Materials Science and Engineering: B最新文献

Dilute magnetic semiconductor oxides (DMSOs) are attractive prospects for improved charge and spin degrees of freedom control. The current research presents an overview of the structural analysis and magnetic characteristics of DMSOs based on binary metal oxide nanomaterials with various ferromagnetic or paramagnetic dopants, such as Mn, Fe, Co, and Ni, which display increased ferromagnetic behaviour at ambient temperature. The co-precipitation approach was used to create nanoparticle samples of pure SnO₂, Sn_0.97Mn_0.03O₂, Sn_0.97Fe_0.03O₂, Sn_0.97Co_0.03O₂, and Sn_0.97Ni_0.03O₂. The emission spectra for the high, wide emission band are 366 nm and 655 nm. Room temperature magnetic hysteresis loops for Mn, Fe, and Ni-doped SnO₂ indicate ferromagnetic behaviour when compared to pure and Co-doped SnO₂, with Sn_0.97Mn_0.03O₂, Sn_0.97Fe_0.07O₂, and Sn_0.97Ni_0.03O₂ samples exhibiting increased coercivity and retentivity. The antibacterial activity of pure SnO₂, Sn_0.97Mn_0.03O₂, Sn_0.97Fe_0.03O₂, Sn_0.97Co_0.03O₂, and Sn_0.97Ni_0.03O₂ nanoparticles was determined.

Lead-free Double Perovskite Solar Cells (DPSCs) have garnered significant research attention in recent times because of its viability as a promising perovskite absorber layer in the device architecture along with its reasonable cost, remarkable stability and high performance. The lead and non-biodegradable material-based Perovskite solar cells (PSCs) are still a hurdle to its commercialization. We have investigated a non-toxic inorganic material i.e., Cs₂AgInBr₆ using SCAPS-1D software. We optimized various parameters like Defect density (N_t), thickness, operating temperature and electron affinity (χ) of perovskite absorber layer (Cs₂AgInBr₆). Effect of various ETLs and HTLs on the performance device is also analyzed. The Simulation result shows that at an absorber layer thickness of 600 nm, the Cs₂AgInBr₆-based DPSC has achieved maximum efficiency of 26.9 %.

Because of increasing demand for CO₂ detection, CO₂ sensors capable of low-temperature operation are desired. However, conventional oxide semiconductor sensors still require high operating temperatures. In this study, we fabricated a CO₂ sensor that can operate at 150 °C. The sensor is based on an open-channel-type thin-film transistor (TFT) structure with an In₂O₃(4 0 0) polar plane as a channel. Because the In₂O₃(4 0 0) surface is polar, many OH groups are adsorbed onto the as-prepared surface. When CO₂ gas is introduced, CO₂ molecules react with the OH groups and the TFT characteristics change. As a result, CO₂ can be detected with a sensitivity 2.9 times greater than that under an inert N₂ atmosphere despite the operating temperature of only 150 °C. In a TFT with nonpolar In₂O₃(2 2 2) planes, the sensitivity remains at 1.3 times. We therefore believe that TFTs fabricated with the polar surface of an oxide semiconductor are useful for gas-sensing applications.

A SLs quaternary nitride alloy-based UV-C LED with a uniquely designed electron blocking region is proposed in this article. At 200 A/cm² current density, the proposed design has maximum IQE, ∼121% better than the reference design. Additionally, less than 1% efficiency droop is observed in the proposed design. Due to strain compensation offered by the periodically varying and chirped SLs Al_aIn_bGa_(1-a-b)N/ Al_cIn_dGa_(1-c-d)N/ Al_eIn_fGa_(1-e-f)N/ Al_gIn_hGa_(1-g-h)N/ Al_iIn_jGa_(1-i-j)N/ Al_0.70Ga_0.30N electron blocking region, there is no abrupt potential barrier present, which makes it possible for hole injection in the active region to increase and hence improve the LED performance. The substantial improvement in the IQE is attributable to the proposed structure's enhancement in the carrier wave function overlap by 30%.

A series of polycrystalline mixed spinel ferrites, Mg_0.5Zn_0.5La_xFe_2-xO₄ (x = 0, 0.025, 0.05, 0.075, 0.1) were synthesized by hydrothermal method, where NaBH₄ was a reductant. The Rietveld refinement analysis demonstrated the La³⁺ occupancy in A and B positions. FESEM and HRTEM have shown nearly spherical nanoparticles with an average size of 7 nm. The existence of all the component elements were confirmed by EDS and XPS studies. Raman analysis have shown slight blue shift with higher La³⁺ concentration. These nano-ferrites were noticed to behave ferromagnetically, with small remanent magnetization. The nano-ferrites were tested for the LPG sensing, where the sensor response was understood by proposing the charge carrier (Fe²⁺ and Fe³⁺) hopping mechanism. The sensor response (%) of the sample (x = 5%) at 500 ppm exhibited highest value ∼36, as compared to sample (x = 0%). To conclude, Mg_0.5Zn_0.5La_0.05Fe_1.95O₄ showed better response and recovery time, rather than other spinel ferrites.

A defective system of V-doped Fe₂O₃ with Pt as a cocatalyst was employed for photoelectrochemical (PEC) water oxidation. The contained defects in VFPt-2.5 photoanode were revealed by XPS and EPR analyses. Interestingly, the morphology of electrodeposited V-doped α-Fe₂O₃ is observed to be nanosized with an average diameter size of ∼12 nm and thickness of 300 nm by SEM and TEM analyses. Under light irradiation, VFPt-2.5 photoanode achieved a remarkable onset potential of 0.22 V_RHE and a photocurrent density of 2.5 mA/cm² with an applied external bias at 1.23 V_RHE in 1 M KOH electrolyte solution (pH = 14). The calculated IPCE and ABPE values of VFPt-2.5 were ∼37% and 0.85%, respectively. The generated oxygen and hydrogen by VFPt-2.5//Pt were found to be 82 and 170 μmol. The stability of VFPt-2.5 reached 95.2% revealing that Pt could help to overcome the reversed effect of surface states that cause the charge recombination.

Rare earth doped aluminate-based phosphors are being preferred as efficient luminescent materials over sulfide-based phosphors. Present focus is to utilize unique luminescence features of lanthanide-based materials for multidisciplinary research and inventive applications. The growing research interest in aluminate-based phosphors over the past years has headed to the achievement in the enhancement in their long-lasting phosphorescence, phosphorescence efficiencies. Combustion synthesis route is a proficient technique due to the easier process, self-propagation ability, less time-consuming and cost effective as compared with many other routes for preparing nano-phosphor. In this article, our objective is to elaborate the uniqueness of combustion synthesis route for the preparation of phosphor materials composed of calcium aluminate (CaAl₂O₄). The combined results of persistence luminescence, luminescence properties of RE ion doped CaAl₂O₄ phosphor are discussed and critically reviewed. The effect of various dopant to favour the emission of radiation with different colors in the visible spectrum are also narrated.

Water is a vital component for the survival of living organisms. Due to the swift expansion of industrialization, water sources have become contaminated with heavy metals and harmful pollutants. The presence of heavy metal ions in water sources even at low concentrations can lead to various health complications. Researchers have reported that magnetic nano ferrites show significant potential in effectively removing heavy metals from water (remove over 90%) due to excellent magnetic characteristics, high specific surface area, surface active sites, high chemical stability, and the ease with which they can be modified or functionalized. This review explores recent literature on the synthesis and application of magnetic ferrites (MFe₂O₄, M = Co, Mg, and Ni) for removing heavy metals from water. It aims to provide a comprehensive understanding of the potential in addressing water pollution, as well as introducing the factors influencing adsorption performance and health effects for future research.