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Real colloidal quantum dot structures revealed by high resolution analytical electron microscopy
摘要： The development of bright and photostable colloidal quantum dots has been a truly interdisciplinary feat. Designing a specific composition of core and shell materials and then producing the desired nanoarchitecture through chemical routes require a blend of physical and inorganic chemistry, solid-state physics, and materials science. In a battle to separate charge carriers from a surface wrought with defect states, complex shell structures with precisely specified gradient compositions have been engineered, producing nanosized emitters with exceptional stability and color purity. However, much of the success has resided in II-VI materials, such as CdSe, and progress is only just being made on cadmium-free quantum dots. This perspective will discuss the primary challenges in engineering colloidal quantum dots and highlight how the advent of advanced analytical electron microscopy is revealing the structure-function relationships of these complex systems.
关键词： photostability,nanocrystals,CdSe,colloidal quantum dots,electron microscopy
更新于2025-09-11 14:15:04
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Removal of Methyl Tertiary-Butyl Ether via ZnO-AgCl Nanocomposite Photocatalyst
摘要： ZnO-AgCl nanocomposites with different mass ratios were synthesized via a one-pot wet chemical method. The synthesized nanocomposites were characterized by SEM, XRD and photoluminescence spectroscopy. The ZnO-AgCl nanocomposites exhibited a significant enhancement of photocatalytic activity towards degradation of methyl tertiary butyl ether in aqueous solution due to the effective carrier separation performance. In addition, the proposed ZnO-AgCl also exhibited an excellent photostability.
关键词： ZnO,Methyl tertiary butyl ether,Photostability,AgCl,Photocatalysis
更新于2025-09-11 14:15:04
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Extremely Photostable Electron-Deficient Phthalocyanines That Generate High Levels of Singlet Oxygen
摘要： A robust lead-mediated synthetic procedure for the generation of phthalocyanines substituted with electron-withdrawing groups has been developed. The free-base phthalocyanine and various metal complexes were prepared without discernible degradation of the peripheral electron-withdrawing substituents. Upon irradiation with red light, some of the thus obtained metal complexes generated high levels of singlet oxygen. Especially a palladium complex exhibited attractive photostability upon exposure to singlet oxygen as a bleaching agent. The photostability of such complexes that may manifest concomitantly to the generation of high levels of singlet oxygen was attributed to the presence of the electron-withdrawing groups, which results in energetically low-lying highest occupied molecular orbitals.
关键词： lead,phthalocyanine,singlet oxygen,electron-withdrawing group,photostability
更新于2025-09-10 09:29:36
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Synthesis, Structure, Photophysical Properties, and Photostability of Benzodipyrenes
摘要： We explored the syntheses, structure, photophysical properties, and photostability of benzodipyrenes (BDPs). BDPs were synthesized through an InCl3-AgNTf2 catalyzed, four-fold alkyne benzannulation reaction. The structures of BDP 4a and its corresponding endoperoxide product were unambiguously confirmed by X-ray crystallography. The BDPs reported here can also be recognized as peri- and cata-benzannulated pentacenes with a non-functionalized central ring. Unlike the previous reported pentacene-based polycyclic aromatic hydrocarbons, the absorbance of the BDPs was blue-shifted by ca. 40 nm relative to pentacene, even after extension of π–conjugation. The newly synthesized BDP products exhibit good relative stability with half-lives as high as 4612 min in THF.
关键词： pentacene,benzannulation,alkyne,singlet oxygen,photostability
更新于2025-09-10 09:29:36
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Well-dispersed zero-valent iron supported on Fe3O4/g-C3N4 composites via a facile approach with versatile photoredox catalysis
摘要： A well-dispersed Fe0/Fe3O4/g-C3N4 ternary hybrid composition was successfully synthesized through a calcination route followed by a hydrothermal treatment. It was significant to find that Fe0/Fe3O4/g-C3N4 possesses the optimal photocatalytic efficiency and excellent reusability toward Cr(VI) and RhB. The enhanced photocatalytic efficiency was attributable to the comprehensive factors including intimate contact of Fe0/Fe3O4 with g-C3N4, efficacious recombination inhibition of photoexcited carries, and synergistic interaction between each composition. Moreover, the photoredox catalytic mechanism of Fe0/Fe3O4/g-C3N4 was clearly proved by transient photocurrent responses, PL spectra properties, and exploring the formed active radicals that contribute to the improved photoredox activity. It is expected that our work could offer a notional guidance to design a promising photocatalytic compound for simultaneously degrading heavy metal ions and organic pollutant.
关键词： High-dispersed,Photostability,Synergistic,Fe0/Fe3O4/g-C3N4,Photocatalytic,Nanostructured catalysts
更新于2025-09-10 09:29:36
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Phenyl and Pyrazolyl Functionalized Pyrimidine: Versatile Chromophore of Bis-Tridentate Ir(III) Phosphors for Organic Light Emitting Diodes
摘要： There is a growing interest in the bis-tridentate Ir(III) emitters as they are expected to display both the improved emission efficiency and photostability. Herein, we turned to the new emitters m2h-1 - 3 and m6h-1 - 3, bearing a pincer carbene ancillary and a chromophoric chelate derived from judiciously selected phenyl-pyrimidine-pyrazole entities (pzm2hF)H2 or (pzm6hF)H2, which differ in terms of the location of phenyl and pyrazole substituents on central pyrimidine. DFT calculations revealed a notable change of spin density distribution from the pyrimidine-pyrazolate entity in m2h to pyrimidine-phenyl fragment in m6h. As a consequence, the m6h emitters exhibited both the shortened emission lifetime and improved stability under extensive photolysis in solution, while corresponding OLEDs doped with green emitting m6h-1 and sky-blue emitting m6h-2 and m6h-3 exhibited external quantum efficiencies of 17.6%, 15.9% and 17.6%, superior to all their m2h counterparts at a practical luminance of 103 cd/m2. This finding suggests a new methodology in fine-tuning the electronic transition that is important to high-performance and durable phosphorescent OLEDs.
关键词： phosphorescent OLEDs,organic light emitting diodes,bis-tridentate Ir(III) emitters,photostability,pyrimidine
更新于2025-09-09 09:28:46
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An efficient fabrication of ZnO–carbon nanocomposites with enhanced photocatalytic activity and superior photostability
摘要： Synthesis of carbon nanoparticles (CNPs) and their composite with ZnO has proposed for the first time by combustion of camphor and chemical precipitation method. TEM image shows the surface of ZnO covered by tiny CNPs and acts as structure directing agent that transforms ZnO nanorods to uniform spherical ZnO. CNPs play a vital role to improve the photocatalytic activity and photostability of ZnO up to five runs due to impeding the photo-corrosion of ZnO. Enhance in the photocatalytic activity of ZnO–carbon nanocomposite could be attributed to the excellent dye adsorption capacity, direct photooxidation of dye and suppression of photoinduced electron–hole recombination. The presence of CNPs in nanocomposite served as the main role in accepting the photogenerated electrons due to electronic interaction between ZnO and CNPs. The cytotoxicity studies of meristematic root tip cells of Allium cepa reveals that photocatalytically degraded products were less toxic.
关键词： Photostability,ZnO–carbon nanocomposites,Photocatalytic activity,Chemical precipitation method,Camphor combustion
更新于2025-09-09 09:28:46
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Application of a photostable silver-assisted Z-scheme NiTiO3 nanorod/g-C3N4 nanocomposite for efficient hydrogen generation
摘要： The performance and reaction mechanism of a silver (Ag)-assisted one-dimensional NiTiO3 nanorod/CN heterostructure nanocomposite (NTACN) photocatalyst for hydrogen (H2) production were explored with simulated sunlight. The physicochemical properties of the synthesized catalysts were examined using various spectrophotometers. The newly developed NTACN samples displayed an enhanced photocatalytic activity in producing hydrogen. Specifically, the H2 production rate of NTACN-5 (with a NT-to-ACN weight ratio of 5) was 3351 mmol/g-h, which was 1.42 times higher than that of ACN-4 with a Ag-to-CN ratio of 4 (2325 mmol/g-h). The effects of the Ag-to-CN and NiTiO3-to-ACN ratios on the photocatalytic activity of NTACN photocatalysts were determined. The NTACN photocatalysts exhibited a high long-term photostability under simulated sunlight irradiation. The increased photocatalyst performance and photostability were primarily ascribed to an improved charge separation efficiency due to a Z-scheme reaction mechanism as well as the assistance provided by Ag as a charge transfer shuttle and in the surface plasmon resonance effect. A photocatalytic mechanism for hydrogen generation over the NTACN photocatalysts under simulated sunlight irradiation is suggested.
关键词： Photostability,Simulated sunlight,One dimension,Z-Scheme mechanism,Charge transfer shuttle
更新于2025-09-09 09:28:46
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Triarylmethane Fluorophores Resistant to Oxidative Photobluing
摘要： Spectral stability of small-molecule fluorescent probes is required for correct interpretation and reproducibility of multicolor fluorescence imaging data, in particular under high (de)excitation light intensities of super-resolution imaging or in single-molecule applications. We propose a synthetic approach to a series of spectrally stable rhodamine fluorophores based on sequential Ru- and Cu-catalyzed transformations, evaluate their stability against photobleaching and photoconversion in context of other fluorophores using chemometric analysis, and demonstrate chemical reactivity of fluorophore photoproducts. The substitution patterns providing the photoconversion-resistant triarylmethane fluorophores have been identified, and the applicability of non-bluing labels in live-cell STED nanoscopy is demonstrated.
关键词： STED nanoscopy,photostability,triarylmethane fluorophores,rhodamine fluorophores,oxidative photobluing
更新于2025-09-04 15:30:14
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Highly Stable Luminous “Snakes” from CsPbX3 Perovskite Nanocrystals Anchored on Amine-Coated Silica Nanowires
摘要： CsPbX3 (X=Cl, Br and I) perovskite nanocrystals (NCs) are known for their exceptional optoelectronic properties, yet the material’s instability towards polar solvents, heat or UV irradiation greatly limits its further applications. Herein, an efficient in-situ growing strategy has been developed to give highly stable perovskite NC composites (abbr. CsPbX3@CA-SiO2) by anchoring CsPbX3 NCs onto silica nanowires (NWs), which effectively depresses the optical degradation of their photoluminescence (PL) and enhances stability. The preparation of surface-functionalized serpentine silica NWs is realized by a sol-gel process involving hydrolysis of a mixture of tetraethylorthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES) and trimethoxy(octadecyl)silane (TMODS) in a water/oil emulsion. The serpentine NWs are formed via an anisotropic growth with lengths up to 8 μm. The free amino groups are employed as surface ligands for growing perovskite NCs, yielding distributed monodisperse NCs (~8 nm) around the NW matrix. The emission wavelength is tunable by simple variation of the halide compositions (CsPbX3, X=Cl, Br or I) and the composites demonstrate a high photoluminescence quantum yield (PLQY 32-69%). Additionally, we have demonstrated the composites CsPbX3@CA-SiO2 can be self-woven to form a porous 3D hierarchical NWs membrane, giving rise to a superhydrophobic surface with hierarchical micro/nano structural features. The resulting composites exhibit high stability towards water, heat and UV irradiation. This work elucidates an effective strategy to incorporate perovskite nanocrystals onto functional matrices as multifunctional stable light sources.
关键词： colloidal CsPbX3 nanocrystal,superhydrophobic,photostability,assembled hierarchical membrane,serpentine silica nanowires
更新于2025-09-04 15:30:14