Open Access

Grazing-incidence small-angle scattering (GISAS) is a relatively young technique with important applications in thin-film technology and untapped potential when it comes to 2D analysis on an absolute intensity scale. Approaching standardization and reference methods early is foundational for reproducibility and comparability across laboratories and reduction of systematic error sources. It underpins trust in data obtained and accelerates innovation by ensuring that scientists work from a common methodological baseline. Accordingly, obtaining reproducible results from different GISAS instruments requires an agreement on how measurements are performed, instruments calibrated and terms defined. To pave the way for standardization and reference methods, we surveyed GISAS practitioners on what comes before an experiment: hardware, software, sample alignment and instrument calibration. Twenty-two questions were designed to elucidate the state of the art, which can be used for the development of reference methods. Our data on 27 instruments provide the basis for standardization. With very few exceptions, we found laboratories prepared to implement future reference methods, but no consensus emerges naturally for sample alignment and instrument calibration. We, that is the GISAS community, are thus in a position to embark on the journey of standardization.

This study investigates sulfur spillover, the spontaneous and rapid spread of sulfur over carbon surfaces at ambient temperature. The process is studied by small-angle X-ray scattering (SAXS), X-ray radiography, and microcalorimetry from which a number of physicochemical properties are derived. The results confirm that sulfur immediately interacts with porous carbon upon mixing, with most signal changes occurring within a few hours. For the first time, thermodynamic data of the process are determined. Using microcalorimetry, the lower bound of the reaction enthalpy is determined to be Δsp H = − 28.2 kJ molS8 − 1 . With an estimated reaction entropy of Δsp S = 273.78 J molS8 − 1 K− 1 , the Gibbs Free Energy of the spillover process is estimated as Δsp G = − 100.23 kJ molS8 − 1 , which reduces the theoretical cell voltage of Li-S batteries by about 64 mV. Furthermore, depending on the configuration, DFT calculations have revealed repulsive and attractive interactions; the latter are caused by defects that eventually result in ring opening and the formation of S ─C bonds. This suggests that spillover includes various processes that occur simultaneously. Considering metal-sulfur batteries, sulfur spillover may be critical for preparing and cycling sulfur-carbon composite cathodes, which is demonstrated for a Li–S solid-state battery.

In search for less environmentally harmful materials, lead-free double halide perovskites (DPs) have emerged as promising candidates with tuneable photoluminescence properties. In this study, we present a comparative analysis of DPs with composition Cs2Ag0.4Na0.6BiyIn1−yCl6 (CANBIC, y = 0.01–0.04, y is Bi content in mol%) obtained via solution-based (SB) and green solvent-free mechanochemical (MC) methods. Comprehensive characterization of the resulting materials was performed via X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning and transmission electron microscopy (SEM/TEM), optical diffuse reflectance and photoluminescence (PL) spectroscopies. Both synthesis routes yielded cubic (Fm-3 m) perovskite structures, with all CANBIC samples exhibiting broad emission spectra ranging from 400 to 900 nm (1.3–3.1 eV), originating from the recombination of self-trapped excitons (STEs). Bi3+ doping significantly enhanced photoluminescence quantum yield (PLQY) up to 84%. The solution-based (SB) method produced samples with higher PLQY, attributed to improved control over particle morphology and dopant distribution as compared to the mechanochemistry (MC) route. Thermal analysis confirmed the structural integrity of CANBIC samples up to 300 °C, with no significant decomposition below ~ 560 °C, indicating their suitability for optoelectronic applications requiring moderate thermal stability. This work provides valuable insights into the relationship between synthesis methodology and material performance, advancing the development of environmentally friendly lead-free perovskites for next-generation optoelectronic devices such as white-LEDs.

This study explores the crystallization kinetics in multicomponent and lauric acid-containing fat blends. The role of the dominating saturated fatty acid (palmitic versus stearic acid) was explored. The blends contained predominantly three main triglyceride groups: trisaturated triglycerides (H3), trisaturated/medium-chain triglycerides (H2M), and monounsaturated triglycerides (H2U). Each group contains more than one triglyceride. This grouping was used as a compositional framework to compare trends across model and commercial systems. The impact of H3 content (8% vs 4%) and dominant saturated fatty acid (palmitic versus stearic acid) on crystallization was investigated using differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS/WAXS). To further our understanding of the crystallization kinetics in ternary mixtures, symmetrical academic replicates (true ternary blends) PPP-PLaP-POP and SSS-SLaS-SOS in rapeseed oil were studied. All samples were analyzed during cooling and short isothermal holding to capture initial differences in mixed crystal formation/cocrystallization. Results revealed a multistep crystallization process, with commercial blends displaying a long-persisting α-phase coexisting with β′ and β phases. The multiple β′ phases differed in composition and dissolution temperature. In contrast, academic blends showed a short-lived α-phase followed by late recrystallization into the β phase. Blends containing a higher amount of H3 triglycerides (8%) exhibited a strong recrystallization into a β phase, indicating that the H3 content exceeded the limit for H3 inclusion into a mixed crystalline phase with H2M and other groups. The transition into β was slowed down in the S-based systems. Overall, the H3 level played a greater role in the P-based systems with no β phase in C4-P─the P-based commercial system containing 4% of H3. This renders the factors dominant saturated fatty acid and H3 level interrelated. The academic blends demonstrated relatively simple crystallization and melting behavior with a drastic difference to the commercial systems observed in SAXS/WAXS. These findings emphasize the difficulty in simplifying the triglyceride composition in fat crystallization. Still, breaking down industrial fat crystallization into the main triglycerides proved to be a useful approach to further our understanding.

Pore size analysis is essential for understanding and optimizing structure-performance relations of functional carbon-basedmaterials including activated carbons, supercapacitor electrodes and atomically dispersed metal-nitrogen-doped carbon (M-N-C) catalysts. Pore size distribution (PSD) plots based on gas sorption porosimetry often show narrow micropores that are relatedto the adsorptive properties of named materials, which must be considered as artefacts arising from approximations in classicaldensity functional theory (cDFT) models. By selectively preparing specific in-plane functionalities using pyrolytic template-ion(salt templating) reactions, we herein show that those apparent pores can be explained by preferential adsorption of the adsorbatemolecules to specific in-plane functionalities. Tetrapyrrolic Zn-N 4 sites are present in ZIF-8 derived carbons, which are convertedby Zn-extraction into nitrogen-doped carbons (NDC) comprising tetrapyrrolic H 2 N4 sites. DFT-based calculation of adsorptionenergies allows the conclusive assignment of corresponding adsorption phenomena in comparative N 2 vs. CO2 vs. Ar adsorptionmeasurements additionally using Langmuir analysis. While the assignment of artefacts may improve the discussion of porosity,the determination of specific adsorption sites may be utilized as a valuable tool in materials science. Advanced models for theimportant material classes may allow accelerated progress in important energy-related research fields.