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Precursor-Mediated Synthesis of Shape-controlled Colloidal CsPbBr <sub/>3</sub> Perovskite Nanocrystals and their Nanofiber-Directed Self-assembly
摘要： Shape control is often necessary to tune the optical and electronic properties of nanocrystals (NCs) and is mostly achieved through manipulation of surface ligands and processing conditions. Here we present a versatile synthesis of colloidal CsPbBr3 perovskite NCs of various shapes (nanorods, nanocubes and nanoplatelets) from an inexpensive steroidal Cs precursor: cesium cholate (CsCh). Cesium cholate has several advantages over the most commonly used Cs-precursor (cesium oleate or Cs2CO3 or CsOAc) such as low-cost, non-hygroscopicity and better reproducibility in the perovskite synthesis. Due to the solubility of this Cs-precursor in polar solvents such as methanol, a miniscule polar environment is created during the nucleation and growth of the nanocrystals leading to the serendipitous formation of nanorods at 180 ℃, whereas using a biphasic mixture of 1-octadecene and methanol, the morphology changes to nanocubes. By lowering the reaction temperature (90 ℃), nanoplatelets with 8-9 monolayers thicknesses are formed. These colloidal NCs of variety of shapes are strongly luminescent with a green emission having narrow emission linewidths (16-17 nm) and high quantum yields (96% for nanocubes, 94% for nanoplatelets). Furthermore, hybrid materials of nanocubes and organogel of a dimeric bile acid-derived ester gelator are obtained through co-assembly in which nanocubes arrange along nanofibers with stable, sharp and bright green emission. This enables spatial ordering of nanocubes ranging from micron to centimeter scale in thin films, which is crucial for advanced optoelectronic applications. To date, there is no report in literature on the anisotropic organization of perovskite CsPbBr3 nanocubes triggered by supramolecular co-assembly involving organogel nanofibers.
关键词： nanocubes,organogel,Shape control,hybrid materials,nanorods,cesium cholate,nanoplatelets,supramolecular co-assembly,colloidal CsPbBr3 perovskite NCs
更新于2025-09-12 10:27:22
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Synthesis of Hollow Silica Nanocubes with Tuneable Size and Shape, Suitable for Light Scattering Studies
摘要： We present a preparation method for hollow silica nanocubes with tuneable size and shape in the range required for light scattering studies. Cuprous oxide nanocubes are prepared by a water-assisted polyol method. By adjusting the water content, the size of the nanocubes can be tuned in the range of 40–120 nm. These cubes function as a shape template in the subsequent coating with St?ber silica, resulting in core-shell nanocubes. Dissolving the core with nitric acid results in hollow silica nanocubes with sizes ranging from 80–120 nm and cubicity shape parameters between 3 and 6.5.
关键词： colloids,nanocubes,microscopy,silica,superballs,synthesis
更新于2025-09-10 09:29:36
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Solvent-Assisted Tuning the Size and Shape of CsPbBr3 Nanocrystals via Re-Dispersion Process at Ambient Condition
摘要： All-inorganic CsPbBr3 perovskite nanocrystals are emerging as a new class of semiconductors with outstanding optoelectronic properties and great potential for various applications, such as, lasing, photon detection, photovoltaics etc. This article provides the effect of solvents on the re-precipitation of CsPbBr3 perovskite at room temperature. The results observed for CsPbBr3 perovskite in various anti-solvent showed various cubes (nano to micro size), self-assembly of nanocubes and nanorods. In addition, all the various size (nano to micro), self-assembly of nanocubes and shape-controlled nanorods exhibited band-gap tuning at the green light region. The corresponding microscopy (FE-SEM and HR-TEM) images and photoluminescence quantum yield as well as lifetime decay are presented. To the best of our literature knowledge this is the first report on various solvent assisted studies on CsPbBr3 perovskite nanocrystals.
关键词： CsPbBr3 Nanocrystals,nanocubes,effect of solvents,lifetime decay,nanorods,self-assembly
更新于2025-09-10 09:29:36
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Hybrid Silver Nanocubes for Improved Plasmon-Enhanced Singlet Oxygen Production and Inactivation of Bacteria
摘要： Plasmonic nanoparticles can strongly interact with adjacent photosensitizer molecules, resulting in significant alteration of their singlet oxygen (1O2) production. In this work, we report the next generation of metal-enhanced 1O2 nanoplatforms exploiting the lightning rod effect, or plasmon hot spots, in anisotropic (non-spherical) metal nanoparticles. We describe the synthesis of Rose Bengal decorated silica-coated silver nanocubes (Ag@SiO2-RB NCs) with silica shell thicknesses ranging from 5 to 50 nm based on an optimized protocol yielding highly homogeneous Ag NCs. Steady-state and time-resolve 1O2 measurements demonstrate not only the silica shell thickness dependence on the metal-enhanced 1O2 production phenomenon, but also the superiority of this next generation of nanoplatforms. A maximum enhancement of 1O2 of approximately 12-fold is observed with a 10 nm silica-shell, which is amongst the largest 1O2 production metal enhancement factor ever reported for a colloidal suspension of nanoparticles. Finally, the Ag@SiO2-RB NCs were benchmarked against Ag@SiO2-RB nanospheres previously reported by our group, and the superior 1O2 production of Ag@SiO2-RB NCs resulted in improved antimicrobial activities in photodynamic inactivation experiments using both gram-positive and -negative bacteria model strains.
关键词： Plasmonic nanoparticles,photodynamic inactivation,singlet oxygen,Rose Bengal,silver nanocubes,bacteria
更新于2025-09-04 15:30:14