水溶性苝系衍生物荧光探针识别金属离子的光物理机制计算研究

随着人们对荧光化合物电子光谱和光物理行为的深入研究,在利用荧光分子作为探针,检测各种不同体系的状态及其变化等方面都有了巨大的进展。其中,N,N′-二天冬氨酸铵盐-3,4,9,10-四羧酸二酰亚胺(PTCDA)是一种水体环境中选择性好灵敏度高的典型荧光分子探针。本文用密度泛函理论对PTCDA的光物理机制进行研究。计算了PTCDA分子在理想状态下的最优构型,电荷布居和激发光谱。根据计算结果,拟合此苝系衍生物激发态与Cu2+结合前后的吸收光谱,与Cu2+结合前后,吸收光谱峰形相似,加铜后整体吸收峰位发生了红移,有猝灭变色现象。通过与实验值的对比,计算所得分子构型合理有效,激发光谱谱峰位置切合实际。分析得出：PTCDA分子对二价铜离子有较好荧光探测活性,其光信号响应机制属于分子内电荷转移(ICT)机制。当分子接收二价铜离子时,吸收光谱谱峰位置红移,分子内电荷转移方向和强度均发生变化,既有猝灭信号,也有光的颜色变化信号,是一种具有猝灭与变色双信号的荧光探针材料,具有很大的开发潜力。所做工作只是用量子化学计算方法在分子荧光探针领域进行光物理响应机制分析的初步探索,可以为该领域提供系统而有价值的理论参考。     

Fluorescence quenching studies of conjugated polymer poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene in the presence of TNT

We report fluorescence quenching of the conjugated polymer poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene (MDMO-PPV) in the presence of nitrated explosives, such as, 2,4,6-trinitrotoluene (TNT). It is found that the conjugated polymer changes color from orange to brownish black when sprayed on traces of TNT within a few seconds. Fluorescence quenching of the conjugated polymer in the presence of TNT is also studied by absorption and emission spectroscopy. The conjugated polymer is highly selective for sensing TNT in daylight and ambient conditions.     

新型蓝绿色磷光配合物二(1-苯基吡唑)铱(吡啶三唑)的发光性能

利用1-苯基吡唑、吡啶三唑与水合三氯化铱反应合成了一种新型铱配合物Ir(2N)₂(PZ),研究了配合物的吸收光谱、光致发光光谱以及光致发光效率。利用该材料作为磷光客体,掺杂到高分子主体材料中制作了电致发光器件,研究了其电致发光光谱。结果表明,该配合物在228,250,328nm处存在自旋允许的¹π-π^*跃迁;荧光光谱结果显示在470nm处有较强的磷光发射;电致发光光谱与光致发光光谱相比却发生较大程度的红移。     

Spectroscopic Study on the Photophysical Properties of Lanthanide Complexes with Long Chain Mono-Docosyl Phthalate

Ortho phthalic anhydride was modified with long chain alcohol (1-docosanol) to its corresponding monodocosyl phthalate (22-Phth). Subsequently, three novel lanthanide (Eu³⁺, Tb³⁺, and Dy³⁺) complexes with the long chain monodocosyl phthalate were synthesized and characterized by elemental analysis and Infrared spectra. The photophysical properties of these complexes were studied in detail with ultraviolet-visible absorption spectra, low temperature phosphorescence spectra and fluorescent spectra. The triplet state energy of 22-Phth was determined to be around 25,000 cm⁻¹ from the maximum phosphorescent peak at 400 nm, suggesting 22-Phth is suitable for the sensitization of the luminescence of Eu³⁺, Tb³⁺, and Dy³⁺. The fluorescence excitation and emission spectra for these lanthanide complexes of the three ligands take agreement with the above predict from energy match principle.     

聚合物O-PPV的链间相互作用的研究

近年来,聚对苯乙炔(PPV)及其衍生物作为一类性能优良的电致发光材料而受到人们的广泛关注[1].这是因为聚合物发光材料能通过化学裁剪方法来改善发光效率、颜色、成膜性等特性.载流子形成激子以及激子的辐射和非辐射衰减过程向来是聚合物发光二极管(LEDs)发光的重要环节,因此研究聚合物的光物理过程对提高器件的发光特性是非常重要的.     

Yb3+离子掺杂钨酸钾钆晶体的光谱参数

从Yb³⁺:KGd(WO₄)₂(KGW)的吸收谱和荧光谱出发,利用倒易理论计算其各个光谱参量,如吸收截面,受激发射截面,辐射寿命等.由于Yb³⁺:KGW晶体较适合用作二极管泵浦的激光器的材料,而激光二极管所发出的光是偏振光,晶体又是双折射晶体,因此研究了泵浦光的不同通光方向和偏振方向对Yb³⁺:KGW晶体荧光光谱的影响.实验表明在不同情况下其对晶体荧光强度影响较大,因此在设计用激光二极管泵浦的激光器时,应考虑合适的泵浦光偏振方向和入射在晶体上的轴向,其中泵浦光的通光方向比泵浦光偏振方向对晶体的荧光强度的影响更大.对按晶轴切割的这两种晶体,相同实验条件下,荧光强度I_c>I_b>I_a.对于按折射率主轴切割的来说,荧光强度I_Np>I_Ng>I_Nm.在通光方向为c轴,偏振方向平行b轴时得到了最大的荧光强度.     

9,9-二辛基聚芴-苯并噻二唑交替共聚物的绿光偏振电致发光

通过缩聚法合成了绿光9,9-二辛基聚芴-苯并噻二唑交替共聚物（PFBT）.该聚合物在一定温度范围内形成向列液晶态,利用其在定向层上的有序排列,实现了峰值发光波长为550 nm的偏振电致发光.采用摩擦后的空穴注入层聚（3,4-乙撑二氧噻吩）∶聚（苯乙烯磺酸）（PEDOT:PSS）作为定向层,通过偏振紫外可见吸收光谱和偏振光致发光谱,研究了聚合物分子在薄膜平面内的单轴取向特性,计算得到薄膜的有序参数为075.制备了结构为ITO/PEDOT:PSS/PFBT/LiF/Al的聚合物电致发光器件,工作电压为15 V时,电致发光偏振率达到4,亮度和流明效率分别为450 cd/m²和021 cd/A. 关键词： 偏振发光 交替共聚物 聚合物电致发光器件     

卟啉掺杂的MEH-PPV薄膜和氯仿溶液的光学性质(英文)

研究了不同质量浓度卟啉(TTP)掺杂的MEH-PPV的紫外吸收和荧光发射光谱。这种掺杂体系在膜中和氯仿溶液中的吸收光谱具有同样的行为,同时,在这两种情况下发现了MEH-PPV链的聚集,以及TTP在420nm的吸收随掺入量的增加而增加。但是,膜的发射光谱与氯仿溶液中的有所不同。因TTP的吸收带与MEH-PPV发射带的重叠,在膜和氯仿溶液中的高浓度掺杂体系中存在从MEH-PPV到TTP的Frster能量转移,但是在高TTP掺杂下的氯仿溶液中能量转移导致MEH-PPV发射峰的劈裂,而当溶液被稀释时,这种现象消失,表明此时能量给体和受体的距离扩大,这种能量转移的速率为1×108mg·mL-1·s-1。     

Photophysical properties of novel organic europium (III) complexes

Based on fluorescence and absorbance spectroscopy, the photophysical properties and mechanisms of novel organic europium (III) complexes in the case of different concentration in ethanol solution and solid flour were studied at room temperature. It was found that the complex absorption spectra are mainly due to the Phenanthroline ligand, gradually exhibit saturated absorption from shortwave to long wave with the concentration increased, and stretch and broaden to long wave. And four characteristic peaks of the fluorescence spectra are all emission spectra of Eu3+ in the complex, and the strongest emission wavelength was 617 nm corresponding to the (5)D0-->(7)F2 transition of Eu2+. And then, it is presented that the perturbation of acetanil ligand changes the parity state of Eu3+ energy field, resulting in the increase of (5)D0-->(7)F2 transition probability, making phenanthroline transfer its energy absorbed to Eu3+, and inducing 617nm strong emission of fluorescence peak.     

Role of aggregation in the amplified spontaneous emission of [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] in solution and films

The amplified spontaneous emission (ASE) spectra of the conjugated polymer [2-methoxy-5-(2′- ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) is investigated under different conditions such as thin film and solution, solvent type and concentration. Results indicate that aggregation has a pronounced effect on ASE spectra. In solution form, as concentration was increased and thus the proportion of aggregates, a decrease in the ASE emission bandwidth and a red shift of the ASE peak was observed. For the thin film samples, the ASE spectra show two emission bands which were assigned to the first and second vibronic transition of the polymer chains.     

Yb:FAP晶体的光谱特性

研究了Yb:FAP晶体的光谱特性.用980nm的InGaAs激光二极管激发测量了Yb:FAP晶体的偏振发射光谱和荧光寿命,结合晶体的偏振吸收光谱,采用对易法计算了晶体的吸收截面和发射截面.讨论了Yb³⁺掺杂浓度对Yb:FAP的光谱参数的影响.在较低掺杂浓度下,Yb:FAP晶体π偏振方向在903nm处的吸收截面为10×10^-20cm²,在1.043μm处的发射截面为5.8×10^-20cm²,激光上能级的荧光寿命为1.1ms.比较了Yb:FAP晶体和Yb:YAG晶体的光谱性能参数.     

A Novel Ratiometric Fluorescent Mercury Probe Based on Deprotonation-ICT Mechanism

A new NBD-rhodamine dye (1) was developed as a colorimetric and ratiometric fluorescent chemosensor for Hg²⁺ with good selectivity in aqueous ethanol solutions under neutral to basic conditions. Sensor 1 showed absorption at 468 nm and a weak emission at 529 nm (? _F ?=?0.063) in ethanol/aqueous tris buffer (9:1, v/v) of pH 9.17 solution. Bathochromic shifts in both absorption (492 nm) and fluorescence spectra (569 nm, ? _F ?=?0.129), respectively upon addition of 2 equiv. of Hg²⁺ were observed. The ring-opening reaction of the spirolactam form to the corresponding xanthene form was not found. The interaction of Hg²⁺ with chemosensor 1 resulted in the deprotonation of the secondary amine conjugated to the NBD component so that the electron-donating ability of the N atom was enhanced. Deprotonation-ICT mechanism of secondary amines was suggested for the ratiometric fluorescent chemosensing for Hg²⁺.     

Luminescence Properties of Poly(3-Methoxythiophene)—Bithiophene Composite Oligomers

The electronic absorption and fluorescence spectra of electrosynthesized poly(3-methoxythiophene)— bithiophene (PMOT-BT) composite oligomers were studied in organic solution (DMSO) and/or in the solid state on ITO plates. Different spectral properties (absorption and fluorescence maximum wavelengths, fluorescence quantum yields, etc.) were found to depend on the bithiophene initial concentration used during electrosynthesis and, subsequently, on the film composition and oligomer chain length.     

Emission spectra and cross-section spectra of neodymium laser glasses

Amplified spontaneous emission spectra and light amplification spectra of some Nd³⁺:glass rods (silicate glass Schott LG680, phosphate glasses Schott LG760 and Hoya LHG5) are measured by pulsed flashlamp excitation. The spontaneous emission distribution, the stimulated emission cross-section spectra and the excited state absorption cross-section spectra are extracted. Excited state absorption prevents laser action around 1320 nm for the⁴F_3/2-⁴L_13/2 transition of Nd³⁺ in the investigated glasses.     

共轭支链含腈基的聚对苯乙烯衍生物的合成及光谱特征

通过HECK法共聚将腈基引入聚对苯乙烯(PPV)的共轭支链,得到聚合物DiCN-PPV。通过核磁共振(¹H-NMR)、质谱(MS)、元素分析及GPC确定了组成和分子量。探索了聚合反应时间和温度对聚合物分子量及产率的影响。结果表明,该聚合物具有较高的热稳定性(T_d>247℃),在100℃反应62 h可以得到产物分子量M_n=1.76×10⁴,分散度P_d=1.9,产率50%。以紫外吸收光谱及荧光光谱分析了该聚合物溶液及其膜的基本光谱特征,表明D iCN-PPV中D-A(Donor-Acceptor)给受体的结构发生分子内的能量转移,从而导致了新的能级结构。它的荧光为红光λ_max=645 nm,是一种潜在的有机红光新材料。     

4-四氢喹啉酮的合成及发光性能

对喹吖啶酮结构改造合成了新型结构荧光体4-四氢喹啉酮,对其吸收光谱及荧光光谱进行了研究,发现该化合物的吸收峰及荧光发射峰随溶剂极性的增加而不断红移,表明荧光来源于分子内激发态电荷转移发光.该化合物在固态即显示荧光,表明经结构改造后,消除了喹吖啶酮类的固态荧光猝灭效应.4-四氢喹啉酮结构简单,易于合成和结构修饰.这对于寻找新的主体荧光发射材料具有重大意义.     

一种共轭聚合物单分子发色团吸收和发射特性动态演变过程的实时测量

利用频域信息重构的散焦宽场成像测量了Poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole](PFO-DBT)共轭聚合物单分子发色团的吸收与发射特性及其动态演变过程.通过调制用于激发共轭聚合物单分子的超短脉冲对的相对相位,对单分子荧光进行傅里叶变换的频域测量,跟踪发色团吸收偶极取向变化;通过测量散焦荧光成像光斑探测发色团发射偶极取向变化.研究发现, PFO-DBT共轭聚合物单分子发色团存在吸收和发射偶极取向均保持不变、其中之一变化以及两者同时变化三种情况.这种对共轭聚合物单分子发色团吸收和发射偶极取向演化过程的实时测量可用于分析共轭聚合物构象变化及其对能量转移过程的影响.     

Multi-responsive poly(N-isopropylacrylamide) hydrogel with D-π-A type dye

To get a multi-responsive polymer hydrogel, metal sensible and acid/base-switchable D-π-A type dye monomer was synthesized first. The synthesized electron donor-π-conjugated-electron acceptor (D-π-A) type dye monomer 3 was investigated with not only the selective Ni²⁺ and Cu²⁺ metal ion sensing effects, but also an acid/base unit sensing effects in optical properties with UV-vis absorption and fluorescence emission. A thermo-responsive poly(NIPAM-co-dye) copolymer with D-π-A type dye was prepared by typical radical copolymerization. The LCST behavior was investigated by UV-vis spectroscopy, which allows the measurement of the phase transition from 20 to 50 °C in an aqueous solution. The poly(NIPAM-co-dye) copolymer also exhibited color change when not only Ni²⁺ or Cu²⁺ cations were used but also when an acid/base unit was used. The morphology of the internal matrix structure of the poly(NIPAM-co-dye) hydrogel was observed by SEM.     

The optical properties and energy transition process in nanocomposite of polyvinyl-pyrrolidone polymer and Mn-doped ZnS

This study has been carried out on the optical properties of polyvinyl-pyrrolidone (PVP), the energy transition process in nanocomposite of PVP capped ZnS:Mn nanocrystalline and the influence of the PVP concentration on the optical properties of the PVP capped ZnS:Mn nanocrystalline thin films synthesized by the wet chemical method. The microstructures of the samples were investigated by X-ray diffraction, the atomic absorption spectroscopy, and transmission electron microscopy. The results showed that the prepared samples belonged to the sphalerite structure with the average particle size of about 2–3 nm. The optical properties of samples are studied by measuring absorption, photoluminescence (PL) spectra and time-resolved PL spectra in the wavelength range from 200 to 700 nm at 300 K. From data of the absorption spectra, the absorption edge of PVP polymer was found about of 230 nm. The absorption edge of PVP capped ZnS:Mn nanoparticles shifted from 322 to 305 nm when the PVP concentration increases. The luminescence spectra of PVP showed a blue emission with peak maximum at 394 nm. The luminescence spectra of ZnS:Mn–PVP exhibits a blue emission with peak maximum at 437 nm and an orange–yellow emission of ion Mn²⁺ with peak maximum at 600 nm. While the PVP coating did not affect the microstructure of ZnS:Mn nanomaterial, the PL spectra of the PVP capped ZnS:Mn samples were found to be affected strongly by the PVP concentration.