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Direct Measurement of Electron Transfer in Nanoscale Host–Guest Systems: Metallocenes in Carbon Nanotubes
Author(s) -
McSweeney Robert L.,
Chamberlain Thomas W.,
Baldoni Matteo,
Lebedeva Maria A.,
Davies E. Stephen,
Besley Elena,
Khlobystov Andrei N.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201602116
Subject(s) - electron transfer , carbon nanotube , cobaltocene , coulometry , cyclic voltammetry , ferrocene , molecule , ruthenocene , materials science , density functional theory , nanotechnology , chemical physics , electrochemistry , doping , fermi level , nanotube , redox , biomolecule , chemistry , computational chemistry , electron , inorganic chemistry , electrode , organic chemistry , optoelectronics , quantum mechanics , physics
Electron‐transfer processes play a significant role in host–guest interactions and determine physicochemical phenomena emerging at the nanoscale that can be harnessed in electronic or optical devices, as well as biochemical and catalytic systems. A novel method for qualifying and quantifying the electronic doping of single walled carbon nanotubes (SWNTs) using electrochemistry has been developed that establishes a direct link between these experimental measurements and ab initio DFT calculations. Metallocenes such as cobaltocene and methylated ferrocene derivatives were encapsulated inside SWNTs (1.4 nm diameter) and cyclic voltammetry (CV) was performed on the resultant host–guest systems. The electron transfer between the guest molecules and the host SWNTs is measured as a function of shift in the redox potential ( E 1/2 ) of Co II /Co I , Co III /Co II and Fe III /Fe II . Furthermore, the shift in E 1/2 is inversely proportional to the nanotube diameter. To quantify the amount of electron transfer from the guest molecules to the SWNTs, a novel method using coulometry was developed, allowing the mapping of the density of states and the Fermi level of the SWNTs. Correlated with theoretical calculations, coulometry provides an accurate indication of n/p‐doping of the SWNTs.