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991.
综合ZnO-Al_2O_3-SiO_2系和锗酸盐玻璃陶瓷的优点,采用熔融-晶化法首次制备了Ho~(3+)/Yb~(3+)共掺以ZnAl_2O_4为主晶相的ZnO-Al_2O_3-GeO_2-SiO_2系玻璃陶瓷。因[GeO_4]四面体和[SiO_4]四面体都是玻璃网络形成体,讨论了GeO_2取代SiO_2对玻璃陶瓷样品硬度及发光性能的影响,最终确定GeO_2的取代量为10.55%(w/w)时,玻璃陶瓷综合性能最佳。在980 nm泵浦光的激发下,发现强的绿色(546 nm)和弱的红色(650 nm)上转换发光,并研究了不同Ho~(3+)/Yb~(3+)掺杂比对样品上转换发光的影响,最终结果表明当Ho~(3+)/Yb~(3+)掺杂比为1∶11(n/n)时样品荧光强度最强,在绿色上转换发光材料方面具有潜在的应用。 相似文献
992.
993.
在温和条件下合成了2种以β-二酮和三苯氧膦为配体的钕三元配合物[Nd(TTA)_3(TPPO)_2](1)(TTA=2-噻吩甲酰三氟丙酮,TPPO=三苯氧膦)和[Nd(BFA)_3(TPPO)_2](2)(BFA=4,4,4-三氟-1-苯基-1,3丁二酮),获得了单晶并通过X射线单晶衍射确定了配合物结构。晶体分析显示,2种配合物均为八配位结构,属于三斜晶系,P1空间群。采用元素分析、红外光谱和热重分析对2种配合物进行了结构表征;通过近红外荧光分析,探讨了配合物的荧光特征。 相似文献
994.
三维光学断层成像(Three Dimensional Optical Tomography Imaging)是以光学探针标记的分子或细胞为成像源,在外部光源的激发下产生发射光,通过测量组织边界处的光强,结合光子在组织中的传播模型,来重建出组织内部发射光分布图像以及组织光学参数。三维光学断层成像能够提供目标物在生物体内的分布信息,克服平面成像的局限性。因此,在肿瘤检测、基因表达、蛋白质分子检测、揭示机体功能变化等方面有着很大的应用潜力。本文总结了光学相干断层成像(Optical Coherence Tomography,OCT)、荧光分子断层成像(Fluorescent Molecular Tomography,FMT)、生物自发光断层成像(Bioluminescence Tomography,BLT)、切伦科夫荧光断层成像(Cerenkov Luminescence Tomography,CLT)等三维光学断层活体成像技术的新进展,分析了其在实际应用中所面临的技术挑战并探讨了相应的解决方案。 相似文献
995.
The ultralong Zn2GeO4:Mn2+ persistent luminescence nanobelts (PLNBs) were synthesized using a direct hydrothermal route. The persistent luminescence performance is fine-turned upon prolonging the hydrothermal time and controlling the doping ratio of Mn2+. This solid-statereaction-free chemical approach will promote the broad use of these unique nanostructured PLNBs in developing imaging device. 相似文献
996.
Ultra‐Narrow‐Band Blue‐Emitting Oxoberyllates AELi2[Be4O6]:Eu2+ (AE=Sr,Ba) Paving the Way to Efficient RGB pc‐LEDs
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Philipp Strobel Christian Maak Volker Weiler Dr. Peter J. Schmidt Prof. Dr. Wolfgang Schnick 《Angewandte Chemie (International ed. in English)》2018,57(28):8739-8743
Highly efficient phosphor‐converted light‐emitting diodes (pc‐LEDs) are popular in lighting and high‐tech electronics applications. The main goals of present LED research are increasing light quality, preserving color point stability and reducing energy consumption. For those purposes excellent phosphors in all spectral regions are required. Here, we report on ultra‐narrow band blue emitting oxoberyllates AELi2[Be4O6]:Eu2+ (AE=Sr,Ba) exhibiting a rigid covalent network isotypic to the nitridoalumosilicate BaLi2[(Al2Si2)N6]:Eu2+. The oxoberyllates’ extremely small Stokes shift and unprecedented ultra‐narrow band blue emission with fwhm ≈25 nm (≈1200 cm?1) at λem=454–456 nm result from its rigid, highly condensed tetrahedra network. AELi2[Be4O6]:Eu2+ allows for using short‐wavelength blue LEDs (λem<440 nm) for efficient excitation of the ultra‐narrow band blue phosphor, for application in violet pumped white RGB phosphor LEDs with improved color point stability, excellent color rendering, and high energy efficiency. 相似文献
997.
Tandem Silver Cluster Isomerism and Mixed Linkers to Modulate the Photoluminescence of Cluster‐Assembled Materials
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Ren‐Wu Huang Xi‐Yan Dong Bing‐Jie Yan Xiang‐Sha Du Dong‐Hui Wei Prof. Shuang‐Quan Zang Prof. Thomas C. W. Mak 《Angewandte Chemie (International ed. in English)》2018,57(28):8560-8566
Silver chalcogenolate cluster assembled materials (SCAMs) are a category of promising light‐emitting materials the luminescence of which can be modulated by variation of their building blocks (cluster nodes and organic linkers). The transformation of a singly emissive [Ag12(SBut)8(CF3COO)4(bpy)4]n (Ag12bpy, bpy=4,4′‐bipyridine) into a dual‐emissive [(Ag12(SBut)6(CF3COO)6(bpy)3)]n (Ag12bpy‐2) via cluster‐node isomerization, the critical importance of which was highlighted in dictating the photoluminescence properties of SCAMs. Moreover, the newly obtained Ag12bpy‐2 served to construct visual thermochromic Ag12bpy‐2/NH2 by a mixed‐linker synthesis, together with dichromatic core–shell Ag12bpy‐2@Ag12bpy‐NH2‐2 via solvent‐assisted linker exchange. This work provides insight into the significance of metal arrangement on physical properties of nanoclusters. 相似文献
998.
Dual Upconverted and Downconverted Circularly Polarized Luminescence in Donor–Acceptor Assemblies
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Dr. Dong Yang Prof. Pengfei Duan Prof. Minghua Liu 《Angewandte Chemie (International ed. in English)》2018,57(30):9357-9361
Through mimicking both the chiral and energy transfer in an artificial self‐assembled system, not only was chiral transfer realized but also a dual upconverted and downconverted energy transfer system was created that emit circularly polarized luminescence. The individual chiral π‐gelator can self‐assemble into a nanofiber exhibiting supramolecular chirality and circularly polarized luminescence (CPL). In the presence of an achiral sensitizer PdII octaethylporphyrin derivative, both chirality transfer from chiral gelator to achiral sensitizer and triplet‐triplet energy transfer from excited sensitizer to chiral gelator could be realized. Upconverted CPL could be observed through a triplet–triplet annihilation photon upconversion (TTA‐UC), while downconverted CPL could be obtained from chirality‐transfer‐induced emission of the achiral sensitizer. The interplay between chiral energy acceptor and achiral sensitizer promoted the communication of chiral and excited energy information. 相似文献
999.
Stimulus‐Triggered Formation of an Anion–Cation Exciplex in Copper(I) Complexes as a Mechanism for Mechanochromic Phosphorescence
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Benjamin Hupp Dr. Jörn Nitsch Tanja Schmitt Dr. Rüdiger Bertermann Dr. Katharina Edkins Florian Hirsch Prof. Dr. Ingo Fischer Michael Auth Dr. Andreas Sperlich Priv.‐Doz. Dr. Andreas Steffen 《Angewandte Chemie (International ed. in English)》2018,57(41):13671-13675
The investigation of the mechanisms of mechanochromic luminescence is of fundamental importance for the development of materials for photonic sensors, data storage, and luminescence switches. The structural origin of this phenomenon in phosphorescent molecular systems is rarely known and thus the formulation of structure–property relationships remains challenging. Changes in the M–M interactions have been proposed as the main mechanism with d10 coinage metal compounds. Herein, we describe a new mechanism—a mechanically induced reversible formation of a cation–anion exciplex based on Cu–F interactions—that leads to highly efficient mechanochromic phosphorescence and unusual large emission shifts from UV‐blue to yellow for CuI complexes. The low‐energy luminescence is thermo‐ and vaporesponsive, thus allowing the generation of white light as well as for recovering the original UV‐blue emission. 相似文献
1000.
Lanthanide(III) (Eu,Gd, Tb,Dy) Complexes Derived from 4‐(Pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole: Crystal Structure,Magnetic Properties,and Photoluminescence
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Dr. Evgeniya S. Bazhina Anna A. Bovkunova Dr. Alexey V. Medved'ko Evgeniya A. Varaksina Dr. Ilya V. Taidakov Dr. Nikolay N. Efimov Prof. Dr. Mikhail A. Kiskin Prof. Dr. Igor L. Eremenko 《化学:亚洲杂志》2018,13(16):2060-2068
The reaction of lanthanide(III) nitrates with 4‐(pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole (L) was studied. The compounds [Ln(NO3)3(H2O)3] ? 2 L, in which Ln=Eu ( 1 ), Gd ( 2 ), Tb ( 3 ), or Dy ( 4 ), obtained in a mixture of MeCN/EtOH have the same structure, as shown by XRD. In the crystals of these compounds, the mononuclear complex units [Ln(NO3)3(H2O)3] are linked to L molecules through intermolecular hydrogen‐bonding interactions to form a 2D polymeric supramolecular architecture. An investigation into the optical characteristics of the Eu3+‐, Tb3+‐, and Dy3+‐containing compounds ( 1 , 3 , and 4 ) showed that these complexes displayed metal‐centered luminescence. According to magnetic measurements, compound 4 exhibits single‐ion magnet behavior, with ΔEeff/kB=86 K in a field of 1500 Oe. 相似文献