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We report on the in situ monitoring of the formation of conductive superlattices of Cu1.1S nanodiscs via cross-linking with semiconducting cobalt 4,4′,4′′,4′′′-tetraaminophthalocyanine (CoTAPc) molecules at the liquid/air interface by real-time grazing incidence small angle X-ray scattering (GISAXS). We determine the structure, symmetry and lattice parameters of the superlattices, formed during solvent evaporation and ligand exchange on the self-assembled nanodiscs. Cu1.1S nanodiscs self-assemble into a two-dimensional hexagonal superlattice with a minor in-plane contraction (∼0.2 nm) in the lattice parameter. A continuous contraction of the superlattice has been observed during ligand exchange, preserving the initial hexagonal symmetry. We estimate a resultant decrement of about 5% in the in-plane lattice parameters. The contraction is attributed to the continuous replacement of the native oleylamine surface ligands with rigid CoTAPc. The successful cross-linking of the nanodiscs is manifested in terms of the high electrical conductivity observed in the superlattices. This finding provides a convenient platform to understand the correlation between the structure and transport of the coupled superstructures of organic and inorganic nanocrystals of anisotropic shape.

To meet the demand for low-cost, lightweight, portable and building-integrated solar cells, developing flexible and cost-efficient photo-active hybrid films is of significant interest. In this work, we investigate the mechanical properties of hybrid layers consisting of mesoporous TiO2 filled with poly(3-hexylthiophene-2,5-diyl) (P3HT) as a function of the number of bending cycles. The TiO2/P3HT layers are deposited on flexible PET substrates at low temperatures (≤140 °C), which is beneficial for reducing the processing energy input and in turn lowering the production costs. Non-filled and partially filled mesoporous titania films are studied for comparison. The surface morphology is examined with scanning electron microscopy (SEM) before and after the bending tests. The inner film morphology is characterized with grazing incidence small-angle X-ray scattering (GISAXS). Based on the observed morphology, micromechanical models are used to analyze the mechanical properties of the investigated films. The results show that the TiO2/P3HT layers have a low elastic modulus and P3HT helps to stabilize the titania nanostructures against fracture. The SEM observations are well explained with the established models in a quantitative way.

We report a facile synthetic approach to create stable radical block copolymers containing a secondary fluorinated block via anionic polymerization using a bulky, sterically hindered countercation composed of a sodium ion and di-benzo-18-crown-6 complex. The synthetic conditions described in this report allowed for controlled molecular weights and dispersity (

Grazing Incidence Small Angle X-ray Scattering (GISAXS) has been used for characterization of a cluster structure of the [Fe/Cr]30 multilayer with ultrathin iron layers. The experiment was performed at the “Langmuir” station of the Kurchatov Center of Synchrotron Radiation and Nanotechnology. Experimental GISAXS image has shown the side satellites and the Bragg peak revealing the existence of density inhomogeneities with an average lateral distance of ∼19 nm periodically repeated along depth. The modelling of the obtained image has been done in the DWBA approximation. It has been shown that for the wavelength used in the experiment (0.0951 nm) it is not possible to distinguish if the inhomogeneities exist in the Fe or in the Cr layers due to the small optical contrast between Fe and Cr layers. However, as it has been demonstrated by model calculations, in the case of the enhanced optical contrast (e.g. for the wavelength corresponding to the L3 edge of Fe) the x-ray standing waves allow ones to select the cases of inhomogeneities in the Fe or in the Cr layers: the simulated GISAXS patterns are rather different for these two cases.

Recently organic photovoltaic (OPV) devices comprising the small-molecule liquid-crystalline donor, benzodithiophene-quaterthiophene-rhodanine (BQR), and fullerene acceptor, [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), were demonstrated to achieve high performance when thermally processed, avoiding the need for slow-drying solvent additives or complex solvent-vapor annealing post-processing. In this investigation we explore the impact of thermal processing on thin film blends of BQR and PC71BM using differential scanning calorimetry (DSC), in situ grazing incidence X-ray scattering (GISAXS, GIWAXS), and photoluminescence spectroscopy (PL) to correlate thermal behavior with morphological changes and photoactivity. We develop a phase diagram of the crystalline and liquid crystalline transitions in BQR and the related high performing electron donor material, benzodithiophene-terthiophene-rhodanine (BTR), and are able to predict phase transitions using Flory-Huggins theory, including suppression of liquid crystalline phase formation in the presence of PC71BM. Further DSC measurements demonstrate the superior thermal stability of PC71BM blends with BQR over blends with BTR. OPV devices with the BQR:PC71BM active layer were prepared using the blade-coating deposition technique and exhibit optimal device performance when annealed at 120 °C for 5 min. The characteristic acceptor/donor domain size in an as-cast BQR:PC71BM film, estimated from GISAXS, was about 60 nm which is sufficient for exciton separation. Domain purity was enhanced by annealing at temperatures above ≈80 °C. Annealing at temperatures above ≈120 °C resulted in over-coarsening of the acceptor/donor-rich phases to domain sizes beyond 80 nm and reduced performance.

Order–order transitions during spin-coating processes in symmetric and asymmetric poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) were investigated by using grazing incidence small-angle X-ray scattering (GISAXS). When the composition was symmetric (e.g., the copolymer P2VP volume fraction, fP2VP, was 0.50), we found that loose-packed nanocylindrical structures formed after the transition from micelles to a body-centered cubic (BCC) lattice structure during evaporation. After the BCC (110) plane aligned perpendicular to the substrate, microdomains coalesced into a cylindrical structure. This coalescence was caused by the convection effect of the solvent, and vitrification of PS and P2VP further prohibited transitions from the cylindrical structure, although generally, the equilibrium morphology in the bulk state is lamellae. For an asymmetric composition with fP2VP = 0.70, lamellar structures formed perpendicular to the substrate. During evaporation, the micelles transformed to hexagonal close-packed (HCP...

Previously, our thin film study of a block copolymer (BCP) consisting of dibranched polystyrene (PS) and linear polylactide (PLA) demonstrated the thickness- dependent distribution of two different parallel cylindrical orientations, “(10)- on” and “(01)-on”. In this paper, we studied the thin film phase behavior of a more branched BCP in order to understand the effect of degree of branching on the thin film morphology. The BCP employed in this study is composed of tetrabranched PS and linear PLA blocks. The grazing incidence small angle X-ray scattering (GISAXS) analysis indicated that the thin films exclusively preferred the “(10)-on” orientation due to the better wettability of the PLA block on the SiO2 substrate. As a unique phenomenon, in contrast to the cylinder structure in the film interior, micellar domains were revealed on the top layer of the films thicker than 79 nm, as identified by atomic force microscopy. The appearance of micellar domains could be explained by the alleviation of the packing frustration of the highly branched BCP assembly at the film surface.

To observe details of three phase contact in a fuel cell catalyst layer and water distribution, we performed grazing incidence small-angle neutron scattering (GISANS) and neutron reflectivity (NR). We prepared a model catalyst on silicon(Si) substrates on which platinum(Pt) and Nafion thin layers are stacked. We employed two machines (KWS-1 and iMATERIA, respectively), which are monochromatic at FRM-II Germany and time-of-flight at J-PARC Japan. In case of Pt flat surface, which was prepared by sputtering, the influence due to humidification was observed in the vertical direction; a water layer could be confirmed between the Pt layer and the Nafion layer, increase in the thickness of the Nafion layer and increase in the water content of Nafion thin layer could be confirmed. The horizontal direction, on the other hand, water channels (microphase separation of Nafion) could not be observed in the core of thin Nafion layer. We also prepared the specimen, first Pt nano-particles are implanted in a surface of Si substrate and second Nafion thin layer covers by spin coating.

Absrtract Adsorbed ethylene glycol based microgel particles on a silicon surface were studied. Neutron reflectometry (NR) and grazing incidence small-angle neutron scattering (GISANS) were performed to investigate their internal structure. Scattering experiments on soft matter systems such as adsorbed microgels often give only partial information about the inner structure of the polymer system. In this contribution, we discuss how the detailed inner structure of adsorbed microgel particles can be reconstructed by a combination of the specular Neutron Reflectivity (NR), Grazing Incidence Small Angle Neutron Scattering (GISANS), Atomic Force Microscopy (AFM) and a simulation in the framework of the Distorted Wave Born Approximation.

We present a structural and dynamical analysis of the influence of NaCl on multilayer stacks of phospholipids on a solid surface. To this end, multilayer stacks of phospholipids (L-α-phosphatidylcholine, abbreviated as SoyPC) are investigated with neutron reflectometry, grazing-incidence small-angle neutron scattering (GISANS) and grazing-incidence neutron-spin echo spectroscopy (GINSES). We show both that the NaCl influence on the structure is predominantly on water-head group interface and also, that the change in dynamics is restricted to an associated change in the inter-plane viscosity. Using this knowledge, it is possible to model the dynamical behavior of a phospholipid membrane in response to a salt concentration of the solvent using only a single parameter, namely the in-plane viscosity. The excellent agreement with our previously published model also strongly supports the existence of a thermally excited surface mode in phospholipid membranes for close-to-physiological conditions.

Atomic motions and morphological evolution of growing Co–Ag nanoparticles are followed in situ and in real time, by wide and small angle X-ray scattering obtained simultaneously in grazing incidence geometry (GISAXS and GIWAXS), in single or multi-wavelength anomalous modes. The structural analysis of the experimental data is performed with the aid of equilibrium Monte Carlo simulations and of molecular-dynamics simulations of nanoparticle growth. Growth is performed by depositing Co atoms above preformed Ag nanoparticles. This growth procedure is strongly out of equilibrium, because Ag tends to surface segregation, and generates complex growth sequences. The real time analysis of the growth allows to follow the nanoparticle evolution pathways almost atom-by-atom, determining the key mechanisms during Co deposition: starting with the incorporation of Co atoms in sub-surface positions, to the off-center Co domain formation, then by which the nanoparticles finally approach their equilibrium quasi-Janus then core–shell structures.

Structural, optical and electrical properties of Al+MoO3 and Au+MoO3 thin films prepared by simultaneous magnetron sputtering deposition were investigated. The influence of MoO3 sputtering power on the Al and Au nanoparticle formation and spatial distribution was explored. We demonstrated the formation of spatially arranged Au nanoparticles in the MoO3 matrix, while Al incorporates in the MoO3 matrix without nanoparticle formation. The dependence of the Au nanoparticle size and arrangement on the MoO3 sputtering power was established. The Al-based films show a decrease of overall absorption with an Al content increase, while the Au-based films have the opposite trend. The transport properties of the investigated films also are completely different. The resistivity of the Al-based films increases with the Al content, while it decreases with the Au content increase. The reason is a different transport mechanism that occurs in the films due to their different structural properties. The choice of the incorporated material (Al or Au) and its volume percentage in the MoO3 matrix enables the design of materials with desirable optical and electrical characteristics for a variety of applications.

Subnanometer copper tetramer–zirconia catalysts turn out to be highly efficient for CO2 hydrogenation and its conversion to methane. The cluster size and substrate morphology are controlled to optimize the catalytic performance. The two types of zirconia supports investigated are prepared by atomic layer deposition (∼3 nm thick film) and supersonic cluster beam deposition (nanostructured film, ∼100 nm thick). The substrate plays a crucial role in determining the activity of the catalyst as well as its cyclability over repeated thermal ramps. A temperature-programmed reaction combined with in situ X-ray characterization reveals the correlation between the evolution in the oxidation state and catalytic activity. Ex situ photoelectron spectroscopy indicates Cu clusters with stronger interactions with the nanostructured film, which can be the cause for the higher activity of this catalyst. Density functional theory calculations based on the Cu4O2 cluster supported on a ZrOx subunit reveal low activation barriers and provide mechanism for CO2 hydrogenation and its conversion to methane. Altogether, the results show a new way to tune the catalytic activity of CO2 hydrogenation catalysts through controlling the morphology of the support at the nanoscale.

ACS applied materials & interfaces 13(47), 56663 - 56673 (2021). doi:10.1021/acsami.1c18324, Large-scale fabrication of metal cluster layers for usage in sensor applications and photovoltaics is a huge challenge. Physical vapor deposition offers large-scale fabrication of metal cluster layers on templates and polymer surfaces. In the case of aluminum (Al), only little is known about the formation and interaction of Al clusters during sputter deposition. Complex polymer surface morphologies can tailor the deposited Al cluster layer. Here, a poly(methyl methacrylate)-block-poly(3-hexylthiophen-2,5-diyl) (PMMA-b-P3HT) diblock copolymer template is used to investigate the nanostructure formation of Al cluster layers on the different polymer domains and to compare it with the respective homopolymers PMMA and P3HT. The optical properties relevant for sensor applications are monitored with ultraviolet-visible (UV-vis) measurements during the sputter deposition. The formation of Al clusters is followed in situ with grazing-incidence small-angle X-ray scattering (GISAXS), and the chemical interaction is revealed by X-ray photoelectron spectroscopy (XPS). Furthermore, atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) yield topographical information about selective wetting of Al on the P3HT domains and embedding in the PMMA domains in the early stages, followed by four distinct growth stages describing the Al nanostructure formation., Published by Soc., Washington, DC

The thermal stability of antireflective moth-eye topographical features fabricated by nanoimprint lithography on poly (methyl methacrylate) (PMMA) incorporating TiO2nanoparticles is explored. The effect of nanoparticle load on the relaxation dynamics of the moth-eye nanostructure is evaluated via grazing incidence small angle x-ray scattering measurements byin situmonitoring the structural decay of the nanopatterns upon thermal annealing. It is demonstrated that the incorporation of TiO2nanoparticles to the imprinted surface nanocomposite films delays greatly the pattern relaxation which, in turn, enhances the stability of the patterned topography even at temperatures well above the polymer glass transition (Tg). The improved thermal behavior of the antireflective films will significantly enhance their functionality and performance in light-trapping applications where temperatures typically rise, such as solar devices or solar glass panels.

We present an in-house, in situ Grazing Incidence Small Angle X-ray Scattering (GISAXS) experiment, developed to probe the drying kinetics of roll-to-roll slot-die coating of the active layer in organic photovoltaics (OPVs), during deposition. For this demonstration, the focus is on the combination of P3HT:O-IDTBR and P3HT:EH-IDTBR, which have different drying kinetics and device performance, despite their chemical structure only varying slightly by the sidechain of the small molecule acceptor. This article provides a step-by-step guide to perform an in situ GISAXS experiment and demonstrates how to analyze and interpret the results. Usually, performing this type of in situ X-ray experiments to investigate the drying kinetics of the active layer in OPVs relies on access to synchrotrons. However, by using and further developing the method described in this paper, it is possible to perform experiments with a coarse temporal and spatial resolution, on a day-to-day basis to gain fundamental insight in the morphology of drying inks.

Amorphous Ge/SiO2 multilayers were deposited in a high vacuum by an e-gun assisted physical vapor deposition technique with continuous Ge layers either 2 or 4 nm thick, separated by 2 nm thick SiO2 layers. The aim was to explore whether annealing of these multilayers at a rather low temperature will produce Ge nanoparticles suitable for solar cell applications. All samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (ARM), transmission electron microscopy (TEM) in cross-section, grazing incidence X-ray diffraction, Raman spectroscopy and grazing incidence small-angle X-ray scattering (GISAXS). It is found that annealing of very thin continuous amorphous Ge layers will lead to mostly spherical crystalline nanoparticles (NPs) of the desired size. On the other hand, from thicker Ge layers, a bimodal distribution is obtained consisting of smaller sphere-like and larger oblate spheroids, as confirmed by a calculated simulation.

Scientific reports 11(1), 18777 (2021). doi:10.1038/s41598-021-97485-z, Semiconductor quantum dot (QD) arrays can be useful for optical devices such as lasers, solar cells and light-emitting diodes. As the size distribution influences the band-gap, it is worthwhile to investigate QDs prepared using different solvents because each of them could influence the overall morphology differently, depending on the ligand network around individual QDs. Here, we follow the nucleation and growth of gold (Au) on CdSe QD arrays to investigate the influence of surface ligands and thereby realized interparticle distance between QDs on Au growth behaviour. We particularly emphasize on the monolayer stage as the Au decoration on individual QDs is expected at this stage. Therefore, we sputter-deposit Au on each QD array to investigate the morphological evolution in real-time using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). The growth kinetics - independent of the template - signifies that the observed template-mediated nucleation is limited only to the very first few monolayers. Delicate changes in the Au growth morphology are seen in the immediate steps following the initial replicated decoration of the QD arrays. This is followed by a subsequent clustering and finally a complete Au coverage of the QD arrays., Published by Macmillan Publishers Limited, part of Springer Nature, [London]

The intensity of small-angle X-ray scattering from GaN nanowires on Si(111) depends on the orientation of the side facets with respect to the incident beam. This reminiscence of truncation rod scattering gives rise to a deviation from Porod’s law. A roughness of just 3–4 atomic steps per micrometre-long side facet notably changes the intensity curves., Small-angle X-ray scattering from GaN nanowires grown on Si(111) is measured in the grazing-incidence geometry and modelled by means of a Monte Carlo simulation that takes into account the orientational distribution of the faceted nanowires and the roughness of their side facets. It is found that the scattering intensity at large wavevectors does not follow Porod’s law I(q) ∝ q −4. The intensity depends on the orientation of the side facets with respect to the incident X-ray beam. It is maximum when the scattering vector is directed along a facet normal, reminiscent of surface truncation rod scattering. At large wavevectors q, the scattering intensity is reduced by surface roughness. A root-mean-square roughness of 0.9 nm, which is the height of just 3–4 atomic steps per micrometre-long facet, already gives rise to a strong intensity reduction.

Bottlebrush block copolymers (BBCPs) are intriguing architectural variations on linear BCPs with highly tunable structure. Confinement can have a significant impact on polymer assembly, giving rise to changes in morphology, assembly kinetics, and properties like the glass transition. Given that confinement leads to significant changes in the persistence length of bottlebrush homopolymers, it is reasonable to expect that BBCPs will see significant changes in their structure and periodicity relative to the bulk morphology. Understanding how confinement influences assembly will be important for designing BBCPs for thin film applications including membranes, integrated photonic structures, and potentially BCP lithography. In order to study the effects of confinement on BBCP conformation and morphology, a blade coating was used to prepare films with continuous variation in film thickness. Unlike thin films of linear BCPs, islands/holes were not observed, and instead mixtures of parallel and perpendicular morphologies emerge after annealing. The lamellar periodicity (L0) of the morphologies is found to be thickness dependent, increasing L0 with decreasing film thickness for blade coated films. Films coated out of tetrahydrofuran (THF) resulted in a single well-defined lamellar periodicity, verified through atomic force microscopy (AFM) and grazing incidence small-angle X-ray scattering (GISAXS), which increases dramatically from the bulk value (30.6 nm) and continues to increase as the film thickness decreases. The largest observed L0 was 65.5 nm, and this closely approaches the estimated upper limit of 67 nm corresponding to a fully extended backbone in a bilayer arrangement. Films coated out of propylene glycol methyl ether acetate (PGMEA) resulted in a mixture of perpendicular lamellae and a smaller, likely cylindrical morphology. The lamellar portion of the film shows the same thickness dependence as the lamellae observed in the THF coated films. The scaling of the lamellar L0 with respect to film thickness follows predictions for confined semiflexible polymers with weak excluded volume interactions and can be related to models for confinement of DNA. Spin coated films shows the same reduction in periodicity, although at very different film thicknesses. This result suggests that the material has shallow free-energy barriers to transitioning between different L0 and morphologies, a property that could be taken advantage of for patterning diverse structures with a single material.

The increasing interest in atomic layer deposition (ALD) of Pt for the controlled synthesis of supported nanoparticles for catalysis demands an in-depth understanding of the nucleation controlled growth behaviour. We present an in situ investigation of Pt ALD on planar Si substrates, with native SiO2, by means of X-ray fluorescence (XRF) and grazing incidence small-angle X-ray scattering (GISAXS), using a custom-built synchrotron-compatible high-vacuum ALD setup and focusing on the thermal Pt ALD process, comprising (methylcyclopentadienyl)trimethylplatinum (MeCpPtMe3) and O-2 gas at 300 degrees C. The evolution in key scattering features provides insights into the growth kinetics of Pt deposits from small nuclei to isolated islands and coalesced worm-like structures. An analysis approach is introduced to extract dynamic information on the average real space parameters, such as Pt cluster shape, size, and spacing. The results indicate a nucleation stage, followed by a diffusion-mediated particle growth regime that is marked by a decrease in average areal density and the formation of laterally elongated Pt clusters. Growth of the Pt nanoparticles is thus not only governed by the adsorption of Pt precursor molecules from the gas-phase and subsequent combustion of the ligands, but is largely determined by adsorption of migrating Pt species on the surface and diffusion-driven particle coalescence. Moreover, the influence of the Pt precursor dose on the particle nucleation and growth is investigated. It is found that the precursor dose influences the deposition rate (number of Pt atoms per cycle), while the particle morphology for a specific Pt loading is independent of the precursor dose used in the ALD process. Our results prove that combining in situ GISAXS and XRF provides an excellent experimental strategy to obtain new fundamental insights about the role of deposition parameters on the morphology of Pt ALD depositions. This knowledge is vital to improve control over the Pt nucleation stage and enable efficient synthesis of supported nanocatalysts.

Polyether ether ketone (PEEK) films irradiated with 170 keV protons were calculated by the stopping and ranges of ions in matter (SRIM) software. The results showed that the damage caused by 170 keV protons was only several microns of the PEEK surface, and the ionization absorbed dose and displacement absorbed dose were calculated. The surface morphology and roughness of PEEK after proton irradiation were studied by atomic force microscope (AFM). GISAXS was used to analyze the surface structural information of the pristine and irradiated PEEK. The experimental results showed that near the surface of the pristine and irradiated PEEK exists a peak, and the peak gradually disappeared with the increasing of the angles of incidence and the peak changed after irradiation, which implies the 170 keV protons have an effect on PEEK structure. The influences of PEEK irradiated with protons on the melting temperature and crystallization temperature was investigated by differential scanning calorimetry (DSC). The DSC results showed that the crystallinity of the polymer after irradiation decreased. The structure and content of free radicals of pristine and irradiated PEEK were studied by Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR). The stress and strain test results showed that the yield strength of the PEEK irradiated with 5 &times, 1015 p/cm2 and 1 &times, 1016 p/cm2 was higher than the pristine, but the elongation at break of the PEEK irradiated with 5 &times, 1016 p/cm2 decreased obviously.

Quantum dots are under intense research, given their amazing properties which favor their use in electronics, optoelectronics, energy, medicine and other important applications. For many of these technological applications, quantum dots are used in their ordered self-assembled form, called superlattice. Understanding the mechanism of formation of the superlattices is crucial to designing quantum dots devices with desired properties. Here we review some of the most important findings about the formation of such superlattices that have been derived using grazing incidence scattering techniques (grazing incidence small and wide angle X-ray scattering (GISAXS/GIWAXS)). Acquisition of these structural information is essential to developing some of the most important underlying theories in the field.

Organosilicate glass-based porous low dielectic constant films with different ratios of terminal methyl to bridging organic (methylene, ethylene and 1,4-phenylene) groups are spin-on deposited by using a mixture of alkylenesiloxane with organic bridges and methyltrimethoxysilane, followed by soft baking at 120&ndash, 200 &deg, C and curing at 430 &deg, C. The films&rsquo, porosity was controlled by using sacrificial template Brij&reg, L4. Changes of the films&rsquo, refractive indices, mechanical properties, k-values, porosity and pore structure versus chemical composition of the film&rsquo, s matrix are evaluated and compared with methyl-terminated low-k materials. The chemical resistance of the films to annealing in oxygen-containing atmosphere is evaluated by using density functional theory (DFT). It is found that the introduction of bridging groups changes their porosity and pore structure, increases Young&rsquo, s modulus, but the improvement of mechanical properties happens simultaneously with the increase in the refractive index and k-value. The 1,4-phenylene bridging groups have the strongest impact on the films&rsquo, properties. Mechanisms of oxidative degradation of carbon bridges are studied and it is shown that 1,4-phenylene-bridged films have the highest stability. Methylene- and ethylene-bridged films are less stable but methylene-bridged films show slightly higher stability than ethylene-bridged films.

In previous reports, Dalfovo et al. showed experimentally that thin films of Au nanoparticles (NP) with organic coating change their optical properties when exposed to several analytes in the vapor phase (Anal Chem 84:4886–4892 2012; J Phys Chem C 119:5098–5106 2015). This optical behavior was associated with changes in the mean distance between nanoparticles, which resulted in a displacement of their plasmon bands towards blue or red in the presence of toluene (Tol) or ethanol (EtOH) vapors, respectively. In the report by Dalfovo et al. (J Phys Chem C 119:5098–5106 2015), in-situ grazing-incidence small-angle X-ray spectroscopy (GISAXS) was performed to determine changes in the inter-NP distance within the film. In the present work, we perform theoretical calculations to interpret the results obtained by Dalfovo et al. (Anal Chem 84:4886–4892 2012; J Phys Chem C 119:5098–5106 2015). For this purpose, we employ two different theoretical approaches, a quasi-static method (QS) and the Korringa-Kohn-Rostoker method (KKR), in order to describe the plasmon resonance shift as a function of the inter-NP distance changes during exposure to Tol and EtOH vapors. Both theoretical approaches describe qualitatively the behavior observed in previous experimental results that correlate the plasmon resonant wavelength with the inter-NP distance obtained by GISAXS. Our theoretical results show that the plasmon resonant wavelength strongly depends on the ratio between the inter-particle distance and the diameter of the nanoparticles and consequently, these films could be used for optical tuning., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

Nanoimprint lithography (NIL) is one of the highest potential candidates for next generation lithography (NGL) in semiconductors. NIL is very useful technology for fine pattern fabrications compared to conventional optical lithography. NIL technology makes use of replication from quartz templates. The cross-sectional profile of the template is directly transferred to the resist profile on a wafer. In relationship to that, the management of cross-sectional profile in quartz templates is needed much more than that of photomask. In our past reports, we had studied the performance of measuring cross-sectional profiles using grazing-incidence small-angle X-ray scattering (GISAXS). GISAXS has made it possible to analyze the periodic nanostructure patterns using 2D scattering X-ray intensity distribution. After much research we had found the application to not only sub-20nm hp lines-and-spaces(LS) patterns but also hole patterns was very effective. We have been developing templates for more scaling, “sub-15nm” by applying Self-Aligned Double Patterning (SADP). We showed the specific issues in SADP and the solution for quality assuranc In this report, we demonstrate the capabilities of measuring the cross-sectional profiles for sub-15 nm patterns using GISAXS. Taking into complicated periodic structures of SADP, we optimize the structural models to meet the demands. This report reveals GISAXS technique has potential for the sub-15nm metrology.

GISAXS has been used to study morphology change of &alpha, Fe2O3 nanocubes after annealing processes. A submonolayer of the nanocubes was deposited on a Si(100) substrate. While an annealing at 400 &deg, C in vacuum does not change a GISAXS pattern from as-prepared nanocubes submonolayer, subsequent annealing in air at the same temperature altered the GISAXS pattern significantly. SEM images showed that the air-annealed nanocubes were coated with thin layers which were identified as amorphous carbon layers based on Raman measurements. GISAXS simulations from morphologies of nanocube with 38 nm side-length and core-shell (nanocube-core and 7 nm thick carbon-shell) reproduced measured patterns from the vacuum- and the air-annealed nanocubes, respectively. The current study provides new approach for in-situ characterization of carbon deposition on a uniform shape nanoparticle through monitoring of deposited carbon thickness.

Nowadays, solar industry becomes the fastest growing industry due to the rising demands to solve energy crisis and environmental problems. Third generation solar cells such as organic and perovskite solar cells are all relying on a semiconducting thin-film active layer to harvest the solar energy. The morphology of the active layer in terms of crystal structure, grain size and nanophase separation behavior is known to be critical to the solar cell device performance. Here, we are going to present our recent work on the active layer morphology and its correlations with device performances for several different types of photovoltaic systems. State-of-art synchrotron-based X-ray scattering techniques are employed for the morphology characterization: grazing incidence wide-angle X-ray scattering (GIWAXS) for Angstrom-scale ordering and grazing incidence small-angle X-ray scattering (GISAXS) for nano-scale ordering.

Three-dimensional (3D) periodic ordering of silicon (Si), an inorganic semiconductor, on the mesoscale was achieved by combining block copolymer (BCP) self-assembly (SA) based mesoporous alternating gyroidal network formation with nonequilibrium transient laser heating. 3D continuous and periodically ordered alternating gyroidal mesoporous carbon thin-film networks were prepared from spin coating, SA under solvent vapor annealing (SVA), and thermal processing of mixtures of a triblock terpolymer with resorcinol resols. The resulting mesoporous thin films, acting as structure-directing templates, were backfilled with amorphous silicon (a-Si). Nanosecond excimer laser heating led to transient Si melts conformally filling the template pores and subsequent Si crystallization. The ordered mesostructure of the organic polymer-derived templates was kept intact, despite being thermally unstable at the high temperatures around the Si melting point (MP), leading to high pattern transfer fidelity. As evidenced by a combination of grazing incidence small-angle X-ray scattering (GISAXS) and scanning electron microscopy (SEM), after template removal, the crystalline Si (c-Si) inherited the inverse network topology of the 3D mesoporous thin-film templates, but with reduced F222 space group symmetry (D2 point group symmetry) from compression of the cubic alternating gyroid lattice. Structures with this reduced symmetry have been proposed as photonic and phononic materials exhibiting topologically protected Weyl points, adding to the emerging field of BCP SA-directed quantum materials promising advanced physics and materials properties.

Communications chemistry 3(1), 88 (2020). doi:10.1038/s42004-020-0335-9, Photopolymerization is a key enabling technology offering spatial and temporal control to allow for future functional materials to be made to meet societal needs. However, gaining access to robust experimental techniques to describe the evolution of nanoscale morphology in photo-initiated polymeric systems has proven so far to be a challenging task. Here, we show that these physical transformations can be monitored and quantified at the nanoscale in situ and in real-time. It is demonstrated that the initial structural features of the liquid precursors significantly affect the final morphology and the physical properties of the resulting solid via the occurrence of local heterogeneities in the molecular mobility during the curing transformation. We have made visible how local physical arrestings in the liquid, associated with both cross-linking and vitrification, determine the length scale of the local heterogeneities forming upon curing, found to be in the 10–200 nm range., Published by Macmillan Publishers Limited, part of Springer Nature, [London]

To describe the 1D and 2D patterns of the grazing-incidence small-angle X-ray scattering (GISAXS) from a rough fractal surface, the novel integral equations for the amplitudes of reflected and transmitted waves are derived. To be specific, the analytical expression for the 2D total intensity distribution $$\frac{{dR_{tot} \left( {\theta ,\phi ;\theta_{0} } \right)}}{d\Omega }$$dRtotθ,ϕ;θ0dΩ is obtained. The latter represents by itself a superposition of terms related to the GISAXS specular $$\frac{{dR_{spec} \left( {\theta ;\theta_{0} } \right)}}{d\Omega }$$dRspecθ;θ0dΩ and diffuse $$\frac{{dR_{dif} \left( {\theta ,\phi ;\theta_{0} } \right)}}{d\Omega }$$dRdifθ,ϕ;θ0dΩ patterns, respectively. Hereafter, $$\theta$$θ is the scattering meridian angle, $$\phi$$ϕ is the scattering azimuth angle; $$\theta_{0}$$θ0 is the angle of incidence. By using the above analytical expressions, the 1D and 2D GISAXS patterns are numerically calculated. Some new experimental measurements of the specular reflectivity curves Rspec($$\theta_{0}$$θ0) related to the fused quartz and crystal Si(111) samples have been carried out. Based on the theoretical approach developed, a direct least-squared procedure in a χ2-fit fashion has been used to determine the corresponding values of the root-mean-square roughness σ from the specular GISAXS reflectivity data.

Low-energy ion irradiation of III-V semiconductor surfaces can lead to the formation of regular hexagonal dot patterns at the surface. We present experimental and computational results for ion irradiation of GaSb surfaces which elucidate the nature of the coupled compositional and morphological pattern-formation mechanisms. We demonstrate by in-situ grazing-incidence small-angle x-ray scattering (GISAXS) and angle-resolved Auger electron spectroscopy (ARAES) that the emergence of an altered compositional depth profile is essential to induce morphological changes at the surface. This morphological evolution of the surface follows nucleation-and-growth kinetics. Furthermore, we show from massive-scale molecular dynamics (MD) simulations that the compositional depth profile evolution leads to thermodynamic phase separation, providing a lateral compositional instability that drives pattern formation. Additionally, high-fluence simulations elucidate the irradiation-induced mechanisms of compositional depth profile formation. Prompt ion effects drive formation of single-element “protoclusters”, predominantly of Sb. Structural and energetic characterization of the simulation results indicate that Sb may be more mobile than Ga, providing a diffusional pathway for long-temporal-scale compositional evolution of the irradiated surface. Our findings motivate the development of new, comprehensive models which consider the total spatial and temporal complexity of multicomponent systems evolving under ion irradiation.

The morphological changes of Nafion thin films with thicknesses from 10 to 200 nm on Pt substrate with various annealing histories (unannealed to 240 °C) were systematically investigated using grazing incidence small-angle X-ray scattering (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS). The results revealed that the hydrophilic ionic domain and hydrophobic backbone in Nafion thin films changed significantly when the annealing treatment exceeded the cluster transition temperature, which decreased proton conductivity, due to the constrained hydrophilic/hydrophobic phase separation, and increased the crystalline-rich domain. This research contributed to the understanding of ionomer thermal stability in the catalyst layer, which is subjected to thermal annealing during the hot-pressing process.

The adsorption, self-organization and oriented attachment of PbSe nanocrystals (NCs) at liquid-air interfaces has led to remarkable nanocrystal superlattices with atomic order and a superimposed nanoscale geometry. Earlier studies examined the NC self-organization at the suspension/air interface with time-resolved in-situ X-ray scattering. Upon continuous evaporation of the solvent, the NC interfacial layer will finally contact the (ethylene glycol) liquid substrate on which the suspension was casted. In order to obtain structural information on the NC organization at this stage of the process, we examined the ethylene glycol/NC interface in detail for PbSe NCs of different sizes, combining in-situ grazing-incidence small-and-wide-angle X-ray scattering (GISAXS/GIWAXS), X-ray reflectivity (XRR) and analytical calculations of the adsorption geometry of these NCs. Here, we observe in-situ three characteristic adsorption geometries varying with the NC size. Based on the experimental evidence and simulations, we reveal fully three-dimensional arrangements of PbSe nanocrystals at the ethylene glycol-air interface with and without the presence of rest amounts of toluene. To understand the self-assembly of semiconductor nanocrystals, the formation mechanism of two-dimensional superlattices needs to be deciphered. Here the authors observe lead selenide nanocrystal organization at the ethylene glycol-air interface combining in-situ grazing-incidence small -and-wide-angle X-ray scattering, X-ray reflectivity and analytical calculations to obtain a three-dimensional picture of the adsorption geometry of the nanocrystals.

International audience; Liquid Crystal (LC) topological defects have been shown to trap nanoparticles (NPs) in the defect cores. The LC topological defects may thus be used as a matrix for new kinds of NP organizations templated by the defect geometry. We here study composites of LC smectic dislocations and gold NPs. Straight NP chains parallel to the dislocations are obtained leading to highly anisotropic optical absorption of the NPs controlled by light polarization. Combining Grazing Incidence Small Angle X-ray scattering (GISAXS), Rutherford Back Scattering (RBS), Spectrophotometry and the development of a model of interacting NPs, we explore the role of the Np size regarding the dislocation core size. We use NPs of diameter D = 6 nm embedded in an array of different kinds of dislocations. For dislocation core larger than the NP size, stable long chains are obtained but made of poorly interacting NPs. For dislocation core smaller than the NP size, the disorder is induced outside the dislocation cores and the NP chains are not equilibrium structures. However we show that at least half of these small dislocations can be filled, leading to chains with strongly enhanced electromagnetic coupling between the NPs. These chains are more probably stabilized by the elastic distortions around the defect cores, the distortion being enhanced by the presence of the grain boundary where the dislocations are embedded.

International audience; Building 3D ordered nanostructures by copolymer deposition on a substrate implies a full control beyond the thin film regime. We have used here block copolymers (BCPs) forming bulk lamellar phases to form thick, i.e. much thicker than the lamellar period, structured films on a substrate. Films are formed by a simple method of multiple successive coatings. The film structure is controlled using the combined action of surface templating and annealing time. Sections of the thick layers were characterized by scanning electron microscopy (SEM) after etching of one of the BCP moieties. We show that perfect hexagonally perforated films (HPL) with lamellae parallel to the substrate are formed for a wide thickness range up to 300 nm. Grazing incidence small angle X-ray scattering (GISAXS) confirms such an organization by revealing that perforations sit on a hexagonal lattice. A lamellar organization perpendicular to the substrate is shown to take over for thicker films. A scenario consistent with our observations is proposed, where the sequence of phases results from the balance between surface and stretching energy effects.

A novel material was developed using sol-gel chemistry and an environmental-friendly grafting process of clay nanoparticles. In a previous work of our group, highly compact coatings had been generated using silicon alkoxides, as tetraethoxysilane (TEOS) and 3-glycidoxypropyl-trimethoxysilane (GPTMS), with the incorporation of silver ions and synthetic smectite-type clay nanoparticles, demonstrating antibacterial behaviour against Escherichia coli cultures. By controlling the loading, the exfoliation and the grafting processes of the clay nanoparticles, it was possible to control the migration kinetics of silver ions from the coating matrix to the surface. Morphological and structural studies, through SEM-FIB, revealed the effect of clay nanoparticles leading to the development of a homogeneous structure in 2-µm thickness coatings. Grazing incidence small angle X-ray scattering (GISAXS) experiments demonstrated that silver is distributed in a strongly anisotropic arrangement when clay nanosheets are absent. The size of the silver particles developed on the surface is rather different from that of those developed in the bulk of the coating. Scattering patterns also revealed that the incorporation of clay nanosheets promotes the development of less anisotropic structures. Electrochemical impedance spectroscopy (EIS) measurements confirmed the integrity of the material and the applicability of a physical model with normal distribution of resistive and capacitive elements.

An accurate knowledge of the parameters governing the kinetics of block copolymer self-assembly is crucial to model the time- and temperature-dependent evolution of pattern formation during annealing as well as to predict the most efficient conditions for the formation of defect-free patterns. Here, the self-assembly kinetics of a lamellar PS-b-PMMA block copolymer under both isothermal and non-isothermal annealing conditions are investigated by combining grazing-incidence small-angle X-ray scattering (GISAXS) experiments with a novel modelling methodology that accounts for the annealing history of the block copolymer film before it reaches the isothermal regime. Such a model allows conventional studies in isothermal annealing conditions to be extended to the more realistic case of non-isothermal annealing and prediction of the accuracy in the determination of the relevant parameters, namely the correlation length and the growth exponent, which define the kinetics of the self-assembly., This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 665919, the Spanish Ministry of Economy and Competitiveness (MINECO) under contract Nos. MAT2015-68307-P, MAT2015-66443-C02-1-R, TEC2015-69864-R, RTI2018-102007-B-I00, PID209-107514GB-100, RYC-2016-21412 and the Generalitat de Catalunya under contract No. 2017 SGR 1187. The ICN2 is funded by the CERCA program/Generalitat de Catalunya. The ICN2 is supported by the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, grant No. SEV-2017-0706) (MINECO/FEDER, UE).

International audience; Localized Surface Plasmon Resonance (LSPR) of noble metal nanoparticles has attracted a lot of attention in recent years as enhancer of the photocatalytic activity in the visible light domain. Rare are the experimental in situ studies, coupling structural and optical responses, but they are mandatory for a deep understanding of the mechanisms underlying LSPR. Herein we present an in situ investigation during the growth of gold nanoparticles (NPs) on TiO 2 (110) in the 2-6 nm size range. We probed the structural and morphological properties of the supported nanoparticles by performing GIXRD and GISAXS simultaneously with their optical response in p and s polarizations recorded by SDRS. The rutile surface state turns out to have a major effect on the Au NPs growth and on their plasmonic response, both in frequency and vibration modes. The roughening of the TiO 2 (110) surface weakens the interaction strength between the NPs and the substrate, favoring the growth of textured in-plane randomly orientated NPs. Compared to the epitaxial clusters growing on the flat TiO 2 surface, these textured NPs are characterized by a LSPR blue shift and by the presence of LSPR vibration modes perpendicular to the surface for sizes smaller than about 4 nm.

Downscaling of supported Pt structures to the nanoscale is motivated by the augmentation of the catalytic activity and selectivity, which depend on the particle size, shape and coverage. Harsh thermal and chemical conditions generally required for catalytic applications entail an undesirable particle coarsening, and consequently limit the catalyst lifetime. Herein we report an in situ synchrotron study on the stability of supported Pt nanoparticles and their stabilization using atomic layer deposition (ALD) as the stabilizing methodology against particle coarsening. Pt nanoparticles were thermally annealed up to 850 degrees C in an oxidizing environment while recording in situ synchrotron grazing incidence small angle X-ray scattering (GISAXS) 2D patterns, thereby obtaining continuous information about the particle radius evolution. Al2O3 overcoat as a protective capping layer against coarsening via ALD was investigated. In situ data proved that only 1 cycle of Al2O3 ALD caused an augmentation of the onset temperature for particle coarsening. Moreover, the results showed a dependence of the required overcoat thickness on the initial particle size and distribution, being more efficient (i.e. requiring lower thicknesses) when isolated particles are present on the sample surface. The Pt surface accessibility, which is decisive in catalytic applications, was analyzed using the low energy ion scattering (LEIS) technique, revealing a larger Pt surface accessibility for a sample with Al2O3 overcoat than for a sample without a protective layer after a long-term isothermal annealing.

International audience; The thin film morphology of binary blends of triblock copolymers (poly(isoprene-blockstyrene-block-(2-vinylpyridine)) ISP after solvent vapor annealing (SVA) was investigated using AFM, GISAXS and TEM. Although bulk samples of binary ISP blends exhibit tetragonal pattern, thin films led either to tetragonal pattern or hexagonal pattern, depending on the annealing time. These transitions were attributed to the formation of non-synchronized wetting layers of I and P, leading to a variation of the inner composition in I and P during SVA. Surprisingly, the hexagonal morphology exhibited centered hexagons of I and surrounding hexagons of P, which is not predicted nor observed for neat block copolymer samples. Although the system must adopt the lowest P/S interface, our results suggest that the effect of chain length with marked difference in the studied blends is playing a major role. Particularly, the presence of long chains of I favors the formation of I domains with bigger size, in order to keep their conformation entropy loss as small as possible.

Highly ordered mesoporous zeolite thin films (MZTFs) are grown at rigid substrates via molecular interaction from ternary structure-directing agents (SDAs) in a Stober-like condition. The ultrathin films (10–20 nm) were deposited layer-by-layer via self-assembly of β-zeolite seeds and SDAs at 40–50 °C, resulting reticular cellular pores and perpendicular nanochannels with average pore sizes (6.7 ± 1.1 nm). The walls of the nanochannels consist of zeolitic structures in microcrystallines. Compared to cylindrical mesochannels of amorphous silica thin films, the MZTFs with reticular mesochannels demonstrate 5R/6R stretching modes (550–650 cm–1) and significantly enhanced hydrothermal stability. The MZTFs were characterized in top-view and cross-sectional electron microscopies (SEM/HRSEM/HRTEM) as well as X-ray scattering techniques (GIXRD/GISAXS), which confirm a body-centered tetragonal (Im3m) unit cell with unique Moire patterns. Upon calcination, the film thickness is reduced to 10.6 nm with a structure ...

We present a compelling evidence for thickness dependence on the order-to-disorder transition (ODT) behavior in cylinder- and lamella-forming polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) films. Such an asymmetric wetting condition that confines the films with selective interactions of the PS/air and P2VP/substrate interfaces generates a parallel orientation of cylindrical and lamellar microdomains. We evaluated thickness-dependent phase transition as a function of interlattice distance (L0) using ex situ grazing incidence small-angle X-ray scattering (GISAXS) and transmission electron microscopy (TEM). Below an onset thickness (t0) above which the ODT temperatures (TODTs) of the films are independent of film thickness, the TODTs of cylinder- and lamella-forming PS-b-P2VP films remarkably increase as the film thickness decreases. Our results confirmed that preferential wetting at the PS/air and P2VP/substrate interfaces in very thin films substantially leads to an ordered state over accessible temperatu...

In recent years, responsive polymer-based structures have been studied extensively due to their unique ability to alter their physical properties upon exposure to external stimuli. Despite this, the nanoscale Q-resolved dynamic properties of these materials have barely been explored, which is limiting the development and applications of these materials. To address this issue, we used inelastic X-ray scattering (IXS) and found evidence for van der Waals mediated molecular vibration-responsive rattling dynamics in bulk poly(isoprene-block-styrene) (SI) and poly(styrene-block-ethylene oxide) (SO) stacked thin film block copolymers. Their cylinder-forming hexagonally arranged static structures were characterized using small-angle X-ray scattering (SAXS) and grazing incidence small-angle X-ray scattering (GISAXS), complemented by scanning electron microscopy (SEM). Specifically, we observed that the longitudinal vibrational mode in bulk SI experiences a strong phonon attenuation as temperature increases from 3...

Nucleation occurs widely in materials synthesis and natural environments. However, in the nucleation rate equation, values for the apparent activation energy (Ea) and the pre-exponential kinetic factor (A) are thus far unknown because real-time nanoscale observations are difficult to perform. Here we experimentally determine Ea and A using heterogeneous calcium carbonate nucleation on quartz as a model system. Nucleation rates are measured with in situ grazing incidence small-angle X-ray scattering and ex situ atomic force microscopy, and the experiments are conducted with a fixed supersaturation of IAP/Ksp(calc) = 101.65 at 12, 25, and 31 °C. Ea is calculated as 45 ± 7 kJ mol−1, and A is 1012.0 ± 1.1 nuclei μm−2 min−1, or 102.9 ± 1.3 mol m−2 min−1. Increasing the temperature shortens the induction time, but does not change nucleus sizes. These parameter values are critical for predicting and controlling the nucleation of materials.

In the current study, we have experimentally and comparatively investigated and compared malignant human cancer cells and tissues before and after irradiating of synchrotron radiation using Grazing-Incidence Small-Angle X-Ray Scattering (GISAXS) and Grazing-Incidence Wide-Angle X-Ray Scattering (GIWAXS). It is clear that malignant human cancer cells and tissues have gradually transformed to benign human cancer cells and tissues under synchrotron radiation with the passing of time.

Ultrahigh molecular weight (UHMW) diblock copolymers (DBCs) have emerged as a promising template for fabricating large-sized nanostructures. Therefore, it is of high significance to systematically study the influence of film thickness and solvent vapor annealing (SVA) on the structure evolution of UHMW DBC thin films. In this work, spin coating of an asymmetric linear UHMW polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) DBC is used to fabricate thin films, which are spherically structured with an inter-domain distance larger than 150 nm. To enhance the polymer chain mobility and facilitate approaching equilibrium nanostructures, SVA is utilized as a post-treatment of the spin coated films. With increasing film thickness, a local hexagonal packing of PMMA half-spheres on the surface can be obtained, and the order is improved at larger thickness, as determined by grazing incidence small angle X-ray scattering (GISAXS). Additionally, the films with locally hexagonal packed half-spherical morphology show a poor order-order-poor order transition upon SVA, indicating the realization of ordered structure using suitable SVA parameters.