Effect of side chain substituents on the electron injection abilities of unsymmetrical perylene diimide dyes

Three near-infrared (NIR) absorbing unsymmetrical perylene diimide D-A-D type dyes containing 6-undecanoxy as donor group were utilized in dye-sensitized nanocrystalline TiO₂ solar cells. Structure of the acceptor side of the molecules were improved by adding 4-[2-methyl-5-(cyanoacrylic acid)-3-thienyl]-phenyl (V), 3-carboxy-2-pyridil (VI) and 3-carboxy-2-pyrazyl (VII) moieties attached to one of the N-side of the dye. The relationship between the molecular structure of the acceptor sites of the dyes and the photovoltaic performances were discussed. Electrochemical measurements indicated that band gaps of the dyes were energetically favorable for electron injection from the excited state of the dyes to the conduction band of TiO₂ nanoparticles. However, three dyes gave lower conversion efficiency on DSSC applications. Strong electron-withdrawing nature of perylene core might not permit to transfer the photo-generated electrons to the carboxyl groups anchoring to TiO₂ surface, and then solar-to-electricity conversion efficiencies of the dyes were reduced.     

Concentration effects on emission of bay-substituted perylene diimide derivatives in a polymer matrix

Reduction of emission quenching in a gain medium based on a dye-doped organic matrix at high doping concentrations is of crucial importance for achieving efficient lasing with a low threshold. In this study, concentration effects on emission properties of bay-substituted perylene diimide derivatives, considered to be promising for lasing application, are reported. Dynamics of emission spectra, quantum yield, lifetime, amplified spontaneous emission, amplified spontaneous emission threshold and photostability of the bromo-, 2,4-di(trifluoromethyl)phenyl- and 4-pyridyl-substituted perylene diimide derivatives in polystyrene films are explored in a wide range of diimide concentrations from 0.06 wt % to 8 wt %. For comparison, emission properties of an unsubstituted perylene diimide derivative are also investigated. An importance of the bay substitution in the perylene diimides is emphasized through i) reduction of emission concentration quenching, which allows for 3-4 times higher doping levels as compared to the doping with an unsubstituted perylene diimide, ii) observation of amplified spontaneous emission at one order of magnitude higher concentrations with reasonable thresholds (up to 200-300 kW/cm²), and iii) high photostability, which is one order of magnitude higher than that of other bay-substituted perylene diimides and various organic compounds. The results imply potential of the perylene diimide substitution at the bay position for tailoring molecular packing and emission properties via steric hindrance effects, and suggest the bay-substituted perylene diimides may be useful as active media for lasing applications.     

Design and synthesis of novel fluorescence sensing perylene diimides based on photoinduced electron transfer

Two novel tetraester- and PAMAM-branched perylene diimides were synthesized and configured as “fluorophore-spacer-receptor” systems based on photoinduced electron transfer. Due to their long alkylester and alkylamine terminal groups the examined compounds were well soluble in organic solvents. Photophysical characteristics of the dyes were investigated in DMF and water/DMF (1:1, v/v) solution. The ability of the synthesized perylene diimides to detect cations was evaluated by the changes in their fluorescence intensity in the presence of metal ions (Zn²⁺, Co²⁺, Cu²⁺, Fe³⁺, Pb²⁺, Hg²⁺, Ag⁺ and Ni²⁺) and protons. The dyes under study displayed “off-on” switching in its fluorescence as a function of pH, which is attributed to disallowing photoinduced electron transfer from the receptor moiety to the fluorophore. PAMAM-branched dye displayed a good pH sensor activity (FE = 6.4), however the pH sensing ability of tetraester was substantially higher (FE = 184). In the presence of Cu²⁺ and Pb²⁺ ions tetraester quenched its fluorescence intensity (FQ = 22 and 12 respectively), while PAMAM-branched dye enhanced its fluorescence intensity with pronounced selectivity to Cu²⁺ and Fe³⁺ (FE = 3.2 and 4.9, respectively). The results obtained indicate the potential of the novel compounds as fluorescent detectors for metal ions with pronounced selectivity towards Cu²⁺, Pb²⁺ and Fe³⁺ ions and highly efficient “off-on” pH switches, especially a tetraester-branched perylene diimide.     

Design and synthesis of novel fluorescence sensing perylene diimides based on photoinduced electron transfer

Two novel tetraester- and PAMAM-branched perylene diimides were synthesized and configured as “fluorophore-spacer-receptor” systems based on photoinduced electron transfer. Due to their long alkylester and alkylamine terminal groups the examined compounds were well soluble in organic solvents. Photophysical characteristics of the dyes were investigated in DMF and water/DMF (1:1, v/v) solution. The ability of the synthesized perylene diimides to detect cations was evaluated by the changes in their fluorescence intensity in the presence of metal ions (Zn²⁺, Co²⁺, Cu²⁺, Fe³⁺, Pb²⁺, Hg²⁺, Ag⁺ and Ni²⁺) and protons. The dyes under study displayed “off–on” switching in its fluorescence as a function of pH, which is attributed to disallowing photoinduced electron transfer from the receptor moiety to the fluorophore. PAMAM-branched dye displayed a good pH sensor activity (FE = 6.4), however the pH sensing ability of tetraester was substantially higher (FE = 184). In the presence of Cu²⁺ and Pb²⁺ ions tetraester quenched its fluorescence intensity (FQ = 22 and 12 respectively), while PAMAM-branched dye enhanced its fluorescence intensity with pronounced selectivity to Cu²⁺ and Fe³⁺ (FE = 3.2 and 4.9, respectively). The results obtained indicate the potential of the novel compounds as fluorescent detectors for metal ions with pronounced selectivity towards Cu²⁺, Pb²⁺ and Fe³⁺ ions and highly efficient “off–on” pH switches, especially a tetraester-branched perylene diimide.     

Dye sensitized CO<Subscript>2</Subscript> reduction over pure and platinized TiO<Subscript>2</Subscript>

TiO₂ thin and thick films promoted with platinum and organic sensitizers including novel perylene diimide dyes (PDI) were prepared and tested for carbon dioxide reduction with water under visible light. TiO₂ films were prepared by a dip coating sol–gel technique. Pt was incorporated on TiO₂ surface by wet impregnation [Pt(on).TiO₂], or in the TiO₂ film [Pt(in).TiO₂] by adding the precursor in the sol. When tris (2,2′-bipyridyl) ruthenium(II) chloride hexahydrate was used as sensitizer, in addition to visible light activity towards methane production, H₂ evolution was also observed. Perylene diimide derivatives used in this study have shown light harvesting capability similar to the tris (2,2′-bipyridyl) ruthenium(II) chloride hexahydrate.     

Conjugated polymers based on benzodithiophene and arylene imides: Extended absorptions and tunable electrochemical properties

Three novel conjugated polymers have been designed and synthesized via the alternative copolymerization of the electron-donating monomer benzodithiophene (BDT) and three different electron-accepting monomers: perylene diimide (PDI), naphthalene diimide (NDI), and phthalimide (PhI). All obtained copolymers show good solubility in common organic solvents as well as broader absorptions in visible region and narrower optical band gaps compared to homopolymers from BDT units. It is found that the absorptions of the copolymers are red-shifted with increasing the electron-withdrawing ability of the co-monomer. In particular, the absorption edge of P(BDT-NDI) film extends to 760 nm, whereas that of P(BDT-PhI) film is only at 577 nm. Cyclic voltammograms of the three polymers disclose that P(BDT-PDI) and P(BDT-NDI) are typical n-type materials because PDI and NDI are strong electron-accepting groups, while P(BDT-PhI) is a stable p-type material where the weak electron-withdrawing monomer (PhI) is introduced. The results suggest that the absorption range and the electrochemical properties of the conjugated polymers can be tuned by appropriate molecule-tailoring, which will help exploring ideal conducting polymers for potential applications in polymer optoelectronics, especially in polymer solar cells.     

Near-infrared reflective properties of perylene derivatives

Dyes and pigments with high reflectance in the near-infrared (NIR) region can extensively control the heat buildup. Perylene-based pigments exhibit considerable reflectance in the NIR region. The reflectance of a material depends upon a number of factors, such as particle size, concentration of the reflective material, the distribution of particles within the material and the material’s refractive index. The refractive index, in turn, depends on the electronic structure of the material. Therefore,differently substituted perylene compounds are expected to exhibit different reflectance in the NIR region. To elaborate this point, different perylene bisimide derivatives have been synthesized, and their ability to reflect in the NIR region has been determined and compared to the results for commercially available pigments. Significant variation in the relative reflectance is observed in the NIR region for differently substituted perylene bisimide compounds. The NIR reflectance of different perylene tetracarboxy diimide derivatives (PCIs) was also compared to the reflectance of 3,4:9,10-perylenetetracarboxylic dianhydride (PTCA), the precursor from which the PCIs are commonly synthesized. PTCA exhibits significantly higher relative reflectance in the given region than any of the diimide derivatives synthesized from it in this study.     

香豆素类染料的荧光光谱性能及应用性能研究

研究了9只香豆素类荧光染料(Ⅰ-Ⅶ)的光谱性能和应用性能。香豆素类荧光染料在5’-位有取代基可使最大可见吸收波长和荧光发射波长产生红移;当共轭双键长度增加,可使染料颜色变深(V:544,VI:552)。这9只染料用于涤纶染色有很好的应用性能,差别不大;嗯唑环结构(Ⅰ、Ⅱ、Ⅲ)和喹唑酮结构(Ⅵ)的染料耐光牢度明显好于噻唑环结构(Ⅴ)和咪唑环结构(Ⅶ)的染料。     

Triphenylamine-based dyes for dye-sensitized solar cells

A novel, soluble, perylene oligomeric diimide dye, termed EOPPI was synthesized in high yield; for comparison, a small dye molecule, termed EOPDI, was also synthesized; both products readily dissolved in a wide range of organic solvents. The compounds were characterized using NMR, IR, MS, UV–vis, MS, GC–MS, HRMS, DSC, TGA, elemental analysis and cyclic voltammetry. The average molecular mass of EOPPI was 4460, its intrinsic viscosity was 0.3 dl g⁻¹ in m-cresol at 20 °C. The band gap energy (E_g), LUMO and HOMO energy values were 2.25, −3.78 and −6.03 eV for the small dye molecule and 2.24, −3.85 and −6.09 eV for the oligomer, respectively. The temperatures at which the monomer and oligomer began to lose mass were 300 and 375 °C, respectively. The oligomer showed concentration-dependent color tunability.     

表面活性剂包衣酶用于催化有机溶剂中的反应

用表面活性剂直接对酶进行包衣后用于有机相中的酶催化反应是近 10年来发展起来的一种新方法 ,与通常有机相中的酶催化反应方法相比 ,表面活性剂包衣酶具有制备容易、催化活性高、有机溶剂选择范围广等显著优点。该文介绍了表面活性剂包衣酶的概念、制备方法、催化活性等 ,并探讨了今后的研究方向     

光电功能性有机染料及其应用研究进展

本文论述了不同性能染料的合成方法，尤其是用溶胶-凝胶法合成高分子染料。综述了有机染料在光电功能材料方面的应用及其研究进展，并对光电功能性有机染料今后的发展方向做了展望。有46篇参考文献。     

Liquid phase extraction of azo dyes by novel calixarenes bearing phthalonitrile and diiminoisoindoline groups

This paper presents a study on the removal of azo dyes [Methyl Orange (MO) and Trapaeolin 000 (TP)] from aqueous solution using new phthalonitrile and isoindoline substituted calix[n]arene derivatives into the organic phase in order to explore the potential use of these calixarenes as low-cost efficient extractants for removal of these azo dyes from wastewater. The effect of NaCl concentration, contact time, and pH on the extraction of these azo dyes was also investigated for all calixarene derivatives. The stoichiometric ratio between the calixarene derivatives (5 and 6) and selected azo dyes (MO and TP) was estimated through job’s plot.     

One‐pot preparation of multicolor polymeric nanoparticles with high brightness by single wavelength excitation

Fluorescent nanoparticles with multiplex distinct emission signatures and high brightness by a single wavelength excitation are substantially needed in multiplex bioassays and imaging. In this study, we synthesized fluorescent polymeric nanoparticles incorporated with three polymerizable organic dyes via a one‐pot miniemulsion. By altering the doping ratio of three tandem dyes, the nanoparticles display abundant multiple fluorescence such as blue, cyan, green, orange, pink, red etc., together with distinguishable emission signatures under a single wavelength excitation, which were arising from the effective fluorescence resonance energy transfer (FRET) between the three energy‐matched dyes. Meanwhile, a large Stokes shift (up to 250 nm) can be generated by taking place multiple FRET cascade mechanism between donor and acceptor fluorophores in nanoparticles, which also suggests broad applications in biological labeling and imaging. Moreover, these nanoparticles are uniform in size, highly bright, excellently photostable, and shown prominent longterm stability. Overall, the novel multicolor fluorescent polymeric nanoparticles augur well for their potential applications in multiplexed bioanalysis and emitting displays. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41492.     

VIS absorption spectrophotometry of disperse dyes

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the disazo dye C.I. Disperse Orange 29 and the anthraquinone dye C.I. Disperse Blue 56, were used for spectroscopic analysis in this present work. The absorbance of aqueous dye dispersions and various organic solvent dye solutions was measured to evaluate the effect of the solvent on the shape and intensity of the absorption spectra and on the wavelength shift of maximum absorption. The validity of Beer–Lambert’s law in each system was ascertained. A suggestion is made how VIS absorption spectrophotometry can be used to determine the dye concentration in disperse dyebaths. The addition of organic solvent to the dyebath leads to dye dissolution, and the Beer-Lambert’s law is then fulfilled. The optimum ratio between the dyebath dispersion and the organic solvents for the dyes investigated is also determined.     

New solvatochromic merocyanine dyes based on Barbituric acid and Meldrum's acid

Two new types of solvatochromic merocyanine dyes derived from either Meldrum's acid or Barbituric acid have been synthesized by the condensation of 4-((2-hydro xyethyl)(methyl)amino) benzaldehyde with 5-(2,6-dimethyl-4H-pyran-4-ylidene) Meldrum's acid and 5-(2,6-dimethyl-4H-pyran-4-ylidene) Barbituric acid, respectively. The solvatochromic responses of the merocyanine dyes in 22 solvents of widely different polarities were measured; positive solvatochromism, with a large absorption bathochromic shift, was observed on moving from xylene to DMSO, corresponding to their maximum fluorescence emission with a large bathochromic shift. The dyes have the potential for the development of efficient probes for the detection of volatile organic compounds.     

Synthesis and characterization of solubility enhanced metal-free phthalocyanines for liquid crystal display black matrix of low dielectric constant

For the liquid crystal display (LCD) black matrix (BM) with a low dielectric constant and high light absorption property, it is advantageous to employ dyes instead of carbon black or pigments. For this purpose, the dyes should have high solubility in industrial organic solvents. For improved solubility in industrial solvents, three metal-free phthalocyanines (PC), peripherally substituted with bulky groups, were synthesized and dye-based BMs were fabricated. The solubility as well as the spectral and thermal properties of the dyes were examined, and the optical, thermal and dielectric properties of a dye-based black matrix were tested. The greenish phthalocyanine dyes with high molar extinction coefficients and high thermal stability showed enhanced solubility in industrial solvents as a result of the greater steric hindrance among the dye molecules and higher affinity between the dye molecules and solvents. The dye-based BMs had low dielectric constants and exhibited superior optical properties and satisfactory thermal stability.     

The synthesis of novel perylene-like dyes and their aggregation properties in Langmuir and Langmuir-Blodgett films

The synthesis of novel perylene-like dyes with different length and molecular structure of terminal chains substituted to the main perylene core is described. The dyes are able to form compressible and stable monolayers at the air-water interface (Langmuir films), which can be easily transferred onto solid substrates (Langmuir-Blodgett films). In the Langmuir and Langmuir-Blodgett films, the dye molecules show tendency to creation of self-aggregates, both in the ground and excited electronic states. The influence of the molecular structure of the substituents on the aggregation properties is observed and discussed.     

溴代苝二酰亚胺衍生物的光谱及其在溶液中的聚集

设计合成了一种新型的苝二酰亚胺衍生物1,6,7,12-四溴代-N,N-丙酸2-(2-氨基乙氧基)乙醇酯苝四羧酸酐.研究了在不同有机溶剂中的紫外、荧光光谱性能以及相应的聚集行为.光谱研究表明,在4种不同的溶剂中,临界聚集浓度不同.随着溶液浓度的增加,化合物分子呈斜线发生面-面堆积.SEM观察了在有机溶液中的聚集形貌,受分...     

蓝-绿波段激光染料的研究

合成了 4个蓝 -绿波段的激光染料 ,测定了它们的光谱数据和激光性能 ,结果表明含三氟甲基的 2个染料具有较宽的调谐范围 :470～ 540nm和 456～ 51 6nm ;较高的激光效率 :41 4%和2 6 6%。同时 ,分别采用Nicol理论和Lippert理论对其中 2个香豆素型激光染料的吸收光谱和发射光谱的溶剂效应进行了研究 ,揭示了染料Stokes红移的内在本质。     

6种燕尾形苝二酰亚胺类双子表面活性剂对碱性锌电极缓蚀机理理论研究

为了研究燕尾型苝二酰亚胺类双子表面活性剂对碱性锌电极缓蚀机理,利用密度泛函理论（DFT）和分子动力学模拟（MD）方法,探讨了两类共6种燕尾型苝二酰亚胺类双子表面活性剂的吸附行为。DFT计算结果表明,前线分子轨道分布主要位于分子核心的苝二酰亚胺骨架上,且苝二酰亚胺骨架上的N原子为分子的反应活性中心。分子动力学模拟表明,6种燕尾型苝二酰亚胺类双子表面活性剂均能与水溶液中的金属锌表面发生相互作用,N₂、P₂在两类双子表面活性剂中均表现出有较高的吸附能和较大的扩散系数,吸附能分别为-11315.868 kcal/mol、-10785.698 kcal/mol,扩散系数分别为2.5、1.32;研究结果同时表明,N₂和P₂形成的双子表面活剂膜层对腐蚀粒子OH^-的阻止效果较好,能够在金属锌表面起到很好的缓蚀效果。