Intertube Excitonic Coupling in Nanotube Van der Waals Heterostructures

Abstract

Strong intertube excitonic coupling is demonstrated in 1D van der Waals heterostructures by examining the ultrafast response of radial C/BN/MoS2 core/shell/skin nanotubes to femtosecond infrared light pulses. Remarkably, infrared excitation of excitons in the semiconducting carbon nanotubes (CNTs) creates a prominent excitonic response in the visible range from the MoS2 skin, even with infrared photons at energies well below the bandgap of MoS2. Via classical analogies and a quantum model of the light–matter interaction these findings are assigned to intertube excitonic correlations. Dipole–dipole Coulomb interactions in the coherent regime produce intertube biexcitons, which persist for tens of femtoseconds, while on longer timescales (>100 ps) hole tunneling—from the CNT core, through the BN tunnel barrier, to the MoS2 skin—creates intertube excitons. Charge transfer and dipole–dipole interactions thus play prominent roles on different timescales, and establish new possibilities for the multi‐functional use of these new nanoscale coaxial cables.

Zigzag HgTe Nanowires Modify the Electron–Phonon Interaction in Chirality-Refined Single-Walled Carbon Nanotubes

“…e ., the picture of transitions between single-particle van Hove singularities applies), as the exciton binding energy is small or negligible. Here, given the pump energy (1.98 eV) was below the energy region probed, the observed ground-state bleach absorption change can be understood as resulting from the depopulation of the ground state, 6 as well as filling the upper state via Auger scattering, which may promote an S 22 exciton into an S 33 state. 59 While the S 33 (7,6) dynamics were not affected by HgTe encapsulation ( Figure 5 (f)), the transient absorption for (7,5) was blue-shifted from 3.5 eV to 3.6 eV after filling, and the decay dynamics were slowed from a monomolecular lifetime τ = 0.18 ps to 0.31 ps after filling (fit parameters are reported in Table S4 ).…”

“… 5 , 6 These methods provide opportunities to tailor the optical and electrical properties of single-walled carbon nanotubes (SWCNTs), as well as creating composites with distinct functionality and where charge or energy can flow between the constituents. 6 , 7 …”

Synthesis, Sorting, and Applications of Single-Chirality Single-Walled Carbon Nanotubes

“…These emitters exhibit ultrahigh response speed comparable to laser diodes [ 149 ]. In addition, for all semiconducting SWCNTs, the excitonic transitions E 11 and E 22 locate in the infrared spectral region, important for telecommunications [ 150 , 151 , 152 ]. To distinguish pure large diameter s-SWNTs with a fundamental transition centered at 1550 nm and strong PL excitonic emission, Sarti and coworkers used PFH-A.…”

Nanotube Functionalization: Investigation, Methods and Demonstrated Applications

“…The carbon nanotubes (CNTs) are modified by different routes, such as covalent and non-covalent modification of the outer surface, the substitution of atoms or the filling of CNT channels [ 1 , 2 , 3 , 4 ].…”