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Halloysite based nanocomposites and photocatalysis: A Review
摘要： Heterogeneous photocatalysis is an e?cient, relatively cheap and environmentally friendly technology for decomposing various organic and air pollutants. Halloysite is a natural clay mineral usually in the form of nanotubes that has many applications as well as potential uses including photocatalysis. In this paper the photocatalytic activities of halloysite-based nanocomposites in combination with various photocatalysts that have been synthesized and tested in decomposing organic and air pollutants are reviewed. Many photocatalysts have been synthesized and among them TiO2 in the form of anatase, or rutile, or a mixture of both is the most common photocatalyst due to its e?ectiveness and low cost. Researches by many investigators are summarized and discussed. The possibilities and limitations of halloysite-based nanocomposites for future applications are also discussed and new ?elds of research are proposed. It is suggested that Halloysite-based nanocomposites are more promising in positively charged organic substrates like tetracycline and Rhodamine B where the organic pollutant is attracted by halloysite's negatively charged external surfaces close to the photocatalysts, than neutral like paracetamol or negatively charged which that attraction does not occur.
关键词： Azo dyes,Halloysite nanocomposite,Halloysite,TiO2,VOCs,Heterogeneous catalysis,Air pollutants,Photocatalysis
更新于2025-09-09 09:28:46
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Non-linear Optical Response of Triphenylamine Dyes with D-A-π-A Structure
摘要： In this study, we have designed new triphenylamine dyes with D-A-π-A structure and calculated their electro-optical and non-linear properties. Computational techniques were used to study the effect of additional acceptor in π-conjugated systems on absorption spectra and non-linear properties. All the dyes show absorbance in visible region. During theoretical examination polarizability (α), hyperpolarizability (β) and electronic transitions were calculated. Results indicated that the selection of appropriate lengths of conjugated bridges in dye is very important to design high efficiency dyes. This theoretical frame work would be useful to design other organic dyes.
关键词： Hyperpolarizability,Organic dyes,DFT,Polarizability
更新于2025-09-09 09:28:46
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Mix-&-Read Determination of Mercury(II) at Trace Levels with Hybrid Mesoporous Silica Materials Incorporating Fluorescent Probes by a Simple Mix-&-Load Technique
摘要： The synthesis, characterization, and application of mesoporous materials containing boron–dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of HgII in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye I containing a thia-aza crown ether receptor as the fluorescent probe for the detection of HgII in aqueous environments is encapsulated into mesoporous materials to avoid self-quenching or aggregation in water. Determination of HgII is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt. The determination of trace amounts of HgII in natural waters and in fish extracts is demonstrated by using our sensing material. The incorporation of the material into several m-PAD strips yields a portable, cheap, quick, and easy-to-handle tool for trace HgII analysis in water.
关键词： dyes/pigments,mercury,fluorescence,mesoporous materials,test strips
更新于2025-09-09 09:28:46
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Triphenylethylene- and Tetraphenylethylene-Functionalized 1,3-Bis(pyrrol-2-yl)squaraine Dyes: Synthesis, Aggregation-Caused Quenching to Aggregation-Induced Emission, and Thiol Detection
摘要： Three novel pairs of 1,3-bis(pyrrol-2-yl)squaraine dyes, N-alkylated SQ1a?1b, and N-phenylated SQ2a?2b in which triphenylethylene moieties functionalized at 5-position of pyrrole, as well as SQ3a?3b with tetraphenylethylene (TPE) moieties attached at N-position of pyrrole, were synthesized. All six dyes were found not to exhibit aggregation-induced emission (AIE) properties. Spectrophotometric studies showed that N-TPE-functionalized SQ3a?3b exhibited much larger molar extinction coefficients (ε: 1.36?2.14 × 105 M?1 cm?1) than 5,5′-triphenylethylene-functionalized SQ1a?2b (ε: 2.17?8.22 × 104 M?1 cm?1). Surprisingly, SQ2b showed a remarkable red-shifted maximum absorption (λmax: 723 vs 631?652 nm) compared to that of other squaraine dyes. All six squaraine dyes selectively responded to the addition of thiol-containing biomolecules, such as cysteine and gluthatione, with the disappearance of λmax in the near-infrared region in their respective absorption spectra. Interestingly, the thiolated species of SQ3a?3b were AIE active, with the characteristic AIE emission of TPE at λmax = 484?490 nm upon addition of water. Further thiol sensing on solid supports was examined, indicating the potential applications of TPE-functionalized squaraine dyes as bioprobes for the detection of important thiol-containing biomolecules, with a clear change from aggregation-caused quenching to AIE.
关键词： bioprobes,aggregation-induced emission,near-infrared,thiol detection,squaraine dyes
更新于2025-09-09 09:28:46
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Photochemistry and Photophysics - Fundamentals to Applications || Tailoring the Photophysical Signatures of BODIPY Dyes: Toward Fluorescence Standards across the Visible Spectral Region
摘要： The modern synthetic routes in organic chemistry, as well as the recent advances in high-resolution spectroscopic and microscopic techniques, have awakened a renewable interest in the development of organic fluorophores. In this regard, boron-dipyrrin (BODIPY) dyes are ranked at the top position as luminophores to be applied in photonics or biophotonics. This chromophore outstands not only by its excellent and tunable photophysical signatures, but also by the chemical versatility of its core, which is readily available to a myriad of functionalization routes. In this chapter, we show that, after a rational design, bright and photostable BODIPYs can be achieved along the whole visible spectral region, being suitable as molecular probes or active media of lasers. Alternatively, the selective functionalization of the dipyrrin core, mainly at meso position, can induce new photophysical phenomena (such as charge transfer) paving the way to the development of fluorescent sensors, where the fluorescent response is sensitive to a specific environmental property.
关键词： fluorescent probes,laser dyes,charge transfer,organic synthesis,BODIPY,fluorescent sensors
更新于2025-09-09 09:28:46
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Nanotechnology in Water and Wastewater Treatment || Photocatalytic Decolorization of Two Remazol Dyes Using TiO2 Impregnated Pumice Composite as Catalyst
摘要： This study, as a first attempt, aimed to evaluate photocatalytic decolorization of of two remazol dyes (blue and red) using TiO2 impregnated pumice composite catalyst. The SEM-EDX analysis showed that TiO2 nanoparticules were mostly impregnated on the pores of pumice with a ratio of 1.60% Ti. A 97.8% and 97.6% of color removal was achieved for RB and RR at pH 3, respectively, whereas those color removal percentages decreased to 57.4% and 53.9%, respectively, at pH 11 after 2 hours illumination. The color removal efficiencies of 97.8%, 82.7%, and 75.3% for RB dye and of 97.6%, 85.3%, and 84.0% for RR dye were observed after first, second, and third cycles reuse of the synthesized catalyst. Toxicity of photocatalytic treated samples of both dyes decreased below 50% after 90 and 120 minutes irradiation when they were diluted at 75%. This result indicate there is an urgent need to prolong the irradiation time and/or for increasing catalyst dose to completely remove toxicity in the undiluted samples.
关键词： TiO2 impregnated pumice composite,Remazol dyes,Photocatalytic decolorization,Toxicity,UV-A illumination
更新于2025-09-09 09:28:46
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Media Dependent Switching of Selectivity and Continuous Near Infrared Turn-on Fluorescence Response through Cascade Interactions from Noncovalent to Covalent Binding for Detection of Serum Albumin in Living Cells
摘要： Abnormal level of proteins is proved to be associated with diseases. Thus, protein sensing is helpful for clinical diagnosis and therapy. However, there is a great variety of protein species and relatively low concentration of each protein in complicated biological systems including other non-protein biomolecules. Therefore, it remains challenging to develop an effective method for detecting protein with high selectivity and sensitivity. Herein, a new self-assembly method based on a robust dye SQSS of which two squaraine molecules were conjugated through disulfide bond was developed for highly selective and sensitive detection of serum albumin (SA) in aqueous solution and live cells. SQSS can self-assemble into “compact” aggregates, offering “inert” disulfide group and very low background fluorescence through the combination of aggregation quenching and homogeneous fluorescence resonance energy transfer (homoFRET) quenching. The response of SQSS to SA undergoes two cascade stages. At the first stage, SA drives the compact assemblies of SQSS to form loose ones with fast speed (30 s) through noncovalent interaction, resulting in the enhancement of fluorescence to some extent. In this loose assembly state, the disulfide bond in SQSS is reactive. At the second stage, the Cys34 in SA slowly induced further disassembly through covalent binding with reactive disulfide bond, resulting in fluorescence further increasing and SQSS labeling to SA that cannot be displaced by site binding ligands of SA. The self-assemblies of SQSS can selectively detect SA with continuous near infrared (NIR) turn-on fluorescence response in 100% aqueous buffer solution. In addition, SQSS showed the potential application of imaging SA in living cells. On the other hand, the loose assembly state of SQSS was also achieved in aqueous solution with 20% CH3CN. In this media, thiol-containing glutathione (GSH) caused the disassembly of SQSS with turn-on fluorescence response through interaction with disulfide bond. SQSS can selectively recognize GSH over other amino acids even in the presence of other sulfhydryl amino acids. As a proof-of-concept method, the molecular self-assembly through multi-steps interactions would provide an ideal strategy for detection and live-cell imaging of bio-related molecules with high selectivity and signal-to-noise ratio.
关键词： squaraine dyes,disulfide linkage,glutathione,live-cell imaging,serum albumin,self-assemblies,noncovalent and covalent interactions
更新于2025-09-09 09:28:46
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Photocatalytic Degradation of Reactive Dyes Over Titanates
摘要： MTiO3 (M = Sr, Ca, Ba and Pb) catalysts were synthesized by polymeric precursor method and characterized by using various instrumental techniques such as X-ray diffraction (XRD), UV-diffuse reflectance spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TiO2 were also synthesized by sol–gel method and used for the optimization of reaction parameters such as catalyst weight, dye concentration and pH in the photocatalytic degradation of reactive dyes such as reactive blue 198 (RB 198), reactive black 5 (RB 5) and reactive yellow 145 (RY 145) under UV irradiation. MTiO3 (M = Sr, Ca, Ba and Pb) catalysts were evaluated towards the photocatalytic decolourization of RB 198, RB 5 and RY 145 under optimized reaction conditions. Among the different metal titanates, strontium titanate showed the highest decolourization (≈90%) of all the three reactive dyes under UV irradiation at 120 minutes and also found to be active under visible irradiation as it decolourises the dyes in about 450 minutes. The degradation rate of strontium titanate was monitored by TOC analyzer. Kinetic studies of the photocatalytic degradation of reactive dyes confirmed that the reaction followed the pseudo first order kinetics.
关键词： Perovskites,Reactive Dyes,Polymeric Precursor,UV-Visible Degradation,Sol–Gel
更新于2025-09-04 15:30:14
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Photoelectric Properties and Drive Characteristics of GH Liquid-Crystal Cells in Various Alignment Modes
摘要： Photoelectric properties and drive characteristics of guest-host (GH)-type liquid crystal cells with yellow, magenta, cyan, green, and gray colors using 4-cyano-4'-pentylbiphenyl (5CB) and three diazo-based dichroic dyes were systematically investigated in different driving modes. The dichroic dyes have structures similar to 5CB; therefore, they uniformly mixed and dispersed into the liquid crystal matrix. The green and gray colors were obtained by mixing appropriate ratios of two or more dyes. Impedance of the GH cells decreased upon the incorporation of the dyes into 5CB. However, the photoelectric properties and drive characteristics of the liquid crystal cells were not altered after the inclusion of the dye. In particular, the alignment of the molecules strongly depended on the cell structure. The GH cells in twisted nematic mode exhibited a low driving voltage of approximately 1.5 V.
关键词： Dichroic dyes,Guest-host cell,Liquid crystal,In-plane-switching,Twisted nematic
更新于2025-09-04 15:30:14
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Amorphous Quantum Nanomaterials
摘要： In quantum materials, macroscopic behavior is governed in nontrivial ways by quantum phenomena. This is usually achieved by exquisite control over atomic positions in crystalline solids. Here, it is demonstrated that the use of disordered glassy materials provides unique opportunities to tailor quantum material properties. By borrowing ideas from single-molecule spectroscopy, single delocalized π-electron dye systems are isolated in relatively rigid ultra-small (<10 nm diameter) amorphous silica nanoparticles. It is demonstrated that chemically tuning the local amorphous silica environment around the dye over a range of compositions enables exquisite control over dye quantum behavior, leading to efficient probes for photodynamic therapy (PDT) and stochastic optical reconstruction microscopy (STORM). The results suggest that efficient fine-tuning of light-induced quantum behavior mediated via effects like spin-orbit coupling can be effectively achieved by systematically varying averaged local environments in glassy amorphous materials as opposed to tailoring well-defined neighboring atomic lattice positions in crystalline solids. The resulting nanoprobes exhibit features proven to enable clinical translation.
关键词： photodynamic therapy (PDT),optical super-resolution microscopy,organic dyes,amorphous silica nanoparticles
更新于2025-09-04 15:30:14