We study the transient photoluminescence (PL) of photoexcited metals by solving the Boltzmann equation considering the effects of electron-electron (e-e) and electron-phonon (e-ph) collisions, where the e-ph coupling function is calculated from first-principles in order to account for the energy transfer rate between electrons and phonons accurately. We apply the present scheme to the transient PL of silver and demonstrate that the agreement between the theory and experiment is good, where the effect of nonequilibrium electron distribution is significant to fit the experimental data. The effects of the nanoscale roughness at metal surfaces and the e-e umklapp scattering on ultrafast electron dynamics are also discussed.
Our examination of the interplay of ultrafast charge dynamics and electron-phonon interaction in bilayer MoS2 provides a microscopic basis for understanding the features (two peaks) in the emission spectrum. We demonstrate that while the initial accumulation of excited charge occurs at and near the Q point of the two-dimensional Brillioun zone, emission takes place predominantly through two pathways: direct charge recombination at the K point and indirect phonon-assisted recombination of electrons at the K valley and holes at Γ hill of the Brillouin zone. Analysis of the wave vector dependenci…
Resolving nonlinear recombination dynamics in semiconductors via ultrafast excitation correlation spectroscopy: Photoluminescence versus photocurrent detection
Atomistic Origin of Photoluminescence Quenching in Colloidal MoS2 and WS2 Nanoplatelets
Eberhard Karls University of Tübingen（蒂宾根大学）；NMI Natural and Medical Sciences Institute at the University of Tübingen（蒂宾根大学国家自然和医学研究所）；Leibniz University of Hannover（汉诺威莱布尼茨大学）；University of Cambridge（剑桥大学）；University of Tübingen, Institute of Applied Physics（蒂宾根大学应用物理研究所）
We present photoluminescence measurements in monolayer WSe$_2$, which point to the importance of the interaction between charged particles and excitonic complexes. The theoretical analysis highlights the key role played by exchange scattering, referring to cases wherein the particle composition of the complex changes after the interaction. For example, exchange scattering renders bright excitonic complexes dark in monolayer WSe$_2$ on accounts of the unique valley-spin configuration in this material. In addition to the ultrafast energy relaxation of hot excitonic complexes following their inte…
We provide a microscopic approach to describe the onset of radial oscillation of a silver nanoparticle. Using the Heisenberg equation of motion framework, we find that the coupled ultrafast dynamics of coherently excited electron occupation and the coherent phonon amplitude initiate periodic size oscillations of the nanoparticle. Compared to the established interpretation of experiments, our results show a more direct coupling mechanism between the field intensity and coherent phonons. This interaction triggers a size oscillation via an optically induced electron density gradient occurring dir…
