, such as low dark currents, ≈10 – 20 nA at 10 V of bias voltage, and high responsivities ≈1–20 A/W. [ABSTRACT FROM AUTHOR]

Inkjet printing has emerged as a promising technique for the fabrication of halide perovskite (HP) thin films, as it enables precise and controlled deposition of the perovskite ink on a variety of substrates. One main advantage of inkjet printing for the fabrication of HP thin films is its ability to produce uniform films with controlled thickness and high coverage, which is critical for achieving high‐performance devices. Additionally, inkjet printing allows for the deposition of patterned thin films, enabling the fabrication of complex device architectures such as light‐emitting diodes (LEDs). In this work, flexible LEDs based on inkjet printed Pb‐free HP thiophene‐ethylammonium tin iodide (TEA2SnI4) are produced that has gained attention as a potential alternative to Pb‐based HPs in optoelectronic devices due to its lower toxicity, environmental impact, and high performance. The role of ink solutions is compared using pure solvents: toxic dimethyl formamide (DMF) and more eco‐friendly dimethyl sulfoxide (DMSO). Red‐emitting devices (λmax = 633 nm) exhibit, in ambient conditions, a maximum external quantum efficiency (EQEmax) of 0.5% with a related brightness of 21 cd m−2 at 54 mA cm−2 for DMSO‐based LEDs. The environmental impacts of films prepared with DMSO‐based solvents ensure only 40% of the impact caused by DMF. [ABSTRACT FROM AUTHOR]

After establishing themselves as promising active materials in the field of solar cells, halide perovskites are currently being explored for fabrication of low‐cost, easily processable, and highly efficient light‐emitting diodes (LEDs). Despite this, the highest efficiencies reported for perovskite‐based LEDs (PeLEDs) are achieved through spin coating or vacuum evaporation deposition techniques, which are not adequate, in most of the cases, for an industrial‐scale production. Additionally, the long‐term stability is still a big handicap, even though all inorganic perovskites, such as CsPbBr3, are found to be more stable to external variables. In this context, herein, the fabrication of fully inkjet‐printed (IJP) CsPbBr3‐based PeLEDs in ambient conditions, on rigid and flexible substrates, on a proof‐of‐concept basis, with the successful incorporation of NiO and SnO2 as hole‐ and electron‐selective contacts, respectively, is reported. Despite the moderate luminance (324 cd m−2) value obtained, this result paves the way toward the development of upscalable fabrication of PeLEDs based on deposition techniques with controlled spatial resolution. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) have shown outstanding optical emissive properties and can be employed in several optoelectronics devices. In contrast with materials of well‐established technologies, which are prone to degradation or require expensive processes, MHPs can be obtained by solution processing methods and increase stability. Inkjet printing is proposed as an industrial friendly technique to deposit MHPs. The inks have been developed from colloidal CsPbBr3 nanocrystals and printing procedures that allow the deposition of thin layers with intense green emission. High emissive printed layers are assured by carrying out thermal annealing in vacuum oven, which is demonstrated to promote compact layers with low roughness, corroborated by SEM and AFM. XRD measurements show CsPbBr3 crystalline layers with cubic symmetry and XPS provides insight into the stoichiometric composition and local bonding. Optical properties of inkjet‐printed CsPbBr3 films have been analyzed by UV–vis absorbance and photoluminescence (PL), to extract the bandgap energy and photoluminescence quantum yield (PLQY). CsPbBr3 printed layers emit at 524 nm with a narrow emission (FWHM ≈ 15 nm), exhibiting a PLQY up to 20%. These results enabled the large‐scale fabrication by inkjet printing of CsPbBr3 color conversion layers (CCLs) and pave the way for flexible LEDs. [ABSTRACT FROM AUTHOR]

This study investigates the influence of the deposition temperature Td on the Si-mediated excitation of Er ions within silicon-rich silicon oxide layers obtained by magnetron cosputtering. For Td exceeding 200 °C, an efficient indirect excitation of Er ions is observed for all as-deposited samples. The photoluminescence intensity improves gradually up to a maximum at Td=600 °C before decreasing for higher Td values. The effects of this 'growth-induced annealing' are compared to those resulting from the same thermal budget used for the 'classical' approach of postdeposition annealing performed after a room temperature deposition. It is demonstrated that the former approach is highly beneficial, not only in terms of saving time but also in the fourfold enhancement of the Er photoluminescence efficiency. [ABSTRACT FROM AUTHOR]

We report a joint experimental and theoretical study of the lattice dynamics of cubic Tb2O3. Up to 16 optical Raman‐active modes have been observed with polarized and unpolarized Raman scattering measurements on a high‐quality Tb2O3 single crystal. The measured wavenumbers have been compared with those of other rare‐earth (RE) and related sesquioxides with cubic (C‐type or bixbyite) structure. First‐principles calculations have allowed us to assign the symmetry of the experimentally observed Raman‐active modes. Additional lattice‐dynamical calculations on the related cubic RE sesquioxides Dy2O3, Gd2O3, Eu2O3, and Sm2O3 indicate that the phonon wavenumbers of the Raman‐active modes in these compounds are monotonically reduced with increasing the lattice parameter along the Dy2O3‐Tb2O3‐Gd2O3‐Eu2O3‐Sm2O3 series, thus prompting for a revision of the experimental Raman spectra of some of these compounds (mainly Eu2O3 but also Gd2O3). The lattice dynamics of cubic Tb2O3 is studied both experimentally and theoretically. Up to 16 optical Raman‐active modes are observed with Raman scattering measurements on a high‐quality single crystal. The measured wavenumbers have been compared with those of other cubic rare‐earth sesquioxides. Density functional theory lattice‐dynamical calculations on cubic Tb2O3 and also on cubic Dy2O3, Gd2O3, Eu2O3, and Sm2O3 predict a monotonic wavenumber reduction for the high‐wavenumber phonons along the Dy2O3‐Tb2O3‐Gd2O3‐Eu2O3‐Sm2O3 series. Our data and analysis suggest that the experimental Raman spectra of some of these compounds (mainly Eu2O3 but also Gd2O3) should be revised. [ABSTRACT FROM AUTHOR]