We have determined that a 20-nanometer nano-structured zirconium oxide surface accelerates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs) by stimulating the deposition of calcium in the extracellular matrix and elevating the expression levels of several osteogenic markers. 20 nm nano-structured zirconia (ns-ZrOx) substrates, when used for bMSC seeding, resulted in randomly oriented actin filaments, altered nuclear morphology, and a diminished mitochondrial transmembrane potential, in contrast to control groups grown on flat zirconia (flat-ZrO2) and glass coverslips. A heightened concentration of ROS, a known promoter of osteogenesis, was found subsequent to 24 hours of culture on 20 nm nano-structured zirconium oxide. The ns-ZrOx surface's modifications are completely reversed after the initial period of cell culture. We suggest that the cytoskeletal reorganization prompted by ns-ZrOx conveys extracellular signals to the nucleus, thus impacting the expression of genes determining cell fate.
While metal oxides, such as TiO2, Fe2O3, WO3, and BiVO4, have been researched as photoanodes for photoelectrochemical (PEC) hydrogen production, their substantial band gap negatively impacts photocurrent, preventing their efficient use of incident visible light. We propose a novel method to effectively produce PEC hydrogen with high efficiency, based on a unique photoanode composed of BiVO4/PbS quantum dots (QDs), thereby overcoming this limitation. Through the electrodeposition of crystallized monoclinic BiVO4, thin films were created, followed by the SILAR deposition of PbS quantum dots (QDs), resulting in a p-n heterojunction. This represents the initial implementation of narrow band-gap QDs in sensitizing a BiVO4 photoelectrode. The surface of nanoporous BiVO4 was uniformly covered with PbS QDs, and an increase in SILAR cycles led to a decrease in their optical band-gap. Importantly, the modification did not influence the crystal structure and optical properties of BiVO4. For PEC hydrogen production, the photocurrent on BiVO4 was elevated from 292 to 488 mA/cm2 (at 123 VRHE) after the surface modification with PbS QDs. This amplified photocurrent directly correlates to the increased light-harvesting capacity, facilitated by the narrow band gap of the PbS QDs. Subsequently, incorporating a ZnS overlayer on the BiVO4/PbS QDs fostered a photocurrent increase to 519 mA/cm2, owing to the diminished interfacial charge recombination.
The influence of post-deposition UV-ozone and thermal annealing procedures on the properties of aluminum-doped zinc oxide (AZO) thin films, prepared by atomic layer deposition (ALD), is explored in this paper. Through X-ray diffraction, a polycrystalline wurtzite structure was revealed, displaying a strong (100) crystallographic orientation preference. The augmentation of crystal size due to thermal annealing was observed, in sharp contrast to the insignificant crystallinity alteration resulting from UV-ozone treatment. XPS analysis of ZnOAl after undergoing UV-ozone treatment showed an elevated concentration of oxygen vacancies. However, the annealing of the ZnOAl material produced a reduced concentration of oxygen vacancies. The transparent conductive oxide layer application of ZnOAl, among other important and practical uses, showcases highly tunable electrical and optical properties after post-deposition treatment. This treatment, particularly UV-ozone exposure, proves a convenient and non-invasive means to lower the sheet resistance. Despite the UV-Ozone treatment, there were no considerable alterations observed in the polycrystalline structure, surface morphology, or optical properties of the AZO films.
The anodic oxygen evolution process benefits significantly from the electrocatalytic prowess of Ir-based perovskite oxides. This work presents a structured investigation into the doping effects of iron on the OER activity of monoclinic SrIrO3, to lower the required amount of iridium. SrIrO3's monoclinic structure persisted provided the Fe/Ir ratio remained below 0.1/0.9. NXY-059 With an escalation in the Fe/Ir ratio, the SrIrO3 crystal structure exhibited a transition, progressing from a 6H to a 3C phase arrangement. The investigated catalyst, SrFe01Ir09O3, showed the highest activity, featuring a minimum overpotential of 238 mV at a current density of 10 mA cm-2 in a 0.1 M HClO4 solution. This exceptionally high performance is attributed to oxygen vacancies introduced by the Fe dopant and the formation of IrOx arising from the dissolution of strontium and iron. The formation of oxygen vacancies and uncoordinated sites, at a molecular level, might account for the better performance. The study explored the influence of Fe substitution on SrIrO3's oxygen evolution reaction efficacy, supplying a detailed model for tuning perovskite-based electrocatalysts using iron for other applications.
Crystallization serves as a crucial determinant for crystal dimensions, purity, and morphology. Consequently, a detailed atomic-level understanding of nanoparticle (NP) growth patterns is crucial for precisely engineering nanocrystals with tailored geometries and characteristics. Employing an aberration-corrected transmission electron microscope (AC-TEM), in situ atomic-scale observations of gold nanorod (NR) growth were performed through particle attachment. Results show that the attachment of spherical gold nanoparticles, approximately 10 nanometers in diameter, involves the development of neck-like structures, transitioning to five-fold twinned intermediate configurations and ending with a complete atomic rearrangement. According to statistical analyses, the number of tip-to-tip gold nanoparticles and the size of colloidal gold nanoparticles independently control the length and diameter, respectively, of the gold nanorods. Spherical gold nanoparticles (Au NPs), with diameters spanning 3 to 14 nanometers, exhibit a five-fold increase in twin-involved particle attachments, as demonstrated in the results, and offer insight into the fabrication of gold nanorods (Au NRs) using irradiation-based chemistry.
Constructing Z-scheme heterojunction photocatalysts represents an optimal approach for addressing environmental concerns, using the limitless solar energy. A heterojunction photocatalyst, comprising anatase TiO2 and rutile TiO2, arranged in a direct Z-scheme configuration, was produced using a straightforward B-doping strategy. Variations in the B-dopant level result in manageable alterations to the band structure and oxygen-vacancy concentration. Synergistically-mediated oxygen vacancy contents, a markedly positively shifted band structure within B-doped anatase-TiO2 and rutile-TiO2 via the Z-scheme transfer path, and an optimized band structure, collectively enhanced the photocatalytic performance. NXY-059 Additionally, the optimization study demonstrated that the incorporation of 10% B-doping into R-TiO2, while maintaining an A-TiO2 weight ratio of 0.04, yielded the best photocatalytic outcome. Synthesizing nonmetal-doped semiconductor photocatalysts with tunable energy structures, this work may offer an effective strategy to enhance charge separation efficiency.
Laser pyrolysis, a point-by-point process on a polymer substrate, is instrumental in the synthesis of laser-induced graphene, a form of graphenic material. This method, which is both fast and cost-effective, is ideally suited for flexible electronics and energy storage devices, like supercapacitors. Nonetheless, the reduction in device thickness, crucial for these applications, remains a largely uninvestigated area. Consequently, this research outlines an optimized laser parameter configuration for the fabrication of high-quality LIG microsupercapacitors (MSCs) from 60-micrometer-thick polyimide substrates. NXY-059 This outcome is attained through the correlation of their structural morphology, material quality, and electrochemical performance. At 0.005 mA/cm2, the capacitance of 222 mF/cm2 in the fabricated devices results in energy and power densities comparable to those found in pseudocapacitive-enhanced devices of similar design. Through structural characterization, the LIG material is ascertained to be composed of high-quality multilayer graphene nanoflakes with excellent structural connections and ideal porosity.
Our paper proposes an optically controlled broadband terahertz modulator based on a high-resistance silicon substrate and a layer-dependent PtSe2 nanofilm. Compared to 6-, 10-, and 20-layer PtSe2 nanofilms, the 3-layer PtSe2 nanofilm displayed superior surface photoconductivity in the terahertz range, as revealed by the optical pump and terahertz probe system. The Drude-Smith model analysis gave a higher plasma frequency of 0.23 THz and a reduced scattering time of 70 fs for the 3-layer sample. A 3-layer PtSe2 film's broadband amplitude modulation, determined using a terahertz time-domain spectroscopy system, was measured across the 0.1-16 THz frequency range, reaching 509% modulation depth under a pump power density of 25 W/cm2. This investigation demonstrates the suitability of PtSe2 nanofilm devices for the purpose of terahertz modulation.
The increasing heat power density in contemporary integrated electronics necessitates the use of thermal interface materials (TIMs). These materials, with their high thermal conductivity and exceptional mechanical durability, are essential for bridging the gaps between heat sources and heat sinks and thereby improving heat dissipation. The exceptional intrinsic thermal conductivity of graphene nanosheets within graphene-based TIMs has propelled their prominence among all emerging thermal interface materials (TIMs). While significant progress has been made, the creation of graphene-based papers possessing high through-plane thermal conductivity continues to be challenging despite their high thermal conductivity along the in-plane. This study proposes a novel strategy for boosting graphene paper's through-plane thermal conductivity by in situ depositing silver nanowires (AgNWs) onto graphene sheets (IGAP). This approach could increase the material's through-plane thermal conductivity to as high as 748 W m⁻¹ K⁻¹ under typical packaging conditions.