Materials Letters最新文献

In this work, five dyes-based on Ru(II) complexes with 2,2́- bipyridyl ligands substituted at the 4,4́-positions with a different number of nitrile anchoring groups and distinct −X electronic donor units were tested as TiO₂ electrode sensitizers in solar cells (SCs). All dyes were PF₆^- salts: three complexes of formulae [Ru(4,4́-(X)₂-bpy)₂(Mebpy-CN)]²⁺ with one nitrile group and X =  − CH_3, –OCH_, −N(CH₃)₂; and two of formulae [Ru(4,4′-(X)₂-bpy)(Mebpy-CN)₂]²⁺, with two nitrile units and X = –OCH₃, −N(CH₃)₂. In all cases, bpy = 2,2′-bipyridine and Mebpy-CN = 4-methyl-2,2′-bipyridine-4′-carbonitrile. After characterizing the electrodes morphologically and optically, they were employed in DSSCs (dye-sensitized SCs) using Pt/FTO as counter-electrode (CE) and a KI/I₂ in CH₃CN as liquid electrolyte. Current density–voltage (J-V) and impedance spectroscopy (IS) measurements highlighted that the SC with the highest efficiency (η) is the one that contains − N(CH₃)₂ as donor units and two nitrile groups as anchoring entities. It could be concluded that higher electronic delocalization that occurs between the bpys substituted with strong electronic donor groups and the metal orbitals impose excellent properties to improve efficiency, which further improves if two anchoring groups are employed.

The rock structure determines the stability and reliability of underground engineering. Great achievements have been made in the study of rock structural damage, but there are few studies on real-time monitoring of rock structural changes under different increasing and unloading decreasing pressures. In this paper, the dynamic evolution rule of pore structure in rock under the combined action of water pressure and different confining pressure of increasing and decreasing is monitored by NMR technique. The porosity and permeability of rock under different confining pressures are consistent. The increase of confining pressure leads to the closure of pores, which leads to the decrease of porosity and permeability, but the amplitude and time of change are different. During the process of decreasing confining pressure, the T₂ spectral curve, porosity and permeability of the rock did not fully recover due to the reduction of confining pressure, indicating that plastic deformation occurs inside the rock at this time. The mathematical relationship between porosity and permeability is established, and the permeability of rock is not only related to the size of porosity, but also closely related to the pore structure of rock.

In this study, a porous polycaprolactone (PCL) −based scaffold was treated with lipase to create a hierarchical pore structure. The lipase treatment increased the surface roughness and hydrophilicity, leading to enhanced cell adhesion compared to the untreated scaffold. The hierarchical pore structure of the lipase-treated scaffold shows promise for bone regeneration. This lipase treatment approach offers a new method for designing tissue engineering scaffolds.

At present, research bottleneck on electromagnetic absorption materials lied in achieving strong absorption with broadband and multi-band responses. In this paper, Fe₇S₈ anchoring S-doped porous graphene was synthesized for multi-band electromagnetic absorptions. Rhodanine played the role of ‘two birds in one stone’, converting Fe₃O₄ to Fe₇S₈ and constructing porous S-doped carbon. The hybrids exhibited multi-band electromagnetic absorptions at 10.52, 12.56 and 15.03 GHz, with effective bandwidth achieved up to 12.07 GHz. This paper showcases reference path for the design of multi-band electromagnetic absorption materials.

SiO₂/TiO₂ composite films with different phase ratios have been successfully fabricated via the one-step plasma electrolytic oxidation (PEO) method in an alkaline electrolyte on Ti foil to obtain a binder-free anode for Li-ion batteries. The formed composite films present porous morphology of TiO₂ with a uniform distribution of SiO₂. The specific capacity can stabilize above 400 mAh/g at the current density of 100 μA cm⁻² for 500 cycles, together with the apparent improved initial coulombic efficiency of 88.7 % and excellent rate capability, which arises from the peculiar structure and the synergic enhancement effect of SiO₂ active materials and TiO₂ matrix. This work provides an efficient and low-cost route for the preparation of Li-ion battery binder-free anodes and enriches the application of plasma electrolysis technology in energy field.

In the current work, we explored the direct synthesis of S-doped porous carbons employing cesium methanesulfonate as a novel bifunctional chemical activator. The obtained carbons showed high surface area (654–2264 m²/g) and high S content (6.56–15.13 wt%). Effects of activation temperature and cesium methanesulfonate amount on the carbons’ properties were also studied. The obtained carbons showed CO₂ uptake of 3.58–4.76 mmol/g at 0 °C and 1 bar. Effects of textural properties and S-doping on CO₂ adsorption performances were discussed.

To explore whether in-situ (TiC + Ti₅Si₃)/TC4 composites with network structure have simultaneously excellent corrosion and tribocorrosion resistance, the corrosion and tribocorrosion properties of the composites were studied. In-situ TiC and Ti₅Si₃ particles can effectively enhance the corrosion and tribocorrosion properties of the composites. The composite with 5 vol% Ti₃SiC₂ exhibits the highest corrosion and tribocorrosion resistance. Grain refinement and the effect of TiC and Ti₅Si₃ are important factors in enhancing the corrosion and tribocorrosion resistance of the composites.

The Zn-0.5Ti alloy bone regeneration membranes, prepared via powder metallurgy, hot extrusion, and hot rolling, exhibit robust mechanical properties (tensile strength: 122.5 ± 1.8 MPa, elongation: 18.3 ± 0.7 %), appropriate degradation rate (0.127 mm/year in SBF solution), and good biocompatibility (cytotoxicity grade 0–1). After 4 and 8 weeks of implantation, the alloy showed significant bone growth (bone volume ratios (BV/TV): 11.3 ± 1.8 % and 23.1 ± 3.5 %, respectively, measured by Micro-CT), indicating promising potential as a GBR membrane material.

In this work, we report the fabrication of a novel and reusable CuO-gC₃N₄ based photocatalyst. The Alg/CuO-gC₃N₄ was prepared by two step process; first CuO-gC₃N₄ was synthesized by co-precipitation method, followed by its incorporation in the calcium alginate (Alg) through a facile ionotropic gelation method. The resultant material was characterized using appropriate techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV Diffuse Reflectance Spectroscopy (UV-DRS). The photocatalytic activity of the CuO-gC₃N₄ and Alg/CuO-gC₃N₄ were assessed to degrade tetracycline (TC) under UV–vis irradiation. This research presents a promising avenue for the design of biocompatible and cost-effective materials for environmental remediation applications.

In this study, we successfully synthesized α-phase Cs_1-xDMA_xPbI₂Br(0 ≤ x ≤ 0.3) without impurity and conducted device performance research and stability testing on it. The champion photoelectric conversion efficiency of α phase Cs_0.8DMA_0.2PbI₂Br in inverted perovskite solar cells is 8.24 %. Compared with pure CsPbI₂Br without DMA⁺, humidity stability of α-Cs_0.8DMA_0.2PbI₂Br has been improved and it also maintains thermal and ultraviolet stability. This strategy shows bright application prospect for improving the stability of CsPbI₂Br perovskite solar cells.