scholarly journals Quantifying the Aggregation Factor in Carbon Nanotube Dispersions by Absorption Spectroscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Hari Pathangi ◽  
Philippe M. Vereecken ◽  
Alexander Klekachev ◽  
Guido Groeseneken ◽  
Ann Witvrouw
Keyword(s):  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Wavelength Region ◽  
Single Walled Carbon Nanotubes ◽  
Sonication Time ◽  
Liquid Media ◽  
Aggregation Factor ◽  
On Chip ◽  
Walled Carbon Nanotubes

Absorption spectroscopy in the ultraviolet-visible-near infrared (UV-Vis-NIR) wavelength region has been used to quantify the aggregation factor of single-walled carbon nanotubes (SWCNTs) in liquid media through a series of controlled experiments. SWCNT bundles are dispersed in selected solvents using a calibrated ultrasonicator, which helps in determining the true amount of energy used in the exfoliation process. We also establish the selectivity of the centrifugation process, under the conditions used, in removing the nanotube aggregates as a function of the sonication time and the dispersion solvent. This study, along with the calibration of the sonication process, is shown to be very important for measuring the true aggregation factor of SWCNTs through a modified approach. We also show that the systematic characterization of SWCNT dispersions by optical spectroscopy significantly contributes to the success of dielectrophoresis (DEP) of nanotubes at predefined on-chip positions. The presence of individually dispersed SWCNTs in the dispersions is substantiated by dielectrophoretic assembly and post-DEP electromechanical measurements.

Optical Absorption Spectroscopy of DNA-Wrapped HiPco Carbon Nanotubes

2019 ◽  
Vol 943 ◽  
pp. 95-99
Author(s):  
Li Jun Wang ◽  
Kazuo Umemura
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Optical Characterization ◽  
Optical Absorption Spectroscopy ◽  
Double Stranded Dna

Optical absorption spectroscopy provides evidence for individually dispersed carbon nanotubes. A common method to disperse SWCNTs into aqueous solution is to sonicate the mixture in the presence of a double-stranded DNA (dsDNA). In this paper, optical characterization of dsDNA-wrapped HiPco carbon nanotubes (dsDNA-SWCNT) was carried out using near infrared (NIR) spectroscopy and photoluminescence (PL) experiments. The findings suggest that SWCNT dispersion is very good in the environment of DNA existing. Additionally, its dispersion depends on dsDNA concentration.

SEMICONDUCTING CARBON NANOTUBE PHOTOVOLTAIC PHOTODETECTORS

2011 ◽  
Vol 20 (03) ◽  
pp. 687-695 ◽  
Author(s):  
DOMINICK J. BINDL ◽  
MICHAEL S. ARNOLD
Keyword(s):  
Carbon Nanotubes ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Near Infrared ◽  
Series Resistance ◽  
Single Walled Carbon Nanotubes ◽  
Infrared Band ◽  
Device Architecture ◽  
Heterojunction Device ◽  
Walled Carbon Nanotubes

A photovoltaic photodetector harnessing near infrared band gap absorption by thin films of post-synthetically sorted semiconducting single walled carbon nanotubes ( s -SWCNTs) is described. Peak specific detectivity of 6×1011 Jones at -0.1 V bias at 1210 nm is achieved using a heterojunction device architecture: indium tin oxide/ ca. 5 nm s -SWCNT / 120 nm C60 / 10 nm 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) / Ag. The photodiodes are characterized by a series resistance of 2.9 Ω cm2 and a rectification ratio of 104 at ±1V. These results are expected to guide the exploration of new classes of solution-processable, mechanically flexible, integrable, thin film photovoltaic photodetectors with tunable sensitivity in the visible and infrared spectra based on semiconducting carbon nanotubes.

Sign in / Sign up

Export Citation Format

Share Document