Electropolymerized Polythiophene Photoelectrodes with Density-Controlled Gold Nanoparticles

Abstract

A polythiophene thin film was fabricated on gold nanoparticle (AuNP)-deposited indium-tin-oxide (ITO) electrodes with electropolymerization, whereas AuNPs were predeposited on the ITO surface. A photocurrent via photoexcited polythiophene increased with AuNPs which was attributed to the localized surface plasmon resonance. Investigation of the AuNP-density dependence on the relative enhancement of photocurrent revealed the maximum effect at 14% of AuNP-density, while 68% of AuNP-density exhibited smaller photocurrent than the polythiophene electrode without AuNPs. We have revealed that the effects of AuNPs saturate in the fairly low density region, and that the excess AuNPs even in the range of submonolayer resulted in the decrement of photocurrents.

Effects of Silver and Gold Nanoparticles on Photon Upconversion Based on Sensitized Triplet-Triplet Annihilation

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Recently, we found the large enhancement of photocurrents of a porphyrin or a phthalocyanine derivative or a poly(3-hexylthiophene) as an organic dye in dye-metal NPs composite films on indium-tin-oxide (ITO) electrodes were performed by the electrostatic layer-by-layer adsorption technique [4][5][6][7][8][9][11][12][13] . We also found the remarkable enhancements of photocurrent responses in the composite films of donor -acceptor linked compound and metal NP [silver nanoparticle (AgNP) or gold nanoparticle (AuNP)] on ITO electrodes attributable to the combination of localized surface plasmon resonance (LSPR) due to AgNP or AuNP and photoinduced intramolecular electron-transfer.…”

Metal and Metal Oxide Nanoparticles for Photoelectrochemical Materials and Devices

“…[13][14][15][16][17][18] In a system of polythiophene with AgNPs, both photocurrents and fluorescence are enhanced by AgNPs, indicating that the photocurrent enhancement is due to enhancement of dye excitation. 13 The thickness of the polymer layer thus can be optimized.…”

“…16,17 A correlation between photocurrents of polythiophene and the density of electrostatically adsorbed 15 or electrodeposited 18 AuNP (³20 nm) was also investigated with a constant amount of polythiophene, which was controlled by degree of electropolymerization. The maximum photocurrent enhancement is reached when the interparticle spacing estimated from the particle density is approximately twice as large as the particle diameter (Fig.…”

“…In particular, efficient light harvesting is an important issue, because ambient photon flux density is low in general. With this in mind, we have developed the following three new classes of nanomaterials and photoelectrochemical devices based on the nanomaterials: (1) photocatalysts with energy storage abilities, [1][2][3][4][5][6][7][8] which can store energy derived from light and continue redox reactions even in the night, (2) plasmonic metal nanoparticle ensembles stabilized by metal oxide nanomasks and ultrathin metal oxide coatings, 9,10 as well as solid-state photovoltaic cells 11 and plasmon resonance sensors 9,10,12 based on the ensembles, and (3) organic [13][14][15][16][17][18] or organic-inorganic hybrid [19][20][21] photoelectrodes with optimally arranged plasmonic metal nanoantennas. The former one stores surplus energy during the day and uses it in the night, while the latter two trap photons efficiently taking advantage of the large absorption cross-section of plasmonic metal nanoparticles.…”

Vibrational Spectroscopic Studies on the Formation Processes and Characteristics of Octadecanethiol Monolayers on the Surfaces of Gold Nanoparticles

“…Especially, AuNPs exhibit collective oscillations of their free electrons under the resonant light irradiation, known as localized surface plasmon resonance (LSPR). Recently, enhancement effects of photocurrent [4][5][6][7][8] , photoluminescence [7][8][9][10][11] and photocatalytic reaction 12 based on LSPR have been studied, because LSPR exhibits enhancement effects on both absorption and emission processes of molecules and semiconductors. Although these unique phenomena based on LSPR depend on size, shape, and refractive index of surrounding medium, the practical devices have not yet been realized because tailor-made plasmonic nanoparticles such as AuNPs are difficult to design precisely by means of conventional methods.…”