Luminescence properties of anodic aluminum oxide films with organic luminophores embedded into pores

Luminescence properties of porous anodic aluminum oxide films formed in a 0.6 M solution of citric acid and luminescence of paraterphenyl, perylene, coumarin 7, and rhodamine 6G dyes adsorbed by the films are investigated. The nature of emitting centers in anodic aluminum oxide is revealed. Intense photoluminescence of all tested dyes embedded into pores of anodic aluminum oxide has been found. A redshift of fluorescence spectra of dyes adsorbed by the matrix and emergence of an additional longwave band have been detected. Data obtained can be used in developing new thin-film luminescent coatings for future applications in optoelectronics and molecular electronics. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No 4, pp. 483–488, July–August, 1997.     

非典型发光化合物的簇聚诱导发光

不含大共轭结构的非典型发光化合物因其理论研究的重要性和潜在应用前景引起研究者的广泛关注。非典型发光化合物的结构通常含有N、O、S、P等杂原子,C≡N、C=O、C=C等不饱和单元,及相应的组合功能团(如羟基、胺基、酯基、酐、酰胺、脲基、肟基、砜基等)。近年来,尽管这一领域正快速发展,其发光机理仍存争议。前期,我们提出了簇聚诱导发光(CTE)机理,即含π电子和/或孤对(n)电子的非典型生色团的簇聚及其带来的空间共轭使体系离域扩展,构象刚硬化;同时,其他分子内/间相互作用也有利于簇生色团的刚硬化,从而易于受激发射。基于CTE机理,本文综述了非典型发光化合物的发光特性,包括浓度增强发光、聚集诱导发光(AIE)、激发波长依赖性及磷光发射。CTE机理可合理解释天然产物、合成化合物、生物分子等不同体系的光物理行为,并可用来指导发现和设计新的非典型发光化合物。本文总结了上述不同体系的发展,并对未来研究进行了展望。     

Physicochemical Principles of the Creation of Highly Efficient Organic Luminophores with Anomalously High Stokes' Shifts

Published data and the author's own results on the creation of organic luminophores with anomalously high fluorescence Stokes' shifts are reviewed.     

Topology-Controlled AIEE of Iminocoumarin Luminophores

Aggregation-induced emission enhancement (AIEE) is an unusual phenomenon where luminophores show a higher photoluminescence efficiency in the aggregated and solid state. We report the design and synthesis of a series of luminophores 1 – 4 with imine functionality at 6 position of coumarin and studied their AIE propensities on self-assembly. The effect of the topology of the phenolic hydroxyl group on the emission behaviour of the luminophores has been investigated. The imines show significant solvatochromism with high emission in non-polar solvents, whereas the emission gets quenched in the polar solvent. The fluorescence in the toluene-hexane mixture arises due to the aggregation of fluorophores and falls under the category of AIEE. Not only the solution state emission of the isomeric iminocoumarin luminophores is notably varied, but also their solid-state emission found to be significantly different from each other. Moreover, the iminocoumarin 1 selectively recognizes Fe(III) over Fe(II) with a prominent color change. In situ oxidation of Fe(II) with H₂O₂ exhibits the same effect like Fe(III) and developed a chemical combinational logic gate.     

Pyrrolodiazine derivatives as blue organic luminophores: synthesis and properties. Part 3

A fast, efficient, general and environmentally friendly method for preparation of highly fluorescent derivatives containing the pyrrolodiazine moiety using microwave (MW) irradiation, in liquid phase, is reported. Under MW irradiation the yields are much higher, sometimes substantially (by almost double) and, the amount of solvent used is at least 5-fold less. The pyrrolopyridazine (PP) derivatives are very intense blue emitters and have high quantum yields (up to 90%) while pyrrolophthalazine (PHP) compounds are still intense blue emitters but the quantum yield is negligible. A certain influence of the substituents concerning fluorescence was found, those ones at the 7 position being crucial for fluorescence. The number of the substituents from the pyrrolo ring seems not to play an important role in regard with the fluorescence but, with an increasing number of substituents a certain hypsochromic shift in the absorption spectra was found.     

Clustering-Triggered Efficient Room-Temperature Phosphorescence from Nonconventional Luminophores

Pure organic room-temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Herein, we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boosts the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5 % is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results will spur the future fabrication of nonconventional phosphors and advance the understanding of the underlying emission mechanism.     

Synthesis of a new conjugated 2,2′-(1,4-phenylenedivinylene)bis-quinoxaline and a series of styryl derivatives of quinoxaline and quinoline as promising electro- and photoluminescent materials

A new poly(p-phenylenedivinylene) oligomer 2,2'-(1,4-phenylenedivinylene)bisquinoxaline, a promising candidate in organic electroluminescent devices, was synthesised via a Knoevenagel condensation reaction of 2-methylquinoxaline with 1,4-benzenedicarbaldehyde. The same synthetic strategy was applied to obtain substituted styryl dyes, derivatives of quinoxaline, whereas styryl derivatives of quinoline were prepared by "Anil Synthesis". The considered dyes are of interest as fluorescence emitting materials. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 95–100, January, 2009.     

具有同质多晶依赖性发射的非芳香性发光化合物

不含芳(杂)环、单键-重键交替单元等大共轭结构的纯有机发光材料引起了人们的广泛关注,但其结构与发光性质间的关系仍需进一步明确.本文研究了氧杂酸酐与氧杂酰亚胺两种非芳香性发光化合物.通过在不同溶剂中培养单晶,得到了具有不同发光颜色及荧光-磷光双发射的同质多晶体,发光效率最高达17.0％.这种高效发射可归因于含π电子与n电...     

Recent Advances in Aggregation-Induced Electrochemiluminescence

The emergence of the rising alliance between aggregation-induced emission (AIE) and electrochemiluminescence (ECL) is defined as aggregation-induced electrochemiluminescence (AIECL). The booming science of AIE has proved to be not only distinguished in luminescent materials but could also inject new possibility into ECL analysis. Especially in the aqueous phase and solid state for hydrophobic materials, AIE helps ECL circumvent the dilemma between substantial emission intensity and biocompatible media. The wide range of analytes makes ECL an overwhelmingly interesting analytical technique. Therefore, AIECL has gained potential in clinical diagnostics, environmental assays, and biomarker detections. This review will focus on introduction of the novel concept of AIECL, current applied luminophores, and related applications developed in recent years.     

Synthesis and optical properties of novel unsymmetrically substituted benzothiadiazole-based luminophores

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