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Aggregation-amplified circularly polarized luminescence from axial chiral boron difluoride complexes
摘要： The development of small organic molecules with intense and switchable circularly polarized luminescence (CPL) is currently attracting great interest due to their promising applications in chiroptical devices and sensors. In this paper, CPL-active BF2-bridged azaanthracene dimers (BA1 and BA2) were facilely synthesized by incorporating boron difluoride unit to the bi-naphthalene. BA1 and BA2 show moderate CPL in diluted solutions, however, BA2 exhibited aggregation-amplified red CPL with large dissymmetry factor up to 1.6×10?2. Moreover, acid-/base-triggered CPL switch off/on were also realized via disaggregation/aggregation of BA2 in tetrahydrofuran (THF)/water binary solvents.
关键词： aggregation-induced emission,bodipy,circularly polarized luminescence,switch,dyes and pigments
更新于2025-09-23 15:22:29
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Near-infrared fluorescence laparoscopy of the ureter with three preclinical dyes in a pig model
摘要： Background Ureteric injury is reported to occur in 1–7.6% of colorectal surgeries. To reduce the incidence of ureteral injury, it is essential to identify the ureters. The use of near-infrared fluorescence (NIRF) imaging with intravenously administered dyes might be of added value for ureteral visualization during laparoscopy. The aim of this study is to assess the performance of three preclinical dyes; IRDye? 800BK, IRDye? 800NOS and IRDye? 800CW, for near-infrared fluorescence laparoscopy of the ureter in pigs. Methods In three female Dutch landrace pigs, the new dyes were evaluated. In each pig, 1 dye was tested using a 6-mg intravenous dose in a concentration of 1?mg/ml. Imaging was performed in fluorescence mode and white light mode with a laparoscopic imaging system. In order to further evaluate the dyes, an ex?vivo imaging experiment was performed, in which 8 decreasing concentrations per dye, diluted in PBS, were evaluated in a transparent test tube with NIRF mode at a distance of 1, 5 and 10?cm from the laparoscope. Results All three dyes were effective in allowing the identification of the ureter with NIRF imaging. The ureter became fluorescent after 35, 45 and 10?min, respectively, for IRDye? 800BK, IRDye? 800NOS and IRDye? 800CW with a maximum target-to-background ratio (TBR) of 2.14, 0.66 and 1.44, respectively. In the ex?vivo imaging experiment, all three dyes produced a strong fluorescence signal at all concentrations and all distances evaluated. Conclusions Intravenous administration of the preclinical dyes IRDye? 800CW, IRDye? 800 BK and IRDye? 800NOS facilitated successful identification of the anatomical course of the ureter in living pig models. The highest measured TBR occurred with the use of IRDye? 800BK. Ex?vivo, a correlation was observed between the fluorescence intensities of the signal with the concentration of the dye and with the distance to the object.
关键词： laparoscopic colorectal surgery,Near-infrared fluorescence imaging,Ureter,Fluorescent dyes
更新于2025-09-23 15:21:21
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Kinetic Analysis of Liquid Phase Photocatalysis and Photolysis: A Frequent Disguise!
摘要： Studies of phenol photocatalyzed oxidation, and organic dye photolyzed or photocatalyzed destruction which involve variable initial concentrations, Co, often assume pseudo first order behavior, and fit data to a semilog plot of concentration, C(t) vs time, and find that the apparent first order rate constant decreases with increasing Co. We show from multiple literature examples that this behavior often disguises a true zero order initial rate of reaction. We recommend a re-analysis of existing literature reporting first order rate constants which vary with initial reactant concentration, Co.
关键词： Photocatalysis,rate law,phenol,kinetics,dyes
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM ON CURRENT PROGRESS IN MATHEMATICS AND SCIENCES 2017 (ISCPMS2017) - Bali, Indonesia (26–27 July 2017)] - Bismuth vanadate (BiVO4) as counter electrode in the newly developed catalysis zone of modified cadmium sulfide (CdS) sensitized solar cell for hydrogen production
摘要： Recently we developed a modified quantum dot dyes sensitized solar cell (QD-DSSC) having catalysis zone extension for hydrogen production. The DSSC section comprised of CdS sensitized highly order Titanium dioxidenanotube (CdS-HOTN) immobilized on Ti plate, Na2S/S containing electrolyte, and Pt covered SnO-F (fluorine doped tin oxide) glass plate (hence Pt/SnO-F/Glass). While the catalysis zone comprised of an extension of Ti support, as cathode, and the respected counter electrode was an extension of SnO-F glass, which was covered by BiVO4 film, both from respected DSSC section. In this presentation, we will focus on the role of the BiVO4 in our newly developed system. The bismuth vanadate was prepared by co-precipitation method with ammonia and calcination to obtain a fine powder. The BiVO4 fine powder were then deposited onto SnO-F glass plate and characterized by FT-IR, UV–vis diffused reflectance spectroscopy, SEM and X-ray diffraction. The characterization results revealed that the BiVO4 film, typically, has a band gap of 2.35 eV, characteristic of IR peaks represent the –V-O-, and –Bi-O-V- bonds, having a crystal phase as BiVO4 monoclinic scheelite with a typically crystallite size of 74.06 nm. The photo-electro-chemical properties of the BiVO4 film photo-anode was investigated by a linear sweep voltammetry and multi pulse amperometry, which revealed that the current response under the visible light was 0.03 mA/cm2. Further investigation when the BiVO4 film was incorporated into the modified QD-DSSC, the system (catalysis zone section), under solely visible light, was able to split the water into hydrogen and molecular oxygen. A brief discussion of the newly developed modified QD-DSSC, especially on the role of BiVO4 counter electrode in the catalysis zone will be presented, to gain a better insight in our new type artificial photosynthesis.
关键词： water splitting,titanium dioxide nanotubes,cadmium sulfide,artificial photosynthesis,modified dyes sensitized solar cell,Bismuth vanadate
更新于2025-09-23 15:21:21
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Novel A2-D-A1-D-A2 type NIR absorbing symmetrical squaraines based on 2, 3, 3, 8-tetramethyl-3H-pyrrolo [3, 2-h] quinoline: Synthesis, photophysical, electrochemical, thermal properties and photostability study
摘要： Two novel acceptor–donor-acceptor-donor-acceptor type pi-conjugated symmetrical squaraine dyes, denoted by PQSQ 1 and PQSQ 2 based on 2, 3, 3, 8-tetramethyl -3H-pyrrolo [3,2-h] quinoline were successfully synthesized for the first time to arrive absorption and emission at NIR region. These dyes comprise indolenines as electron donor units, squaryl ring as a central electron acceptor and pyridines as terminal electron acceptor units. The relationship between molecular structures and photophysical properties of these dyes was studied in comparison with their parent compounds (ISQ and N-Et ISQ). These novel squaraine dyes displayed an intense absorption within the range 671 to 692 nm in polar to non- polar solvents respectively with good molar extinction coefficients (? 105 Lmol-1cm-1). Compared to their parent squaraines, both dyes showed red-shifted absorption (33 - 44 nm) as well as emission (38 - 59 nm) due to the electron-accepting ability of the ancillary pyridine acceptors and extended pi-conjugation. These dyes exhibited negative solvatochromism and Reichardt's ET (30) scale was applied to propose a quantitative relationship of the relative stability of ground and excited-state of these squaraines with solvent polarity. The electrochemical and computational properties of these symmetrical squaraines were investigated with the help of cyclic voltammetry and density functional theory (DFT). Moreover, PQSQ 1-2 exhibited high thermal and photo-stability. These A2-D-A1-D-A2 type dyes showed improved photostabilities compared to their parent D-A-D type dyes.
关键词： 2, 3, 3, 8-tetramethyl -3H-pyrrolo [3, 2-h] quinoline,NIR absorbing dyes,acceptor-donor-acceptor-donor-acceptor,squaraines,DFT computations,red shift
更新于2025-09-23 15:21:21
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Self-Assembly of a Carboxyl-Functionalized BODIPY Dye via Hydrogen Bonding
摘要： We report the synthesis, characterization, and self-assembly behavior of a 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dye functionalized at the meso-position with a butyric acid group. Various spectroscopic investigations (UV-Vis, emission, and Fourier-transform infrared spectroscopy (FTIR) studies) supported by X-ray analysis revealed the formation of self-assembled structures in the solid state with translationally stacked BODIPY units driven by hydrogen bonding between the carboxyl groups.
关键词： hydrogen bonding,Self-Assembly,weak non-covalent interactions,BODIPY dyes
更新于2025-09-23 15:21:21
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Glass-forming derivatives of 2-cyano-2-(4H-pyran-4-ylidene) acetate for light-amplification systems
摘要： A series of 2-cyano-2-(4H-pyran-4-ylidene) acetate derivatives with triphenyl and 9H-carbazole moieties were synthesized and investigated, mostly for potential applications in organic solid state lasers. Synthesized compounds show remarkable amorphous film formation ability, tunable thermal properties (thermal stability varies from 190 °C to 387 °C and glass transition temperature from 94 °C up to 141 °C) with light absorption from 400 nm to 600 nm and photoluminescence from 600 nm up to 800 nm. Dyes with incorporated mono-styryl-electron donating fragment (KTB, KTBC and KTB3K) showed higher photoluminescence quantum yield (PLQY) (from 16% up to 23%), significantly lower amplified spontaneous emission (ASE) excitation threshold values (24–52 μJ/cm2) in pure thin films comparing to bis-styryl- electron donating fragment containing molecules (Bis-K4C, Bis-K5C and Bis-K4CK) with PLQY of 5–7% and ASE excitation threshold between 165 and 223 μJ/cm2. Some of the investigated KTB-type laser dyes could be perspective materials for organic lasers as well as for laser technology investigation and applications.
关键词： 4H-pyran-4-ylidene,Laser dyes,2-cyanoacetates,Amplified spontaneous emission,Amorphous materials
更新于2025-09-23 15:21:21
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Synthesis and Photophysical Properties of Multichromic Nanocrystals of Polymethine Dyes
摘要： A unique method for the self-assembly of multilayer multichromic molecular crystals from three various polymethine dyes absorbing light in the broad spectral range has been developed. This method is based on the formation of an anionic platform of J-aggregates of magnesium complexes of thiamonomethinecyanines in an aqueous solution followed by the matrix synthesis of J-aggregates of two cationic trimethinecyanines on the surface of the platform. Spectral, luminescent, and photoelectric properties of the multichromic crystals of dyes have been studied. It has been shown that each multichromic organic crystal is a multilayer photoelement which possesses photoconductivity in three maxima of exciton absorption in the blue, green, and red spectral ranges with efficiency from 2.7 to 6.1%. The results form the basis for the technological development of high-organized molecular structures possessing unique optical and photoelectric properties with the aim of applying them in organic and hybrid organic/inorganic photonics and optoelectronics, including in the form of thin-film photoconverters in broad spectral ranges.
关键词： multichromic nanocrystals,polymethine dyes,nanophotonics,photoelectric properties,J-aggregates
更新于2025-09-23 15:21:21
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Engineering of ZnO/rGO nanocomposite photocatalyst towards rapid degradation of toxic dyes
摘要： ZnO quantum dot (QD) is prepared in a soft chemical route by ageing process and successfully embedded on reduced graphene oxide (rGO) surface using solvothermal method as confirmed by XRD, TEM and Raman studies. Due to charge transfer from the lowest unoccupied molecular orbital of the rGO layer to the conduction band of ZnO, the luminescence of rGO is also found to be quenched in ZnO/rGO composites. A brief systematic study of photocatalytic behavior towards degradation of various toxic medical and textile dyes, like Safranin O, Methylene blue and Rhodamine 6G by ZnO QD and ZnO/rGO composites are showcased in this work. As a result of high surface to volume ratio, ZnO QD showed good photocatalytic activity towards degradation of different dyes under ultraviolet (UV) irradiation. A composite with ZnO and rGO in 3:1 wt ratio degraded almost 100% of dyes under UV irradiation within 15, 25 and 30 min, showing good efficacy in dye degradation. Photoluminescence lifetime measurement revealed the charge transfer process from rGO to ZnO resulting a Prompt recombination of the UV light induced electron-hole pair in ZnO/rGO composite.
关键词： Reduced graphene oxide,ZnO QD,Composite,Toxic dyes,Photocatalyst
更新于2025-09-23 15:21:21
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Improving the Visible-Light Photocatalytic Activity of Graphitic Carbon Nitride by Carbon Black Doping
摘要： Hydrogen production by water splitting and the removal of aqueous dyes by using a catalyst and solar energy are an ideal future energy source and useful for environmental protection. Graphitic carbon nitride can be used as the photocatalyst with visible light irradiation. However, it typically suffers from the high recombination of carriers and low electrical conductivity. Here, we have developed a facile mix-thermal strategy to prepare carbon black-modified graphitic carbon nitrides, which possess high electrical conductivity, a wide adsorption range of visible light, and a low recombination rate of carriers. With the help of carbon black, highly crystallized graphitic carbon nitrides with built-in triazine and heptazine heterojunctions are obtained. Improved photocatalytic activities have been achieved in carbon black-modified graphitic carbon nitride. The dye removal rate can be three times faster than that of pristine graphitic carbon nitride and the photocatalytic H2 generation is 234 μmol h?1 g?1 under visible light irradiation.
关键词： aqueous dyes removal,hydrogen production,carbon black doping,graphitic carbon nitride,visible-light photocatalytic activity
更新于2025-09-23 15:21:21