We present transient absorption studies with femtosecond time resolution on the electron-hole dynamics in CdTe tetrapod nanostructures. Electron-hole pairs are generated by optical excitation in the visible spectral range, and an immediate bleach and induced absorption signal are observed. The relaxation dynamics to the lowest excitonic state is completed in about 6 ps. Experiments with polarized excitation pulses give information about the localization of the excited-state wave functions. The influence of the nanocrystal shape on the optical properties of CdTe nanoparticles is discussed.
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http://dx.doi.org/10.1021/jp0615306 | DOI Listing |
Sci Rep
December 2024
College of Engineering and Technology, American University of the Middle East, 54200, Egaila, Kuwait.
The Dynamic Hubbard Model (DHM) has been introduced as a framework for the electron-hole asymmetry observed in materials like high-temperature superconductors. In this study, we aim to understand the intricate dynamics of hole interactions, particularly focusing on the competition between on-site repulsion and hole-lattice coupling. Our results reveal a striking feature-an effective nearest-neighbor attraction between holes, even in the presence of the on-site repulsion typical of Mott insulators.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Key Laboratory of Green Chemical Process of Ministry of Education, School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, PR China. Electronic address:
Employing metallic nanoclusters as cocatalysts for semiconductor-based photocatalysts and understanding their roles in enhancing photocatalytic performance is crucial. Herein, a nickel thiolate with cyclohexanethiol as the ligands (i.e.
View Article and Find Full Text PDFNanoscale
December 2024
Regional Leading Research Center for Smart Energy System, Kyungpook National University, Daegu 41566, Korea.
As a leading Pb-free perovskite material (ABO-type), potassium sodium niobate (K,Na)NbO (KNN)-based ferroelectrics/piezoelectrics have been widely used in electronics, energy conversion, and storage due to their exceptional ability to interconvert mechanical and electrical energies. Beyond traditional applications, the piezoelectric potential generated by mechanical strain or stress modifies their energy band structures and facilitates charge carrier separation and transport, drawing increasing attention in emerging fields such as piezocatalysis and photo-piezocatalysis. With excellent piezoelectric properties, chemical/thermal stability, and strain-tuning capability, KNN-based materials show great promise for high-performance piezocatalytic applications.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
State Key Lab of High-Performance Ceramics and Superfine microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
Superlattice materials have emerged as promising candidates for water electrocatalysis due to their tunable crystal structures, electronic properties, and potential for interface engineering. However, the catalytic activity of transition metal-based superlattice materials for the hydrogen evolution reaction (HER) is often constrained by their intrinsic electronic band structures, which can limit charge carrier mobility and active site availability. Herein, a highly efficient electrocatalyst based on a VS-VS heterodimensional (2D-1D) superlattice with sulfur vacancies is designed addressing the limitations posed by the intrinsic electronic structure.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
In the dynamics of atoms and molecules at metal surfaces, electron-hole pair excitations can play a crucial role. In the case of hyperthermal hydrogen atom scattering, they lead to nonadiabatic energy loss and highly inelastic scattering. Molecular dynamics with electronic friction simulation results, based on an isotropic homogeneous electron gas approximation, have previously aligned well with measured kinetic energy loss distributions, indicating that this level of theoretical description is sufficient to describe nonadiabatic effects during scattering.
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