Physical Chemistry Chemical Physics最新文献

Model validation of a well-known class of solid polymer electrolyte (SPE) is utilized to predict the ionic structure and ion dynamics of alternative alkali metal ions, leading to advancements in Na-, K-, and Cs-based SPEs for solid-state alkali metal batteries. A comprehensive study based on molecular dynamics (MD) is conducted to simulate ion coordination and the ion transport properties of poly(ethylene oxide) (PEO) with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt across various LiTFSI concentrations. Through validation of the MD simulation results with experimental techniques, we gain a deeper understanding of the ionic structure and dynamics in the PEO/LiTFSI system. This computational approach is then extended to predict ion coordination and transport properties of alternative alkali metal ions. The ionic structure in PEO/LiTFSI is significantly influenced by the LiTFSI concentration, resulting in different lithium-ion transport mechanisms for highly concentrated or diluted systems. Substituting lithium with sodium, potassium, and cesium reveals a weaker cation-PEO coordination for the larger cesium-ion. However, sodium-ion based SPEs exhibit the highest cation transport number, indicating the crucial interplay between salt dissociation and cation-PEO coordination for achieving optimal performance in alkali metal SPEs.

Topological insulators have emerged as one of the most promising candidates for the fabrication of novel electronic and optoelectronic devices due to the unique properties of nontrivial Dirac cones on the surface and a narrow bandgap in the bulk. In this work, the Sb₂Te₃ and Bi₂Te₂Se materials, and their heterostructure are fabricated by metal–organic chemical vapour deposition and evaporation techniques. Photodetection of these materials and their heterostructure shows that they detect light in a broadband range of 600 to 1100 nm with maximum photoresponse of Sb₂Te₃, Bi₂Te₂Se and Sb₂Te₃/Bi₂Te₂Se at 1100, 1000, and 1000 nm, respectively. The maximum responsivity values of Sb₂Te₃, Bi₂Te₂Se, and their heterostructure are 183, 341.8, and 245.9 A W⁻¹ at 1000 nm, respectively. A computational study has also been done using density functional theory (DFT). Using the first-principles methods based on DFT, we have systematically investigated these topological insulators and their heterostructure's electronic and optical properties. The band structures of Sb₂Te₃ and Bi₂Te₂Se thin films (3 QL) and their heterostructure are calculated. The bandgaps of Sb₂Te₃ and Bi₂Te₂Se are 26.4 and 23 meV, respectively, while the Sb₂Te₃/Bi₂Te₂Se heterostructure shows metallic behaviour. For the optical properties, the dielectric function's real and imaginary parts are calculated using DFT and random phase approximation (RPA). It is observed that these topological materials and their heterostructure are light absorbers in a broadband range, with maximum absorption at 1.90, 2.40, and 3.21 eV.

Generating field-free (non-stationary) orientation of molecules in space has been a longstanding goal in the field of quantum control of molecular rotation, which has significant applications in physical chemistry, chemical physics, strong-field physics, and quantum information science. In this Perspective, we review and examine several representative control schemes developed in recent years and implemented in theoretical and experimental areas for generating field-free orientation of molecules. By conducting numerical simulations of different control schemes on the same molecular system, we demonstrate that quantum coherent control, specifically targeting a limited number of the lowest-lying rotational levels to achieve an optimal superposition, can result in a high degree of orientation. To this end, we provide an overview of our latest developed analytical method, which enables the precise design of terahertz field parameters through resonant excitation. This design approach facilitates the attainment of desired field-free orientations by optimizing the amplitudes and phases of rotational wave functions for the selected rotational levels. Finally, we outlook the significance of such progress in multiple frontier research fields, highlighting its potential applications in ultracold physics, quantum computation, quantum simulation, and quantum metrology.