相关论文: Intrinsically slow cooling of hot electrons in CdS…
The capture of photoexcited hot electrons in semiconductors before they lose their excess energy to cooling is a long-standing goal in photon energy conversion. Semiconductor nanocrystals have large electron energy spacings that are…
In semiconductor materials, hot exciton cooling is the process by which highly excited carriers nonradiatively relax to form a band edge exciton. While cooling plays an important role in determining the thermal losses and quantum yield of a…
Hot-exciton relaxation in semiconductor nanocrystals (NCs) is often described using perturbative theories, but their accuracy is difficult to assess for realistic exciton--phonon Hamiltonians. Here, we benchmark the perturbative quantum…
The relaxation of strongly-confined electrons and holes between 1P and 1S levels in colloidal PbSe nanocrystals has been time-resolved using femtosecond transient absorption spectroscopy. In contrast to II-VI and III-V semiconductor…
In semiconductors, photoexcited electrons and holes (carriers) initially occupy high-energy states, but quickly lose energy to phonons and relax to the band edge within a picosecond [1]. Increasing the lifetime of carriers in…
We report spin-polarized transient absorption for colloidal CdSe nanoplatelets as functions of thickness (2 to 6 monolayer thickness) and core/shell motif. Using electro-optical modulation of co- and cross-polarization pump-probe…
Two-dimensional electron-hole gases in colloidal semiconductors have a wide variety of applications. Therefore, a proper physical understanding of these materials is of great importance. In this paper we present a detailed theoretical…
Hot electrons are theoretically predicted to be long-lived in strongly confined quantum dots, which could play vital roles in quantum dot-based optoelectronics; however, existing photoexcitation transient spectroscopy investigations reveal…
Using semi-analytical models we calculate the energy, effective Bohr radius and radiative lifetime of neutral excitons confined in CdSe colloidal nanoplatelets (NPLs). The excitonic properties are largely governed by the electron-hole…
Perovskite nanocrystals are a convenient model system for optical spin orientation and manipulation. However, its real potential might be underestimated due to the incomplete knowledge on spin relaxation times, which are obscured by the…
The rate at which excited charge carriers relax to their equilibrium state affects many aspects of the performance of nanoscale devices, including switching speed, carrier mobility and luminescent efficiency. Better understanding of the…
The description of carrier dynamics in spatially confined semiconductor nanocrystals (NCs), which have enhanced electron-hole and exciton-phonon interactions, is a great challenge for modern computational science. These NCs typically…
While cadmium telluride (CdTe) thin films are being used in solar cell prototyping for decades, the recent advent of two-dimensional (2D) materials challenges the fundamental limit for thickness of conventional CdTe layers. Here, we report…
Optical and vibrational properties of bare and CdS shelled CdSe nanocrystalline particles are investigated. To confirm the formation of such nanocrystals in our samples we estimate their average particle sizes and size distributions using…
Luminescent colloidal CdSe nanorings are a new type of semiconductor structure that have attracted interest due to the potential for unique physics arising from their non-trivial toroidal shape. However, the exciton properties and dynamics…
We experimentally demonstrate ultralong spin lifetimes of electrons in the one-dimensional (1D) quantum limit of semiconductor nanowires. Optically probing single wires of different diameters reveals an increase in the spin relaxation time…
Colloidal core/shell nanocrystals are key materials for optoelectronics, enabling control over essential properties via precise engineering of the shape, thickness, and crystal lattice structure of their shell. Here, we apply the growth…
Time-resolved Faraday rotation is used to study both transverse and longitudinal spin relaxation in chemically-synthesized CdSe nanocrystals (NCs) 22-80 Angstroms in diameter. The precession of optically-injected spins in a transverse…
We present a detailed analysis of hole dynamics in noble metals (Cu and Au), by means of first-principles many-body calculations. While holes in a free-electron gas are known to live shorter than electrons with the same excitation energy,…
Hot electrons injection in carbon nanotubes (CNTs ) where in addition to applied dc field ($\mathbf{E}$), there exist simultaneously a quasi-static ac electric field (i.e. when the frequency $\omega$ of ac field is much less than the…