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61.
池利生  苏锵 《应用化学》1993,10(6):27-30
本文报道了不同组成的YPxV1-xO4(0≤x≤1):Dy^3+的合成和结构。YPxV1-xO4(0≤x≤1)为四方晶系,晶胞参数随x的增大呈线性减小。基质的Stokes位移随x的增大逐渐变大,而激发光谱峰值则向短波方向移动。在YPxV1-xO4:0.006Dy^3+体系中,x>0.4时出现的基质发射是由PO^3-4引起的。基质及Dy^3+的发光效率和Dy^3+的发光强度的黄蓝比均与x有关。同时探  相似文献   
62.
在77K下测定了Eu(TTA)3·1/2(4,4′-bipyN2O2)配合物的激发光谱、发光光谱和时间分辨光谱。光谱数据表明,在标题配合物中存在化学环境不同的两种Eu3+格位,但它们的局部对称性都属于C2V点群,这可能表明该配合物的激发态电子结构稍有不同  相似文献   
63.
The recent advances in the study of light emission from matter induced by synchrotron radiation: X‐ray excited optical luminescence (XEOL) in the energy domain and time‐resolved X‐ray excited optical luminescence (TRXEOL) are described. The development of these element (absorption edge) selective, synchrotron X‐ray photons in, optical photons out techniques with time gating coincide with advances in third‐generation, insertion device based, synchrotron light sources. Electron bunches circulating in a storage ring emit very bright, widely energy tunable, short light pulses (<100 ps), which are used as the excitation source for investigation of light‐emitting materials. Luminescence from silicon nanostructures (porous silicon, silicon nanowires, and Si–CdSe heterostructures) is used to illustrate the applicability of these techniques and their great potential in future applications.  相似文献   
64.
Spectroscopical properties and photocurrent (or photovoltage) of tetraphenyloporphyrins and metallotetraphenyloporphyrins in nematic liquid crystal have been studied. Photoelectric response has been measured in an electrochemical cell made of the semitransparent semiconducting and golden electrodes with porphyrin dyes embedded in liquid crystal. Fluorescence, time-resolved luminescence in microsecond time scale and photoacoustic spectra have also been measured. The competition between radiative, non-radiative processes and charge transfer is discussed. It has been shown that effectivity of porphyrins for photocurrent generation depends on the presence/absence of central metal in the macrocycle of porphyrin skeleton and the kind of metal. The schematic model of the contributions of the dye molecule and semiconducting electrode in the electron transfer process is shown.  相似文献   
65.
The crystal structures of five new alkali rare earth diphosphates were obtained by Rietveld refinement of powder X-ray diffraction (XRD) profiles, including four alkali lutetium diphosphates ALuP2O7 (A=Na, K, Rb, Cs) and the low temperature phase of KYP2O7. The scintillation properties of Ce3+-doped AREP2O7 (A=Na, K, Rb, Cs; RE=Y, Lu) powder samples were studied under static and pulsed X-ray excitations, and featured outstanding scintillation properties with light yields 1–2 times of that of Bi4(GeO4)3 and relatively short decay time of 20–28 ns. Considering the suitable emission wavelength range, large light yield, short decay time, and non-hygroscopic nature, Ce3+-doped AREP2O7-type alkali rare earth diphosphates are potential candidates for high-counting-rate scintillation applications.  相似文献   
66.
固体表面化学发光分析 Ⅰ.不渗透阻挡技术的应用和研究   总被引:2,自引:0,他引:2  
本文应用不渗透阻挡技术在固体基质上保持恒定的化学发光区域,实现了固体表面化学发光分析,并对固体表面化学发光特性,发光的均匀性和重视性,固体基质的选择和纯化等方面进行了研究,测定了13种无机及生物活性物质固体表面化学发光的线性范围及检测限。由于此法克服了固体基质荧光分析和固体表面室温磷光分析的散射光背景的影响,获得了更高的信噪比和更好的检测限。  相似文献   
67.
To explore their suitability for applications in molecular optoelectronics and as sensory materials, novel dithieno[3,2-b:2',3'-d]phospholes have been synthesized and their reactivity and properties investigated. An efficient two-step synthesis allowed for a modular assembly of differently functionalized compounds. The dithieno[3,2-b:2',3'-d]phosphole system exhibits extraordinary optoelectronic properties with respect to wavelength, intensity, and tunability. Owing to the nucleophilic nature of the central phosphorus atom, its significant electronic influence on the conjugated pi system can be altered selectively by chemically facile modifications such as oxidation or complexation with Lewis acids or transition metals. All the dithienophosphole species presented show very strong blue photoluminescence with excellent quantum yield efficiencies supporting their potential utility as blue-light emitting components in organic light emitting diodes (OLEDs). Furthermore, depending on the electronic nature of the phosphorus center, the materials exhibit distinctive optoelectronic properties suggesting that the dithieno[3,2-b:2',3'-d]phosphole system may be useful as sensory material. Theoretical calculations, including time-dependent DFT methods, revealed the excellent predictability of the structures and optoelectronic properties of the functionalized dithienophospholes allowing the design of future dithieno[3,2-b:2',3'-d]phosphole-based materials to be "stream-lined". By using tin-functionalized dithienophosphole monomers, a strategy, which involves Stille coupling, towards extended pi-conjugated materials with significantly redshifted optoelectronic properties is also presented.  相似文献   
68.
提出了用草酸.邻菲哕啉去除硅灰石中Fe^2 的方法,研究了浸取剂的浓度、浸取时间和温度等条件对Fe^2 的去除率的影响,在最佳的浸取条件下,Fe^2 的去除率达到98.35%。在去除猝灭剂后的硅灰石矿物中,掺加适量的稀土激活剂Eu^3 ,通过高温固相法制成荧光发光材料,发光强度明显提高,接近于化学试剂合成的发光材料。  相似文献   
69.
Molecular switches that are controllable, reversible and readable at molecular level are an essential compo-nent of molecular electronics1 and chemical sensors.2-6 Of particular interest are the molecules which show dramatic and reversible changes in color and/or lumi-nescence in visible spectral region upon exposure to specific substrates. A number of chromophore- spacer-receptor systems that can selectively recognize specific guest molecules at their receptor site and pro-duce measurable col…  相似文献   
70.
The temperature-dependent luminescence of tris (β-diketone) chelates of europium was used for in situ temperature measurements during cationic photopolymerizations of vinyl ethers. These molecular-level luminescent probes provided a real-time, noninvasive method for monitoring temperature during these high-speed polymerizations. Two specific probes, tris (benzoyl-1, 1, 1-trifluoroacetone) europium and tris (1,1,1,5,5,5,-hexafluoroacetylacetone) europium, met several stringent spectral and performance requirements for application in our system. The luminescence from these probes exhibits a reproducible temperature dependence over a wide temperature range and is not sensitive to changes in viscosity. In situ temperature profiles obtained using this novel technique verified the importance of thermal effects during these highly exothermic photopolymerizations. These studies have demonstrated the utility of the tris(β-diketone) europium chelates for characterizing the temperature during high-speed photopolymerizations that cannot be monitored using conventional techniques. © 1995 John Wiley & Sons, Inc.  相似文献   
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