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Synthesis of thermally stable and highly luminescent spherical shaped ligand-free Cs4PbBr6 nanospheres with a single polar solvent
摘要： We demonstrate a simple method to synthesis thermally stable and green luminescent ligand-free Cs4PbBr6 nanospheres (NS) with a polar solvent. In this approach, a single polar solvent, N,N-dimethylformamide (DMF) is sufficient enough to convert precursors into cubic shaped ligand-free Cs4PbBr6 crystals. Further, the morphology of cubic shaped Cs4PbBr6 crystals is reformed into spherical shaped Cs4PbBr6 NS by prolonged DMF washing (overnight stirring, 15 h). Besides, the reduction in average particle size of spherical shaped Cs4PbBr6 NS (~70 nm) to one-fourth to the original size of cubic Cs4PbBr6 crystals (~310 nm). The ligand-free spherical shaped Cs4PbBr6 NS showed a high photoluminescence quantum yield of 42.5%, which could compete the conventional ligand mediated Cs4PbBr6 crystals. Moreover, spherical shaped Cs4PbBr6 NS exhibited a high thermal stability even at 200 °C without sacrificing luminescence intensity. Hence, it is foreseen that this approach brings a new strategy to prepare ligand-free Cs4PbBr6 NS as a promising material in optoelectronic devices.
关键词： Perovskites,Single solvent,Nanospheres,Ligand-free,Cs4PbBr6
更新于2025-09-19 17:15:36
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Reliability of rare-earth-doped infrared luminescent nanothermometers
摘要： The use of infrared-emitting rare-earth-doped luminescent nanoparticles as nanothermometers has attracted great attention during the last few years. The scientific community has identified rare-earth-doped luminescent nanoparticles as one of the most sensitive and versatile systems for contactless local temperature sensing in a great variety of fields, but especially in nanomedicine. Researchers are nowadays focused on the design and development of multifunctional nanothermometers with new spectral operation ranges, outstanding brightness, and enhanced sensitivities. However, no attention has been paid to the assessment of the actual reliability of the measurements provided by rare-earth-doped luminescent nanothermometers. In fact, it is assumed that they are ideal temperature sensors. Nevertheless, this is far from being true. In this work we demonstrate that the emission spectra of rare-earth-doped nanothermometers can be affected by numerous environmental and experimental factors. These include the numerical aperture of the optical elements used for their optical excitation and luminescence collection, the local concentration of nanothermometers, optical length variations, self-absorption of the luminescence by the nanothermometers themselves, and solvent optical absorption. This work concludes that rare-earth-doped luminescent nanothermometers are not as reliable as thought and, consequently, special care has to be taken when extracting temperature estimations from the variation of their emission spectra.
关键词： reliability,solvent absorption,self-absorption,excitation power dependence,infrared luminescent nanothermometers,rare-earth-doped
更新于2025-09-19 17:15:36
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Transistor Characteristics of Single Crystalline C<sub>8</sub>-BTBT Grown in Coated Liquid Crystal Solution on Photo-Alignment Films
摘要： We examined single crystal growth of benzothienobenzothiophene-based organic semiconductors by solution coating method using liquid crystal and investigated its electrical characteristics. As the results, we revealed that the averaged mobility in the saturation region reached 2.08 cm2/Vs along crystalline b-axis, and 1.08 cm2/Vs along crystalline a-axis.
关键词： organic semiconductor,liquid crystal solvent,single crystal,solution coating,organic field effect transistor
更新于2025-09-19 17:15:36
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Organic Fractal Nano-Dimensional Structures Based on Fullerene C <sub/>60</sub>
摘要： The ways for a synthesis of nanoporous and close-packed types of fullerene C60 aggregates in two-component organic solvents (toluene + tetrahydrofuran) were established as well as their structural and dimensional features - were studied by high-resolution transmission electron microscopy and atomic-force microscopy methods. The physical features and regularities that characterize the processes of self-organization of fullerene molecules in the initial molecular solution were determined. The method for producing nanoscale fullerene C60 fractal coatings (thickness up to ~1200 nm) on a flat dielectric glass surface was proposed.
关键词： self-assembles,AFM,solvent,fullerene C60,TEM,fractal,nanocoating
更新于2025-09-19 17:15:36
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Amphipathic carbon dots with solvent-dependent optical properties and sensing application
摘要： Carbon dots (CDs) have been regarded as novel heavy-metal-free fluorescent materials because of their prominent optical features. In this work, one type of amphipathic CDs is prepared by facile one-step solvothermal treatment of p-Phenylenediamine. The obtained CDs own numerous surface function groups which endow them prominent dispersibility in different solvents. Absorption, steady-state and time-resolved spectroscopy have been adopted to investigate the mutual influence between the surface groups and different solvent molecules on the optical properties of the CDs. Strong solvatochromic behavior with tunable emission from blue to green and strict excitation-independent emission characteristic can be observed when the as-prepared CDs are dissolved in different solvents, suggesting their feasible sensing applications as an alternative of solvatochromic dye molecules. Furthermore, highly selective detection of Cu2+ ions using the as-synthesized CDs as sensing probes is achieved. It is expected that the investigated CDs with solvent-dependent optical properties as well as selective Cu2+ detection may have broad application prospects in bioimaging and biodetecting.
关键词： Cu2+ detection,Optical properties,Solvent-dependent,Carbon dots
更新于2025-09-19 17:15:36
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Selective formation of ternary Cu–Ge–S nanostructures in solution
摘要： Selective formation of ternary Cu–Ge–S nanostructures in solution. In this paper, special attention is given to ternary copper germanium sulfides (Cu–Ge–S), which belong to an important class of mixed-metal chalcogenide materials called the copper-based multinary sulfides (CMSs). Like most members of the CMS family, the Cu–Ge–S compounds display enormous potential in energy-related applications especially in their nanostructured forms, but there exists very little research on the preparation of Cu–Ge–S materials in the nanometer size range. Herein, we report a simple noninjection protocol for the selective synthesis of Cu–Ge–S nanomaterials. We show that variations in the solvent environment can lead to different types of Cu–Ge–S nanostructures (i.e., from large, faceted Cu8GeS6 to smaller, irregularly-shaped Cu2GeS3). Our investigation of the growth process revealed interesting formation pathways, which could help advance our understanding of the selective formation of compositionally and structurally diverse multinary materials in solution.
关键词： selective synthesis,solvent environment,formation mechanism,Cu–Ge–S nanostructures,noninjection protocol
更新于2025-09-19 17:15:36
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Photocontrolled Iodine-Mediated Green Reversible-Deactivation Radical Polymerization of Methacrylates: Effect of Water in the Polymerization System
摘要： Photocontrolled iodine-mediated reversible-deactivation radical polymerization (RDRP) is a facile and highly efficient access to precision polymers. Herein, a facile photocontrolled iodine-mediated green RDRP strategy was successfully established in water by using 2-iodo-2-methylpropionitrile (CP-I) as the initiator and water-soluble functional monomers including poly(ethylene glycol) methyl ether methacrylate (PEGMA), 2-hydroxyethyl methacrylate (HEMA), and 2-hydroxypropyl methacrylate (HPMA) as the model monomers under blue-light-emitting diode (LED) irradiation at room temperature. Well-defined polymers (PPEGMA, PHEMA, PHPMA) with narrow polydispersities (1.09?1.21) were obtained, and amphiphilic block copolymers which can form nanospheres in situ in water (PPEGMA-b-poly(benzyl methacrylate) (PPEGMA-b-PBnMA) and PPEGMA-b-PHPMA) were prepared. To explore the role of water in our polymerization, control experiments were successfully carried out by using oil-soluble monomer methyl methacrylate (MMA) with the help of trace amounts of water. Notably, the green solvent—water—has an additionally positive effect in accelerating the polymerization and makes our polymerization system an environmentally friendly polymerization system. Therefore, this simple strategy conducted in the presence of water enables the green preparation of well-defined water-soluble or water-insoluble polymers and clean synthesis of amphiphilic copolymer nanoparticles in situ.
关键词： blue-light-emitting diode,water-soluble functional monomers,amphiphilic block copolymers,green solvent,RDRP,Photocontrolled iodine-mediated reversible-deactivation radical polymerization
更新于2025-09-19 17:13:59
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Er:YAG laser cleaning of a??San Marziale in Gloriaa?? by Jacopo Tintoretto in the Church of San Marziale, Venice
摘要： This article presents a parameter optimisation study for the use of an Er:YAG laser in combination with different solvent mixes for the cleaning of a large oil painting on canvas by Jacopo Tintoretto. The painting underwent restoration work between the 1700s and the mid-1900s in which it was lined and some areas were coated with a pig-mented protective varnish, which has oxidised over time and has completely obscured the work. Analysis was undertaken in order to study the condition of the work, the paint-ing technique used, and to monitor and verify the effectiveness of the cleaning treat-ments considered to remove the oxidised varnish. The article reports how the careful calibration and use of cleaning techniques involving the Er:YAG laser and solvent mixes have led to a full recovery of the vibrant chromatic intensity to the pictorial surface of the work.
关键词： painting on canvas,cross-section analysis,laser cleaning,Er:YAG,Tintoretto,solvent cleaning
更新于2025-09-19 17:13:59
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Laser induced graphene /ceramic membrane composite: Preparation and characterization
摘要： In this work, laser induced graphene (LIG) was successfully fabricated on microporous ceramic membranes. The surface area, morphology, and chemical characterizations were performed on the LIG layer. Water contact angle measurements showed the hydrophobicity of LIG. Pure water and solvents with different polarities were used to understand the solvent flux behavior of LIG membrane. The LIG membrane showed very high non-polar solvent fluxes and remarkably low water permeability, and thus, the transport through the LIG membrane is related to dipole moment and dielectric constant, represented by solvent polarity. The LIG membrane achieved 90% rejection for 255 nm diameter silica particles, suggesting the presence of submicron size connecting pore channels that dominate the transport mechanism.
关键词： Laser induced graphene,LIG/Ceramic composite,Solvent permeation
更新于2025-09-19 17:13:59
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Solvent-free and large-scale preparation of silver@polypyrrole core@shell nanocomposites; structural properties and terahertz spectroscopic studies
摘要： There is a growing interest over the environmental safety and mass-production of polymer nanocomposites. Solvent-free synthetic pathways are considered as promising alternative green techniques because of their high efficiency, simplicity and negligible liberation of hazardous waste. A new synthetic route has been developed to synthesize silver@polypyrrole core@shell nanocomposites at ambient condition. The silver nanoparticles are directly synthesized via solid-state reaction with poly(vinylpyrrolidone) and then pyrrole is polymerized in Ag/PVP powder. The band gap value decreases with the increased addition of pyrrole in the preparation step due to the formation of more silver nanoparticles. Scanning and transmission electron microscope confirm the formation of core@shell structure. The negatively charged carbonyl group of poly(vinylpyrrolidone) can bind to polycationic polypyrrole by an electrostatic effect to form the core@shell structure. The terahertz spectroscopy characterizes the prepared core@shell nanocomposites that are well fit to the Drude-Smith model. The DC optical conductivity in the terahertz range (0.3–2 THz) is increased with increasing Py addition.
关键词： Core@shell,Solvent-free method,Silver,Polypyrrole,Optical conductivity
更新于2025-09-19 17:13:59