一种具有稳定发射光谱的高效率白色有机电致发光器件

报道一种具有稳定发射光谱的新型白色有机电致发光器件. 选择DCJTB 作为红光染料将其掺入空穴传输材料NPB 中作为空穴传输层和第一发光层, 提供蓝光和红光; 选择AlQ 作为电子注入敏化剂, 将其掺入NPB 中作为第二发光层, 提供蓝光和绿光. DCJTB和AlQ 的掺杂浓度分别被优化为0.4%和1.4%, 第二发光层的厚度被优化为3 nm. 最终,得到了纯白色发射的有机电致发光器件; 该器件启亮电压仅3.1 V, 最大亮度高达32749 cd/m², 器件的最大电流效率为8.67 cd/A, 器件的最大功率效率为8.78 lm/W. 而且, 空穴型主体材料的选择导致该器件的色稳定性非常理想. 随着电流密度的提高, 该器件的色坐标始终稳定在(0.343, 0.342)到(0.328, 0.336)的范围内.     

Confocal full‐field X‐ray microscope for novel three‐dimensional X‐ray imaging

A confocal full‐field X‐ray microscope has been developed for use as a novel three‐dimensional X‐ray imaging method. The system consists of an X‐ray illuminating `sheet‐beam' whose beam shape is micrified only in one dimension, and an X‐ray full‐field microscope whose optical axis is normal to the illuminating sheet beam. An arbitral cross‐sectional region of the object is irradiated by the sheet‐beam, and secondary X‐ray emission such as fluorescent X‐rays from this region is imaged simultaneously using the full‐field microscope. This system enables a virtual sliced image of a specimen to be obtained as a two‐dimensional magnified image, and three‐dimensional observation is available only by a linear translation of the object along the optical axis of the full‐field microscope. A feasibility test has been carried out at beamline 37XU of SPring‐8. Observation of the three‐dimensional distribution of metallic inclusions in an artificial diamond was performed.     

新基激复合物探针检测指定序列DNA

研究目的是拓展基激复合物荧光探针方法在检测指定序列DNA中的应用。实验选择细胞色素P450 CYP2C9基因中容易发生突变的包含24个碱基的基因片段作为靶点DNA,选择两个分开的与靶点碱基相对应的包含12碱基的寡核苷酸作为探针,将荧光集团连接到探针末端3′或5′磷酸基上形成荧光探针,两个荧光探针与靶点DNA杂交后自动装备基激复合物荧光系统,实验考察芘的新衍生物与不同荧光团配对、荧光团连接不同位置、不同激发波长对基激复合物形成及发射光谱的影响,芘的新衍生物探针形成的基激复合物在505 nm的特征发射光谱最强,伴随着单体荧光的猝灭和大约120～130 nm的Stokes位移,大大减少了DNA检测过程中的背景干扰,灵敏度高,而且这对荧光物质形成的基激复合物对所处的空间位置及微环境非常敏感,可尝试用于基因遗传多态性的识别。     

聚(苯乙烯-alt-马来酸酐)-b-聚苯乙烯亲水/亲油嵌段共聚物在溶液中的聚集行为研究

采用RAFT方法合成了由马来酸酐／苯乙烯和苯乙烯组成的交替序列两嵌段共聚物P(MAn-alt-St)-b-PSt。将其中的马来酸酐用PEO进行水解,得到了支化的亲水亲油两嵌段共聚物。通过H—NMR和IR对共聚物的结构组成进行表征。以二甲基氨基黄酮化舍物为荧光探针,测定了形成共聚物胶束的临界浓度(CMC)。用TEM和SEM现察不同酸碱条件下所得纳米材料形貌,并对其形成机制进行了讨论。     

量子点的荧光共振能量转移在生物分析中的应用

量子点良好的光谱特性和自身优点,使其可以作为生物荧光探针,而替代传统荧光染料。近年来这方面的研究已经取得了一定的进展。目前,量子点在共振能量转移方面的研究,进一步扩展了它在生物分析中的应用。介绍了量子点基于共振能量转移原理在生物分析中的应用,即利用量子点设计的两种类的蛋白-蛋白特异性结合分析和3种生物传感器的模型设计。     

催化剂对SiO2凝胶结构及复合体系发光性能的影响

用溶胶—凝胶的方法制备了染料掺杂的SiO2凝胶复合体系。无机基质制备过程中的各种条件对无机基质的微结构有很大影响,从而对复合材料的性能有很大影响。大量的研究表明,凝胶制备过程的诸多因素如催化剂、水的加入量及凝胶的后处理等因素影响最大,这些因素对凝胶结构的影响已有系统的研究,但其对有机—无机复合体系发光影响的研究还未多见。详细研究了在其他条件不变的情况下酸碱催化条件对复合体系结构及染料发光性能的影响。香豆素102(C102)在不同状态下的荧光分析表明,无论是碱还是酸催化所得薄膜复合材料,C102分子在其中基本都以单体的形式存在,与在溶液中相比发光移向短波。碱催化的样品其结构更有利于染料以单体的形式存在,但碱催化的膜表面粗糙,结构疏松,而酸催化的膜表面平整,结构致密。所以以HCl为催化条件的样品适合更进一步的应用。     

CdTe量子点酸度敏感荧光探针测定水样中铵根离子含量

本研究在水相中合成了高质量的巯基乙酸包被的CdTe量子点.在pH 5.8～8.0范围内的PBS缓冲溶液中,CdTe量子点荧光强度与体系酸度存在良好的线性关系.利用NH+4 对量子点荧光的猝灭作用,实现了对水溶液中NH+4 的定量检测.在最优条件下,CdTe量子点酸度敏感探针荧光的猝灭程度与NH+4浓度呈良好的线性关系,线性范围为0.05～6.0 mmol/L,检出限为0.15 μmol/L.对1.0 mmol/L标准溶液平行测定11次,相对标准偏差为3.2%.利用标准加入法对水样中NH+4含量进行了测定,其结果与蒸馏-酸滴定法的结果基本一致.     

Novel long alkyl side chain benzo[a]phenoxazinium chlorides: synthesis, photophysical behaviour and DNA interaction

Several fluorescent benzo[a]phenoxazinium chlorides possessing a propyl-, octyl-, decyl-, dodecyl- or tetradecylamino at the 5-position of the heterocyclic moiety were efficiently synthesised. The absorption and emission maxima of all compounds lie in the range 627-638 nm and 654-678 nm, respectively, with good fluorescence quantum yields. Studies of their photophysical properties in ethanol allowed for the estimation of the acid-base dissociation constant, K_a, revealing an enhancement with the increase in the alkyl side-chain length. It is in the aqueous medium only that the acid form is observed as coexisting with H-aggregates. The solubility markedly decreased when the chain length increased. The residual ethanol (0.2% v/v) used to facilitate the solubilisation of the benzo[a]phenoxazinium dyes allow for the existence of the basic form in an aqueous solution, possibly through preferential solvation. Photophysical studies in the presence of DNA revealed that the compounds with an alkyl side chain of up to eight carbon atoms could intercalate between DNA nucleotides. Moreover, other forms of DNA binding were found to be operative, involving also the basic form of benzo[a]phenoxazinium dyes.     

Polyfluorophore Labels on DNA: Dramatic Sequence Dependence of Quenching

We describe studies carried out in the DNA context to test how a common fluorescence quencher, dabcyl, interacts with oligodeoxynucleoside fluorophores (ODFs)—a system of stacked, electronically interacting fluorophores built on a DNA scaffold. We tested twenty different tetrameric ODF sequences containing varied combinations and orderings of pyrene (Y), benzopyrene (B), perylene (E), dimethylaminostilbene (D), and spacer (S) monomers conjugated to the 3′ end of a DNA oligomer. Hybridization of this probe sequence to a dabcyl‐labeled complementary strand resulted in strong quenching of fluorescence in 85 % of the twenty ODF sequences. The high efficiency of quenching was also established by their large Stern–Volmer constants (K_SV) of between 2.1×10⁴ and 4.3×10⁵ M ^?1, measured with a free dabcyl quencher. Interestingly, quenching of ODFs displayed strong sequence dependence. This was particularly evident in anagrams of ODF sequences; for example, the sequence BYDS had a K_SV that was approximately two orders of magnitude greater than that of BSDY, which has the same dye composition. Other anagrams, for example EDSY and ESYD, also displayed different responses upon quenching by dabcyl. Analysis of spectra showed that apparent excimer and exciplex emission bands were quenched with much greater efficiency compared to monomer emission bands by at least an order of magnitude. This suggests an important role played by delocalized excited states of the π stack of fluorophores in the amplified quenching of fluorescence.