Broadband Cr3+, Sn4+‐Doped Oxide Nanophosphors for Infrared Mini Light‐Emitting Diodes

Light‐emitting diodes break barriers of size and performance for displays. With devices becoming smaller, the materials also need to get smaller. Chromium(III)‐doped oxide phosphors, which emit near‐infrared (NIR) light, have recently been used in small electronic devices. In this work, mesoporous silica nanoparticles were used as nanocarriers. The nanophosphor ZnGa₂O₄:Cr³⁺,Sn⁴⁺ formed in the mesopore after sintering. Good dispersity and morphology were performed with average diameters of 71±7 nm. It emitted light at 600–850 nm; the intensity was optimized by tuning the doping ratio of Cr³⁺ and Sn⁴⁺. Meanwhile, the light conversion efficiency increased from 7.8 % to 37 % and the molar concentration increased from 0.125 m to 0.5 m . The higher radiant flux of 3.3 mW was obtained by operating an input current of 45 mA. However, the NIR nanophosphor showed good performance on mini light‐emitting diode chips.     

Ein grünes,paramagnetisches Goldfluorid – Sn1−xAuxF4?

A Green Paramagnetic Gold Fluoride – Sn_1?xAu_xF₄? Green single crystals were obtained by heating (Au-tube, 450° – 500°C) a mixture of SnF₂ and AuF₃ (Sn : Au = 1 : 1) which correspond to the SnF₄-type [2, 3] (two single crystals, A: 762 I_o, R1 = 2.4%; B: 1591 I_o, R1 = 1.2% (SHELXL-93); I4/mmm (No. 139); B: a = 404.8(1) pm, c = 796.4(1) pm, c/a = 1.97, Z_F2 = 0.2354). Due to atom absorption and Mössbauer measurements the crystals contain Au. The compound is paramagnetic and follows the Curie-Weiß law (14.7–251.3 K, θ = ?12 K, μ/μ_B = 1.55). ESR-experiments confirm that Au is surrounded by 6 F^? according to Sn in SnF₄ (2 short (187.5 pm) and 4 longer (202.4 pm) distances). The observed Mössbauer spectra could not be interpreted yet, but they don't correspond to any known.     

Fe4Si2Sn7O16: Eine Kombination von FeSn6-Oktaedern mit Schichten von (Fe3Sn)O6-Oktaedern; Präparation,Eigenschaften und Kristallstruktur [1]

Fe₄Si₂Sn₇O₁₆: A Combination of FeSn₆-Octahedra with Layers of (Fe₃Sn)O₆-Octahedra; Preparation, Properties, and Crystal Structure Fe₄Si₂Sn₇O₁₆ has been prepared by a solid state reaction at 900 °C from a mixture of Fe₂O₃, SnO₂, Sn, and Si. The compound is a paramagnetic semiconductor. Results of Mössbauer and suszeptibility measurements as well as bond length-bond strength calculations lead to the possible ionic formulation Fe₄²⁺Si₂⁴⁺Sn₁²⁺Sn₁⁴⁺O₁₆^2–. The compound crystallizes in the trigonal space group P3m1 (no. 164), with one formula unit per cell. Lattice parameters obtained by powder measurements are: a = 6.8243(6) Å, c = 9.1404(6) Å, γ = 120°, V = 368.6(1) ų. The structure consists of layers of edge linked oxygen octehedra exactly centered by Sn and Fe in the ratio 1 : 3. Three plains of isolated SiO₄ tetrahedra, FeSn₆ octahedra and again SiO₄ terahedra are inserted between two such layers. The layers are stacked along [001] and linked three-dimensionally by oxygen.     

Zur Benennung von Verbindungen im Si‐Al‐O‐N‐System

Die Übersetzung basiert auf der „Terminology for Compounds in the Si‐Al‐O‐N System“ der Commission on High Temperature Materials and Solid State Chemistry der Inorganic Chemistry Division der International Union of Pure and Applied Chemistry, veröffentlicht in Pure Appl. Chem. 1999 , 71, 1765–1769. Das Original wurde von R. Metselaar, Technische Universiteit Eindhoven (Niederlande) und D. S. Yan, Academia Sinica, Shanghai (China) für die Veröffentlichung vorbereitet.