Incidence of Quantum Confinement on Dark Triplet Excitons in Carbon Nanotubes

Author(s)
J. Palotas, M. Negyedi, S. Kollarics, A. Bojtor, P. Rohringer, T. Pichler, F. Simon
Abstract

The photophysics of single-wall carbon nanotubes (SWCNTs) is intensively studied due to their potential application in light harvesting and optoelectronics. Excited states of SWCNTs form strongly bound electron-hole pairs, excitons, of which only singlet excitons participate in application relevant optical transitions. Long-living spin-triplet states hinder applications, but they emerge as candidates for quantum information storage. Therefore, knowledge of the triplet exciton energy structure, in particular in a SWCNT chirality dependent manner, is greatly desired. We report the observation of light emission from triplet state recombination, i.e., phosphorescence, for several SWCNT chiralities using a purpose-built spectrometer. This yields the singlet-triplet gap as a function of the SWCNT diameter, and it follows predictions based on quantum confinement effects. Saturation under high microwave power (up to 10 W) irradiation allows the spin-relaxation time for triplet states to be determined. Our study sensitively discriminates whether the lowest optically active state is populated from an excited state on the same nanotube or through Forster exciton energy transfer from a neighboring nanotube.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Budapest University of Technology and Economics, Radboud University, Eberhard Karls Universität Tübingen, HighFinesse Laser and Electronic Systems GmbH, École polytechnique fédérale de Lausanne
Journal
ACS Nano
Volume
14
Pages
11254-11261
No. of pages
8
ISSN
1936-0851
DOI
https://doi.org/10.1021/acsnano.0c03139
Publication date
09-2020
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics, 103021 Optics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/incidence-of-quantum-confinement-on-dark-triplet-excitons-in-carbon-nanotubes(91e44815-76b8-4db7-903c-6d26ef23e17a).html