Double perovskites exhibit great potential in solid-state hydrogen storage. However, the regulatory mechanism of B-site elements-particularly those from Group IVA (Si, Ge, Sn)-in Rb-based double perovskites and their quantitative impact on hydrogen storage performance remain unclear, which limits the rational design of high-efficiency storage materials. This study employs first-principles calculations based on density functional theory (DFT) to systematically investigate Rb2LiXH6 (X = Si, Ge, Sn), focusing on the structural, electronic, optical, and hydrogen storage properties modulated by B-site (X) substitution. Results show their lattice parameters are 8.31 & Aring;, 8.29 & Aring;, and 8.53 & Aring;, with formation enthalpies of -0.94 eV, -0.35 eV, and -0.35 eV, respectively. Only Rb2LiGeH6 and Rb2LiSnH6 are kinetically stable, possessing gravimetric hydrogen storage capacities of 2.34 wt% and 1.98 wt%, as well as dehydrogenation temperatures of 257.6 K and 259.82 K-values that meet the 2025 hydrogen storage targets issued by the U.S. Department of Energy (DOE). These two materials exhibit metallic characteristics and strong low-energy ultraviolet absorption, with absorption intensity enhanced by the increasing atomic radius of X. This work clarifies the structure-property relationships of Rb-based double perovskites regulated by B-site elements, provides a reliable strategy for tuning light-responsive hydrogen storage via IVA-group doping, and offers valuable theoretical insights for the development of high-performance solid-state hydrogen storage materials, thereby advancing the practical application of hydrogen energy systems.
We present a compact analytical thermal model for coaxial dielectric barrier discharge reactors, providing reliable gas-temperature estimates for system-level analysis and design of non-thermal plasma processes; NOx abatement is the target of the presented experimental validations. Gas temperature has a major impact on most chemical treatments and is a critical parameter for plasma kinetic solvers (ZdPlaskin in our case for NOx abatement efficiency evaluation). Our model couples a volumetric heat source (plasma power deposition) to heat transfer by conduction, convection, and radiation. We validate it experimentally by comparisons across a wide range of power and flow between predicted gas temperatures and measured rotational temperatures obtained from optical emission spectroscopy and between calculated surface temperatures and measured ones obtained by infrared thermography. The model captures very well the main trends and provides temperature estimates with good agreement to the experimental measures. We discuss how the model parameters and outputs can be exported for integration into global chemical kinetics simulations and system-level studies of NOx abatement, or any other gas treatment.
In this work, copper oxide thin films are deposited on glass and silicon substrates by tilt chemical spray pyrolysis (CSP). Then, the films are electrochemically etched by ammonia for different etching times and currents. The effect of etching is studied with respect to structural, optical, and electrical properties of CuO thin films. XRD examination exhibited distinct diffraction peaks corresponding to the monoclinic phase at 2 theta approximate to 32.5 degrees, 35.5 degrees, and 38.7 degrees. FESEM analysis revealed spherical nanostructures for etched CuO films. AFM analysis confirmed that the surface of etched CuO was uniform with a higher particle size and modified surface roughness. The optical bandgap energy values of the etched CuO thin films were in the range between 2.14 and 2.25 eV. The CuO films deposited on n-type Si and p-type are used as CuO/nSi and CuO/pSi heterojunction photodetectors in the visible and near-IR regions. The results demonstrated that electrochemically textured CuO/Si photodetectors for certain texturing conditions exhibited superior performance compared to their untextured counterparts, offering enhanced absorption coefficients, improved spectral responsivity, and reduced dark current.
Nanoparticle (NP)-based organic solar cells have the ability to stimulate localized surface plasmon resonance (LSPR) and far-field scattering mechanisms, which potentially leads to an improvement in power conversion efficiency (PCE). In the current investigation, we primarily utilized the Semiconducting Thin Film Optics Simulation (SETFOS) environment to investigate the efficient functioning of an organic solar cell doped with gold (Au) NPs and compared it to an undoped reference cell. It was shown that by inserting the Au NPs in the polymer-based active layer, poly (3-hexylthiophene): [6, 6]-phenyl-butyric acid methyl ester (P3HT: PCBM), the absorption, external quantum efficiency (EQE), and exciton generation rate were significantly enhanced in the bulk heterojunction organic solar cell. Comparing the doped device to the undoped reference device, the short-circuit current density (JSC) was determined to have risen from -9.79 to -16.09 mA/cm2, resulting in an overall improvement in power conversion efficiency from 5% to 8.7%. Additionally, incorporating Au NPs results in a 1.7-fold increase in the exciton generation rate and it was determined by impedance spectroscopy that the total resistance of the device dropped by 24.2%.
A central challenge in spintronics is the development of materials for efficient spin-polarized current generation. While crystalline Heusler alloys often fall short of predicted half-metallicity due to structural disorder, their amorphous analogs present a promising avenue. In this work, we investigate how the composition-dependent structural evolution of short-range order controls room temperature electronic transport in amorphous FexSi1-x (0.44 <= x <= 0.75) alloy thin films. This structural evolution, revealed by X-ray reflectivity, underpins a transition from hopping to metallic conduction across distinct amorphous phases (FeSi -> Fe2Si -> Fe3Si). In the FeSi-like phase region, electronic transport is governed by Mott variable-range hopping, resulting in high resistivity and low Hall mobility. The onset of metallic conduction within the amorphous Fe2Si- and Fe3Si-like composition ranges yields lower resistivity alongside enhanced hole mobility. Our results establish a direct structure-property relationship in amorphous FexSi1-x alloys, demonstrating the ability to selectively design electronic transport through fine compositional tuning. Understanding the interplay between local atomic order and electronic transport in amorphous Fe-Si alloys provides key insights for engineering next-generation spintronic devices.
