Low-Voltage Electrodeposition of Fullerol Thin Films from Aqueous Solutions

Abstract

A low-voltage ͑Ͻ2 V, three-electrode system͒ method for the cathodic electrodeposition of fullerol ͓polyhydroxylated fullerene, C 60 ͑OH͒ n ͔ from an aqueous solution has been developed for the synthesis of thin films. Scanning electron microscopy of the electrodeposited fullerol films shows that the films are microscopically uniform; the film thickness was observed to vary linearly with the deposition charge. X-ray photoelectron spectroscopy of the C 1s peak indicates that the carbon constituents of the electrodeposited films are electronically similar to the fullerol precursor. Infrared spectroscopy ͑IRS͒ confirmed that the fullerol moiety is intact upon electrodeposition and that the films are thermally stable up to 150°C. At higher temperatures IRS data suggest there is cleavage of a ketal or hemiketal group followed by hydroxyl group cleavage. The ͑direct͒ optical bandgap obtained from UV-visible spectroscopy of the electrodeposited film was 2.6 eV.Fullerene and its derivates have been widely investigated during the last decade. The unique properties of C 60 have been thought to have potential applications in a variety of areas, including optoelectronics, catalysis, superconductivity, and medical therapeutics. Examples of specific applications that have incorporated fullerene materials are optical limiting devices, 1,2 sensors, 3 polymer-based solar cells, 4-7 and solar sensitizers for wide-bandgap materials. [8][9][10][11] Several different synthetic methods for preparing films of fullerenes and derivates have been demonstrated, including thermal evaporation, 12,13 Langmuir-Blodgett film deposition, 14-16 monolayer adsorption on metals, 17,18 self-assembly of monolayers, 8,14 solution casting, 19,20 polymer blends, 21 and sol-gel 22 methods. The major limitations of the previous synthetic methods include poor morphological control, limits on film area and substrate geometry, limits on film thickness ͑Ͻ100 nm͒, 23 and high costs associated with some of these techniques.Electrochemical deposition of C 60 or its derivates is particularly attractive because of the suitability to commercial applications. Commercial electrodeposition is relatively low-cost and has a high degree of process control. One example is cathodic electropolymerization, which has been used to synthesize fullerene-containing polymers including fullerene epoxide ͑C 60 O͒ polymers from fullerene in the presence of oxygen 24,25 and directly from C 60 O. 26,27 Fullerene derivate polymers containing metal groups such as Ir in C 60 ͕Ir͑CO͒ 2 ͖ n 28 and other metals 29,30 have also been synthesized. Various other fullerene polymers have also been electrodeposited/electropolymerized 31-34 to fabricate thin films. These methods require nonaqueous solvents and in some cases an oxygen-free electrolyte, which could make the process difficult to commercialize. Cation intercalation in the electropolymerized film has been observed in some cases, 26 which would be undesirable for certain applications. Kamat et al. 35,36 and others 37 have used electrochemi...

The isotopic effects of13C-labeled large carbon cage (C70) fullerenes and their formation process

“…[1][2][3][4][5][6][7] Their biological efficiency depends on both the modification on the cage and the cage size (C 60 , C 70 , C 82, etc.). To date, pristine C 60 and their functionalized derivatives have been fully investigated and commercialized.…”

“…Fullerenes, one category of the most popular carbon nanomaterials, have been widely used in solar energy, cosmetics, personal care, electronics and biomedicine due to their unique chemical and physical properties. [1][2][3][4][5][6][7] Their biological efficiency depends on both the modication of the cage and the cage size (C 60 , C 70 , C 82 , etc.). To date, pristine C 60 and its functionalized derivatives have been fully investigated and commercialized.…”

Characterization and Liquid Chromatography-MS/MS Based Quantification of Hydroxylated Fullerenes

“…In addition, fullerol films are under investigation for possible use in the conversion of solar energy. 19…”

“…This functionalization can change the solubility of these compounds from less than 10 −9 mg/L for C 60 to >50 mg/L for fullerols. , Higher derivatized C 60 fullerols with a solubility of 6 g/L also have been reported . These fullerols are under investigation for use in biomedical applications, due to their antioxidant abilities and also are in development as drug carriers for their ability to bypass protective bodily interfaces, including the blood−retina and the blood−brain barriers. − Using different modifications, water-solubilized fullerenes were also found to possess antioxidative, antibacterial, and antiviral properties, thereby opening up a wide range of possible applications. − In addition, fullerol films are under investigation for possible use in the conversion of solar energy …”

Rate-Limited Electroless Gold Thin Film Growth: A Real-Time Study

“…Scanning electron and atomic force microscopy of EL films fabricated by deposition of metal ions from an adjacent flowing bulk fluid indicate that flow-enhanced deposition could offer improved film continuity and reduced variability in thickness . Flow-enhanced deposition could be utilized in electrodeposition, for which the nanoscale deposition rate varies due to edge effects, local variations in current due to changes in deposited metal thickness, and electrode variation with time. ,− However, it has been reported that very thin films deposited by EL plating are not uniform because the initial deposition is confined to discrete nucleation sites that grow laterally and coalesce into a continuous film . Mechanistically, EL Au deposition from aqueous sodium Au(I) sulfite occurs by galvanic displacement of Ag on tin (Sn)-wetted substrates.…”