CdS量子点的酿酒酵母仿生合成及光谱表征

以酿酒酵母为载体,常温下利用仿生法成功合成了CdS量子点。荧光发射光谱、紫外吸收光谱以及荧光显微镜照片证明,该方法合成的CdS量子点的荧光发射峰位置在443nm,在紫外灯下能发蓝绿色荧光。透射电子显微镜(TEM)表征结果表明,该仿生法合成的CdS量子点为六方纤锌矿结构。以荧光发射和紫外吸收光谱为性能指标,考察了酿酒酵母生长时期、Cd2+的反应浓度以及反应时间等条件对合成CdS量子点的影响。当酿酒酵母处于生长稳定期初期时,与浓度为0.5mmol.L-1的Cd2+共培养24h后所合成的CdS量子点荧光最强。实验中观察到,换液培养可有效提高酿酒酵母合成CdS量子点的产量。     

CdZnSe三元量子点敏化TiO_2纳米管的谱学分析及可见光光催化

以六水合硝酸镉为镉源,硝酸锌为锌源,通过硼氢化钠还原硒单质制得NaHSe,并作为硒源,通过胶体化学法制备了一系列具有不同组分的水溶性Cd1-xZnxSe三元量子点。利用X射线粉末衍射仪(XRD)和高分辨透射电镜(HRTEM)分析所制得的Cd1-xZnxSe的晶体结构和形貌,表明所制得三元量子点为立方结构,呈规则球状,平均粒径约为4nm。通过改变三元量子点的Cd和Zn元素的配比,调节Cd1-xZnxSe的能带结构,有效调控其光谱学性质;与ZnSe和CdSe等二元量子点相比,Cd1-xZnxSe的紫外可见光吸收光谱及荧光发射光谱都发生明显的红移。采用直接浸渍法,制备Cd0.5Zn0.5Se三元量子点敏化TiO2纳米管(TNTs)复合材料(Cd0.5Zn0.5Se@TNTs)。TEM结果显示Cd0.5Zn0.5Se三元量子点紧密结合在纳米管表面,红外谱图表明TiO2和Cd0.5Zn0.5Se之间形成Ti—Se键,有利于提高复合材料的稳定性。相对于纯TNTs,复合材料的紫外可见光吸收光谱在可见光区的吸收明显增强,吸收带边从400nm红移至700nm左右;同时,复合Cd0.5Zn0.5Se三元量子点后,可以有效地抑制光生电子-空穴对的复合,提高复合材料在可见光区域的光催化效率。可见光照射60 min后,催化剂Cd0.5Zn0.5Se@TNTs对罗丹明B(RhB)光降解率可达到100%,分别约为纯TNTs和纯Cd0.5Zn0.5Se的3.3倍和2.5倍。     

新型红外染料的光谱和激发态寿命

本文着重讨论了三种新型红外染料的光谱性质(吸收光谱,荧光光谱,激发态寿命和相对量子产额),并比较分子结构上的差异所造成的影响.同时介绍了测定微微秒激发态寿命及有关光谱的实验技术.     

NEA GaN光电阴极量子产额研究

围绕NEA GaN光电阴极光电发射过程的光谱响应理论,研究了其量子产额问题。分别给出了反射模式和透射模式NEA GaN光电阴极的量子产额计算公式,分析了影响量子产额的因素。分析了国外制备的反射模式和透射模式NEA GaN光电阴极的量子产额曲线。结果表明,目前制备的NEA GaN光电阴极已具有高达30%的量子效率和良好的发射性能。相同条件下,反射模式比透射模式的量子效率要高,而且反射模式不像透射模式那样存在短波限制。     

2(水杨醛缩苯胺)-(1,10-邻菲罗啉)合钙的光谱特性

合成了一种新型的蓝光发射材料2(水杨醛缩苯胺)-(1,10-邻菲罗啉)合钙,并利用红外光谱、X射线衍射谱、DSC热分析、UV-vis吸收谱、荧光激发光谱和荧光发射光谱研究了其结构、晶态、热稳定性以及光学特性,分析了它的能态结构和发光机理。结果表明,2(水杨醛缩苯胺)-(1,10-邻菲罗啉)合钙的热稳定性较高,是一种多晶粉末发光材料,禁带宽度2.93eV,在紫外光的激发下,固态荧光发射峰在449.7nm处,在乙醇溶液体系中的荧光发射峰在491nm处,均为蓝色荧光,色纯度高,荧光量子效率高,其荧光发射主要来源于长波吸收带,最大波长吸收带对荧光发射贡献最大。     

低浓度掺杂的量子点粒度分布对荧光辐射谱的影响

当量子点粒度分布为高斯分布时,应用有效质量近似,在低浓度掺杂范围内,得到了量子点荧光辐射谱线形函数与量子点尺寸之间的一般关系,解释了尺寸涨落对线形展宽的影响。对II-VI族的Cd Se量子点和IV-VI族的Pb Se量子点的数值计算表明:量子点荧光谱线的半峰全宽、荧光辐射强度、峰值波长等与实验结果基本一致。量子点尺寸的粒度分布对荧光辐射谱线展宽有较大的影响。荧光辐射谱展宽是一种非均匀展宽。     

CdTe∶Eu量子点的合成及其光学性能研究

采用1-十八烯作为高温反应溶剂,利用氯化铕和磷酸三丁酯制备铕前驱体。分别采用正三辛基膦和碲粉制备的碲前驱体,以及油胺和二水乙酸镉制备的镉前驱体,在200℃合成Eu掺杂Cd Te量子点。实验发现随着反应溶液中Eu的含量上升,Cd Te量子点的荧光峰发生显著红移,但Eu的含量过高则会导致量子点的荧光强度下降。     

CdTe,核 壳型CdTe/CdS及CdTe/ZnS量子点的合成及表征

在水相中制备了半导体CdTe纳米晶,核 壳型CdTe/CdS和CdTe/ZnS纳米晶（即量子点;QDs）.利用扫描隧道显微镜（STM）和荧光光谱(FS)对合成的纳米晶量子点进行了研究,并且根据FS的数据进行了量子效率的计算.STM的结果表明合成的量子点直径约为3 nm并且分布良好.为了提高量子效率,对Cd2+浓度和Cd2+∶S2－比例等反应条件进行了研究,结果表明随着回流时间的增加,核 壳型量子点CdTe/CdS的量子效率总体上呈下降趋势.CdTe/CdS在pH8.5,Cd2+∶S2－=10∶1（摩尔比）时可获得80.0%的最大量子效率.同时制备了核 壳型量子点CdTe/ZnS,其最大发射波长由551 nm（CdTe）红移到635 nm（CdTe/ZnS）表明量子点的尺寸在增长,但是量子效率下降到14.4%. 当前研究的量子点可适用于生物标记,生物成像,以及基于共振能量转移的生物传感研究.     

CdSe量子点的S-K模式自组装生长

近年来 ,由于半导体量子点 (QD)材料可望提高器件的光电特性而成为研究的热点。如以量子点作为激活层的激光器 (L D)与量子阱 LD相比会有更低的阈值电流 ,更高的增益和特征温度。 - 族半导体量子点的研究主要集中在Cd Se/Zn Se[1～ 4 ] ,近年来也有 Zn Se/Zn S[5] 、Cd Te/Zn Te[6 ] 的报道。量子点的制备大多使用分子束外延 (MBE)方法 [7] ,而以金属有机化学气相淀积 (MOCVD)法生长的 Cd Se/Zn Se[8]量子点一般为 V-W模式。 Stranski-Krastanow(S-K)模式生长量子点与其他方法如电子束刻蚀等相比 ,具有方法简单、表面缺陷少…     

CdSe量子点凝胶快速制备及其光谱特性

以水为反应溶剂,采用NaBH₄还原SeO₂并与过量CdSO₄反应,制备CdSe量子点凝胶。所得CdSe量子点凝胶直接干燥即得到固态粉体,若用聚乙二醇或谷胱甘肽等作为分散修饰剂可方便的转化成相应的溶胶,制备方法快速简单、成本低。CdSe量子点凝胶、粉体、溶胶均具有良好的光致发光特性,且性质稳定。结果表明反应物CdSO₄与SeO₂用量的摩尔比（Cd/Se值）和反应温度影响CdSe量子点的荧光特性。当制备凝胶的Cd/Se值由2.4:1增加12:1时,CdSe量子点-聚乙二醇溶胶的荧光强度增加,荧光发射峰由560nm红移到610nm;当制备凝胶的反应温度由40℃增加到90℃时,CdSe量子点-聚乙二醇溶胶的荧光发射峰由560nm红移到600nm。CdSe量子点-聚乙二醇溶胶的荧光量子产率20%左右。     

邻苯二甲酸—邻菲罗啉—铕—铽络合体系的荧光性能研究

波长为３６５ｎｍ的紫外光激发下均可发出特征荧光的邻苯二甲酸－邻菲罗啉－铕和铽固体络合物以机械研磨和化学作用两种方式进行混合，研究了这两系列混合络合物的荧光光谱和红外光谱。结果表明，由于铕、铽之间存在相互影响，其荧光强度变化较大，而荧光发射峰位基本不变。经化学混合后铽对铕的荧光强度有极强的敏化作用，铕对铽具有很强的猝灭作用，并用红外光谱对上述四种络合物体系的结构进行了表征     

DMANS在聚合物中的荧光性质

本文研究了DMANS(4-二甲胺基-4′-硝基二苯乙烯)在聚苯乙烯和改性聚苯乙烯中的荧光性质。测量了两类样品的吸收光谱、荧光光谱、荧光强度和荧光寿命,讨论了介质对荧光性质影响的机理。     

INTENSITY STUDY OF LIF SPECTRUM FOR THE B0u→X0g SYSTEM OF A TELLURIUM NATURAL SAMPLE

The fluorescence spectrum of a tellurium sample in its natural isotopic abundance, induced by the 4764.8 Å line of an argon ion laser is studied. The study of natural tellurium samples allows us to bring out and analyze the intensity of three fluorescence series not previously reported. Photographic plates and densitometric techniques were used when recording experimental intensities. The radiative transition probabilities for the observed fluorescence series were calculated by using hybrid Perturbed-Morse-Oscillator (PMO)-Rydberg–Klein–Rees (RKR)- Long Range potential energy curves for the B0⁺_u and X0⁺_g states and a function for the transition dipole moment in the framework of the r-centroid approximation. Radiative lifetimes of the rovibrational levels for the upper state pumped by the laser line have also been calculated. The transition probabilities and lifetimes are in good agreement with the corresponding observed measurements usually within the experimental uncertainty.     

浅埋泥炭中的木栓质体的荧光光度术研究

对滇西镇安盆地浅埋泥炭中的木栓质体进行了较详细的研究。研究表明木栓质体是稳定组分中最不稳定的，它可以被氧化分解，导致结构和光学性质的变化，尤其是后者的变化显著，未氧化的木栓质体的荧光光谱颜色为绿色，Ｉ５４６介于１．５－２．０之间，荧光光谱呈单峰状；λｍａｘ介于４８０－５１０ｎｍ，Ｑ６５０／５００介于０．１２－０．２６畔滤宽１５０ｎｍ，但是，被氧化，分解的木栓质体则发黄色或黄褐色的荧光，Ｉ５４６减小     

消荧光现象与表面谐波产生

消荧光现象是激光与物质表面非线性相互作用的结果，这是一种普遍现象。在表面谐波产生的研究中，它常常被忽略。大量研究表明：表面谐波产生与消荧光现象，有着密切的内在联系。本文以消荧光观点详细讨论了表面谐波产生的机制，提出了表面谐波产生的消荧光模型。新机制可归纳为：（ａ）多光子受激吸收产生消荧光光斑，（ｂ）激光热效应等促进自发辐射转向准受激辐射，（ｃ）伴随荧光消失，部分产生荧光的激光能量转换为产生表面谐波     

Synthesis and Fluorescence Investigation of Differently Substituted Benzo[b][1,8]Naphthyridines: Interaction with Different Solvents and Bovine Serum Albumin (BSA)

A series of benzo[b][1, 8]naphthyridines has been synthesized by Friedl?nder condensation of 2-aminoquinoline-3-carbaldehyde 1 (o-aminoaldehyde) with active methylenes in basic medium. The fluorescence spectroscopic properties of some representative compounds has been studied in different organic solvents; moreover interaction with bovine serum albumin (BSA) in phosphate buffer was examined by UV-vis and fluorescence spectroscopy. The effect of electron donor-acceptor substituents on fluorescence properties of benzo[b][1, 8]naphthyridines 13(a-n) has been investigated along with their fluorescent quantum yields.     

Fluorescence Sensor Design for Transition Metal Ions: The Role of the PIET Interaction Efficiency

Multicomponent systems 1, 2, and 3 having fluorophore-spacer-receptor architecture have been prepared with a view to understand the role of the photoinduced intramolecular electron transfer (PIET) interactions in transition metal ion sensing efficiency of these systems. Structurally similar compounds 4-amino-1,8-naphthalimide (4), 4-aminophthalimide (5), and 4-methoxy-1,8-naphthalimide (6) were used as the fluorophore moieties. Dimethylamino group (as in the case of 1a, 2a, and 3a, series A) and an aniline moiety (like in 1b, 2b, and 3b, series B) have been employed as the receptor components. A two-carbon ethylene chain serves as a spacer unit. The absorption and fluorescence spectral features of the systems have been studied in the absence and presence of various transition metal ions. All the multicomponent systems (except 1a) show weak fluorescence intensities compared to that of their constituent fluorophores (4, 5, and 6) in any given solvent. The reason for this low fluorescence quantum yield could be ascribed to the efficient PIET interaction between receptor moiety and the electron deficient fluorophore component of the systems. This has been corroborated with the estimated thermodynamic driving force (delta G*) for the PIET process in the multicomponent systems, calculated using electrochemical and spectral properties of individual components, is more negative for 2 and 3 than for 1 having electron deficient fluorophores 5, and 6, respectively. Especially, as evidenced by their low fluorescence quantum yield values, the PIET interaction is found to be more significant in the systems of series B (1b, 2b, and 3b) than the respective system of series A (1a, 2a, and 3a, respectively). The sensing capability of the systems is directly related to the efficiency of the PIET interaction in the unbound state. Accordingly, all these systems (except 1a) show significant fluorescence enhancement in the presence of transition metal ions, well known for their high fluorescence quenching behavior. The present paper describes, the feasibility of optimizing the PIET interaction in the multicomponent sensor system in unbound state, and thus transition metal ion signaling capability of the system.     

Nature of the influence of a solvent on the fluorescence quantum yield of solutions of the fluorescent probe 4-dimethylaminochalcone

The fluorescence quantum yields of solutions of 4-dimethylaminochalcone (DMC) in a series of individual solvents of different chemical nature have been measured using a technique based on studying the kinetics of fluorescence decay. A new quantitative regularity, namely, the dependence of the fluorescence quantum yield on the absolute solvation shift in the fluorescence spectrum due to the gas-solution phase transition, has been revealed. The opinion has been advanced and justified that the revealed regularity has a fundamental character, which is determined by the dominant contribution from the universal intermolecular interactions to the formation of the properties of the solvated DMC molecule in the excited electronic state.     

某些查耳酮化合物的发光

本文叙述了两个同质查耳酮系列的合成.一个带有查耳酮中心链(系列Ⅰ),另一个是系列Ⅰ的酯类(系列Ⅱ).研究了每个系列中三种化合物的发光,发现两个系列的所有化合物都能见到发光.系列Ⅰ中的化合物在峰值为360nm处可见到发光,而系Ⅱ列中的化合物未能观测到这一波长的发光.然而,在峰值为470nm处两者均可见到发光.得出的结论是,消除非键电子微扰作用的氢键是系列Ⅰ中的化合物在360nm处出现发光的原因.     

牛血清白蛋白与血卟啉之间的能量转移

首次报导了蛋白质分子对血卟啉衍生物分子之间的荧光敏化现象。通过离体模拟实验,证实了牛血清白蛋白分子(Bovine albumin) (BALB)与血卟啉衍生物分子(HPD)之间存在着能量转移,其中能量供体为BALB,能量受体为(HPD)。估算了其转移效率,讨论了BALB与HFD之间的相互作用类型。