共查询到20条相似文献,搜索用时 281 毫秒
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目的 从增强稀土离子发光的角度考察上转换发光调控及性能,综述稀土发光材料在光学防伪领域的应用,以期为上转换材料与包装材料的功能化研究提供参考。方法 检索近几年文献,介绍上转换发光纳米材料的发光机理、发光性能及调控、光学材料打印技术的研究进展。结果 稀土掺杂的上转换发光纳米材料表现出优异的发光性能,但随着粒径减小,纳米颗粒出现发光效率、量子产量低的问题。利用纳米颗粒表面钝化、表面等离子体耦合、与有机配体结合和外场调节等手段,可以使发光材料的发光效能显著增强。利用喷墨打印、丝网印刷、纳米压印光刻和气溶胶喷印等技术,可以使稀土掺杂的上转换发光纳米材料被打印成多样的防伪图案,在光学防伪、信息存储与标记等领域具有重大应用潜力,有望成为新型功能包装材料。结论 在光学材料合成技术、光学调控和打印技术的共同推动下,稀土掺杂上转换发光纳米材料因其特殊的光学特性,有望为功能化包装防伪技术作出贡献。 相似文献
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R. Mogilevsky S. Nedilko L. Sharafutdinova S. Burlay V. Sherbatskii V. Boyko S. Mittl 《Optical Materials》2009,31(12):1880
A relation between photoluminescence (PL) characteristics of different starting materials used for crystal growth and un-doped sapphire single crystals manufactured using various methods of crystal growth (Kyropolus, HEM, Czochralski, and EFG) was found. The crystals grown using the Verneuil starting material exhibited significant PL when any method of crystal growth was used. On the contrary, sapphire samples grown by the same technologies wherein the starting material was EMT HPDAR revealed very low PL. (HPDAR is produced by EMT, Inc., with proprietary and patented technology.) 相似文献
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《Optical Materials》2010,32(12):1880-1882
A relation between photoluminescence (PL) characteristics of different starting materials used for crystal growth and un-doped sapphire single crystals manufactured using various methods of crystal growth (Kyropolus, HEM, Czochralski, and EFG) was found. The crystals grown using the Verneuil starting material exhibited significant PL when any method of crystal growth was used. On the contrary, sapphire samples grown by the same technologies wherein the starting material was EMT HPDAR revealed very low PL. (HPDAR is produced by EMT, Inc., with proprietary and patented technology.) 相似文献
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《Optical Materials》2005,27(3):597-603
The up-conversion luminescence and near infrared luminescence of the Er3+ in transparent oxyfluoride glass-ceramics have been investigated. The formation of PbF2 nano-crystals in the glass was confirmed by XRD. From optical absorption spectra, the oscillator strengths for several transitions of the Er3+ in the glass and glass-ceramic have been obtained and then the Judd–Ofelt parameters were calculated by a least squares fitting. The split near infrared emission peaks of the Er3+ ions in the glass-ceramics can be observed because the Er3+ ions have entered into crystalline environment of the β-PbF2 nano-crystals. The up-conversion luminescence intensity of the Er3+ in the glass-ceramics can be observed to be much stronger than that in the glasses. The dependence of the up-conversion luminescence intensity on the current of the LD laser used as excited source indicated that the transition mechanism of the up-conversion luminescence can be ascribed to two-photon absorption process. 相似文献
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A thermal luminescence (TL) spectroscopy method for detecting organic impurities in water solution is presented. Infrared emissions by the dissolved organic matter are measurable, once a thermal gradient between it and the water medium is established, at those TL frequencies that are absorbed by the contaminant, following irradiation by a pulsed microwave beam. This detection window of opportunity closes as the liquid reaches thermal equilibrium at elevated temperatures and on collapse of the gradient. TL radiance liberated by a suspected contaminated water sample is scanned interferometrically about the maximum thermal gradient event, where N interferograms are acquired and grouped into contiguous sets of two, with N/2 interferogram elements per set. The coadded averages of these sets enhance the sensitivity of measurement to a small variance in emissivity and are Fourier transformed, and the adjacent spectra are subtracted. The difference spectrum is preprocessed with linear baseline, noise filtration, scaling, and parity operators to reveal a clear emissions band signature of the solute of dimethylmethylphosphonate to concentrations of parts per 10(3) and less. An artificial neural network facilitates detection of the contaminant by pattern recognition of the contaminant's infrared band signature. 相似文献
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L. Grigorjeva D. Millers K. Smits V. Pankratov W. ojkowski J. Fidelus T. Chudoba K. Bienkowski C. Monty 《Optical Materials》2009,31(12):1825
Fast photoluminescence spectra in the spectral region of 3.1–3.45 eV in ZnO and ZnO:Al ceramics were studied at 14 and 300 K. Ceramics with grains smaller than 100 nm were sintered from nanopowders by high pressure (8 GPa) and low temperature (350 °C). Ceramics with grain sizes 1–5 μm were sintered at 1400 °C. It is shown that excitonic luminescence spectra depend on the ceramics grain size, post preparing annealing and doping. The excitonic luminescence decay time was faster than 2 ns and the afterglow at 30 ns was 0.05%. 相似文献