Effect of Lumophore and Plasticiser Concentration on The Heterogeneity of Oxygen Quenching in Thin Film Oxygen Sensors

Kinetic heterogeneity of the luminescence decay and oxygen quenching of Pt and Pd octaethylporphyrin/ethyl cellulose (OEP/EC) thin film oxygen sensors has been investigated with respect to (a) concentration of lumophore and (b) addition of plasticiser. The source of kinetic heterogeneity shown by PtOEP films under N₂ is a monomer–dimer equilibrium in which the dimer luminescence decays with k = 0.0527×10⁶ s⁻¹ and the monomer luminescence with k = 0.0101×10⁶ s⁻¹ and K _D = 790 (±20) mol dm⁻³. For PdOEP/EC films there is no detectable aggregation and luminescence decays under N₂ show good fits to single exponential curve fits at all concentrations studied. The addition of either tripbutyl phosphate or dimethylphthalate as plasticiser does not decrease kinetic heterogeneity for oxygen quenching of luminescence in the films.     

Luminescence quenching of cyclometalated Pt(II) complexes in acetonitrile and methanol by molecular oxygen

A method is developed for quenching the luminescence of methanol and acetonitrile solutions of cyclometalated Pt(II) complexes with molecular oxygen. A mechanism of luminescence quenching is suggested and bimolecular quenching rate constants are calculated.     

Luminescence quenching of complexes immobilized on a cation-exchange membrane by molecular oxygen

A technique is developed and luminescence quenching of complexes immobilized on cation-exchange membranes is considered. The mechanism of the luminescence quenching of the complexes by molecular oxygen is discussed.     

氧对钌(Ⅱ)配合物溶胶-凝胶膜荧光响应的影响

利用蓝光LED(λmax =4 6 0nm )构建的氧荧光猝灭检测系统 ,考察了不同Ru配合物以甲基硅氧烷(TMOS)和二甲基二甲氧基硅烷 (DiMe DMOS)为共先驱体 ,制备的有机改性溶胶 凝胶 (sol gel)膜内荧光猝灭行为。DiMe DMOS的加入量会影响敏感膜的极性 ,从而影响敏感膜对氧浓度的响应。利用自行构建的装置对水体中氧进行了检测 ,传感膜对氧饱和水溶液测定的相对标准偏差为 1 12 % (n =6 ) ,响应时间为 30s,对氮饱和水溶液测定相对标准偏差为 0 39% (n =6 ) ,响应时间为 90s,敏感膜使用寿命大于 6个月。     

Spectroscopic and Morphological Properties of Divinylbenzoxazolylbiphenyl Thin Films

The thin organic films based on 4,4′-bis-[(Z)-1-(1,3-benzoxazol-2-yl-2-ethenyl)]biphenyl and its partly fluorinated derivatives are studied. Absorption, luminescence, and excitation spectra, luminescence decay and film morphology were found to depend sensitively on the changes in molecule structure, nature and temperature of the substrate, as well as the thermovacuum deposition rate, being the origins of bad reproducibility of the optical properties of such films. Molecular aggregation with chromophore dipoles arranged parallel to each other has been observed in absorption and luminescence spectra. The fluorescence characteristics can be explained by the combination of radiation of aggregated and non-aggregated molecules. The main characteristics of the molecules under study are calculated using DFT approach. The unusual behaviour of photodegradation in fluorinated film is found.     

Quenching of luminescence of cyclometalated Pt(II) complexes by molecular oxygen

A method of studying the quenching of luminescence of cyclometalated ethylenediamine complexes of Pt(II) by molecular oxygen is developed. The bimolecular rate constants of quenching are determined.     

Determination of the rate constant of oxygen quenching of the excited states of molecules from the singlet oxygen luminescence

We have pioneered a method of determining the rate constant of quenching of the excited electronic states of molecules by molecular oxygen from measurements of the kinetics of photosensitized luminescence of singlet molecular oxygen (^lδ_g). The method can be used in the case where the lifetime of the excited electronic state in an air-saturated solution is comparable with or larger than the luminescence time of the singlet molecular oxygen in the given solvent. It is shown that this situation is implemented on quenching, by molecular oxygen, of the excited triplet states associated with the biopolymers of tetrapyrrole molecules in aqueous (H₂O and D₂O) solutions. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 401–404, May–June, 2000.     

Photoluminescence and electroluminescence studies of polyvinyl carbazole films

Polyvinyl carbazole (PVK) film has been prepared by solution method. Its absorption, photoluminescence (PL) and electroluminescence (EL) have been studied. For PL and absorption studies, film of PVK was prepared by spreading PVK solution on clean glass plate. The dried film was taken out of the glass plate and used for absorption, thickness measurement and PL studies. The film is transparent in the visible region and absorption starts at 340 nm wavelength. The absorption peaks are obtained at 280, 250 and 220 nm, indicating that optical gap of film is 3.65 eV and molecular orbitals exist at 4.43, 4.96 and 5.64 eV. PL studies reveal that excitation by violet light gives luminescence at 430, 480 and 690 nm. For EL studies, cell is prepared by depositing PVK film on a portion of conducting glass plate and taking aluminum foil as second electrode. It is observed from the characteristics that the current varies linearly, where as EL intensity varies non-linearly with increasing voltage. Higher brightness has been observed at higher frequencies. EL spectrum shows a sharp peak at 400 nm and a broad and less intense peak at 700 nm, which are attributed to radiative decay of singlet exciton and defect centers, respectively.     

Optoelectronics and formaldehyde sensing properties of tin-doped ZnO thin films

Sn-doped ZnO thin films were deposited on clean glass substrates using the chemical spray pyrolysis technique. XRD analyses confirm stable ZnO hexagonal wurtzite structure of the films with crystallite size in the range of 20–28 nm. The surface roughness of the films increases on Sn doping, which favors to higher adsorption of oxygen species on the film surface, resulting in higher gas response. Optical studies reveal that the band gap decreases on Sn doping. All the films show near band edge emission, and on Sn doping the luminescence peak intensity has been found to increase. Photocurrent in the 1.5 at.% doped film enhances about three times to that observed in the undoped ZnO film. Among all the films examined, the 1.5 at.% Sn-doped film exhibits the maximum response (～94.5 %) at the operating temperature of 275?°C for 100 ppm concentration of formaldehyde, which is much higher than the response (～35 %) in the undoped film. The gas response of the film is attributed to the chemisorption of oxygen on the film surface and the subsequent reaction between the adsorbed oxygen species and the formaldehyde molecules.     

钌(Ⅱ)配合物有机改性溶胶-凝胶氧传感膜荧光行为的研究

本文考察了利用甲基硅氧烷（TMOS）和二甲基二甲氧基硅烷（DiMe-DMOS)为共先驱体制备的有机改性溶胶－凝胶（sol-gel）氧荧光繁感传感膜，比较了5种不同配体的Ru配合物在不同极性溶剂和sol-gel膜内的荧光行为，考察了膜极性的改变对Ru化合物荧光光谱的影响，以及氧对不同极性有机改性sol-gel包埋Ru化合物荧光猝灭的程度。研究结果表明，在sol-gel膜内，Ru化合物的荧光寿命都有不同程度的增加，同时对氧的猝灭程度增加。另外膜的极性对氧猝灭的程度也有很大的影响，增加膜的疏水性，将提高传感膜对氧浓度的响应。     

Influence of UV irradiation and heat treatment on the luminescence of molecular silver clusters in photo-thermo-refractive glasses

The luminescence spectra of photo-thermo-refractive (PTR) glasses containing cerium, silver, and antimony ions before and after UV irradiation and after heat treatment have been thoroughly investigated for the first time. It is shown that silver is present in the initial PTR glass in the form of ions and positively charged molecular clusters. After UV irradiation into the absorption band of cerium ions, silver partially passes to the neutral state in the form of atoms and neutral molecular clusters Ag₂, Ag₃, and Ag₄, which exhibit bright luminescence in the visible spectral range. Subsequent heat treatment at a temperature below the glassformation temperature leads to an increase in the luminescence intensity due to the increase in the concentration of neutral molecular clusters. Heat treatment at a temperature above the glass-formation temperature leads to the formation of silver nanocrystals and luminescence quenching. It is proposed to use PTR glasses with molecular silver clusters as phosphors for converting UV radiation into the visible range for solar power engineering and white LEDs.     

发光液晶材料的合成及发光特性研究

具有聚集诱导发光增强效应的发光液晶材料,能有效地解决一般发光材料聚集时荧光猝灭和液晶自组装之间的矛盾,在液晶显示等领域有极大的应用价值。本文报道了一种自发光液晶材料(2Z,2'Z)-2,2'-(1,4-亚苯基)二(3-(4-己氧基)苯基)丙烯腈(PHPA)。研究了PHPA的聚集态发光性质、溶剂化效应、热力学性质及发光各向异性。结果表明,PHPA同时具有聚集态诱导发光增强效应和液晶性,其有序取向的薄膜发出的光具有各向异性。该发光液晶材料应用于液晶显示将能简化器件结构、增加亮度、对比度和能效。     

芪3在铅-锡-氟磷酸盐玻璃中的聚集及光谱特性

采用低温熔融法制备了有机染料芪3掺杂的不同浓度的铅-锡-氟磷酸盐玻璃,通过对掺杂玻璃激发光谱、发射光谱和吸收光谱的测试,研究了芪3在无机玻璃中的聚集状态和光谱性能。 结果表明,有机染料芪3以单体和二聚物的形式共存于无机玻璃中,和芪3单体分子的激发峰相比,二聚物的激发峰位于短波段,随掺杂浓度的增加,掺杂玻璃的发射峰发生红移,同时在荧光光谱中观察到浓度猝灭现象;芪3分子与无机玻璃通过亲水作用发生了键合,从而导致芪3在无机玻璃中的吸收光谱和发射光谱比在乙醇溶液中出现较大红移;与芪3在乙醇溶液中的荧光强度相比,芪3分子受无机玻璃的“笼”化作用有效的提高了其荧光强度。     

提高多孔硅传感特性的一种新方法(英文)

研究了多孔硅(PS)吸附有机溶剂分子后对多孔硅荧光谱的淬灭效应。结果表明:淬灭多孔硅发光的有机溶剂分子是极性分子,有机溶剂分子的极性不同对多孔硅发光的淬灭程度也不同,且有些有机溶剂分子吸附氧化多孔硅比吸附多孔硅引起的发光淬灭具有更好的可逆性和选择性;用含有胺基的正丁胺(CH3CH2CH2CH2-NH2)作碳源,用射频辉光放电等离子系统在多孔硅表面沉积c n膜对多孔硅进行钝化处理后发现:其电致发光强度明显增强,发光峰位兰移,且在大气中存放60天后,其电致发光谱强度基本不衰减,峰位不再移动。经钝化处理的器件较未经处理的器件具有小的串联电阻Rs和低的驱动电压。这为提高多孔硅的传感特性提供了一种新方法。     

射频磁控溅射法制备SnO2:Sb薄膜的结构和光致发光性质研究

采用射频磁控溅射法在玻璃衬底上制备出锑掺杂的氧化锡（SnO2₂:Sb）薄膜.制 备薄膜是具有纯氧化锡四方金红石结构的多晶膜薄，晶粒生长的择优取向为［110］.室温下光致发光测量结果表明，在392nm附近存在强的紫外-紫光发射.研究了不同氧分压对薄膜结构及发光性质的影响，并对SnO2₂:Sb的光致发光机制进行了探索性研究.     

In situ isothermal monitoring of the enhancement and quenching of Sm3+ photoluminescence in Ag co-doped glass

A novel in situ concurrent photoluminescence and absorption microspectroscopy technique is proposed for the real-time monitoring of the optical properties of rare-earth and noble metal co-doped dielectrics during isothermal processing. The technique has been successfully applied to an Ag and Sm co-doped phosphate glass, where both enhancement and quenching regimes of Sm³⁺ luminescence have been observed well separated in time, practical for an ‘optical tuning’ of the solid-state luminescent material. Further, relating simultaneously the luminescence with the time evolution in optical absorption allowed for discerning the effects of Ag non-plasmonic clusters as enhancers and nanoparticles as quenchers. Opportunities come forward for studying a variety of systems with relevance to a wide range of applications.     

纳米ZnO薄膜的光致发光性质

利用溶胶－凝胶法制备了纳米ZnO薄膜,室温下测量了样品的光致发光谱(PL)、吸收谱(ABS)、X射线衍射谱(XRD)．X射线衍射(XRD)的结果表明：纳米ZnO薄膜呈多晶状态,具有六角纤锌矿晶体结构和良好的C轴取向．观察到二个荧光发射带,中心波长分别位于395 nm的紫带、524 nm的绿带和450 nm附近的蓝带．证实了纳米ZnO薄膜绿光可见发射带来自氧空位(VO)形成的浅施主能级和锌空位(VZn)形成的浅受主能级之间的复合;450 nm附近的蓝带来自电子从VO的浅施主能级到价带顶或锌填隙(Zni) 到价带顶或导带底到VZn的浅受主能级的复合．     

Luminescence of polymorphous SiO2

The luminescence of self-trapped exciton (STE) was found and systematically studied in tetrahedron structured silica crystals (α-quartz, coesite, cristobalite) and glass. In octahedron structured stishovite only host material defect luminescence was observed. It strongly resembles luminescence of oxygen deficient silica glass and γ or neutron irradiated α-quartz. The energetic yield of STE luminescence for α-quartz and coesite is about 20% of absorbed energy and about 5(7)% for cristobalite. Two types of STE were found in α-quartz. Two overlapping bands of STEs are located at 2.5–2.7 eV. The model of STE is proposed as Si–O bond rupture, relaxation of created non-bridging oxygen (NBO) with foundation of a bond with bridging oxygen (BO) on opposite side of c or x,y channel. The strength of this bond is responsible for thermal stability of STE. Similar model of STE was ascribed for coesite and cristobalite with difference related to different structure. STE of Silica glass is strongly affected by disordered structure.     

Specific features of the luminescence of silicate glasses with silver introduced by ion exchange

The luminescence spectra of silicate glasses with silver introduced by ion exchange have been investigated. It is shown that silver introduced into glass by ion exchange exists not only in the form of ions, but also as neutral atoms and charged and neutral molecular clusters, which provide intense luminescence in the visible spectral range. Cerium ions in glass facilitate the formation of neutral molecular silver clusters, due to which the luminescence intensity increases. It is shown that Ag _n -Ce ^x+ complexes can be formed in glass containing cerium ions and neutral molecular silver clusters.     

Sm3+在玻璃中的发光以及Sb6+、Ce6+、Gd3+对Sm3+发光性质的影响

本文研究了单掺(Sm3+,Ce3+、Gd3+.Sb3+、双掺(Sm3++Ce3+、Sm3++Gd3+,Sm3++Sb3+)和兰掺(Sm3++Gd3++Ce3+)约四十余种不同玻璃的发射谱和激发谱.探讨了玻璃成份和掺杂离子浓度对Sm3+发光性质的影响以及Ce3+,Gd3+、Sb3+、Ce3++Gd3+对Sm3+的敏化作用。