How to recognize clustering of luminescent defects in single-wall carbon nanotubes




Sebastian, Finn L.; Settele, Simon; Li, Han; Flavel, Benjamin S.; Zaumseil, Jana

PublisherROYAL SOC CHEMISTRY

CAMBRIDGE

2024

Nanoscale Horizons

NANOSCALE HORIZONS

NANOSCALE HORIZ

9

12

2286

2294

9

2055-6756

2055-6764

DOIhttps://doi.org/10.1039/d4nh00383g(external)

https://doi.org/10.1039/D4NH00383G(external)

https://research.utu.fi/converis/portal/detail/Publication/458590284(external)



Semiconducting single-wall carbon nanotubes (SWCNTs) are a promising material platform for near-infrared in vivo imaging, optical sensing, and single-photon emission at telecommunication wavelengths. The functionalization of SWCNTs with luminescent defects can lead to significantly enhanced photoluminescence (PL) properties due to efficient trapping of highly mobile excitons and red-shifted emission from these trap states. Among the most studied luminescent defect types are oxygen and aryl defects that have largely similar optical properties. So far, no direct comparison between SWCNTs functionalized with oxygen and aryl defects under identical conditions has been performed. Here, we employ a combination of spectroscopic techniques to quantify the number of defects, their distribution along the nanotubes and thus their exciton trapping efficiencies. The different slopes of Raman D/G+ ratios versus calculated defect densities from PL quantum yield measurements indicate substantial dissimilarities between oxygen and aryl defects. Supported by statistical analysis of single-nanotube PL spectra at cryogenic temperatures they reveal clustering of oxygen defects. The clustering of 2-3 oxygen defects, which act as a single exciton trap, occurs irrespective of the functionalization method and thus enables the use of simple equations to determine the density of oxygen defects and defect clusters in SWCNTs based on standard Raman spectroscopy. The presented analytical approach is a versatile and sensitive tool to study defect distribution and clustering in SWCNTs and can be applied to any new functionalization method.Defect clustering in carbon nanotubes can be recognized by a new analytical approach combining quantum yield measurements and Raman spectroscopy.


This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 817494 “TRIFECTS”). B. S. F. and H. L. gratefully acknowledge support by the DFG under grant numbers FL 834/5-1, FL 834/9-1 and FL 834/12-1. H. L. acknowledges financial support from the Turku Collegium for Science, Medicine and Technology (TCSMT). The authors thank Kerstin Brödner and Marcus Dodds for their technical support during initial tests of the ozone functionalization reaction.


Last updated on 2025-27-01 at 19:33