Tailoring the optical and electronic properties of nanostructured polymer−metal composites demonstrates great potential for efficient fabrication of modern organic optical and electronic devices such as flexible sensors, transistors, diodes, or photovoltaics. Self-assembled polymer−metal nanocomposites offer an excellent perspective for creating hierarchical nanostructures on macroscopic scales by simple bottom-up processes. We investigate the growth processes of nanogranular silver (Ag) layers on diblock copolymer thin film templates during sputter deposition. The Ag growth is strongly driven by self-assembly and selective wetting on the lamella structure of polystyrene-block-poly-(methyl methacrylate). We correlate the emerging nanoscale morphologies with collective optical and electronic properties and quantify the difference in Ag growth on the corresponding homopolymer thin films. Thus, we are able to determine the influence of the respective polymer template and observe substrate effects on the Ag cluster percolation threshold, which affects the insulator-to-metal transition (IMT). Optical spectroscopy in the UV−vis regime reveals localized surface plasmon resonance for the metal−polymer composite. Their maximum absorption is observed around the IMT due to the subsequent long-range electron conduction in percolated nanogranular Ag layers. Using X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, we identify the oxidation of Ag at the acrylate side chains as an essential influencing factor driving the selective wetting behavior in the early growth stages. The results of polymer-templated cluster growth are corroborated by atomic force microscopy and field emission scanning electron microscopy.

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.

Polymer−metal composite films with nanostructured metal and/or polymer interfaces show a significant perspective for optoelectronic applications, for example, as sensors or in organic photovoltaics (OPVs). The polymer components used in these devices are mostly nanostructured conductive polymers with conjugated π-electron systems. Enhanced OPV's power conversion efficiencies or sensor sensitivity can be achieved by selective metal deposition on or into polymer templates. In this study, we exploit time-resolved grazing-incidence X-ray scattering to observe the metal−polymer interface formation and the cluster crystallite size in situ during silver (Ag) sputter deposition on a poly(3-hexylthiophene-2,5-diyl)-b-poly(methyl methacrylate) (PMMA-b-P3HT) template. We compare the arising nanoscale morphologies with electronic properties, determine Ag growth regimes, and quantify the selective Ag growth for the diblock copolymer (DBC) template using the corresponding homopolymer thin films (P3HT and PMMA) as a reference. Hence, we are able to describe the influence of the respective polymer blocks and substrate effects on the Ag cluster percolation: the percolation threshold is correlated with the insulator-to-metal transition measured in situ with resistance measurements during the sputter deposition. The Ag cluster percolation on PMMA-b-P3HT starts already on the network of the hexagonal P3HT domain before a complete metal film covers the polymer surface, which is complemented by microscopic measurements. In general, this study demonstrates a possible method for the selective Ag growth as a scaffold for electrode preparation in nanoelectronics and for energy harvesting applications.

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.

Reducing the operating temperature to room temperature is a serious obstacle on long-life sensitivity with long-term stability performances of gas sensors based on semiconducting oxides and this should be overcome by new nano-technological approaches. In this work, we report the structural, morphological, chemical, optical and gas detection characteristics of Eu-doped ZnO (ZnO:Eu) columnar films as a function of Eu content. The scanning electron microscopy (SEM) investigations showed that columnar films, grown via synthesis from chemical solutions (SCS) approach, are composed of densely packed columnar type grains. The sample sets with a content of ~0.05, 0.1, 0.15 and 0.2 at% of Eu in ZnO:Eu columnar films were studied. The surface functionalization was achieved using PdCl2 aqueous solution with additional thermal annealing in air at 650 ºC. The temperature dependent gas-detection characteristics of Pd-functionalized ZnO:Eu columnar films were measured in detail, showing a good selectivity towards H2 gas at operating OPT temperatures of 200-300 ºC among several test gases and volatile organic compounds (VOCs) vapors; such as methane, ammonia, acetone, ethanol, n-butanol and 2propanol. At an operating temperature OPT of 250 ºC a high gas response Igas/Iair ~ 115 for 100 ppm H2 was obtained. Experimental results indicate that Eu-doping with an optimal content about 0.05-0.1 at% along with Pd-functionalization of ZnO columns leads to a reduction of the operating temperature of the H2 gas sensor. DFT based computations provide mechanistic insights into the gas sensing mechanism by investigating interactions between the Pd-functionalized ZnO:Eu surface and H2 gas molecules supporting the experimentally observed results. The proposed columnar materials and gas sensor structures would provide a special advantage in the fields of fundamental research, applied physics studies, ecological and industrial applications.