Carrier transfer in quasi-2D perovskite/MoS monolayer heterostructure.

Two-dimensional layered semiconductors have attracted intense interest in recent years. The van der Waals coupling between the layers tolerates stacking various materials and establishing heterostructures with new characteristics for a wide range of optoelectronic applications. The interlayer exciton dynamics at the interface within the heterostructure are vitally important for the performance of the photodetector and photovoltaic device.

Ultrafast energy transfer dynamics in CsPbBr nanoplatelets-BODIPY heterostructure.

Understanding and directing the energy transfer in nanocrystals-chromophore heterostructure is critical to improve the efficiency of their photocatalytic and optoelectronic applications. In this work, we studied the energy transfer process between inorganic-organic molecular complexes composed of cesium halide perovskite nanoplatelets (CsPbBr NPLs) and boron dipyrromethene (BODIPY) by photoluminescence spectroscopy (PL), time-correlated single photon-counting (TCSPC) and femtosecond transient absorption spectroscopy. The quenching of PL in CsPbBr NPLs occurred simultaneously with the PL enhancement of BODIPY implied the singlet energy transfer process.

Observation of carrier transfer in a vertical 0D-CsPbBr/2D-MoS mixed-dimensional van der Waals heterojunction.

Two-dimensional transition metal dichalcogenides with outstanding properties open up a new way to develop optoelectronic devices such as phototransistors and light-emitting diodes. Heterostructure with light-harvesting materials can produce many photogenerated carriers via charge and/or energy transfer. In this paper, the ultrafast dynamics of charge transfer in zero-dimensional CsPbBr quantum dot/two-dimensional MoS van der Waals heterostructures are investigated through femtosecond time-resolved transient absorption spectroscopy.

Nonlinear THz radiation investigated by quantum simulations.

Terahertz (THz) waves can be generated by the nonlinear interaction between ultrashort laser pulses and air. The semiclassical photocurrent model is widely used. It is simple, but neglects the quantum effects.

High-order harmonic generation from 2D periodic potentials in circularly and bichromatic circularly polarized laser fields.

We studied the high-order harmonic generation (HHG) from 2D solid materials in circularly and bichromatic circularly polarized laser fields numerically by simulating the dynamics of single-active-electron processes in 2D periodic potentials. Contrary to the absence of HHG in the atomic case, circular HHGs below the bandgap with different helicities are produced from intraband transitions in solids with symmetry driven by circularly polarized lasers. Harmonics above the bandgap are elliptically polarized due to the interband transitions.

Nonadiabatic redshifts in high-order harmonic generation from solids.

We studied the multi-plateau high-order harmonic generation (HHG) from solids numerically. It is found that the HHG spectra in the second and higher plateaus are redshifted in short laser pulses due to the nonadiabatic effect. The corresponding FWHMs also increase as a function of the harmonic order, suggesting the step-by-step excitation of higher conduction bands in the HHG process.

Alignment dependent ultrafast electron-nuclear dynamics in molecular high-order harmonic generation.

We investigated the high-order harmonic generation (HHG) process of diatomic molecular ion H in non-Born-Oppenheimer approximations (NBOA). The corresponding three-dimensional time-dependent Schrödinger equation is solved with arbitrary alignment angles. It is found that the nuclear motion can lead to spectral modulation of HHG in both the tunneling and multiphoton ionization regimes.

[A primary study of 8-14 microm band emittance].

According to the previous experimental results, the band emittance of two materials were computed for 8-14 mm bandwidth in infrared measuring. The band emittance of several materials was surveyed by a simple experiment. The experiment and reckoning show that there is some kind of functional relation between band emittance and temperature.