Ultrafast carrier and energy dynamics in 2D materials

Here, the authors develop a predictive, material-specific many-body model for moiré heterostructures of transition metal dichalcogenides that tracks exciton dynamics across time, space, and momentum, fully accounting for the moiré potential and the complex non-parabolic exciton band structure.

The study reveals strikingly different nonlinear Rabi splitting dynamics in MoSe₂ monolayers and (Ga,In)As quantum wells, highlighting the pivotal role of Coulomb interactions in shaping light–matter coupling in two-dimensional semiconductors.

Understanding the transient changes in complex refractive index due to XUV excitation requires obtaining both intensity and phase responses. In this study, the authors measure the transient relative changes in complex refractive index during the autoionization of argon by using a spectral interferometry with double attosecond pulses

The effect of multiple energy valleys in the conduction band of semiconductor molybdenum ditelluride on energy dissipation remains unclear. Here, the authors employ time resolved measurements to reveal the pathways and timescales of carrier relaxation and phonon dynamics in different valleys, identifying the phonon bottlenecks of such relaxation.

All-optical logic devices could overcome the speed limitations of conventional electronic devices. Here, authors demonstrate sub-ps all-optical switching exploiting the ultrafast transition from strong to weak light-matter coupling in microcavities with bilayers of transition metal dichalcogenides.

Perovskite-based solar cells provide exceptional efficiency, but optimizing their performance requires precise control over material preparation methods. In this study, the authors use a hot-drop casting technique to fabricate 2D layered Ruddlesden-Popper perovskites and investigate exciton energy funneling dynamics through two-dimensional electronic and transient-grating spectroscopy.

Charge migration is one of the key applications of attosecond science mainly studied in molecular systems. Here the authors propose the extension of this process to two-dimensional materials by exploiting the excitonic interactions typical on these systems, performing numerical simulations to demonstrate the possibility to produce and read exciton migration in monolayer hBN.

Here, the authors investigate the interfacial charge/energy transfer dynamics in a WSe₂/graphene heterostructure. They unveil an energy transfer mechanism from WSe₂ to graphene mediated by an interfacial Meitner-Auger process, resulting in a transient hole distribution in the Dirac cone at energies larger than the photon energy of the optical excitation.

2D materials are promising substrates for surface-enhanced Raman scattering (SERS)-based molecular sensing, but their performance is usually inferior to their plasmonic counterparts. Here, the authors report the synthesis of 1D/2D WO_3-x/WSe₂ heterostructures, showing high molecular sensitivity associated to ultrafast charge transfer timescales of ~1 ps.

The formation dynamics of excitons in 2D transition metal dichalcogenides are challenging to probe directly because of their inherently fast timescales. Here, the authors use extremely short optical pulses to excite an electron-hole plasma, and show the formation of 2D excitons in MoS₂ on the timescale of 30 fs.

Knowledge of the energy transfer pathways in transition metal dichalcogenides is essential to design efficient optoelectronic devices. Here, the authors use megaelectronvolt ultrafast electron diffraction to unveil the sub-picosecond lattice dynamics in MoSe₂ following photoexcitation of charge carriers

The investigation into the dynamical transitions of charged quasiparticles on interfaces remains technically challenging. Here, the authors use ultrafast, mid-infrared micro-spectroscopy to unveil the formation of tightly bound interlayer excitons between conducting graphene and semiconducting MoSe₂.