Noncovalent modification of carbon nanotubes by conjugated polymer: A theoretical study

The energetic and optical properties of (n, n) carbon nanotubes (CNTs) for n = 3–11 noncovalently modified with poly(phenylenethynylene) (PPE) were studied using a density‐functional tight‐binding method. The binding energies between the PPE and (n, n) CNTs were found increasing with the diameter increase for n ≤ 9 and then decreasing due to steric hindrance effect. It was verified that the binding is due to π–π interaction and van der Waals attraction, with very small charge transfers involved. Significant blue shifts in the absorption and fluorescent spectra of the PPE upon interacting with the CNTs were revealed in the calculation, which are responsible to the optical “quenching” observed in experiment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011