Technologically relevant gas phase processes rely on reactants in vapor form for the production of thin films and nanoparticles. An instrument is described which enables the investigation of such vapors by x-ray absorption spectroscopy. Corresponding in situ studies provide information about gas phase precursor chemistry and optimized synthesis processes. The setup consists of a sealed vapor container heated by a hot air bath. Inert gas filling and temperature monitoring are implemented. Fluid dynamic simulations reveal a homogeneous temperature distribution without hot or cold spots. Temperature stability better than 1 K for at least 190 min allows time-dependent measurements or improved signal to noise ratios by averaging of datasets. Iron acetylacetonate is studied as a model system. X-ray absorption spectra measured by fluorescence are of high quality, allowing a detailed analysis of X-ray Absorption Near Edge Structure (XANES) and extended x-ray absorption fine structure. A molecular structure transformation is observed in XANES spectra of iron acetylacetonate vapor above 480 K probably due to the loss of one ligand. The setup allows the investigation of low volatility compounds with vapor pressures above 2 kPa at temperatures up to 520 K.
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http://dx.doi.org/10.1063/5.0006721 | DOI Listing |
Small
January 2025
Department of Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
Extreme ultraviolet (EUV) lithography has enabled significant reductions in device dimensions but is often limited by capillary force-driven pattern collapse in conventional wet processes. Recent dry-development approaches, while promising, frequently require toxic etchants or specialized equipment, limiting their broader applicability and highlighting the need for more sustainable, cost-effective alternatives. In this study, highly reactive, etchant-free dry-developable EUV photoresists using N-heterocyclic carbene (NHC)-based metal-ligand complexes, achieving half-saturation at EUV doses of 8.
View Article and Find Full Text PDFJ Biomed Opt
January 2025
CIFICEN (UNCPBA - CICPBA - CONICET), Tandil, Argentina.
Significance: In the last years, time-resolved near-infrared spectroscopy (TD-NIRS) has gained increasing interest as a tool for studying tissue spectroscopy with commercial devices. Although it provides much more information than its continuous wave counterpart, accurate models interpreting the measured raw data in real time are still lacking.
Aim: We introduce an analytical model that can be integrated and used in TD-NIRS data processing software and toolkits in real time.
J Biomed Opt
January 2025
Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States.
Significance: Accurate values of skin optical properties are essential for developing reliable computational models and optimizing optical imaging systems. However, published values show a large variability due to a variety of factors, including differences in sample collection, preparation, experimental methodology, and analysis.
Aim: We aim to explore the influence of storage conditions on the optical properties of the excised skin from 400 to 1100 nm.
Nat Commun
January 2025
Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, PR China.
The H-evolution kinetics play a pivotal role in governing the photocatalytic hydrogen-evolution process. However, achieving precise regulation of the H-adsorption and H-desorption equilibrium (H/H) still remains a great challenge. Herein, we propose a fine-tuning d-p hybridization strategy to precisely optimize the H/H kinetics in a Ni-B modified CdS photocatalyst (Ni-B/CdS).
View Article and Find Full Text PDFNat Mater
January 2025
Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands.
Cathodic corrosion is an electrochemical phenomenon that etches metals at moderately negative potentials. Although cathodic corrosion probably occurs by forming a metal-containing anion, such intermediate species have not yet been observed. Here, aiming to resolve this long-standing debate, our work provides such evidence through X-ray absorption spectroscopy.
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