We address spin properties and spin dynamics of carriers and charged excitons in CdSe/CdS colloidal nanoplatelets with thick shells. Magneto-optical studies are performed by time-resolved and polarization-resolved photoluminescence, spin-flip Raman scattering and picosecond pump-probe Faraday rotation in magnetic fields up to 30 T. We show that at low temperatures the nanoplatelets are negatively charged so that their photoluminescence is dominated by radiative recombination of negatively charged excitons (trions). Electron g-factor of 1.68 is measured, and heavy-hole g-factor varying with increasing magnetic field from -0.4 to -0.7 is evaluated. Hole g-factors for two-dimensional structures are calculated for various hole confining potentials for cubic- and wurtzite lattice in CdSe core. These calculations are extended for various quantum dots and nanoplatelets based on II-VI semiconductors. We developed a magneto-optical technique for the quantitative evaluation of the nanoplatelets orientation in ensemble.
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http://dx.doi.org/10.1021/acs.nanolett.7b04203 | DOI Listing |
Sci Adv
January 2025
New Cornerstone Science Laboratory, Department of Physics, The University of Hong Kong, Hong Kong 999077, China.
Real multi-bandgap systems have non-abelian topological charges, with Euler semimetals being a prominent example characterized by real triple degeneracies (RTDs) in momentum space. These RTDs serve as "Weyl points" for real topological phases. Despite theoretical interest, experimental observations of RTDs have been lacking, and studies mainly focus on individual RTDs.
View Article and Find Full Text PDFChemphyschem
January 2025
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, PS-ISRR, GERMANY.
Two-dimensional layered double hydroxides (LDHs) are ideal candidates for a large number of (bio)catalytic applications due to their flexible composition and easy to tailor properties. Functionality can be achieved by intercalation of amino acids (as the basic units of peptides and proteins). To gain insight on the functionality, we apply resonant inelastic soft x-ray scattering and near edge x-ray absorption fine structure spectroscopy to CaFe LDH in its pristine form as well as intercalated with the amino acids proline and cysteine to probe the electronic structure and its changes upon intercalation.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Biochemical Engineering, School of Chemical Engineering and Technology, State Key Laboratory of Synthetic Biology, Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), Tianjin University, Tianjin 300350, China.
Organisms that survive at freezing temperatures produce antifreeze proteins (AFPs) to manage ice nucleation and growth. Inspired by AFPs, a series of synthetic materials have been developed to mimic these proteins in order to avoid the limitations of natural AFPs. Despite their great importance in various antifreeze applications, the relationship between structure and performance of AFP mimics remains unclear, especially whether their molecular charge-specific effects on ice inhibition exist.
View Article and Find Full Text PDFAnn Sci
January 2025
Niels Bohr Institute, Copenhagen University, Copenhagen, Denmark.
So-called antimatter in the form of elementary particles such as positive electrons (antielectrons alias positrons) and negative protons (antiprotons) has for long been investigated by physicists. However, atoms or molecules of this exotic kind are conspicuously absent from nature. Since antimatter is believed to be symmetric with ordinary matter, the flagrant asymmetry constitutes a problem that still worries physicists and cosmologists.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
Introduction of non-DLVO forces by nonionic surfactants brings about fascinating changes in the phase behavior of silica nanosuspensions. We show here that alterations in the interaction and wetting properties of negatively charged silica nanoparticles (Ludox® LS) in the presence of polyethylene oxide-polypropylene oxide-polyethylene oxide-based triblock copolymers called Pluronics lead to the formation of stable o/w Pickering emulsions and interparticle attraction-induced thermoresponsive liquid-liquid phase separations. The results make interesting comparisons with those reported for Ludox® TM nanosuspensions comprising larger silica nanoparticles.
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