Nanostructured thin films obtained by electrodeposition over a colloidal crystal template: applications in electrochemical devices

Abstract

Partículas coloidais têm sido empregadas na síntese dirigida por molde de diversos materiais, tais como semicondutores, metais e ligas. Esse método permite um controle da espessura do material resultante através da escolha adequada da carga aplicada no sistema e é possível produzir materiais densamente depositados, sem rachaduras. Esses materiais são fidedignos à estrutura do molde e, devido às amplas áreas superficiais obtidas, são muito interessantes em aplicações eletroquímicas. Neste trabalho, a distribuição de um molde de poliestireno monodisperso foi realizada sobre substratos de ouro, platina e carbono vítreo com o intuito de exemplificar a eletrodeposição de um óxido, um polímero condutor e um material híbrido orgânico-inorgânico, com aplicações em supercapacitores e sensores. Os desempenhos dos eletrodos nanoestruturados foram comparados com os análogos massivos e os resultados obtidos são descritos.Colloidal particles have been used to template the electrosynthesis of several materials, such as semiconductors, metals and alloys. The method allows good control over the thickness of the resulting material by choosing the appropriate charge applied to the system, and it is able to produce high density deposited materials without shrinkage. These materials are a true model of the template structure and, due to the high surface areas obtained, are very promising for use in electrochemical applications. In the present work, the assembly of monodisperse polystyrene templates was conduced over gold, platinum and glassy carbon substrates in order to show the electrodeposition of an oxide, a conducting polymer and a hybrid inorganic-organic material with applications in the supercapacitor and sensor fields. The performances of the resulting nanostructured films have been compared with the analogue bulk material and the results achieved are depicted in this paper. Keywords: colloidal particle templates, polystyrene, macroporous materials, sensors, supercapacitors IntroductionThree dimensional close packed arrays of monodisperse polystyrene or silica particles have attracted attention because of their potential to template synthesis of various materials.1 These spherical colloidal particles can be either synthesized 2 or commercially acquired in a range of diameters from few nanometers up to micrometer scale.Much of the interest in applying colloidal particles to template material synthesis has come from studies in photonic crystals, 3 and the first reported electrodeposition through colloidal templates concerned the synthesis of macroporous CdS and CdSe films for photonic bandgap studies. 4 Later papers have used colloidal particles to electrodeposit ordered macroporous films of other semiconductors, 5 metals, 6,7 alloys, 8 oxides 9 and conducting polymers. [10][11][12] The template technique is able to produce high density deposited materials, since the compounds are electrodeposited inside the template voids and around the surface of the colloidal particles. When the template is removed, there is no shrinkage o...

Macroporous MnO2 electrodes obtained by template assisted electrodeposition for electrochemical capacitors

“…16 Briefly, two additions of 20 µL of 0.5% wt. polystyrene nanospheres, with a 460 nm diameter and suspended in a 10 -6 mol L -1 Triton X-100 aqueous solution, were added over the gold substrate and dried slowly at room temperature.…”

“…14 The major interest is to use MnO 2 as positive electrode together with carbon as negative electrode in hybrid systems, improving the cell voltage, thus, improving energy and power densities. 15 In a previous work 16 the obtention of macroporous MnO 2 electrodes has been briefly reported together with the preparation of other electroactive porous thin films, showing the potential application of the methodology.…”

Urea Amperometric Biosensors Based on Nanostructured Polypyrrole

“…Many studies have been developed aiming to nanostructure polymeric [1][2][3], metallic [4], hybrid [1] and metal oxide films [5], among others. In particular, conducting polymers with micro and nanometric dimensions have attracted a lot of attention mainly due to their potential application in electronic circuits [6], photovoltaic cells [7], electrochromic devices [8] and in chemical sensors [9].…”

“…In the literature, there are examples of synthesis and characterization of different polypyrrole nanostructures, as macropores [1][2][3], micro/nanotubes [10] and microcontainers [11,12].…”

Nanomaterial-Based Electrochemical and Colorimetric Sensors for On-Site Detection of Small-Molecule Targets

“…37 Such films can be manufactured by either layout-coordinated or template-free strategies. Layoutcoordinated techniques ordinarily comprise electrodeposition, [38][39][40][41] filtration, 42 or thermal evaporation/sputter coating 43,44 on unbending latex or SiO 2 sphere templates, followed by hydrofluoric acid corrosive etching to remove the template. Gold films generated by such means exhibit uniform pore distribution, but post-dissolution of the template is timeconsuming.…”