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Up-conversion luminescence of RE3+ -doped polymer composites KGd(WO4)2&PMMA
摘要： Poly(methyl methacrylate) (PMMA)-based luminescent materials are of prime interest for many new optoelectronic devices. This work presents the spectroscopic properties of PMMA-based composites containing KGd(WO4)2:Yb3+/Er3+/Tm3+, KGd(WO4)2:Yb3+/Tm3+ and KGd(WO4)2:Yb3+/Er3+ powders. These systems exhibit effective multicolor up-conversion luminescence in VIS and NIR spectral range under 980 nm excitation. The vibrational properties of the composites were investigated for the first time using the μ-Raman spectroscopy. The obtained results suggest that the KGd(WO4)2:Yb3+/Er3+/Tm3+&PMMA integrated system can be successfully used as a new phosphor for the up-conversion based optoelectronic devices.
关键词： Micro-crystals,Rare earth ions,PMMA,KGd(WO4)2,Composites,Up-conversion
更新于2025-09-04 15:30:14
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Rare earth phosphors based on spherical infinite coordination polymers
摘要： A novel luminescent infinite coordination polymer (Tb-M), constructed by the interaction between Tb3+ ions and 3,5-pyrazoledicarboxylate and malonate linkers, was prepared by water microwave-assisted synthesis. The material self-assembles into amorphous microspherical particles. Under UV excitation, a very intense green luminescence is observed by the naked eye at room temperature for Tb-M. A Gd3+ analogue compound (Gd-M) was also synthesized. Successful attempts at codoping Tb-M and Gd-M samples with Eu3+ and Dy3+ ions were carried out and different emission colors were obtained, including white-light emission.
关键词： infinite coordination polymers,rare earth phosphors,microwave-assisted synthesis,luminescence,white-light emission
更新于2025-09-04 15:30:14
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Effect of Tm3+ Sensitization to Ho3+ Doped GeO2-B2O3-BaF2-Al2O3-ZnO2-Na2O Glass on Spectral Properties
摘要： A series of Tm3+/Ho3+ sensitized 65GeO2-7BaF2-10B2O3-4Al2O3-4ZnO2-10Na2O glass samples were synthesized by using high temperature melting method. The spectral properties were systematically studied when Ho3+ concentration was 0.1, 0.3, 0.5 mol % and Tm2O3 changed from 0.3 to 2.5 mol %. Differential thermal analysis showed that ?T was higher than 190 oC, which illustrated this kind of matrix glass have better thermal stability. The absorption cross section peak height, free energy of Ho3+ from 5I8 to 5I7 and emission cross section were calculated according to Mc-Cumber theory. Under the excitation of 808 nm laser diode, fluorescence intensity at 1954 nm reached the highest value when the concentration of Ho3+ was 0.1 mol % and Tm3+ was 0.7 mol %. However the fluorescence intensity reduced greatly when Ho3+ concentration was 0.5 mol % and Tm3+ exceeded 1.5 mol %. The sensitized function and influence of different Tm3+/Ho3+ doped ion ratios on the spectral properties was studied.
关键词： Glasses,Growth from high temperature solutions,Rare earth compounds,Adsorption
更新于2025-09-04 15:30:14
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Y2(CO3)3?H2O and (NH4)2Ca2Y4(CO3)9?H2O: Partial Aliovalent Cation Substitution Enabling Evolution from Centrosymmetry to Noncentrosymmetry for Nonlinear Optical Response
摘要： An effective approach, the partial aliovalent cation substitution (PACS), was successfully employed to develop nonlinear optical (NLO) material. Two novel rare earth carbonates, Y2(CO3)3·H2O (YC) and (NH4)2Ca2Y4(CO3)9·H2O (CYC), were synthesized, which feature the same honeycomb-like framework structure. From YC to CYC, the partial substitution of Y3+ with Ca2+ led to the evolution of space group from centrosymmetric P63/mcm to noncentrosymmetric P63mc. The CYC exhibited a second harmonic generation (SHG) effect of 2.1 × KH2PO4 (KDP) and a deep-UV cut-off edge (<200 nm). It was concluded that the SHG effect originates from the ordered arrangement of (CO3)2- groups and the dipole polarization enhancement of [Ca0.33Y0.67O9] polyhedra. Specifically, the long-range ordered electric field of channels induced the ordered arrangement of (CO3)2- groups. This synthetic approach and SHG-activated induction mechanism may afford new strategies for the design and synthesis of NLO materials.
关键词： nonlinear optical materials,partial aliovalent cation substitution,rare earth carbonates,deep-UV cut-off edge,second harmonic generation
更新于2025-09-04 15:30:14
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Luminescent Nd <sub/>2</sub> S <sub/>3</sub> thin films: a new chemical vapour deposition route towards rare-earth sulphides
摘要： Neodymium sulphide (Nd2S3) belongs to the exciting class of rare earth sulphides (RES) and is projected to have a serious potential in a wide spectrum of application either in pure form or as dopant. We demonstrate a facile and first growth of Nd2S3 thin films via metal–organic chemical vapour deposition (MOCVD) at moderate process conditions using two new Nd precursors, namely tris(N,N’-diisopropyl-2-dimethylamido-guanidinato)Nd(III) and tris(N,N’-diisopropyl-acetamidinato)Nd(III). The promising thermal properties and suitable reactivity of both Nd precursors towards elemental sulphur enabled the formation of high purity γ-Nd2S3. While the process temperature for film growth ranged from 400 °C to 600 °C, the films were crystalline above 500 °C. We also demonstrate that the as-deposited γ-Nd2S3 are luminescent, with the optical bandgap ranging from 2.3 eV to 2.5 eV. The process circumvents post-deposition treatments such as sulfurisation to fabricate the desired Nd2S3, which paves the way for large scale synthesis and also opens up new avenues for exploring the potential of this class of materials with properties for functional applications.
关键词： MOCVD,Nd2S3,thin films,rare earth sulphides,luminescent
更新于2025-09-04 15:30:14