相关论文: Triplet excitations in carbon nanostructures

Excitons in organic crystalline semiconductors play a crucial role in the operation of optoelectronic devices such as organic solar cells, light-emitting diodes, and photodetectors. The excitonic properties of materials are dramatically…

We study one dimensional (1D) carbon ribbons with the armchair edges and the zigzag carbon nanotubes and their counterparts with finite length (0D) in the framework of the H\"{u}ckel model. We prove that a 1D carbon ribbon is metallic if…

The energy spectra and wavefunctions of bound excitons in important two-dimensional (2D) graphene derivatives, i.e., graphyne and graphane, are found to be strongly modified by quantum confinement, making them qualitatively different from…

We present calculations of the quasiparticle energies and band gaps of graphene nanoribbons (GNRs) carried out using a first-principles many-electron Green's function approach within the GW approximation. Because of the quasi-one-dimension…

Coherent one photon ($2 \omega$) and two photon ($ \omega$) electronic excitations are studied for graphene sheets and for carbon nanotubes using a long wavelength theory for the low energy electronic states. For graphene sheets we find…

Doping can profoundly affect the electronic- and optical-structure of semiconductors. Here we address the effect of surplus charges on non-radiative (NR) exciton and trion decay in doped semiconducting single-wall carbon nanotubes. The…

Excitonic emission from atomically precise graphene nanoribbons (GNRs) synthesised on a metal surface is probed with atomic-scale spatial resolution using a scanning tunneling microscopy (STM) approach. A STM-based strategy to transfer the…

Doping substantially influences the electronic and photophysical properties of semiconducting single-wall carbon nanotubes (s-SWNTs). Although prior studies have noted that surplus charge carriers modify optical spectra and accelerate…

Single air-suspended carbon nanotubes (length 2 - 5 microns) exhibit high optical quantum efficiency (7 - 20%) for resonant pumping at low intensities. Under ultrafast excitation, the photoluminescence dramatically saturates for very low…

We present some computational simulations of graphene-based nanoribbons with a number of half-twists varying from 0 to 4 and two types of defects obtained by removing a single carbon atom from two different sites. Optimized geometries are…

Micromechanical modeling and mechanical properties of polyurethane (PU) hybrid nanocomposite foams with multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were investigated by mean of tensile strength, hardness, impact…

The dipole-dipole interactions between excitons are of paramount importance in the nanoscale structures. When two excitons are placed together they can exchange the energy can manifest in the resonant Raman cross sections. We provide…

We review all symmetry-allowed spin-singlet and spin-triplet superconducting (SC) order parameters in graphene ($s$-wave, $d$-wave, $p$-wave, and $f$-wave) generated by generic onsite, nearest-neighbor (NN), and next-to-nearest-neighbor…

Change of the bonding environment at the free edges of graphene monolayer leads to excess edge energy and edge force, depending on the edge morphology (zigzag or armchair). By using a reactive empirical bond-order potential and atomistic…

We studied the nonlinear time-resolved luminescence signals due to multiexciton recombination processes in single-walled carbon nanotubes (SWNTs) using femtosecond excitation correlation (FEC) spectroscopy. From theoretical analysis of the…

We show that the optical absorption spectra of boron nitride (BN) nanotubes are dominated by strongly bound excitons. Our first-principles calculations indicate that the binding energy for the first and dominant excitonic peak depends…

We have realized nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The…

Graphene nanoribbons display an imperfectly understood transport gap. We measure transport through nanoribbon devices of several lengths. In nanoribbons of length greater than or equal to 250 nm we observe transport through multiple quantum…

The formation of graphen-nanotube composites addresses a few basic problems. First, both partners are good donors and acceptors of electrons, which significantly complicates the intermolecular interaction between them leading to a two-well…

Measurements of the diffusion length L for triplet excitons in small molecular-weight organic semiconductors are commonly carried out using a technique in which a phosphorescent-doped probe layer is set in the vicinity of a supposed exciton…