Intense ultraviolet photoluminescence at 314 nm in Gd^3+-doped Silica

Photoluminescence (PL) of Gd-doped silica in the ultraviolet (UV) is investigated. The efficient emission detected at 314 nm is due to the 6P7/2 to 8S7/2 transition of a 4f electron of the Gd3+ ion

Fully inorganic oxide-in-oxide ultraviolet nanocrystal light emitting devices

The development of integrated photonics and lab-on-a-chip platforms for environmental and biomedical diagnostics demands ultraviolet electroluminescent materials with high mechanical, chemical and environmental stability and almost complete compatibility with existing silicon technology. Here we report the realization of fully inorganic ultraviolet light-emitting diodes emitting at 390 nm with a maximum external quantum efficiency of ~0.3%, based on SnO(2) nanoparticles embedded in SiO(2) thin films obtained from a solution-processed method. The fabrication involves a single deposition step onto a silicon wafer followed by a thermal treatment in a controlled atmosphere. The fully inorganic architecture ensures superior mechanical robustness and optimal chemical stability in organic solvents and aqueous solutions. The versatility of the fabrication process broadens the possibility of optimizing this strategy and extending it to other nanostructured systems for designed applications, such as active components of wearable health monitors or biomedical devices

UV light generation in optical fibres

UV light has been generated in optical fibers using nonlinear optics (harmonic generation) and rare earth doping with Gd3+

Radiation hardness of Ce-doped sol-gel silica fibers for High Energy Physics applications

The results of irradiation tests on Ce-doped sol-gel silica using X- and g-rays up to 10 kGy are reported, in order to investigate the radiation hardness of this material for high energy physics applications. Sol-gel silica fibers with Ce concentrations of 0.0125 mol% and 0.05 mol% are characterized by means of optical absorption and attenuation length measurements before and after irradiation. The two different techniques give comparable results, evidencing the formation of a main broad radiation-induced absorption band, peaking at about 2.2 eV, related to radiation-induced color centers. The results are compared with those obtained on bulk silica. This study reveals that an improvement of the radiation hardness of Ce-doped silica fibers can be achieved by reducing Ce content inside the fiber core, paving the way for further material development

Metodologie di sintesi e caratterizzazione di materiali inorganici a funzionalita' specifica

Dottorato di ricerca in scienze chimiche. 11. ciclo. A.a. 1999-00. Relatore Franca MorazzoniConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Ce doped SiO₂ optical fibers for remote radiation sensing and measurement

Scintillating materials, able to efficiently operate the conversion of energy absorbed in the form of ionizing radiation into light in the visible UV interval, are presently used in a wide class of applications as medical imaging, industrial inspection, security controls and high energy physics detector. In the last few years we studied and developed a new radiation sensor based on silica-glass fiber-optic technology. In its simplest configuration such device is composed by a short portion (about 10 mm) of scintillating fiber coupled to a photomultiplier by a suitably long passive silica fiber.At the early stage of its market introduction it is the smallest radiation sensor, also with respect to MOSFET and diode technology and it appears to be the ideal choice for in vivo measurements in medical field or remote sensing

Hierarchies and Dominance Behaviors in European Pond Turtle (Emys orbicularis galloitalica) Hatchlings in a Controlled Environment

Few species of reptiles are known to establish stable social structures and among these, chelonians provided scarce and conflicting results. Moreover, studies on turtles are usually performed on adult individuals. In this study, we checked whether and when hatchlings of the European Pond Turtle (Emys orbicularis galloitalica) established stable hierarchical structures in their first year of life, whether hierarchies were stable in time and how steady they were. We also verified whether social ranks were associated to the individuals’ size. We observed dyadic interactions daily within three small groups of turtles reared in a controlled environment for seven months. After two months, the hatchlings started to interact and progressively established stable hierarchical structures. However, the effectiveness of the three types of observed aggressive behaviors in reversing social ranks was low and the resulting hierarchies were flat. We did not find a significant effect of the turtles’ size on their interactions’ outcome and hierarchy structure. Our results provide clear evidence of the development and the characteristics of social behaviors in young reptiles in captivity. This study could be a starting point for investigating social structures in wild populations

Enhanced ultraviolet photoluminescence in Gd3+-doped silica glass

Photoluminescence (PL) of Gd-doped silica in the ultraviolet (UV) is investigated. The strong emission detected at 314 nm is assigned to the 6P7/2 to 8S7/2 transition under excitation of 6DJ, 6IJ, and 6PJ energy levels of the Gd3+. After glass densified by rapid thermal treatment (RTT), significant enhanced luminescence and decreased loss covering the UV band are observed

Enhanced ultraviolet photoluminescence in Gd³⁺-doped silica glass

Photoluminescence (PL) of Gd-doped silica in the ultraviolet (UV) is investigated. The strong emission detected at 314 nm is assigned to the 6P7/2 to 8S7/2 transition under excitation of 6DJ, 6IJ, and 6PJ energy levels of the Gd3+. After glass densified by rapid thermal treatment (RTT), significant enhanced luminescence and decreased loss covering the UV band are observed

Dual Cherenkov and Scintillation Response to High-Energy Electrons of Rare-Earth-Doped Silica Fibers

The investigation of the characteristic luminescent response of Ce-doped silica fibers exposed to electrons in the 20–200-GeV energy range is reported in this work to explore the feasibility of using silica-based fibers for a simultaneous dual-readout approach. The sol-gel method allows the preparation of either doped or undoped fibers with high aspect ratio and high purity, providing good flexibility and spatial resolution for the realization of a dual-readout detector. The dual Cherenkov and scintillation light emitted by silica-based fibers potentially offers applications in high-energy-physics calorimetry as well as in other fields, such as radiation monitoring in medicine, security, and industrial control. The response of the fibers, embedded in a tungsten-copper absorber block to obtain a spaghetti-like geometry in a high-energy-physics environment, is investigated through a test-beam campaign at the CERN Super Proton Synchrotron facility. The discrimination of Cherenkov and scintillation light is demonstrated and discussed, along with a detailed investigation of the scintillation properties of the material: time-resolved spectroscopy, relative light output, and attenuation length are evaluated. The results presented in this study can pave the way for further material engineering and future applications