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 CsPbBr 3 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 Cs 2 CO 3 or CsOAc) such as low cost, nonhygroscopicity, 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 °C, whereas using a biphasic mixture of 1octadecene and methanol, the morphology changes to nanocubes. By lowering the reaction temperature (90 °C), nanoplatelets with 8−9 monolayers thicknesses are formed. These colloidal NCs of a variety of shapes are strongly luminescent with a green emission having narrow emission line widths (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 coassembly in which nanocubes arrange along nanofibers with stable, sharp, and bright green emission. This enables spatial ordering of nanocubes ranging from micrometer to centimeter scale in thin films, which is crucial for advanced optoelectronic applications. To date, there is no report in the literature on the anisotropic organization of perovskite CsPbBr 3 nanocubes triggered by supramolecular coassembly involving organogel nanofibers.
The development of synthetic scaffolds that nucleate well-folded secondary structures is highly challenging. Herein, we designed and synthesized a series of core-modified peptides (F1, F2, F3, and F4) that fold...
In
the last two decades, extending spin memory in NMR has been
used for several purposes. Long-lived states (LLS) or singlet states
are one of the first spin memory enhancement techniques used. LLS
have the potential to extract structural information and intra- and
intermolecular interactions of complex systems other than studying
slow phenomenon. The motional regime of β-cyclodextrin (β-CD)
drug inclusion complexes generally lies in the intermediate region,
where ωτ
c
≈ 1, and the standard methods of studying these interactions,
i.e., NOE and chemical shift monitoring, suffer from insufficient
output information. The sensitivity of LLS toward the environmental
changes is utilized here to gain insights into the drug assemblies
formed by β-CD. One can use change in relaxation of LLS to study
the structural changes during complexation. The examples of β-CD
with the drugs indomethacin, paracetamol, gliclazide, and CI-933 (a
precursor 4-methoxybenzamide) were studied. Indomethacin, paracetamol,
and 4-methoxybenzamide show strong interaction through the para-substituted
benzene ring, unlike gliclazide. Relaxation of LLS in β-CD–drug
complexes is modeled using standard Redfield Relaxation Theory. Computational
studies performed support the experimental observations. Docking and
molecular dynamics simulation provided the explanation of the relaxation
properties of these drug molecules.
Analysing active chemical components of explosives, propellants and post-blast residues have been challenging as it involves massive complexity. The increased use of energetics in various activities like military conflicts, terrorist's activities, and accidental explosions has made the task even more difficult for forensic scientists and environmentalists to analyse post-blast debris. The present studies reported the quantitative analysis of energetic materials present in post-blast soil by 1 H qNMR. The three methods have been used for quantitative studies, i. e. calibration curve method, co-axial stem insert method, and ERETIC method (Electronic to Access In Vivo Concentration). All three methods have been compared with the studies of post-blast residues of explosives such as PETN, Tetryl and TNT. The technique is selective, sensitive, rapid, reliable, and reproduce the result with good accuracy. The study merely requires a nuclear magnetic resonance spectrometer (400 MHz or 500 MHz) as an instrument.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.