Fullerene C₆₀ Films Cross-Linked with Octane-1,8-Dithiol: Preparation, Characterization and the Use as Template for Chemical Deposition of Gold Nanoparticles

Abstract

We report on the preparation of fullerene C60 thin films chemically cross-linked with octane-1,8-dithiol, which are capable of binding gold nanoparticles. The formation of a polymer was directly proved by means of laser desorption/ionization time-of-flight mass spectra, in which we observed the cleavage of fullerene-dithiol polymer at different bonds. Fourier-transform infrared, Raman and UV-visible spectra of the functionalized films exhibited notorious changes due to the formation of new covalent bonds between C60 molecules and bifunctional thiol. We further demonstrated that the dithiol-functionalized fullerene can be employed as a support for stable and homogeneous deposition of gold nanoparticles. Their average size is about 5 nm according to high-resolution transmission electron microscopy observations, and up to 20 nm, as found from scanning tunneling microscopy images. The proposed binding mechanism is through a strong coordination attachment between Au nanoclusters and sulfur donor atoms of the functionalized fullerene, as supported by density functional theory calculations.

Optical and photoluminescent properties of nanostructured hybrid films based on functional fullerenes and metal nanoparticles

“…The Ag and Au nanoparticle deposition is based on the reduction of AgNO 3 or HAuCl 4 with citric acid, respectively. The details concerning the samples preparation and analysis of their structure were reported formerly [4][5][6].…”

“…The cross-linking molecules with spacers of various lengths allows to control, to some extent, over interparticle spacing, and in its turn, the interparticle spacing influences the material properties such as conductivity. We applied the direct solvent-free functionalization of C 60 films with aliphatic bifunctional amines and thiols, such as octane-1,8-diamine and octane-1,8-dithiol, to prepare covalently functionalized, cross-linked fullerene supports capable of strong binding and immobilization of noble metal (e.g., silver and gold) nanoparticles [4,5]. However, the properties of fullerene thin films depend considerably on the interface configuration, and the study of the absorption and luminescence behavior, charge transfer interactions of fullerene with the metal surface is of crucial importance.…”

“…The photoluminescence(1)(2)(3)(4) and absorption coefficient (5-8) spectra for structures of series 1: pristine C 60 layer (1, 5), C 60 -DA (2, 6), C 60 -Ag (3, 7) and C 60 -DA-Ag(4,8). λ excPL = 488.0 nm, T = 300 K. The photoluminescence (1-4) and absorption coefficient (5-8) spectra for structures of series 2: pristine C 60 layer(1,5), C 60 -DT (2, 6), C 60 -Au (3, 7) and C 60 -DT-Au(4,8). λ excPL = 488.0 nm, T = 300 K.…”

Electrical properties of Au/C<inf>60</inf>/n-Si photodiode structures with pristine and dithioloctane-functionalized C<inf>60</inf> nanolayers

“…The functionalization of C 60 films with octane-1,8-dithiol was performed by means of the gas-phase reaction at a pressure of ca. 1 Torr and 140°C [7]. The investigated photodiode structures were prepared by vacuum evaporation of a set of semitransparent gold electrodes (~25 nm thickness) on the C 60 film surfaces through an opaque mask (opening diameter of 1.3 mm and an interval of ~1 mm), with ohmic contact deposited all over the rear side of Si substrate (of ~1 cm 2 size).…”

“…So, the methods of control the nanoparticles parameters and their disposition on the semiconductor surface are of great importance. The method of the gold (or silver) nanoparticles deposition on C 60 layer surface, ensuring the immobilized spherical nanoparticles of the controlled size and shape, was proposed in [7,8] by using preceding functionalization of C 60 films with octane-1,8-dithiol (or octane-1,8-diamine). The deposition of nanoparticles on pristine C 60 films by the same method results in formation of particles with different size and shape and nonuniform allocation.…”