Synthesis and Luminescence of MeSiO_3:Eu,Bi Luminophors(Me=Mg,Ca,Sr,Ba)

The luminophors of four kinds of alkaline earth meta-silicates doped with Eu^3 and/or Bi^(3+)ion(s)were synthesized and the luminescence properties of Bi^(3+)and Eu^(3+)ions were studied.The regularities that Me(Ⅱ) ions affect the luminescence of Eu^(3+)ion sensitized by Bi^(3+)ion were investigated.The optimum composition and synthesis condition were obtained.The absorption and emission peak are situated at 283 and 353nm with the optimum concentration 0.02 mol of Bi^(3+)in CaSiO_3:Bi.In CaSiO_3:Bi,the optimum concentration of Bi^(3+)is 0.007 mol and that of Eu^(3+)is 0.040 mol.For all of the alkaline earth ions concerned in MeSiO_3:Eu,Bi,the Bi^(3+)can sensitize the Eu^(3+)and the Me(Ⅱ)ions in host and make a great difference in the adsorption hand of Bi^(3+)ion.by exciting Bi^(3+)ion,the emissions are from both Eu^(3+)and Bi^(3+)ions and the best sensitization effect is achieved when Me(Ⅱ)is Sr.

Chiroluminophores based on non-conjugated benzenes

Point-chiral groups as pendants conjugated to the aromatic luminophore generate weak chiroptical signals without self-assembly,showing the dependence on the flexibility of tethers,which hinders the development of point-chiral molecular materials with chiroptical properties such as the circularly polarized luminescence(CPL).Herein we introduce the molecular chiroptical materials based on the point chirality on a single benzene luminophore scaffold.Substitutes were stepwise conjugated to single benzene luminophores to boost the steric hindrance and tension,whereby the chirality transfer efficiency from point-chiral substituents to luminophores was enhanced.Multiple intramolecular CH-πinteractions anchor the whole asymmetric geometry with ultra-high rotation energy barriers and excellent thermostability.Dissymmetry g-factors of circular dichroism and CPL spectra up to 10^(-3)order of magnitude were realized in solutions,which are comparable to the inherent-chiral luminophores such as helicene and binaphthyl derivatives.The acridine-appended single benzene system shows the emergence of thermally activated delayed fluorescence(TADF),which extends the potentials of the single benzene chiral system in the TADF-based chiroptical devices.

Clustering-triggered phosphorescence of nonconventional luminophores

Nonconventional luminophores have attracted significant attention for their unique photophysical properties and potential applications in different areas.Unlike classic luminogens consisting of remarkably conjugated segments,nonconventional luminophores generally possess merely nonconjugated or short-conjugated structures based on electron-rich units.Fluorescence,phosphorescence,and even color tunable room temperature phosphorescence(RTP)could be readily obtained from these unique luminophores.Herein,we summarized recent advances in the phosphorescence of nonconventional luminophores,with focus on RTP and color tunable RTP.The clustering-triggered emission(CTE)mechanism could be applied to explain the luminescence as clustering-triggered phosphorescence(CTP).Furthermore,strategies toward the RTP regulation are summarized,and corresponding applications are demonstrated.

Construction of chiral through-space luminophores via symmetry breaking triggered by sequenced chlorination

The construction of molecular chirality is crucial for exploring novel luminophores with chiroptical properties.Classic asymmetric synthesis of chiral center or axial is not powerful enough on through-space architecture.Accessible methodologies for breaking molecular symmetry could be promising but remain less investigated.Herein,we report a novel methodology for constructing chiral through-space luminophores via simple chlorination on bridged carbazole motifs.The chlorination breaks the molecular symmetry and thus results in molecular chirality by eliminating the mirror plane or rotating axis.Interestingly,continuous multiple chlorinations can rebuild and break the symmetry of the skeleton in succession.Several chiral and achiral isomeric analogues are synthesized and characterized with impressive chiroptical properties.Results of chiral high performance liquid chromatography(HPLC),single-crystal X-ray diffraction,kinetic racemization,and chiroptical property investigation demonstrate the effectiveness of our rational design strategy.It provides a feasible methodology for exploring novel chiral luminescent materials based on versatile though-space skeletons.

电致化学发光传感技术的种类及在食品分析中的研究进展

电致化学发光传感技术(Electrochemiluminescence,ECL)是一种结合了电化学和光化学的分析方法,因其可控性强、灵敏度高和响应速度快等优势在食品分析领域引起了广泛关注。ECL是通过改变发射物或共反应物的浓度,使其信号强度发生变化,从而实现对目标物质的灵敏检测。首先,该文总结了经典ECL检测体系及基于新型发射物和共反应物的检测体系,并重点介绍了新型发射物中金属纳米团簇和量子点的最新进展,举例阐述其ECL传感器的结构和检测原理。其次,综述了ECL传感器在食品分析领域中的研究进展。最后对ECL传感技术的未来发展趋势进行了展望,为食品中营养成分和污染物的检测提供参考,同时也促进该技术的进一步研究,助力未来食品检测发展。

An Integration Strategy to Develop Dual-State Luminophores with Tunable Spectra,Large Stokes Shift,and Activatable Fluorescence for High-Contrast Imaging

Developing dual-state luminophores(DSLs)with strong fluorescence in both the monomer and aggregate states is urgently needed but remains a huge challenge because most current luminophores are either aggregation-induced emission or aggregation-caused quenching molecules.Moreover,limited by the structural conservation of the few existing DSLs,there are not enough response sites that can be used to customize various activatable fluorescent probes for specific molecular imaging.Herein,we engineered a general integration strategy for the fabrication of such DSLs with excellent photophysical properties.The DSLs,with their tunable spectra,a large Stokes shift(>170 nm),and achievable near-infrared(NIR)emission,show great potential for high-contrast imaging.Importantly,DSLs can be used as a universal platform for probe customization due to their activatable fluorescence through protection-deprotection of the phenolic hydroxyl group.Based on this,an NIR fluorescent probe DSL-Gal was developed for sensing of β-galactosidase in solutions,senescent cells,and liver metastases with high contrast,further confirming the superiority and universal feasibility of DSLs in probe design.The integration strategy may provide a novel approach for the generation of other DSLs and have great potential applications in bioimaging.

LOW-TEMPERATURE SYNTHESIS AND STUDY OF LUMINOPHOR Al_2O_3-SiO_2:Eu^(3+), Bi^(3+) USING METAL ALKOXIDE

Ⅰ. INTRODUCTION A kind of chemical wet process developed at the beginning of the seventies is the sol-gel method. Because of its lower synthesis temperature in inorganic materials, it is also called lowtemperature synthesis method. The sol-gel method has many obvious advantages compared with the high-temperature solid state reaction. On the one hand, the lower

Pairs of Ln(Ⅲ)dopant ions in crystalline solid luminophores:an ab initio computational study

Formation of dopant ions clusters in solid （glass） luminophores may affect efficiency of non-radiative energy transfer proc- esses between dopant （photoactivator） ions via shortening of the effective distance between them. This study was based on the as- sumption that the distance between the dopant ions affects the energy of crystal volume at proximity. According to this idea, semi-empirical and ab initio density functional theory （DFT） calculations were performed on various supercells of YVO4：Eu3＋ as a model system. It was noted that a shorter Eu-Eu distance resulted in lower total energy of the system, compared to an analogous structure with distant Eu3＋ ions. As lower energy configurations are preferred, the observed phenomenon was considered to be related to dopant ions clusters formation. Additionally, the values of energies obtained from DFT calculations were used to estimate the per- centage of dopant ions occurring as pairs, for different dopant concentrations. The estimation agreed quite well with the available lit- erature data.

溶胶-凝胶法合成发光玻璃陶瓷材料的研究

采用溶胶-凝胶法低温合成了CaO-SiO_2:Eu^(3+),Bi^(3+)发光玻璃陶瓷材料。研究了复杂体系中溶胶-凝胶转变过程,得到了pH值、含水量对胶凝时间、孔隙率、表观密度、比表面积的影响。利用小角X射线散射探讨了溶胶-凝胶转变过程中酸、碱催化的不同机理。通过X射线粉末衍射、红外光谱、热重及差热分析研究了由凝胶至发光晶体的转变过程。通过激发光谱和发光光谱的测试,讨论了材料的发光特性及Bi^(2+)对Eu^(3+)的敏化作用。

新型转光剂的制备及在农膜中的应用

通过溶胶 -凝胶法将有机荧光体包覆在无机凝胶中 ,制得了一种新的有机 -无机杂化材料。该杂化材料能有效吸收 2 5 4-36 5nm范围的紫外光 ,在约 45 0nm处产生强的蓝色荧光 ,并具有很好的光热稳定性 ;与聚乙烯薄膜具有良好的结合力 ,且不影响薄膜的加工工艺与物理性能 ;在薄膜加工中原有组分的光学性能基本保持不变。

一种发红光的电子陷获型红外上转换材料的制备

本文研制的电子陷获（ＥＴ）型红外上转换材料是在改进传统工艺的基础上，使用硫化助熔法，在石英反应管中，基质合成和掺杂一次完成，具有工艺简单、生长周期短、重复性好的优点。由于反应在密闭系统中完成，安全可靠，对实验室环境保护好，用这种方法制备出的红外上转换材料，在室温下用紫外光或可见光激励后，用红外激发时发红光，并测得了其激发光谱（红外）和发射光谱（红光）。

免疫荧光分析的研究进展

综述了近年来免疫荧光分析的研究进展,介绍了常用的免疫荧光体和它们的优缺点;对于荧光体与生物分子的结合方法,介绍了较常用的基团与生物分子的结合的方法;介绍了免疫荧光复合物常用的分离纯化方法及适用的体系、优缺点等;对免疫荧光标记复合物的重要表征手段和特点进行了介绍。

室温磷光免疫分析研究的进展

对磷光免疫分析研究现状和发展趋势 ,作简要的概述 ,并对开展固体基体室温磷光免疫分析的可能性和优势 ,及其采用多发光分子微球作标记物的几种技术作了介绍 ,引用文献 36篇。

SrO-Al_2O_3-SiO_2:Eu^(3+),Bi^(3+)发光体的溶胶-凝胶法合成

制备无机固体材料大都采用高温固相反应,1971年Dislich报导了用溶胶-凝胶法制备多组份固体材料。近年来,有报导利用此法研制玻璃、玻璃陶瓷和陶瓷。我们在过去工作的基础上,合成了SrO-Al2O3-SiO2:Eu3+,Bi3+发光体,研究了从凝胶至发光晶体的转变过程、Eu3+和Bi3+在SrO-Al2O3-SiO2基质中的发光性质以及Bi3+对 EU3+的能量传递。

溶胶－凝胶法合成（Mg，Ca）O－SiO_2∶Eu^（3＋），Bi^（3＋）发

以Ｍｇ（ＮＯ３）２、Ｃａ（ＮＯ３）２、Ｅｕ（ＮＯ３）３、Ｂｉ（ＮＯ３）３、ＬｉＮＯ３和Ｓｉ（ＯＣ２Ｈ５）４为反应物，采用溶胶－凝胶法，在比较低的温度下，首次合成０．７０１ｍｏＩＭｇＯ－０．１７５ｍｏｌＣａＯ－１．２５ｍｏＩＳｉＯ２∶０．０６ｍｏｌＥｕ（３＋），０．００２ｍｏＩＢｉ（３＋）（加入Ｌｉ＋作为电荷补偿剂）发光体。得到了最佳合成条件。研究了由溶胶向凝胶转变和凝胶向发光晶体的转变过程。探讨了发光体在不同激发波长激发下的发光特性以及在激活剂、敏化剂不同掺杂量下的发光行为。讨论了在（Ｍｇ（ａ）Ｏ－ＳｉＯ２基质中Ｂｉ（３＋）对Ｅｕ（３＋）的能量传递和敏化作用。

Mg(Y,Gd)_4Si_3O_(13)∶Eu,Bi 的溶胶-凝胶法合成、结构和发光性能

采用溶胶-凝胶法首次合成出 MgY_(4-x-y-z)Si_3O_(13)∶Eu_z^(3+),Bi_y^(3+),Gd_x^(3+)系列发光体.其结构与ASTM 卡片记载的 MgY_4Si_3O_(13)的结构相同,属于六方晶系.在每 mol 基质中,Eu^(3+)、Bi^(3+)和 Gd^(3+)的最佳掺杂量分别为0.07,0.025和0.2mol.在发光体由非晶态向晶态的转变过程中,Eu^(3+)的发光强度和所处位置对称性都发生了显著变化.当基质以 Eu^(3+)、Bi^(3+)共掺杂时,Bi^(3+)的兰色发光和 Eu^(3+)的橙红色发光都很强,但 Bi^(3+)向 Eu^(3+)的能量传递效率很低,适量的 Gd^(3+)的加入可增强 Bi^(3+)对Eu^(3+)发光的敏化效果.

La_2Sn_2O_7:Ce、Tb的合成及发光性能研究

用柠檬酸络合法合成了La_2Sn_2O_7:Ce^(3+)、Tb^(3+)发光体,并利用X-射线粉未衍射进行结构分析,确定了发光体柏晶体结构通过激发光谱和发射光谱的分析,研究了试样的发光特性以及在激活剂、敏化剂掺杂下的发光行为,并对La_2Sn_2O_7基质中Ce^(3+)对Tb^(3+)的能量传递和敏化作用进行了探讨.

基于SiO_2荧光纳米粒子快速检测果汁中大肠杆菌的免疫传感器研究

目的设计一种基于SiO_2荧光纳米粒子快速检测果汁中大肠杆菌O157:H7的新型传感器。方法采用超分子组合法将荧光基团嵌入到SiO_2纳米颗粒中合成SiO_2荧光纳米粒子,然后将抗大肠杆菌O157:H7的单抗偶联到纳米粒子表面,最后通过抗原-抗体反应使纳米粒子与待检细菌结合,使用荧光显微镜观察并统计大肠杆菌O157:H7的个数。结果本方法与革兰氏染色法相比,对大肠杆菌O157:H7计数结果无统计学差异(P=0.930);该方法整个检测过程能够在15 min内完成,检测下限小于10 CFU/mL。结论该方法能增强检测果汁中大肠杆菌O157:H7的灵敏度,缩短检测时间,对其他病原体检测方法的改进具有重要的指导意义。

LiGdSiO_4:Eu^(3+),Bi^(3+)的低温合成及其发光行为的研究

在实验室中.采用溶胶一凝胶法,在比较低的温度下。合成出Li Gd_(0.958)SiO_4:0.035Eu^(3+),0.007Bi^(3+)发光体。利用红外光谱、X射线粉末衍射谱、热重及差热分析、激发光谱和发光光谱,研究了由凝胶至发光晶体的转变过程,讨论了Eu^(3+)、Bi^(3+)在稀土硅酸盐中的发光行为。

发光体Mg_2Y_（8－x－y）（SiO_4）_6O_2：Eu_x^（3＋），B

采用Ｓｏｌ－Ｇｅｌ方法首次在比较低的温度下制备了具有氧磷灰石结构的发光体Ｍｇ２Ｙ８－ｘ－ｙ（ＳｉＯ４）６Ｏ２：Ｅｕ，Ｂｉ（ｘ，ｙ≥０），利用ＸＲＤ、ＩＲ、ＴＧ－ＤＴＡ三种手段研究了发光体的形成过程。室温（２９３Ｋ）和液氮温度（７７Ｋ）的荧光光谱表明Ｅｕ３＋和Ｂｉ３＋在这种基质中分别发射红光和蓝光，每ｍｏｌ基质中其最佳掺杂浓度分别为０．１４ｍｏｌ和０．０３ｍｏｌ，并且其发光都存在温度猝灭。Ｅｕ３＋的激光感生荧光光谱中存在两条５Ｄ０－７Ｆ０跃迁线，表明Ｅｕ３＋同时进入４ｆ格位和６ｈ格位。在Ｅｕ３＋、Ｂｉ３＋共掺杂的发光体中，观察到了Ｂｉ３＋→Ｅ３＋的部分能量传递。