Optics and Photonics Journal, 2013, 3, 34-40 http://dx.doi.org/10.4236/opj.2013.36A007 Published Online October 2013 (http://www.scirp.org/journal/opj) Carbon Nanotubes/Metal Nanoparticle Based Nanocomposites: Improvements in Visible Photoluminescence Emission and Hydrophobicity M. Barberio 1,2* , P. Barone 1,2 , F. Stranges 1,2 , A. Romano 1 , F. Xu 1 , A. Bonanno 1 1 Physics Department, University of Calabria, Rende (cs), Italy 2 Biology, Ecolgy and Earth Science Department, University of Calabria, Rende (cs), Italy Email: * marianna.barberio@fis.unical.it. Received June 8, 2013; revised July 11, 2013; accepted August 27, 2013 Copyright © 2013 M. Barberio et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT In this work, we present a study of growth and characterization of nanocomposites, based on multiwalled carbon nano- tubes and metal nanoparticles (Al, Ag, Au, Co, Cu, Fe, Ni and Ti). We observe a very different behavior between noble and transitions metals. All the nanocomposites are characterized by a network of carbon nanotubes with randomly in- sertion of spherical metal particles with dimensions of about 100 nm (clearly visible in SEM images). In particular, in transition metal nanocomposites, each tube on sheet surface is covered by particles of about 40 - 50 nm and for all met- als the XPS measurements indicate the absence of chemical bonds and the simply physisorption of nanoparticle on car- bon nanotube buckypaper. Furthermore, the nanocomposites show very different properties respect to pure carbon nanotubes: they are hydrophobic, their roughness is about 50% smaller than carbon nanotube and they exhibit a strong visible photoluminescence, which is absent in pure nanotube. Keywords: Metal Nanoparticle; Carbon Nanotube; Nanocomposite; Laser Ablation; Photoluminescence 1. Introduction The strategy to incorporate in a single matrix two diffe- rent nanostructures with specific properties is a versatile method to transfer and to integrate in a single material the different properties of two materials, enabling to re- alize multifunctional composites, for using in advanced applications like catalysis, energy storage, nanobiotec- nology, optoelectronics, etc. [1-3]. In particular, a widely used approach is given by the combination of carbon nanotubes (in both configuration multi walled and single walled) and metals, semiconduc- tors or insulators [4-6]. In effect, carbon nanotubes (CNT) are one of the most attractive nanomaterials because their unique physicochemical properties and wide potential applications in nanoelectronics [4], nanolithography [5] and photovoltaic [6]. Two approaches are commonly used to decorate CNT with organic and inorganic com- pounds: covalent and non covalent bonds formation [4-8]. The first, include mainly oxidation and formation of am- ide bonds [7], while non covalent approaches utilize van der Waals interactions between functional compounds and CNT [8]. Recently, non covalent approach has at- tracted more attention because permit to obtain nano- composites with new properties, preserving all the prop- erties of the nanotubes [9]. The combination between CNT and metal nanoparti- cles is much interesting because metal exhibits very im- portant optical and electronic properties that can be im- proved by the mix with CNT [1,10,11]. In particular metal, decorated CNT (as example Ag/CNT composites) have gained extensive attention due to their potential ap- plications as catalyst [12], optical limiters [13], advanced materials [14], etc. The possibility to obtain composites with large visible photoluminescence for optoelectronic devices becomes particularly interesting. The study of optical properties of CNT based heterostructures in this framework assume considerable importance to try improve the luminescence properties of carbon nanotubes in the visible range (pure carbon nanotube not exhibit visible luminescence emis- sion). For this purpose, our group carried out different studies on cathode-luminescence and photo-lumines- cence emission from CNT macroscopic samples [15-18]. We observed a luminescence signal in the visible region * Corresponding author. Copyright © 2013 SciRes. OPJ