Photoconductivity studies on amorphous and crystalline TiO2 films doped with gold nanoparticles

Valverde-Aguilar, Guadalupe; García-Macedo, Jorge A.; Rentería-Tapia, Víctor; Aguilar-Franco, Manuel

doi:10.1007/s00339-010-6199-6

Cited by 14 publications

(6 citation statements)

References 17 publications

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“…with a good control of the size distribution and shape [2,15]. NPs produced by liquid phase have been integrated in wide band gap semiconductors [16]. For instance, Au and Ag NPs were successfully infiltrated in TiO2 thin films by Valverde et al [16] and Qi et al [17] in order to improve the photoconductivity of thin film photovoltaic devices (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Engineering plasmonic nanostructured surfaces by pulsed laser deposition

Ghidelli

Mascaretti

Bricchi

et al. 2018

Applied Surface Science

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The synthesis and the optical response of gold nanoparticles (NPs) and thin nanostructured films grown by pulsed laser deposition (PLD) are here studied. Different PLD process parameters-including background gas pressure and the number of laser shots as well as post-deposition annealing treatments-have been varied to control the growth of Au NPs and films, thus tuning the surface plasmon characteristics. The mechanisms of NPs and film growth have been explored performing a morphological characterization by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), and the correlation with the optical behavior is investigated. We show that the size distribution and the morphology of the as deposited Au NPs depend on growth mechanisms which are controlled by tuning the deposition process, while the optical behavior is strongly affected by the average size and surface density of NPs or by the length of percolated Au domains. Furthermore, nucleation in gas phase has been reported at high (1000 Pa Ar) background pressures, enabling independent control of NP size and coverage, contrary to surface driven NP growth by diffusion and aggregation on substrate.

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Section: Introductionmentioning

confidence: 99%

“…In addition, a two-step procedure -namely the synthesis of thin film followed by the NPs infiltration -combined with the presence of contaminants (i.e. the reaction products) represents a further limitation of this technique [2,13,16,17] in terms of integration efficacy and available morphologies.…”

Section: Introductionmentioning

confidence: 99%

Engineering plasmonic nanostructured surfaces by pulsed laser deposition

Ghidelli

Mascaretti

Bricchi

et al. 2018

Applied Surface Science

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“…Plasmonic concentration and propagation have recently been proposed as strategies for enhancing photovoltaic and photocatalytic performance. − In this Letter we describe a device, fabricated entirely using foundry processes with which a wide band gap semiconductor is photosensitized by embedding plasmonic nanoparticles within it, thereby significantly broadening its photoconversion ability beyond the ultraviolet region. The active element of the device is a composite solid film consisting of multiple, dense two-dimensional planar arrays of gold nanoparticles with each layer well separated by TiO 2 .…”

mentioning

confidence: 99%

Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers

et al. 2011

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A fruitful paradigm in the development of low-cost and efficient photovoltaics is to dope or otherwise photosensitize wide band gap semiconductors in order to improve their light harvesting ability for light with sub-band-gap photon energies.(1-8) Here, we report significant photosensitization of TiO2 due to the direct injection by quantum tunneling of hot electrons produced in the decay of localized surface-plasmon polaritons excited in gold nanoparticles (AuNPs) embedded in the semiconductor (TiO2). Surface plasmon decay produces electron-hole pairs in the gold.(9-15) We propose that a significant fraction of these electrons tunnel into the semiconductor's conduction band resulting in a significant electron current in the TiO2 even when the device is illuminated with light with photon energies well below the semiconductor's band gap. Devices fabricated with (nonpercolating) multilayers of AuNPs in a TiO2 film produced over 1000-fold increase in photoconductance when illuminated at 600 nm over what TiO2 films devoid of AuNPs produced. The overall current resulting from illumination with visible light is ∼50% of the device current measured with UV (ℏω>Eg band gap) illumination. The above observations suggest that plasmonic nanostructures (which can be fabricated with absorption properties that cover the full solar spectrum) can function as a viable alternative to organic photosensitizers for photovoltaic and photodetection applications.

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“…For this purpose, they used chemical and physical methods as well as adsorption of preformed Au colloids, depositionprecipitation, co-sputtering and Chemical Vapor Deposition (CVD). More recently, a similar approach has been used by Valverde et al [26] and Gomes Silva et al [19] reporting the adsorption of colloidal Au NPs on TiO 2 surface for photovoltaic devices and for solar water splitting. Other possible chemical techniques are the photodeposition of Au on TiO 2 [20,27] and the chemical spray pyrolysis [28].…”

Section: Introductionmentioning

confidence: 99%

“…However, chemical approaches have some drawbacks including the use of aggressive solvents and the presence of remaining contaminants [29], while requiring a two steps procedure, namely the synthesis of Au NPs and subsequent infiltration in the TiO 2 films, which are typically nanoporous in order to achieve high surface area as required for the mentioned applications [30]. For these reasons, a proper dispersion of NPs within TiO 2 structures is difficultly achieved [1,26,31]. On the other hand, a physical method of synthesis allows the production of highly pure NPs without the presence of contaminants, keeping a good control of size distribution.…”

Section: Introductionmentioning

confidence: 99%

Integration of plasmonic Au nanoparticles in TiO2 hierarchical structures in a single-step pulsed laser co-deposition

et al. 2018

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The plasmonic resonance of noble metal nanoparticles (NPs) can be exploited to enhance the photoresponse of wide band gap oxides in view of several solar energy applications. Here, we demonstrate single-step synthesis of plasmonic Au nanoparticles integrated in TiO 2 hierarchical nanoporous layers through a vapor phase pulsed laser co-deposition approach. Specifically, we report the fabrication and characterization of Au NPs-decorated TiO 2 forest-like systems with tunable porosity and density as well as the morphological/structural evolution as a function of Au content and we discuss the corresponding optical properties. The effect of post-deposition thermal treatment has been investigated as well in order to control TiO 2 crystallization and Au NPs nucleation and growth. Optical analyses show the onset of characteristic plasmonic resonance of Au NPs with the increase of film absorption in the visible range. Preliminary tests of photodegradation of methyl orange dye indicates that the integration of Au NPs leads to a significant increase of the catalytic activity of nanoporous TiO 2 . Our results suggest the potentiality of this approach for the synthesis and the integration of metallic NPs within wide band gap semiconductors, while paving the way toward novel plasmonic-based devices.

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Photoconductivity studies on amorphous and crystalline TiO2 films doped with gold nanoparticles

Cited by 14 publications

References 17 publications

Engineering plasmonic nanostructured surfaces by pulsed laser deposition

Engineering plasmonic nanostructured surfaces by pulsed laser deposition

Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers

Integration of plasmonic Au nanoparticles in TiO2 hierarchical structures in a single-step pulsed laser co-deposition

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