Multicolor up conversion emission and color tunability in Yb/Tm/Ho triply doped heavy metal oxide glasses

Multicolor and white light emissions have been achieved in Yb³⁺, Tm³⁺ and Ho³⁺ triply doped heavy metal oxide glasses upon laser excitation at 980 nm. The red (660 nm), green (547 nm) and blue (478 nm) up conversion emissions of the rare earth (RE) ions triply doped TeO₂–GeO₂–Bi₂O₃–K₂O glass (TGBK) have been investigated as a function of the RE concentration and excitation power of the 980 nm laser diode. The most appropriate combination of RE in the TGBK glass host (1.6 wt% Yb₂O₃, 0.6 wt% Tm₂O₃ and 0.1 wt% Ho₂O₃) has been determined with the purpose to tune the primary colors (RGB) respective emissions and generate white light emission by varying the pump power. The involved infrared to visible up conversion mechanisms mainly consist in a three-photon blue up conversion of Tm³⁺ ions and a two-photon green and red up conversions of Ho³⁺ ions. The resulting multicolor emissions have been described according to the CIE-1931 standards.     

Scale up the collection area of luminescent solar concentrators towards metre‐length flexible waveguiding photovoltaics

Luminescent solar concentrators (LSCs) are cost‐effective components easily integrated in photovoltaics (PV) that can enhance solar cells' performance and promote the integration of PV architectural elements into buildings, with unprecedented possibilities for energy harvesting in façade design, urban furnishings and wearable fabrics. The devices' performance is dominated by the concentration factor (F), which is higher in cylindrical LSCs compared with planar ones (with equivalent collection area and volume). The feasibility of fabricating long‐length LSCs has been essentially limited up to ten of centimetres with F < 1. We use a drawing optical fibre facility to easily scale up large‐area LSCs (length up to 2.5 m) based on bulk and hollow‐core plastic optical fibres (POFs). The active layers used to coat the bulk fibres or fill the hollow‐core ones are Rhodamine 6G‐ or Eu³⁺‐doped organic–inorganic hybrids. For bulk‐coated LSCs, light propagation occurs essentially at the POFs, whereas for hollow‐core device light is also guided within the hybrid. The lower POFs' attenuation (~0.1 m⁻¹) enables light propagation in the total fibre length (2.5 m) for bulk‐coated LSCs with maximum optical conversion efficiency (η_opt) and F of 0.6% and 6.5, respectively. For hollow‐core LSCs, light propagation is confined to shorter distances (6–9 × 10⁻² m) because of the hybrids' attenuation (1–15 m⁻¹). The hollow‐core optimised device displays η_opt = 72.4% and F = 12.3. The F values are larger than the best ones reported in the literature for large‐area LSCs (F = 4.4), illustrating the potential of this approach for the development of lightweight flexible high‐performance waveguiding PV. Copyright © 2016 John Wiley & Sons, Ltd.     

Spontaneous Assembly in Organic Thin Films Spread on Aqueous Subphase: A Scanning Force Microscope (SFM) Study

Structure, morphology, and mechanical properties of mono- and several-layer structures of amphiphiles or pure n-alkane crystallites generated by spontaneous self-assembly on aqueous subphase have been analyzed by scanning force microscopy (SFM). Pure-component and heterogeneous mixtures of molecules were allowed to spread and self-assemble without compression on an aqueous subphase. The self-assembled films were transferred to an atomically smooth mica substrate by drainage for measurement using SFM. Results were compared with a variety of techniques including cryo-transmission electron microscopy, grazing incidence X-ray diffraction, X-ray reflectivity, and reflectance/absorption infrared spectroscopy. Whereas the collaborative techniques provide spatially-averaged information, we find that the SFM accesses both individual crystallites and amorphous material, thus providing unique information on the morphology, number of layers, and complementary structural features.     

The Wechsler Object Assembly subtest and bodily concerns.

This study tried to evaluate a hypothesis drawn from clinical impressions and from suggestive incidental data of prior research that concerns about body intactness will be reflected in a Wechsler subtest pattern where the Object Assembly (OA) score is lower than those of other subtests. OA scores were found to be significantly lower in children with bodily concerns than in a control group, and there were no other significant differences on other WISC subtests. Rorschachs of adult patients with low and high OA scores were compared and there was a significantly greater percentage of Rorschach responses indicating bodily concern in the group scoring low in OA. These findings are discussed in relation to the assessment of cognitive processes and ego functions in diagnostic testing, the process of clinical inference and prior research on body image. (PsycINFO Database Record (c) 2010 APA, all rights reserved)