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With this work we introduce a novel memristor in a lateral geometry whose resistive switching behaviour unifies the capabilities of bipolar switching with decelerated diffusive switching showing a biologically plausible short-term memory. A new fabrication route is presented for achieving lateral nano-scaled distances by depositing a sparse network of carbon nanotubes (CNTs) via spin-coating of a custom-made CNT dispersion. Electrochemical metallization-type (ECM) resistive switching is obtained by implanting AgAu nanoparticles with a Haberland-type gas aggregation cluster source into the nanogaps between the CNTs and shows a hybrid behaviour of both diffusive and bipolar switching. The resistance state resets to a high resistive state (HRS) either if the voltage is removed with a retention time in the second- to sub-minute scale (diffusive) or by applying a reverse voltage (bipolar). Furthermore, the retention time is positively correlated to the duration of the Set voltage pulse. The potential for low-voltage operation makes this approach a promising candidate for short-term memory applications in neuromorphic circuits. In addition, the lateral fabrication approach opens the pathway towards integrating sensor-functionality and offers a general starting point for the scalable fabrication of nanoscaled devices., Competing Interests: The authors have declared that no competing interests exist.

Positron annihilation lifetime spectroscopy (PALS), a method well established for the study of polymers, is employed to characterize the temperature dependence of the free volume through T(g) in the amorphous pharmaceutical Verapamil hydrochloride. From the PALS spectra analyzed with the routine LifeTime9.0 the size (volume) distribution of local free volumes (subnanometre-size holes), its mean, v(h), and mean dispersion, sigma(h), were calculated. A comparison with the macroscopic volume from PVT-experiments delivered the hole density and the hole free volume fraction and in that way a complete characterization of the free volume microstructure. These data are used in correlation with structural (alpha-) relaxation data from broad-band dielectric spectroscopy in terms of the Cohen-Turnbull free volume model. An extension of this model, distinctions in the free volume behaviour of the glassy and supercooled-liquid state and different ways of extrapolating the equilibrium part of the free volume into the temperature range of the glass are discussed. The potential of the PALS method for the study of pharmaceuticals is briefly reviewed and some recently developed applications (analysis of density fluctuations) are illuminated.

In the strive for energy efficient computing, many different neuromorphic computing and engineering schemes have been introduced. Nanoparticle networks (NPNs) at the percolation threshold have been established as one of the promising candidates, e.g., for reservoir computing because among other useful properties they show self‐organization and brain‐like avalanche dynamics. The dynamic resistance changes trace back to spatio‐temporal reconfigurations in the connectivity upon resistive switching in distributed memristive nano‐junctions and nano‐gaps between neighboring nanoparticles. Until now, however, there has not yet been any direct imaging or monitoring of current paths in NPN. In this study, an NPN comprising of Ag/CxOyHz core/shell and Ag nanoparticles at the percolation threshold is reported. It is shown that this NPN is within a critical regime, exhibiting avalanche dynamics. To monitor in situ the evolving current paths in this NPN, active voltage contrast and resistive contrast imaging are used complementarily. Including simulations, the results provide experimental insight toward understanding the complex current response of the memristive NPN. As such, this study paves the way toward an experimental characterization of dynamic reorganizations in current paths inside NPN, which is highly relevant for validating and improving simulations and finally establishing a deeper understanding of switching dynamics in NPNs. [ABSTRACT FROM AUTHOR]

Neuromorphic computing seeks functional materials capable of emulating brain‐like dynamics to solve computational problems with time and energy efficiency, outclassing current transistor‐based hardware architectures. Major efforts are focused on integrating memristive devices into highly regular circuits (i.e., crossbar arrays), where the information representation in individual memristive devices is closely oriented toward the behavior of artificial neurons. However, artificial neurons are rather rigid mathematical concepts than realistic projections of complex neuronal dynamics. Neuroscience suggests that highly efficient information representation on the level of individual neurons relies on dynamical features such as excitatory and inhibitory contributions, irregularity of firing patterns, and temporal correlations. Here, a conductive atomic force microscopy approach is applied to probe the memristive dynamics of nanoscale assemblies of AgPt‐nanoparticles at the stability border of the conducting state, where physical forces causing the formation and decay of filamentary structures appear to be balanced. This unveils a dynamic regime, where the memristive response is governed by irregular firing patterns. The significance of such a dynamical regime is motivated by close similarities to excitation and inhibition‐governed behavior in biological neuronal systems, which is crucial to tune biological neuronal systems into a state most suitable for information representation and computation. [ABSTRACT FROM AUTHOR]

Gas phase synthesis of nanoparticles (NPs) via magnetron sputtering in a gas aggregation source (GAS) has become a well‐established method since its conceptualization three decades ago. NP formation is commonly described in terms of nucleation, growth, and transport alongside the gas stream. However, the NP formation and transport involve complex non‐equilibrium processes, which are still the subject of investigation. The development of in situ investigation techniques such as UV–Vis spectroscopy and small angle X‐ray scattering enabled further insights into the dynamic processes inside the GAS and have recently revealed NP trapping at different distances from the magnetron source. The main drawback of these techniques is their limited spatial resolution. To understand the spatio‐temporal behavior of NP trapping, an in situ laser light scattering technique is applied in this study. By this approach, silver NPs are made visible inside the GAS with good spatial and temporal resolution. It is found that the argon gas pressure, as well as different gas inlet configurations, have a strong impact on the trapping behavior of NPs inside the GAS. The different gas inlet configurations not only affect the trapping of NPs, but also the size distribution and deposition rate of NPs. [ABSTRACT FROM AUTHOR]

Mixed Metal Oxide NanoparticlesIn article number 2400305, Lorenz Kienle, Salih Veziroglu, and co‐workers introduce a revolutionary single‐step fabrication of TiOx‐CeOx nanoparticles. Using a gas aggregation cluster source with a segmented Ti/Ce target, we achieve diverse compositions and enhanced deposition rates, crucial for practical applications..By Marie Elis; Tim Tjardts; Josiah Ngenev Shondo; Ainura Aliyeva; Alexander Vahl; Ulrich Schürmann; Thomas Strunskus; Franz Faupel; Cenk Aktas; Lorenz Kienle and Salih VezirogluReported by Author; Author; Author; Author; Author; Author; Author; Author; Author; Author; Author [Extracted from the article]

In this study, in situ UV–Vis spectroscopy is used to investigate the growth and transport of nanoparticles inside a gas aggregation source (GAS) dependent on the Ar gas flow and operating pressure. It was found that the nanoparticles were becoming trapped at different positions inside the GAS dependent on the gas flow. Moreover, in situ UV–Vis spectroscopy suggested the presence of large nanoparticles inside the GAS, which were not observed outside. Computational fluid dynamic simulations were performed to study the velocity distribution inside the GAS. Three distinct areas were identified, where nanoparticles can become trapped or lost. The gas flow velocity distribution was found to strongly impact the transport of nanoparticles. [ABSTRACT FROM AUTHOR]

The use of multicomponent targets allows the gas‐phase synthesis of a large variety of alloy nanoparticles (NPs) via gas aggregation sources. However, the redeposition of sputtered material impacts the composition of alloy NPs, as demonstrated here for the case of AgAu alloy NPs. To enable NPs with tailored Au fractions, in operando control over the composition of the NPs is in high demand. We suggest the use of optical emission spectroscopy as a versatile diagnostic tool to determine and control the composition of the NPs. A strong correlation between operating pressure, intensity ratio of Ag and Au emission lines, and the obtained NP compositions is observed. This allows precise in operando control of alloy NP composition obtained from multicomponent targets. [ABSTRACT FROM AUTHOR]

An improved effective medium approximation (EMA) is presented that accounts for higher order interactions between metal nanoparticles in metal-dielectric composite materials and compared to experimental results. The theoretical results of this formalism are applied to a composite material consisting of spherical gold nanoparticles randomly distributed in a dielectric matrix, which has been extensively characterized with respect to its structural and optical properties. The experimental results and theoretical predictions are compared and the results are discussed. It is shown that the modified theory expands the range to which EMA can be applied to a metal filling fraction of ∼20% at very little additional computational expenses. The improved theory also allows extracting more information from the optical characterization of the composite material such as the distribution of the interparticle distances in a composite. [ABSTRACT FROM AUTHOR]

Kinetic aspects of the synthesis of Ag nanoparticles (NPs) by magnetron sputtering are studied by in situ and time‐resolved small angle X‐ray scattering (SAXS). Part of the NPs are found to become confined within a capture zone at 1–10 mm from the surface of the target and circumscribed by the plasma ring. Three regimes of the NP growth are identified: 1) early growth at which the average NP diameter rapidly increases to 90 nm; 2) cycling instabilities at which the SAXS signal periodically fluctuates either due to expelling of large NPs from the capture zone or due to the axial rotation of the NP cloud; and 3) steady‐state synthesis at which stable synthesis of the NPs is achieved. The NP confinement within the capture zone is driven by the balance of forces, the electrostatic force being dominant. On reaching the critical size, large NPs acquire an excessive charge and become expelled from the capture zone via the electrostatic interactions. As a result, significant NP deposits are formed on the inner walls of the aggregation chamber as well as in the central area of the target. [ABSTRACT FROM AUTHOR]

The size, composition, and crystallinity of plasma produced nanoparticles are crucial factors for their physical and chemical properties. Here, we investigate the role of the process gas composition, particularly the hydrogen (H2) flow rate, on germanium (Ge) nanoparticles synthesized from a chlorinated precursor by nonthermal plasma. We demonstrate that the gas composition can significantly change the nanoparticle size and also adjust the surface chemistry by altering the dominant reaction mechanisms. A red shift of the Ge-Clx infrared absorptions with increasing H2 flow indicates a weakening of the Ge-Clx bonds at high H2 content. Furthermore, by changing the gas composition, the nanoparticles microstructure can be controlled from mostly amorphous at high hydrogen flow to diamond cubic crystalline at low hydrogen flow. [ABSTRACT FROM AUTHOR]

A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder. [ABSTRACT FROM AUTHOR]

Plasmonic nanocomposites find many applications, such as nanometric coatings in emerging fields, such as optotronics, photovoltaics or integrated optics. To make use of their ability to affect light propagation in an unprecedented manner, plasmonic nanocomposites should consist of densely packed metallic nanoparticles. This causes a major challenge for their theoretical description, since the reliable assignment of effective optical properties with established effective medium theories is no longer possible. Established theories, e.g., the Maxwell-Garnett formalism, are only applicable for strongly diluted nanocomposites. This effective description, however, is a prerequisite to consider plasmonic nanocomposites in the design of optical devices. Here, we mitigate this problem and use full wave optical simulations to assign effective properties to plasmonic nanocomposites with filling fractions close to the percolation threshold. We show that these effective properties can be used to properly predict the optical action of functional devices that contain nanocomposites in their design. With this contribution we pave the way to consider plasmonic nanocomposites comparably to ordinary materials in the design of optical elements. [ABSTRACT FROM AUTHOR]

While extensive research has been carried out in the field of structural polymer-based nanocomposites much less investigations have been concerned with polymer nanocomposites for functional applications. Among the functional nanomaterials, nanocomposites consisting of metal nanoparticles dispersed in a dielectric matrix are of particular interest due to their novel functional properties offering hosts of new applications. Here, polymers are attractive as matrix, and several approaches have been reported to incorporate metal nanoparticles into polymers. The present review is concerned with the preparation of polymer-based nanocomposites by vapor phase co-and tandem deposition and the resulting functional properties. The techniques involve evaporation and sputtering, respectively, of metallic and organic components and inter alia allow the preparation of composites which contain alloy clusters of well defined composition. Emphasis is placed on soft-magnetic high frequency materials with cut-off frequencies well above 1 GHz and on optical composites with tuned plasmon resonances suitable for ultra thin color filters, Bragg reflectors, and other devices. In addition, antibacterial coatings and sensors for organic vapors are addressed. The latter take advantage of the steep drop of the electrical resistivity at the percolation threshold. First results are also reported on the incorporation of photo-switchable molecules into nanocomposites near the percolation threshold. Moreover, a novel approach to produce magnetic nanorods is present [ABSTRACT FROM AUTHOR]

Nanoscale memristive phenomena are of great interest not only to miniaturize devices and improve their performance but also to understand the details of the underlying mechanism. Herein, we utilize conductive atomic force microscopy (C-AFM) as a non-invasive method to examine the nanoscale memristive properties of individual noble metal alloy nanoparticles that are sparsely encapsulated in a thin SiO2 dielectric matrix. The measurement of current-voltage hysteresis loops at the level of individual nanoparticles, enabled by the nanoscopic contact area of the C-AFM tip, indicates reliable memristive switching for several hours of continuous operations. Alongside the electrical characterization on the nanoscale, the method of C-AFM offers the potential for in situ monitoring of long term operation induced morphological alterations and device failure, which is demonstrated at the example of nanoparticle-based devices with additional Cr wetting layer. The application of alloy nanoparticles as reservoir for mobile silver species effectively limits the formation of stable metallic filaments and results in reproducible diffusive switching characteristics. Notably, similar behaviour is encountered on macroscopic nanocomposite devices, which incorporate multiple stacks of nanoparticles and offer a high design versatility to tune switching properties and engineer scalable memristive devices with diffusive switching characteristics. No additional forming step is required for the operation of the presented alloy nanoparticle based memristive devices, which renders them very attractive for applications. [ABSTRACT FROM AUTHOR]

In‐situ UV–Vis spectroscopy was used for investigating the evolution of silver nanoparticles (NPs) inside the gas aggregation cluster source (GAS). The light beam probed the interior of the GAS at different distances from the magnetron. Plasmon resonance was detected at 365 nm, with the highest intensity found close to the magnetron due to the NP trapping. Time‐resolved measurements revealed that after the discharge switch off the majority of trapped NPs fly out of the GAS. Part of them is redeposited onto the center of the target due to the electrostatic force. NPs collected at the distance of 20 mm and further from the magnetron demonstrate gradual decrease of the size, pointing to the loss of bigger NPs on the walls. [ABSTRACT FROM AUTHOR]

TiO2 thin films are used extensively for a broad range of applications including environmental remediation, self-cleaning technologies (windows, building exteriors, and textiles), water splitting, antibacterial, and biomedical surfaces. While a broad range of methods such as wet-chemical synthesis techniques, chemical vapor deposition (CVD), and physical vapor deposition (PVD) have been developed for preparation of TiO2 thin films, PVD techniques allow a good control of the homogeneity and thickness as well as provide a good film adhesion. On the other hand, the choice of the PVD technique enormously influences the photocatalytic performance of the TiO2 layer to be deposited. Three important parameters play an important role on the photocatalytic performance of TiO2 thin films: first, the different pathways in crystallization (nucleation and growth); second, anatase/rutile formation; and third, surface area at the interface to the reactants. This study aims to provide a review regarding some strategies developed by our research group in recent years to improve the photocatalytic performance of TiO2 thin films. An innovative approach, which uses thermally induced nanocrack networks as an effective tool to enhance the photocatalytic performance of sputter deposited TiO2 thin films, is presented. Plasmonic and non-plasmonic enhancement of photocatalytic performance by decorating TiO2 thin films with metallic nanostructures are also briefly discussed by case studies. In addition to remediation applications, a new approach, which utilizes highly active photocatalytic TiO2 thin film for micro- and nanostructuring, is also presented. [ABSTRACT FROM AUTHOR]

Highlights from the article: Ag Nanoparticles Decorated TiO2 Thin Films with Enhanced Photocatalytic Activity (Phys. In article number 1800898, Salih Veziroglu, Franz Faupel, Oral Cenk Aktas, and co-workers present a facile method to prepare Ag nanoparticles (NPs) decorated TiO SB 2 sb thin film by photocatalytic deposition. The presented method allows easy controlling size, morphology and distribution density of Ag NPs on TiO SB 2 sb to achieve a high photocatalytic activity.

Abstract: During the last decades, metal-polymer nanocomposites have been subject to extensive research as their electrical, magnetic and optical properties are very sensitive to their specific compositions and morphological structures. Although there exist a variety of standardized and well-established production processes based on plasma-assisted physical vapor deposition methods, significant progress in the understanding of the self-organized formation process has only been achieved with the help of computer simulations. In particular, computational approaches based on kinetic Monte Carlo (KMC) and molecular dynamics (MD) simulations turned out to be successful in recent years because they offer the potential to simulate and predict the system behavior on sufficiently long time scales. In this paper, we review several formation processes of metal-polymer systems that have been investigated in joint experimental and theoretical KMC and MD studies. These comprise the growth of metallic nanocolumns in a polymer matrix and the growth of nanogranular structures on a polymer film. Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract: Metal clusters and nanoparticles (NPs) have been studied intensively due to their unique chemical, physical, electrical, and optical properties, resulting from their dimensions, which provided host of applications in nanoscience and nanotechnology. Formation of new materials by embedding NPs into various matrices (i.e. formation of nanocomposites) further expands the horizon of possible application of such nanomaterials. In the last few decades, the focus was put on the formation of metallic and metal oxide NPs via a so-called gas aggregation nanoparticle source employing magnetron sputtering (i.e. Haberland concept). In this paper, an overview is given of the recent progress in formation and deposition of NPs by the gas aggregation method. Examples range from noble metals (Ag, Au) through reactive metals (Al, Ti) to Si and the respective oxides. Emphasis is placed on the mechanism of nanoparticle growth and the resulting properties. Moreover, kinetic Monte Carlo simulations were developed to explain the growth mechanism and dynamics of nanoparticle formation depending on the experimental conditions. In addition, the role of trace amounts of reactive gases and of pulsed operation of the plasma on the nucleation process is addressed. Finally, the treatment of the NPs in the plasma environment resulting in nanoparticle charging, morphological and chemical modifications is discussed. Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract: With an ever increasing interest in functional materials based on nanoparticles a large amount of research in this field is dedicated to the development of new production methods for nanoparticles. A promising class of methods for the production of nanoparticles is reactive plasmas. However, since the particle formation process and the interaction between the particles and the plasma are so far not completely understood, it remains difficult to control the particle formation. As the interaction between the nanoparticles and the plasma in which they are dispersed is complex the use of one or two diagnostics often provides only an incomplete understanding of the involved processes. Thus a multidiagnostic approach is needed. This contribution reviews the latest results from the study of nanoparticle formation in a hydrocarbon-based reactive plasma by such a multidiagnostic approach. It is shown that the use of various diagnostics like an IV-probe, optical emission spectroscopy, and a multipole resonance probe in conjunction with an investigation of the particle formation provides a much more detailed picture of these interesting, yet challenging, systems. Graphical abstract: [ABSTRACT FROM AUTHOR]

Using reactive DC sputtering in a gas aggregation cluster source, we show that pulsed discharge gives rise to a huge increase in deposition rate of nanoparticles by more than one order of magnitude compared to continuous operation. We suggest that this effect is caused by an equilibrium between slight target oxidation (during 'time-off') and subsequent sputtering of Ti oxides (sub-oxides) at 'time-on' with high power impulse. [ABSTRACT FROM AUTHOR]

Synthesis of multifunctional nanomaterials is known as a critical challenge in advanced nanoscience. Multicore@shell nanostructures are generated here via a gas phase synthesis approach. To achieve this objective, we used conventional DC magnetron sputtering in conjunction with a gas aggregation chamber. We employed a customized Au-Ti target to produce metal-metal oxide multicore@shell nanoparticles (NPs) with tunable properties. The deposited NPs were characterized with regard to their chemical composition, morphology, structural status, NP size distribution and optical properties. The obtained data clearly confirms that the crystalline Au cores are encapsulated in a TiOx matrix in each individual NP. Furthermore, the chemical composition and size distribution of the NPs can be affected by the operating pressure. Our approach provides a versatile route with many different possibilities to synthesize multicore@shell NPs from a variety of composite targets for well-desired applications including environmental, optical/plasmonic, and energy. • Multicore@shell NPs using a GAS combined with magnetron sputtering and Au-Ti target. • TEM, XRD and XPS revealed NPs consist of crystalline Au cores embedded in TiOx. • Operating pressure influences chemical composition and size distribution. • Upon annealing agglomeration of Au leads to a strong plasmonic resonance. [ABSTRACT FROM AUTHOR]

Abstract: In the present research we have evaluated residual stress as well as thermal stability of polytetrafluoroethylene (PTFE) and PTFE-based silver (Ag) nanocomposite films fabricated by dual magnetron sputtering. We used a RF magnetron system for sputtering PTFE, and a DC magnetron sputter source for metal. We have demonstrated that thin nanocomposite films of Ag/sputtered PTFE (thickness 800 to 1100nm, Ag concentration 3.5 to 24.5%) deposited on silicon are stressed (6.24 to 12.2MPa). The residual stress depends on the concentration of the nanoparticles. Pure sputter deposited PTFE films are under a small tensile stress, which becomes increasingly more compressive upon increasing the filling factor of the metallic nanoparticles. Depending on the concentration of nanoparticles, the residual stress is determined by a thermal component that is sensitive to temperature variation, even in the range of room temperature. In the evaluation of the thermal response of the nanocomposite-silicon system, both the changes in the thermal expansion coefficient as well as the elastic modulus of the nanocomposite with the concentration should be taken into account. [Copyright &y& Elsevier]

Au/ZnO-CeO 2 hybrid structure was prepared by in-situ synthesis of 15–20 nm CeO 2 particles in aqueous environment, in which ZnO particles (400–500 nm) were dispersed, using surfactant assisted precipitation method. Au was loaded on prepared structures through the reduction of AuCl 3 by ascorbic acid. TEM analysis and Raman spectroscopy showed that synthesized hybrid structure is composed of both hexagonal ZnO and cubic CeO 2 phases. While methylene blue test solution was degraded totally within 8 min in the presence of Au/ZnO-CeO 2 hybrid catalysis, use of Au/ZnO and Au/CeO 2 led to a significantly low degradation rate (about 22% and 11%, respectively). As proven by XPS analysis the incorporation of ZnO to CeO 2 seem to trigger the formation of Ce +3 /Ce +4 dynamic equilibria and this enhances the catalytic efficiency enormously. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sputter-based synthesis of tantalum oxynitride nanoparticles is reported. • Nanoparticles exhibit crystalline core, amorphous periphery, and nitrogen gradient. • Nanoparticles are plasmonic and photoluminescent. • Size, chemical composition, and bandgap can be tuned by adjusting the nitrogen flow. Among strategies of fuel production, photoelectrochemical water splitting for hydrogen generation is garnering significant attention. The challenge for solar energy harvesting is material development with intense photocatalytic activity, efficient free-charge generation, separation, and transport. Tantalum nitride (Ta 3 N 5) and oxynitrides (Ta 3 N y O x) are recognized as promising candidates for this role. This research suggests a new route to engineer Ta 3 N y O x nanoparticles (NPs) with structure, crystallinity, chemical, and optoelectronic properties controlled by design. This work employs a single-step plasma-based technique that takes advantage of dc reactive magnetron sputtering of tantalum in Ar/N 2 mixtures. The NPs with the chemical composition of Ta 3 N 3.9 O 0.6 are synthesized; however, they become partially oxidized when exposed to air, providing an inwardly-directed gradient of the nitrogen concentration. The core-region consists of n -type sub-stoichiometric Ta 3 N y with a band gap of <2.0 eV partially filled with mid-gap states, whereas the outermost region belongs to Ta 3 N y O x , with oxygen enhancing the n -character of the material. The nitridation and the amorphous/crystalline ratio enhance with the concentration of N 2. The NPs exhibit plasmonic and photoluminescent properties in the visible range and are therefore attractive for numerous interdisciplinary fields. In particular, additional annealing in ammonia improves crystallinity and nitridation, making the NP-assembled deposits perform as advanced anodes for photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]

A highly photocatalytic Au-TiO 2 hybrid thin film was prepared by the photocatalytic deposition of Au nanoparticles (NPs) on reactive sputtered TiO 2 thin film. By altering the ratio of the visible (Vis) and ultra-violet (UV) light (Vis/UV), we investigated plasmonic and non-plasmonic contributions of Au NPs to the overall photocatalytic activity. While, a gradual increase of Vis/UV (≤0.24/1) led to a steady enhancement of the photocatalytic performance of Au-TiO 2 hybrid structures, further increase in Vis/UV (≥0.30/1) did not foster the enhancement further. At high Vis/UV, plasmon excited electrons seem to start promoting electron-hole recombination in TiO 2 , which significantly reduces the photocatalytic performance. Unlabelled Image • A highly active TiO 2 film allows the deposition of Au nanostructures under low intensity UV light • Au nanostructures lead to both plasmonic and non-plasmonic contributions on TiO 2 • Au-TiO 2 photocatalyst exhibits an enhanced absorption in the visible region • Vis/UV light ratio governs the photocatalytic performance of Au-TiO 2 hybrid structures [ABSTRACT FROM AUTHOR]