Hybrid organic−inorganic 2-D perovskite bis-benzylammonium lead tetrachloride (BALC) is a room-temperature ferroelectric semiconductor. A structural phase transformation from the ambient Cmc2 1 structure is evident at 1.8 GPa from the Raman spectra, and this is confirmed by our high-pressure Xray diffraction studies that point to a centrosymmetric structure Cmcm at 1.7 GPa. The ambient phase is recoverable on decompression. Using density functional theory calculations, we have studied the intermolecular and intramolecular vibrations to get an idea of the structural changes as a function of pressure. The high-pressure transition is identified to be due to a distortion in the PbCl 6 octahedra and a conformation change in the molecule. There are several discontinuities, broadening, and splitting of the Raman bands, corresponding to NH 3 units above 1.8 GPa that point to rearrangements in the hydrogen bond network in the new phase. The ambient structure shows anisotropic compressibility, with a bulk modulus of 14.5 ± 0.33 GPa. As the new phase is a centrosymmetric structure, BALC is expected to lose its ferroelectricity above ∼1.8 GPa.
Starch [(C6H10O5)
n
]-stabilized bismuth sulfide (Bi2S3) nanoparticles (NPs) were synthesized in a single-pot
reaction
using bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and sodium sulfide (Na2S) as precursors.
Bi2S3 NPs were stable over time and a wide band
gap of 2.86 eV was observed. The capping of starch on the Bi2S3 NPs prevents them from agglomeration and provides regular
uniform shapes. The synthesized Bi2S3 NPs were
quasispherical, and the measured average particle size was ∼11
nm. The NPs are crystalline with an orthorhombic structure as determined
by powder X-ray diffraction and transmission electron microscopy.
The existence and interaction of starch on the NP’s surface
were analyzed using circular dichroism. Impedance spectroscopy was
used to measure the electronic behavior of Bi2S3 NPs at various temperatures and frequencies. The dielectric measurements
on the NPs show high dielectric polarizations. Furthermore, it was
observed that the synthesized Bi2S3 NPs inhibited
bacterial strains (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus
aureus) and demonstrated substantial antibacterial
activity.
In general, the technologically important ferrites nanoparticles, magnetite and maghemite, are converted from cubic to the more stable rhombohedral structure above 500°C-700°C under air/vacuum/inert atmosphere. Here, we report, the superior thermal stability of polymer capped Fe 3 O 4 (PCIO) nanocluster (synthesized using microwave-assisted polyol approach) up to 1000°C under vacuum and inert atmosphere. Raman spectra of post annealed PCIO nanoclusters show the
Reduction of plastic wastes in the environment and solving the energy demands from renewable sources are two important challenging tasks of this century. Modern day lives are highly entangled with polymers, however handling the huge wastes from plastics is also a serious concern. Translating the plastic wastes to useful products such as graphene can be an alternative for nonbiodegradable polymer wastes. Efficient energy storage devices, for instance, batteries are required for storing the renewable energies. With the aim of regulating these issues, we report, for the first time, the preparation of high energy cathode materials from the nanocomposites (NCs) having polyaniline (PANI), waste‐derived graphene (WDG) derived from plastic waste and sulfur (S) for Li–S battery applications. We compare the electrochemical properties of cathodes derived from WDG/S and WDG/PANI/S in Li–S batteries. The specific discharge capacity of WDG/PANI/S at 0.1 C was obtained to be 880 mAhg−1 normalized to sulfur mass at 1st cycle, 472 mAhg−1 at 100th cycle, and 400 mAhg−1 at 160th cycle. The rate capability is also found to be good at C‐rates less than 0.5 C. We found that WDG/PANI/S showed decent electrochemical properties when compared with the reference sample, WDG/S at similar sulfur loading without PANI modification.
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