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691.
This study describes the use of chiral nature of synthetic self-assembled nanofibers for nucleation and growth of Cadmium
sulfide (CdS) nanocrystals with different sizes and shapes in room temperature. The templates are built by immobilizing a
peptide capping agent on the surface of synthetic self-assembled helical or nonhelical nanofibers and CdS nanocrystals were
allowed to grow on them. It is observed that there are differences in shapes and sizes of the nanocrystals depending on the
chiral nature of the nanofibers on which they were growing. Even the CdS nanocrystals grown on different chiral and achiral
nanofibers differ markedly in their photoluminescence properties. Thus, here we introduce a new way of using chirality of
nanofibers to nucleate and grow CdS nanocrystals of different shape, size, and optical property. 相似文献
692.
I. Bose A. K. Pal 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,77(1):139-146
The elementary excitation spectrum of the spin-
\frac12\frac{1}{2} antiferromagnetic (AFM)
Heisenberg chain is described in terms of a pair of freely propagating spinons. In the
case of the Ising-like Heisenberg Hamiltonian spinons can be interpreted as domain walls (DWs)
separating degenerate ground states. In dimension d > 1, the issue of spinons as elementary
excitations is still unsettled.
In this paper, we study two spin-
\frac12\frac{1}{2} AFM ladder models
in which the individual chains are described by the Ising-like Heisenberg
Hamiltonian. The rung exchange interactions are assumed to be pure Ising-type in
one case and Ising-like Heisenberg in the other. Using the low-energy
effective Hamiltonian approach in a perturbative formulation, we show
that the spinons are coupled in bound pairs. In the first model, the
bound pairs are delocalized due to a four-spin ring exchange term
in the effective Hamiltonian. The appropriate dynamic structure factor
is calculated and the associated lineshape is found to be almost symmetric
in contrast to the 1d case. In the case of the second model, the bound
pair of spinons lowers its kinetic energy by propagating between chains.
The results obtained are consistent with recent theoretical studies
and experimental observations on ladder-like materials. 相似文献
693.
Arup Ghorai Somnath Mahato Sudarshan Singh Shaona Bose Baidyanath Roy Unyong Jeong Samit Kumar Ray 《Angewandte Chemie (International ed. in English)》2023,62(22):e202302852
Although α-CsPbI3 is regarded as an attractive optical luminophore, it is readily degraded to the optically inactive δ-phase under ambient conditions. Here, we present a simple approach to revive degraded (“optically sick”) α-CsPbI3 through “medication” with thiol-containing ligands. The effect of different types of thiols is systematically studied through optical spectroscopy. The structural reconstruction of degraded α-CsPbI3 nanocrystals to cubic crystals in the presence of thiol-containing ligands is visualized through high-resolution transmission electron microscopy and supported by X-ray diffraction analysis. We found that 1-dodecanethiol (DSH) effectively revives degraded CsPbI3 and results in high immunity towards moisture and oxygen, hitherto unreported. DSH facilitates the passivation of surface defects and etching of degraded Cs4PbI6 phase, thus reverting them back to the cubic CsPbI3 phase, leading to enhanced PL and environmental stability. 相似文献
694.
695.