Related papers: Charge photogeneration in few-layer MoS2
Atomically thin semi-conductors are characterized by strongly bound excitons which govern the optical properties of the materials below and near the band edge. Efficient conversion of photons into electrical current requires, as a first…
The optical response of semiconducting monolayer transition-metal dichalcogenides (TMDCs) is dominated by strongly bound excitons that are stable even at room temperature. However, substrate-related effects such as screening and disorder in…
The attraction between electrons and holes in semiconductors forms excitons, which largely determine the optical properties of the hosting material, and hence the device performance, especially for low-dimensional systems. Mono- and…
Excitons diffusing to a charge-separating interface is a necessary step to convert energy into current in next-generation photovoltaics. In this report, made possible by a new ultrafast spectrometer design, we compare exciton dynamics…
We combine linear and non-linear optical spectroscopy at 4K with ab initio calculations to study the electronic bandstructure of MoSe2 monolayers. In 1-photon photoluminescence excitation (PLE) and reflectivity we measure a separation…
Multiple exciton generation (MEG) is a widely studied phenomenon in semiconductor nanocrystals and quantum dots wherein photo-excited carriers relax by generating additional electron-hole pairs. Here, we present the first experimental…
Exciton dynamics dictate the evolution of photoexcited carriers in photovoltaic and optoelectronic devices. However, interpreting their experimental signatures is a challenging theoretical problem due to the presence of both electron-phonon…
In high-performance solar cells based on polymeric semiconductors, the mechanism of photocarrier generation on $<100$-fs timescales is yet to be unravelled. In particular the dynamics of early-time electronic coupling between excitons on…
Few- and single-layer MoS2 host substantial densities of defects. They are thought to influence the doping level, the crystal structure, and the binding of electron-hole pairs. We disentangle the concomitant spectroscopic expression of all…
We calculate the excitation spectrum of single-layer MoS$_2$ at several hydrogen coverages by using a method based on first-principles Density-Matrix Time-Dependent Density-Functional Theory (TDDFT). Our results show that the fully…
Unconventional emissions from exciton and trion in monolayer WS2 are studied by photoexcitation. Excited by 532nm laser beam, the carrier species in the monolayer WS2 are affected by the excess electrons escaping from photoionization of…
Monolayer transition-metal dichalcogenide (TMD) semiconductors exhibit strong excitonic effects and hold promise for optical and optoelectronic applications. Yet, electron doping of TMDs leads to the conversion of neutral excitons into…
We present flexible photodetectors (PDs) for visible wavelengths fabricated by stacking centimetre-scale chemical vapour deposited (CVD) single layer graphene (SLG) and single layer CVD MoS2, both wet transferred onto a flexible…
The potential application of the single-layer MoS2 as photocatalyst was revealed in this work based on first-principles calculations. It is found that the pristine single-layer MoS2 is a good candidate for photocatalyst, and its catalyzing…
Excitonic semiconductors such as transition metal dichalcogenides (TMDCs) are attractive for next-generation photovoltaics (PVs) with low cost, light weight, and low material consumption. In WS2 and other TMDCs, the simultaneous large…
A fundamental understanding of the intrinsic optoelectronic properties of atomically thin transition metal dichalcogenides (TMDs) is crucial for its integration into high performance semiconductor devices. Here, we investigate the transport…
The optical and electronic properties of 2D semiconductors are intrinsically linked via the strong interactions between optically excited bound species and free carriers. Here we use near-field scanning microwave microscopy (SMM) to image…
The new generation of two-dimensional (2D) materials has shown a broad range of applications for optical and electronic devices. Understanding the properties of these materials when integrated with the more traditional three-dimensional…
We theoretically investigate excitons in MoS$_2$ monolayers in an applied in-plane electric field. Tight-binding and Bethe-Salpeter equation calculations predict a quadratic Stark shift, of the order of a few meV for fields of 10 V/$\mu$m,…
All-organic-based photovoltaic solar cells have attracted considerable attention because of their low-cost processing and short energy payback time. In such systems the primary dissociation of an optical excitation into a pair of…