稀土夹心双酞菁铥的LB膜及其光谱特性

采用表面压-面积(π～A)等温曲线和紫外-可见吸收光谱研究了稀土夹心双酞菁铥(TmPc2)分子在Langmuir膜及其Langmuir-Blodgett(LB)膜中分子的排列状态和光谱特性。发现TmPc2分子在纯膜中以edge-on方式面对面的排列,在与花生酸(AA)的混合膜中TmPc2分子以face-on方式平躺排列。纯的TmPc2分子在亚相表面可以形成稳定的Langmuir膜,但不易转移到固体基片上,加入花生酸混合后不仅可以在亚相表面形成稳定的Langmuir膜,而且可以较好地转移到固体基片上,制成多层LB膜。TmPc2氯仿溶液和LB膜的紫外-可见吸收光谱具有明显的Soret吸收带和Q吸收带,Soret吸收带有2个吸收峰,分别对应184—187*和178—186的轨道电子跃迁。而Q吸收带有4个吸收峰,分别对应于186—189*,190*和185—187*,188*的轨道电子跃迁。由于分子间的相互作用,TmPc2分子在LB膜中紫外-可见吸收谱的各个吸收峰与氯仿溶液中的吸收峰相比较都发生了红移。层内分子的相互作用比层间分子的相互作用强。     

TMB·TCNQ和硬脂酸混合LB膜的制备及表征

将没有双亲性的电荷转移配合物TMB·TCNQ (TMB：3, 3′,5,5′-Tetramethylbenzidine;TCNQ：7,7,8,8-tetracyanoquinodimethane)通过与硬脂酸混合组装制备了混合LB膜。TMB·TCNQ和硬脂酸的摩尔比例在1∶1, 1∶2和1∶3的情况下都可以成功进行组装。利用紫外-可见-近红外光谱、透射和掠角反射红外光谱、X射线衍射以及原子力显微镜研究了混合LB膜中各组分的结构、分子取向和表面形貌等。研究结果表明,混合LB膜中的TMB·TCNQ是混合堆积排列的,电荷转移度ρ约为0.35。配合物中的电子给体TMB和电子受体TCNQ分子的苯环平面都垂直于基底表面。硬脂酸的碳氢长链以一定角度倾斜于基底表面。混合LB膜的小角X射线衍射图中出现了两组衍射峰。混合比例为1∶1的单层和多层LB膜中出现纳米棒和微粒,而且,纳米棒和粒子的数量随着LB膜层数的增加而增多。     

取代基对双酞菁铥LB膜及光谱特性的影响

采用紫外-可见吸收光谱的方法研究了三种稀土夹心双酞菁铥化合物在溶液和LB膜中的聚集性和光谱特性。实验结果表明三种稀土双酞菁化合物在氯仿溶液中形成了H-聚集体,但当浓度比较低时,溶液中表现出单体的吸收。取代基OC₈H₁₇的加入使氯仿溶液中双酞菁铥化合物的聚集性减弱,而且使得吸收峰发生红移,对吸收峰的强度也有较大的影响,造成了Soret吸收带的分裂。另外,取代基OC₈H₁₇对LB膜中双酞菁分子的存在状态有较大的影响,在LB膜中,TmPc₂和TmPcPc*分子以H-聚集体的形式存在,而TmPc*₂分子以T-聚集体的形式存在。形成LB膜后,由于双酞菁分子之间排列紧密,相互作用加强,使得薄膜中分子聚集体的吸收峰相对于溶液中聚集体的吸收峰发生了一定的红移,薄膜中分子排列方向的不同对吸收光谱也有一定的影响。     

硬脂酸镉和山嵛酸镉混合LB膜的微结构

用X射线衍射研究了沉积于亲水玻璃基底上的硬脂酸镉和山嵛酸镉多层混合LB膜的微区结构和相分离情况．纯的脂肪酸镉衍射峰没有在混合LB膜的XRD谱图中出现,说明混合膜中形成的微区很小而且均匀分布．混合膜样品的面间距随硬脂酸镉和山嵛酸镉混合比例的变化形成一条台阶状的曲线,这表明在它们比例变化的过程中,只形成了三种有序的结构,而且每一种结构,特别是长短链交错的微结构,可以在一定的比例范围内保持;另外,在长短链交错的微结构中,两种脂肪酸长链具有相同的偏离膜平面法线方向的小倾角,这也可由它们傅立叶红外透射谱中表征脂肪酸长链分子取向的亚甲基CH2相同的峰位2847.80和2914.37 cm-1(对应于CH2对称和反对称伸缩振动)得到说明．当混合比例超出1/5?1/1,混合膜将会经历一个纵向有序度降低的过程,表现为混合膜相对X射线衍射强度随混合比例以\W"形变化．     

Role of various LB parameters on the optical characteristics of mixed Langmuir-Blodgett films

This communication reports the spectroscopic characterizations of mixed Langmuir-Blodgett (LB) films of non-amphiphilic N,N-bis (2,5-di-tert-butylphenyl)- 3,4,9-perylenedicarboximide (DBPI) molecules, mixed with polymethyl methacrylate (PMMA) and stearic acid (SA). J- aggregates of DBPI molecules in the mixed LB films have been confirmed by UV-Vis absorption spectroscopic study. Formation of organized structure of molecular stacking in the mixed LB films gives rise to the strong excimeric emission, which is manifested by a broad structureless band in the longer wavelength region of the fluorescence spectra and is confirmed by excitation spectroscopic study. A weak hump at around 576 nm due to monomeric emission is observed in the fluorescence spectra of 0.1 M of DBPI-PMMA mixed LB films of lower number of layers. The intensity of the 0-0 band at 530 nm in the fluorescence spectra is observed to be a function of the molefraction, number of layers, surface pressure of lifting and the matrix materials.     

荧光标记十八胺LB膜的光谱研究

正十八胺以氯化丹酰和8-苯胺基-1-萘磺酸衍生化,单独或与硬脂酸混合后拉制成LB膜,并以稳态和时间分辨荧光研究了膜中分子的微环境和微结构等光物理性质.     

Kinetics of long-lived luminescence of eosin in Langmuir-Blodgett films

The spectral and kinetic properties of photoluminescence of mixed Langmuir-Blodgett (LB) films of eosin decyl ether and palmitic acid on a solid substrate are studied. The electronic absorption and fluorescence spectra of the films are identical to the spectra of the dye in ethanol. An increase in the dye concentration in a monolayer results in the appearance of a dimer absorption band, quenching of fluorescence of monomers, and the red shift of the spectral bands. At 90 K, the distinct phosphorescence and delayed fluorescence bands of LB films were observed. The decay kinetics of phosphorescence and delayed fluorescence is nonexponential. It is shown that the decay curve of delayed fluorescence is determined by triplet-triplet annihilation (TTA) and T ₁→S₁ triplet-singlet intersystem crossing (IS). The initial nonexponential phosphorescence decay is caused the dominant contribution of TTA to the decay of triplet molecules. The experimental data are interpreted based on the mechanisms of exchange-resonance and inductive-resonance annihilation.     

一种可溶喹吖啶酮衍生物LB膜的光谱特性

采用表面压-分子面积(π~A)等温曲线、紫外-可见吸收谱和荧光光谱的方法研究了一种喹吖啶酮衍生物材料LB膜的制备及其光谱特性。实验表明,这种喹吖啶酮衍生物能够在水面上形成稳定的单分子膜,它与花生酸(AA)混合后不仅可以形成很好的单分子膜,而且可以较好的转移到固体基片上制备成LB膜多层膜。这种喹吖啶酮衍生物LB膜的紫外-可见吸收谱的吸收峰位较稀溶液发生了红移,这是由极性溶剂分子与其相互作用的结果。其溶液有很强的荧光效应,但LB膜没有荧光现象,原因是在LB膜中QAC16的浓度过高发生“自我猝息”而失光。它在溶液和LB膜中都是以单体的形式存在。     

Influence of high-energy X-ray irradiation on the optical properties of tetraphenylporphyrin thin films

Tetraphenylporphyrin (TPP) thermally evaporated films were irradiated by different doses (0.5–2.5 kGy) of X-ray with energy 6 MeV. The optical properties for TPP were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 1100 nm. The absorption spectra recorded in the UV-VIS region of spectra showed different absorption bands, namely four Q-bands in the visible region of the spectrum and a more intense band termed as the Soret band in the near-UV region of the spectrum. Two other bands labeled N and M appear in the UV region. The Soret band showed Davydov splitting. Increasing X-ray irradiation dose influences the optical properties of TPP films. All absorption bands show a continuous blue shift in position and a decrease in intensity with increasing X-ray dose. At 2.5 kGy the B, N, and M bands disappeared. The reduction in the absorbency was calculated as a function of X-ray dose. The energy gap was determined and the type of optical transition was found to be an indirect allowed transition.     

Absorption and emission of thin solid films of octaethylporphin

Absorption and emission spectra at room temperature and emission spectra atliquid nitrogen temperature are reported for thin solid films of free base octaethylporphin. The room temperature visible absorption spectrum resembles that of the solution, except all four peaks show a red shift of ≈ 12 nm and all except the farthest red are broadened. The Soret band in the near UV is greatly broadened in the film, and its peak absorbance is substantially reduced. The room-temperature emission of the films is quite similar to that of solution fluorescence, except for a red-shift of ≈ 10 nm. But at low temperature two new peaks appear at 657 and 672 nm. Their intensity as a function of temperature can be explained by a simple exciton trapping model.     

酞菁铜旋涂薄膜的形貌与光谱学性质研究

采用旋涂法制备了2,9,16,23-四-异丙氧基酞菁铜(CuPc(OC3H7-i)4)薄膜,利用AFM、UV-Vis和FT-IR对薄膜的表面形貌和光谱学性质进行了表征。薄膜表面结构是由约为216nm×55nm×4nm的清晰纳米畴组成,旋涂膜中酞菁铜分子是处于一种无序的状态,其Soret带吸收与氯仿溶液相比位置不变,而Q带的聚集体和单体的吸收峰红移约20nm。     

Photophysical Properties of Fluorescent Polymers Containing 1,10-Phenanthroline-3,8-ylene and Diethinylenebenzene Units and Their Model Compounds: A Comparison to 2,2′-Bipyridine Analogues

Investigation of the absorption and emission spectra (stationary and time-resolved) of phenanthroline-based polymers shows that the enforcement of a cisoid geometry in the bipyridine unit of the main chain via an ethenylene bridge does not significantly change the spectral and the deactivation behaviour. In close analogy to similar polymers, containing bipyridine units, the conjugation length in these polymers does not exceed ca. two chromophore units. At low temperatures, the model compounds show an additional, bathochromically shifted, intense luminescence with an increased lifetime which can be interpreted as an excimer (or aggregate) fluorescence. In addition, broad, superimposed emission bands arising from various aggregated species are observed. The relative intensity of these bands depends on the temperature processing occurring during cooling. Intersystem crossing is an insignificant deactivation channel.     

LB薄膜中四新戊氧基酞菁锌和四壬基酞菁铜分子聚集体的吸收光谱的温度特性

本文制备了四新戊氧基酞菁锌(Tetra-neopentoxy phthalocyanine zine)(TNPPeZn)和四壬基酞菁铜(Tetra-nonyl phthalocyanine copper)(TNPeCu)两种酞菁衍生物的Langmuir-Blodgett(LB)薄膜.通过测量10～473K温度下的吸收光谱,研究了两种薄膜的分子聚集状态.TNPPeZn的LB薄膜中,存在着分子单体和分子二聚体,在吸收光谱中分别表现为680nm和620nm的吸收峰.随着温度的升高,分子单体逐渐转变为分子二聚体,这个过程是不可逆的.TNPeCu的LB薄膜中,除了分子单体和分子二聚体以外,还有吸收为740nm的分子J聚集体存在.随着温度的变化,J聚集体发生可逆变化.     

红外透过、反射吸收光谱研究手性液晶(M1)LB膜的结构与取向

利用ＦＴＩＲ光谱研究了一种手性液晶化合物（Ｍ１）ＬＢ膜的结构与取向,该化合物可以形成稳定的单层与多层膜。手性分子中,芳香环平面向于垂直基片表面,分子中的烷基链部分则与基底表面法线方向成一定的角度。     

Thin films of molecular materials synthesized from C32H20N10M (M = Co, Pb, Fe): Film formation, electrical and optical properties

In this work, the synthesis of molecular materials formed from metallic phthalocyanines and 1,4-phenylenediamine is reported. The powder and thin film (∼80-115 nm thickness) samples of the synthesized materials, deposited by vacuum thermal evaporation, show the same intra-molecular bonds in the IR spectroscopy studies, which suggests that the thermal evaporation process does not alter these bonds. The morphology of the deposited films was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and their optical and electrical properties were studied as well. The optical parameters have been investigated using spectrophotometric measurements of transmittance in the wavelength range 200-1200 nm. The absorption spectra recorded in the UV-vis region for the deposited samples showed two bands, namely the Q and Soret bands. The optical activation energy was calculated and found to be 3.41 eV for the material with cobalt, 3.34 eV for the material including lead and 3.5 eV for the material with iron. The effect of temperature on conductivity was measured for the thin films and the corresponding conduction processes are discussed in this work.     

A spectroscopic study of water-soluble pyronin B and pyronin Y in Langmuir-Blodgett films mixed with stearic acid

Mono and multilayer of water-soluble pyronin B (PyB) and pyronin Y (PyY) mixed with stearic acid (SA) have been incorporated in Langmuir-Blodgett (LB) films. The surface pressure-area (π-A) isotherm studies pointed out that pure PyB and PyY are incapable of forming stable films at air-water interface and collapsed readily at low surface pressures. However, mixture of PyB or PyY with SA easily formed stable films at the air-water interface and they were easily transferred onto solid substrates. The average area per molecule of mixed films of PyB and PyY at the air-water interface was observed to decrease with increasing concentrations of PyB and PyY. The spectroscopic characteristics of PyB and PyY in chloroform, in SA containing chloroform and in LB films have also been investigated by using absorption and steady-state and time-resolved fluorescence spectroscopy techniques. The morphology of the LB film surfaces has been characterized by using atomic force microscopy (AFM).     

碘、碘离子和碘三离子的紫外吸收光谱

研究了碘I₂、碘离子I- 和碘三离子I-₃ 水溶液的紫外吸收光谱,测定了三种型体的摩尔吸光系数。I₂水溶液在203 nm呈现一吸收峰,摩尔吸光系数为1.96×104 L·mol-1·cm-1;I- 水溶液在193和226 nm呈现双吸收峰,摩尔吸光系数分别为1.42×104和1.34×104 L·mol-1·cm-1;当I₂水溶液与KI溶液混合时,在288和350 nm出现两个吸收峰,表明I-₃的形成。利用饱和法测得I-₃在288和350 nm处的摩尔吸光系数分别为3.52×104和2.32×104 L·mol-1·cm-1。     

Absorption and photoluminescence properties of silver clusters in SiO<Subscript>2</Subscript> matrix

Absorption and luminescence properties of silver nanoclusters embedded in SiO₂ matrixes were studied experimentally. Thin SiO₂ films with different amount of silver were produced by co-deposition of Ag and SiO₂ onto the silica substrates in vacuum. The thus obtained films possess three peaks in absorption spectra at 297, 329 and 401 nm and two peaks in luminescence spectra at about 500 and 650 nm. We ascribed these spectral features to silver nanoclusters of different sizes that present in the film. Thermal annealing transforms both absorption and emission spectra of the films. Lager clusters that are formed after annealing possess one absorption band at 350–450 nm and one luminescence band at 510 nm. The luminescence was observed only in samples with the silver content of less than 2.2%. Quenching of the luminescence in samples with higher concentration of silver is due to the presence of larger particles with plasmonic properties.     

超声对单层C60LB膜表面形貌的影响及其变温荧光的研究

本文通过控制制备过程中成膜液的超声时间, 利用LB技术制备出了不同形貌和结构的单层C60LB膜, 利用扫描电子显微镜(SEM)观察到超声30分钟制备的薄膜中C60以尺寸较小的球状团簇存在, 超声90分钟制备的薄膜中C60团簇尺寸变大且出现了少量棒状结构, 超声150分钟制备的薄膜中存在一些中空的管状C60结构。利用激光荧光对所制备的单层C60LB膜进行了变温荧光光谱的研究, 室温下的荧光光谱包括两个荧光峰, 当温度降低到120 K时在768 nm处出现了一个新的荧光峰, 原来的两个荧光峰随温度的变化则不是很明显。     

槲皮素与Cu2+反应形成配合物的紫外-可见吸收光谱法研究

采用带有快门的增强型瞬态光谱探测系统ICCD,实时拍摄了槲皮素在中性和酸性条件下与Cu2+反应形成配合物的紫外一可见吸收光谱.光谱每幅曝光时间为0.1 ms,Cu2+与槲皮素的摩尔比分别为0.2,0.5,1.0,2.0,5.0和10.0.实验结果表明不同摩尔比的反应物在其他条件相同时吸收光谱带的变化是相似的,但摩尔比越大反应时间越短;在中性和酸性条件下形成配合物的反应过程不一样,在中性条件下有吸收峰值为428 nm的反应中间产物出现,而在酸性条件下则直接反应生成最终产物,但它们的最终产物都只有一个吸收峰值为296 nm的吸收带;反应物暴露在空气中和隔离空气的反应过程没有差别.文章首次观测到槲皮素与Cu2+反应形成配合物有中间产物出现,且最终产物的吸收峰值为296nm.结果为研究槲皮素-Cu2+配合物的形成机理提供了实验依据.