An efficient nanocomposite based on carbon nanotubes functionalized with a fluorescent ink for ultrafast optical limiting

Functionalization of CNTs with different kinds of molecules is known to alter the optical properties of CNTs, leading to the development of new nanocomposites of interest to optoelctronics. This paper presents the design of a new and efficient optical limiting material based on carbon nanotubes (CNTs) functionalized with a commercial fluorescent ink. High resolution transmission electron microscopy (HRTEM) and optical spectroscopy indicate that the ink molecules get noncovalently attached to the surface of the CNTs. The mechanism of optical nonlinearity of the CNTs gets modified after functionalization. Z-scan studies on functionalized CNTs performed using mode-locked Ti:Sapphire femtosecond pulses at 780 nm reveal the predominance of two photon absorption (TPA). Efficient and low threshold ultrafast optical limiting is demonstrated in the new nanocomposite. (C) 2010 Elsevier B.V. All rights reserved.