We demonstrate the tunability of photoluminescence (PL) properties monolayer (1L)-MoS2 via chemical doping. The PL intensity 1L-MoS2 was drastically enhanced by adsorption p-type dopants with high electron affinity, but reduced n-type dopants. This modulation results from switching between exciton and trion depending on carrier density in 1L-MoS2. Achievement extraction injection carriers this solution-based doping method enables convenient control optical electrical atomically thin MoS2.

The synthesis of a carbon nanobelt, comprising closed loop fully fused edge-sharing benzene rings, has been an elusive goal in organic chemistry for more than 60 years. Here we report the one such compound through iterative Wittig reactions followed by nickel-mediated aryl-aryl coupling reaction. cylindrical shape its belt structure was confirmed x-ray crystallography, and fundamental optoelectronic properties were elucidated ultraviolet-visible absorption, fluorescence, Raman spectroscopic...

We studied multi-exciton dynamics in monolayer WSe2 using nonlinear photoluminescence (PL) spectroscopy and Monte Carlo simulations. observed strong saturation behavior of exciton PL with increasing excitation power density, long-distance diffusion reaching several micrometers. demonstrated that the diffusion-assisted exciton-exciton annihilation model accounts for behavior. The subsequent efficient process determined unusual atomically thin layered transition metal dichalcogenides.

Strongly bound excitons confined in two-dimensional (2D) semiconductors are dipoles with a perfect in-plane orientation. In vertical stack of semiconducting 2D crystals, such excitonic expected to efficiently couple across van der Waals gap due strong interlayer Coulomb interaction and exchange their energy. However, previous studies on heterobilayers group 6 transition metal dichalcogenides (TMDs) found that the exciton decay dynamics is dominated by charge transfer (CT) processes. Here, we...

Single-walled carbon nanotubes theoretically possess ultimate intrinsic tensile strengths in the 100-200 GPa range, among highest existing materials. However, all of experimentally reported values are considerably lower and exhibit a considerable degree scatter, with lack structural information inhibiting constraints on their associated mechanisms. Here, we report first experimental measurements individual structure-defined, single-walled nanotubes. The strength depends chiral structure...

Solution-processed organo-lead halide perovskite solar cells with deep pinholes in the layer lead to shunt-current leakage devices. Herein, we report a facile method for improving performance of by inserting solution-processed polymer between and hole-transporting layer. The photovoltaic conversion efficiency cell increased 18.1% stability decreased only about 5% during 20 days exposure moisture ambient conditions through incorporation poly(methyl methacrylate) (PMMA) improved devices PMMA...

Carbon nanotube-based solar cells have been extensively studied from the perspective of potential application. Here we demonstrated a significant improvement carbon nanotube by use metal oxide layers for efficient carrier transport. The oxides also serve as an antireflection layer and dopant, leading to reduction in loss incident light increase photocurrent, respectively. As consequence, photovoltaic performance both p-single-walled (SWNT)/n-Si n-SWNT/p-Si heterojunction using MoOx ZnO is...

The synthesis and X-ray crystal structure of the first member carbon nanobelt family is reported. [12]Carbon ([12]CNB) was originally obtained from a nickel-mediated reductive coupling reaction dodecabrominated macrocyclic precursor, albeit only in 1% yield. present article reports on development this synthetic strategy its extension to preparation [16] [24]CNB analogues. In particular, our extensive investigations final belt-forming, led new ligand system that provides [12]CNB up 7% yield,...

Transition-metal dichalcogenides exhibit great potential as active materials in optoelectronic devices because of their characteristic band structure. Here, we demonstrated that the photovoltaic performances graphene/Si Schottky junction solar cells were significantly improved by inserting a chemical vapor deposition (CVD)-grown, large MoS2 thin-film layer. This layer functions an effective electron-blocking/hole-transporting We also properties are enhanced with increasing number graphene...

Abstract Photoluminescence phenomena normally obey Stokes’ law of luminescence according to which the emitted photon energy is typically lower than its excitation counterparts. Here we show that carbon nanotubes break this rule under one-photon conditions. We found exhibit efficient near-infrared photoluminescence upon photoexcitation even at an lying >100–200 meV below emission room temperature. This apparently anomalous phenomenon attributed one-phonon-assisted up-conversion processes...

Nano-carbon materials (carbon nanotubes, graphene, and graphene oxide) have potential application for photovoltaics because of their excellent optical electronic properties. Here, we demonstrate that a single-walled carbon nanotubes/graphene oxide buffer layer greatly improves the photovoltaic performance organo-lead iodide perovskite solar cells. The works as an efficient hole transport/electron blocking layer. conversion efficiency 13.3% was achieved in cell due to complementary properties...

ConspectusCarbon nanotubes (CNTs) have been central materials in nanoscience and nanotechnologies. Single-walled CNTs (SWCNTs) consisting of a cylindrical graphene show metallic (met) or semiconducting (sc) property depending on their rolling up manner (chirality). The sc-SWCNTs characteristic chirality-dependent optical properties absorption photoluminescence (PL) the near-infrared (NIR) region. These are derived from highly π-conjugated structures having crystalline sp2 carbon networks...

Cross-polarized absorption peaks of isolated single-walled carbon nanotubes (SWNTs) were observed by polarized photoluminescence excitation (PLE) spectroscopy. Using a simple theory for PL anisotropy, the PLE spectra are decomposed into ``pure'' components photoexcitation incident light parallel and perpendicular to SWNT axis. For several $(n,m)$ SWNTs, distinct corresponding observed. The measured transition energies excitations blueshifted compared qualitative values predicted within...

Graphene quantum dots (GQDs) have attracted a great deal of interest from the viewpoints both fundamental studies and applications. Photoluminescence (PL) is one intriguing properties GQDs, however, mechanism PL in GQDs not fully understood. In present study, drastic change UV to red light region reported among separated by size‐exclusion high performance liquid chromatography. It confirmed transmission electron microscopy images that are difference their overall sizes. Two‐dimensional...