Journal of Photochemistry and Photobiology A-chemistry最新文献

In response to the growing demand for photoluminescent (PL) systems with versatile emission color tuning capabilities, particularly in the realm of contemporary versatile optoelectronic devices, we have developed a straightforward and environmentally friendly PL system. This system is designed to effectively tune its photoluminescence color response to various stimuli, including the system’s composition and excitation wavelength. Notably, our PL system achieves an almost pure white light emission (WLE), which has significant value in diverse applications. To create this interesting system, we combine two nano-Group of Uniform Materials Based on Organic Salts (nano-GUMBOS), namely nPBIL and nRBS, within an aqueous mixture. By precisely adjusting the composition of these nano-GUMBOS, we successfully achieved a near-pure WLE with a Commission Internationale d’Eclairage (CIE) 1931 color profile of (0.31, 0.31) when excited at a wavelength of 365 nm. This achievement demonstrates the system’s capability to produce high-quality WLE, meeting the requirements for efficient and aesthetically pleasing illumination which is significant to various optoelectronic applications. The straightforward synthesis process and environmentally friendly nature of our PL system make it an attractive choice for various lighting and display applications. The adaptability and tunability of the emission color add further versatility to its potential uses, providing opportunities for state-of-the-art solutions in the field of optoelectronic technology.

Iodine in natural and treated waters exists mainly as iodide, iodate, and molecular iodine (I₂). I₂ is a highly volatile and reactive species impacting biological and chemical systems. Iodine, a vital micronutrient, is essential for human and animal growth and metabolism. It also plays a crucial role in synthesising artificial adrenaline within the metabolic processes of humans and animals. It is also widely used as an antiseptic, disinfectant, and for emergency water disinfection. Moreover, iodine deficiency can result in various diseases, especially hypothyroidism and goitre. Given its critical functions, it is imperative to have a straightforward, dependable, and efficient method for monitoring iodine levels. This study introduces a simple and innovative I₂ detection system based on its reactivity, toxicity, and role as an indicator of oxidative conditions in water. It operates in terms of based on optical and electrochemical signal changes, utilising the anti-aggregation mechanism of gold nanoparticles (AuNPs) and 6-mercaptohexanol (MHA) for sensitive and selective detection under mild conditions. I₂ determination is achieved by observing the colour change in AuNPs, which is influenced by competitive interactions between MHA, I₂, and AuNPs. The optical detection system, with its low detection limit (LOD=260 nM), is based on the straightforward observation of colour changes. On the other hand, the electrochemical detection method utilises changing redox peaks observed in anodic region, providing selective and sensitive I₂ detection (LOD=100 nM). The probe effectively detects the presence of I₂ in real water samples as a practical application. Moreover, the proposed method revolutionises I₂ detection by incorporating a smartphone for signal reading, eliminating the need for specialised equipment and significantly reducing the detection cost. This cost-effective approach carries the potential to expedite on-site and naked-eye I₂ detection, opening up new possibilities for research and application.

The main purpose of this work is to study the possibility of using ionic modification of (1-x)WO₃ – xZnO microcomposite ceramics in order to elevate their photocatalytic activity, as well as enhance stability to degradation during long-term use and exposure to aggressive environments. The objects of study were (1-x)WO₃ – xZnO ceramics obtained by solid-phase synthesis from tungsten and zinc oxides. Moreover, according to X-ray phase analysis data, it was found that variations in the ratio of oxide components during their mechanical activation and subsequent thermal annealing result in the formation of two-phase ceramics with different contents of the zinc tungstate phase. The results of experiments on the photocatalytic decomposition of the organic dye Rhodamine B revealed that two-phase WO₃/ZnWO₄ ceramics have the greatest efficiency, for which ion irradiation with fluences of 10¹⁵ ––5 × 10¹⁵ leads to a growth in the decomposition efficiency from 80 to 95 %. At the same time, the dominant effect influencing the photocatalytic decomposition efficiency growth is the change in the band gap of the ceramics, associated with the accumulation of the athermal effect of energy dissipation of incident ions on the change in electron density. The results of assessment of changes in the strength and structural parameters of (1-x)WO₃ – xZnO ceramics depending on the time spent in model solutions (to simulate the effects of environments with different acidity levels) indicate a positive effect of ionic modification on enhancing stability to degradation and softening as a result of the accumulation of amorphous inclusions.

In this study, we investigate the optical, photovoltaic, and structural properties of TiO₂ nanostructures produced by alcoholysis using various alcohols. An X-ray diffraction study highlights how the choice of alcohols affects the process by revealing variations and separation. The anatase phase is confirmed by Raman spectroscopy, which also sheds light on the effects of various alcohols. The granular nature of TiO₂ microstructures is demonstrated using scanning electron microscopy. We demonstrate how the size and shape of microstructures influence the band gap using absorption spectroscopy. Using fluorescence spectroscopy and Franck-Condon analysis, we investigated the performance of the α-Quaterthiophene + 40 % TiO₂ nanocomposite. Important parameters are then taken out of the analysis using the Franck-Condon technique. Studies on the photovoltaic performance of the α-Quaterthiophene + 40 % TiO₂ nanocomposite active layer show significant improvements in both open-circuit voltage and short-circuit current when TiO₂ nanostructures are incorporated. This demonstrates the enormous potential of TiO₂ nanostructures to improve solar cell applications’ efficiency. Self-assembly fabrication of TiO₂ microspheres via the alcolysis process and their effect on exciton dissociation in hybrid systems is a topic of interest in materials science and nanotechnology.

A new heterocyclic Schiff base, 2-(2-benzo(d)thiazol-2yl)hydrazono)methyl)phenol (BTAZ) synthesized from 2-hydrazinobenzothaizole and salicyclaldehyde was characterized by spectral, mass and single crystal XRD data and subjected to sense Ca²⁺ ions in methanol–water mixture (1:1, v/v) using UV–visible absorption and fluorescence emission spectral studies. The probe BTAZ showed specific detection of Ca²⁺ ions in a solution containing various metal ions with a detection limit as low as 5.1 × 10⁻⁶ M via photo-induced electron transfer (PET) pathway. The binding stoichiometry between BTAZ and Ca²⁺ was determined to be 2:1 by Job’s plot method. The stoichiometry and optical properties of both BTAZ and BTAZ-Ca²⁺ complex showed good correlation with theoretical results based on DFT and TD-DFT calculations. The pharmacological evaluation of the probe BTAZ against bacterial and fungal stains also demonstrated its notable efficacy to control their growth in vitro along with anti-oxidant capabilities. Further, toxicity assay of the probe BTAZ against zebrafish embryo did demonstrate that it is non-toxic to the test model in vivo. Ability of the probe BTAZ to inhibit matrix metalloproteinase-9 (MMP-9) enzyme was analyzed in detail using in silico experiments.

Imidazole-based ligand was developed via the Debus–Radziszewski synthetic method by direct reaction of 2,6-diformyl-4-methyl-phenol and 1,10-phenanthroline-5,6-dione and characterized by ¹H NMR, ¹³C NMR, and LCMS. The Density Functional Theory (DFT) studies for the synthesized compound have been carried out at DFT/B3LYP/6-311G(d,p) level of theory to predict the optimized molecular geometry, HOMO-LUMO energy, vibrational frequencies, MEP mapping and global reactivity descriptors. The observed results correlated with experimental results. A synthesized compound bearing an imidazole group was created as an ON-OFF fluorescent chemosensor for Fe³⁺ and V⁵⁺ ions. The probe’s UV–visible absorption and fluorescence spectral behavior towards various cations were investigated in acetonitrile/water (9:1) solution. The absorbance intensity of the probe molecule was considerably enhanced whereas the fluorescence emission intensity was quenched in the presence of these two metal cations, while the presence of other metal ions had no notable interference.

This study presents the synthesis and characterization of ICNOD, a highly selective chemosensor for detecting Ag⁺ ions in environmental and biological samples. ICNOD was synthesized by reacting n-phenyl-o-phenylenediamine with 1-isocyanate naphthalene in absolute ethanol, yielding a novel chemosensor. Fluorescence studies revealed ICNOD’s exceptional selectivity for Ag⁺ ions over other common metal ions, making it a promising detection tool. Competitive complexation experiments showed a strong affinity of ICNOD for Ag⁺ ions, with a 1:2 binding stoichiometry, highlighting its potential for sensitive detection. The detection mechanism involves a combination of Photoinduced Electron Transfer (PET OFF) and Intramolecular Charge Transfer (ICT ON), enabling selective Ag⁺ ion detection. The binding constant (Ka) of ICNOD for Ag⁺ ions was determined to be 3 × 10⁻² M⁻¹ using the Benesi-Hildebrand technique, with limits of detection (LOD) and quantification (LOQ) of 2.87 nM and 8.70 nM, respectively. Molecular modeling using DFT provided valuable insights into ICNOD’s structural features and its interaction with Ag⁺ ions, supporting the experimental findings. Spectroscopic techniques, including FT-IR, 1H NMR titration, and HR-mass spectroscopy, confirmed the binding interactions between ICNOD and Ag⁺ ions. Fukui function analysis identified potential binding sites within ICNOD for Ag⁺ ions, further elucidating the detection mechanism. The practical applicability of ICNOD was successfully demonstrated through real sample analysis, paper strip tests, and bioimaging, showcasing its potential for real-world applications.

Physicochemical properties of atomically precise metal clusters can be modulated by incorporating different metal atoms. In this article, successful one-pot synthesis of single Au-atom doped chiral AuAg₂₈ clusters protected by water-soluble N‑acetyl‑(S)‑penicillamine (=S-NAP) is reported. The reduction of Ag and Au ions at 0 °C in the presence of S-NAP and triphenylphosphine (TPP) using tetramethylammonium borohydride (TMAB) is crucial. Importantly, upon doping of an Au atom to the monometallic Ag₂₉ cluster, which improves the cluster stability, the chiroptical activity or maximum anisotropy factor of the bimetallic AuAg₂₈ cluster is enhanced as compared to that of the monometallic species, which can be due to an increase in the rotatory strength that is probably brought about by the increased contribution of optical transition associated with helically-arranged surface shell layers. Such chiroptical behaviors suggest that the Au dopant position in the bimetallic cluster is not fluxional but rigid. Then the present results will help design some heteroatom-doped silver clusters with excellent chiroptical properties.

In this work, an efficient photocatalytic system for methylparaben (MP) removal, using solar (λ > 360 nm) and visible (λ > 420 nm) light-driven CeO₂/g-C₃N₄ (CeO₂/CN) heterojunctions is reported for the first time. The physicochemical properties of pure CeO₂, CN, and CeO₂/CN composites were investigated using characterization techniques, such as XRD, FESEM-EDS, TEM, UV–Vis, PL, XPS, and electrochemical spectroscopy. Among the catalysts with different mass ratios of CeO₂, 10 %CeO₂/CN showed the best photocatalytic performance. This is attributed to the enhanced charge carrier’s separation because of the proper band-edge alignment between CN and CeO₂ components, and the strong visible light absorbance. The photocatalytic degradation of MP followed the first-order kinetics, and the 10 %CeO₂/CN catalyst exhibited a 3.8- and 11.3-times higher reaction rate (k) constant than that of pure CN, investigated under solar and visible light illumination, respectively. Further, scavenger trapping experiments confirmed that hydroxyl radicals (OH^.) and dissolved oxygen are the predominant active species in MP oxidation over 10 %CeO₂/CN composite catalyst. ¹H NMR and LCMS-HPLC results and observations showed complete degradation of MP (0.1 g/L) to CO₂ and H₂O after 7 h of solar irradiation, due to the absence of the representative peaks of MP and its organic degradation products (e.g. phenols, benzoates).

Here, L- and D-cysteine-functionalized graphene quantum dots (L-/D-cys-GQDs) were designed with the aim of obtaining a selective fluorescent nanosensor to detect L-morphine. Citric acid was pyrolyzed to synthesize the GQDs, which were then functionalized with chiral L- and D-cys species using a thiol-ene click reaction between sulfur group of cysteine species and CC double bonds of GQDs. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopies (XPS) provides elemental analysis data which approved the presence of sulfur and nitrogen elements of L- and D-cysteine species on the surface of GQDs. Transmission electron microscopy (TEM) showed that the particle size of the modified GQDs ranges from 2 to 4.2 nm. The results of fluorescence spectroscopy showed that upon functionalization of GQDs with L-/D-cys the fluorescence intensity decreases as a result of Forster resonance energy transfer (FRET) mechanism. Interestingly, in the presence of L-morphine, the fluorescence intensity of D-cys-GQDs was selectively turned on as the FRET mechanism is ceased between the cysteine species and GQDs. Additional tests demonstrated that this nanosensor cannot interact with other drugs like methamphetamine or ibuprofen. As a result, it can serve as a cheap and precise nanosensor for identifying low quantities of L-morphine.