Search Results (34)

The rational design of transition metal oxides with tailored electronic structures and defect chemistries is critical for advancing high-performance supercapacitors. Herein, we report the engineering of cobalt oxide (Co₃O₄) gels through controlled sol–gel synthesis and rare earth (RE) incorporation using neodymium (Nd), gadolinium (Gd), and dual neodymium/gadolinium (Nd/Gd) doping. X-ray diffraction (XRD) confirmed the preservation of the cubic spinel structure with systematic peak shifts and broadening, evidencing lattice strain, oxygen vacancy generation, and defect enrichment. Field-emission scanning electron microscopy (FE-SEM) analyses revealed distinct morphological evolution from compact nanoparticle assemblies in pristine Co₃O₄ to highly porous, interconnected frameworks in Nd/Gd–Co₃O₄ (Nd/Gd-Co). X-ray photoelectron spectroscopy (XPS) verified the stable incorporation of RE ions, accompanied by electronic interaction with the Co–O matrix and enhanced oxygen defect states. Electrochemical measurements demonstrated that the Nd/Gd–Co electrode achieved a remarkable areal capacitance of 25 F/cm² at 8 mA/cm², superior ionic diffusion coefficients, and the lowest equivalent series resistance (0.26 Ω) among all samples. Long-term cycling confirmed 84.35% capacitance retention with 94.46% coulombic efficiency after 12,000 cycles. Furthermore, the asymmetric pouch-type supercapacitor (APSD) constructed with Nd/Gd–Co as the positive electrode and activated carbon as the negative electrode delivered a wide operational window of 1.5 V, an areal capacitance of 140 mF/cm², an energy density of 0.044 mWh/cm², and 89.44% retention after 7000 cycles. These findings establish Nd/Gd-Co gels as robust and scalable electrode materials and demonstrate that RE co-doping is an effective strategy for bridging high energy density with long-term electrochemical stability in asymmetric supercapacitors. Full article

Random lasers (RLs) based on glasses and glass-ceramics doped with rare-earth ions (REI) deserve great attention because of their specific physical properties such as large thermal stability, possibility to operate at high intensities, optical wavelength tunability, and prospects to operate Fiber-RLs, among other characteristics of interest for photonic applications. In this article, we present a brief review of experiments with RLs based on tellurite and germanate glasses and glass-ceramics doped with neodymium (Nd³⁺), erbium (Er³⁺), and ytterbium (Yb³⁺) ions. The glass samples were fabricated using the melt-quenching technique followed by controlled crystallization to achieve the glass-ceramics. Afterwards, the samples were crushed to obtain the powder samples for the RLs experiments. The experiments demonstrated RLs emissions at various wavelengths, with feedback mechanisms due to light scattering at grain/air and crystalline/glass interfaces. The phenomenon of replica symmetry breaking was verified through statistical analysis of the RLs intensity fluctuations, indicating a photonic phase-transition (corresponding to the RL threshold) analogous to the paramagnetic-to-spin glass transition in magnetic materials. The various results reported here highlight the potential of glasses and glass-ceramics for the development of RLs with improved performance in terms of reduction of laser threshold and large lifetime of the active media in comparison with organic materials. Full article

Single-phase multiferroics exhibiting ferroelectricity and ferromagnetism are considered pivotal for advancing next-generation multistate memories, spintronic devices, sensors, and logic devices. In this study, the magnetic and electric characteristics of bismuth ferrite (BiFeO₃) ceramics were enhanced through compositional design and grain engineering. BiFeO₃ ceramic was co-substituted by neodymium (Nd) and niobium (Nb), two non-isovalent elements, via the spark plasma sintering process using phase-pure powder prepared via sol-gel as the precursor. The symmetry of the sintered Nd–Nb co-doped samples changed from R3c to Pnma, accompanied by a decrease in the loss tangent, grain size, and leakage current density. The reduction in the leakage current density of the co-doped samples was ~three orders of magnitude. Moreover, ferroelectric, dielectric, and magnetic properties were substantially improved. The remanent polarization and magnetization values of the optimized Nd–Nb co-doped BiFeO₃ sample were 3.12 μC cm⁻² and 0.15 emu g⁻¹, respectively. The multiferroic properties were enhanced based on multiple factors such as structural distortion caused by co-doping, grain size reduction, suppression of defect charges via donor doping, space-modulated spin structure disruption, and an increase in magnetic ions. The synergistic approach of composition design and grain engineering sets a paradigm for the advancement of multiferroic materials. Full article

Neodymium-doped yttrium vanadate random lasers have presented exceptional efficiency and output power at the 1064 nm emission wavelength. However, emission at 1340 nm has not yet been observed for these random lasers, even though regular bulk lasers have presented many impressive properties in this infrared region. Here, we present a dual-emission Nd³⁺:YVO₄ pellet random laser, which emits at both 1064 nm and 1340 nm using a 585 nm pump wavelength, showing a new property corresponding to a much lower laser threshold at 1340 nm than with 1064 nm. Full article

Composite plates comprising a blend of rare earth neodymium-(Nd) doped M-type barium ferrite (BaM) with CNTs (carbon nanotubes) and polyethylene WERE synthesized through a self-propagating reaction and hot-pressing treatment. The plates’ microscopic characteristics were analyzed utilizing X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FTIR), thermo–gravimetric analysis (TGA), Raman, and scanning electron microscopy (SEM) analytical techniques. Their microwave absorption performance within the frequency range of 8.2 to 18 GHz was assessed using a vector network analyzer. It showed that CNTs formed a conductive network on the surface of the Nd-BaM absorber, significantly enhancing absorption performance and widening the absorption bandwidth. Furthermore, dielectric polarization relaxation was investigated using the Debye theory, analyzing the Cole–Cole semicircle. It was observed that the sample exhibiting the best absorbing performance displayed the most semicircles, indicating that the dielectric polarization relaxation phenomenon can increase the dielectric relaxation loss of the sample. These findings provide valuable data support for the lightweight preparation of BaM-based absorbing materials. Full article

Magnetic metal absorbing materials have exhibited excellent absorptance performance. However, their applications are still limited in terms of light weight, low thickness and wide absorption bandwidth. To address this challenge, we design a broadband and low-profile multilayer absorber using cobalt–iron (CoFe) alloys doped with rare earth elements (REEs) lanthanum (La) and Neodymium (Nd). An improved estimation of distribution algorithm (IEDA) is employed in conjunction with a mathematical model of multilayer absorbing materials (MAMs) to optimize both the relative bandwidth with reflection loss (RL) below −10 dB and the thickness. Firstly, the absorption performance of CoFe alloys doped with La/Nd with different contents is analysed. Subsequently, IEDA is introduced based on a mathematical model to achieve an optimal MAM design that obtains a balance between absorption bandwidth and thickness. To validate the feasibility of our proposed method, a triple-layer MAM is designed and optimized to exhibit wide absorption bandwidth covering C, X, and Ku bands (6.16–12.82 GHz) and a total thickness of 2.39 mm. Then, the electromagnetic (EM) absorption mechanisms of the triple-layer MAMs are systematically investigated. Finally, the triple-layer sample is further fabricated and measured. The experimental result is in good agreement with the simulated result. This paper presents a rapid and efficient optimization method for designing MAMs, offering promising prospects in microwave applications, such as radar-stealth technology, EM shielding, and reduced EM pollution for electronic devices. Full article

Neodymium-doped yttrium fluoride crystal has emerged as one of the most valuable functional materials, and has thus become a research hotspot and shown promising application value in recent years. In this work, utilizing 460 keV H and 6.0 MeV C ions implantation, the damage behavior, lattice structure change, spectral, and electrical characteristics of the Nd:YLF crystal induced by electronic and nuclear energy loss were investigated, utilizing complementary characterization techniques (X-ray diffraction, hardness and elastic (Young’s) modulus, micro-Raman, absorption, fluorescence spectra, and I–V characteristic curve). Thus, the annealing effect on the waveguide properties and the surface damage of the samples was discussed. The fabricated waveguide structure shows potential application in highly sensitive optoelectronic sensors. Full article

New 3D micro-nanostructured composite materials have been synthesised. These materials comprise SiO₂/CaCO₃/C_org/NdVO₄NPs and SiO₂/CaO/C_org/NdVO₄NPs, exhibiting strong upconversion luminescence. The synthesis was accomplished by metabolically doping diatom cells with neodymium and vanadium. Subsequently, the biomass of these doped diatoms was subjected to pyrolysis at 800 °C. The morphology, structure, and physicochemical properties of the doped diatom biomass as well as dried (SiO₂/CaCO₃/C_org/NdVO₄NPs) and pyrolysed (SiO₂/CaO/C_org/NdVO₄NPs) samples were characterised using scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), thermal analysis (TG), and fluorescence spectroscopy (FS). Studies have shown that the surface of diatom shells is covered with trigonal prismatic nanocrystallites (nanoparticles) of NdVO₄ with dimensions of 30–40 nm, forming the crystallite clusters in the form of single-layer irregular flakes. The synthesised composites produced intense anti-Stokes fluorescent emission in the visible region under xenon lamp excitation in the near-infrared (λ_ex = 800 nm) at room temperature in an ambient atmosphere. Such materials could be attractive for applications in solar spectrum conversion, optical sensing, biosensors, or photocatalysts. Full article

Background and Objectives: Posterior capsular opacification (PCO) is the most common long-term complication of successful cataract surgery and can cause visual impairment. We aimed to investigate the effects of intraocular lens (IOL) characteristics on PCO by comparing the incidence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy for different types of intraocular lenses. Materials and Methods: A retrospective analysis was performed on 2866 eyes that underwent cataract surgery between January 2010 and December 2017, with at least 5 years of follow-up. The IOLs used for surgery were the hydrophobic lenses SN60WF (Alcon, Fort Worth, TX, USA), ZCB00 (Johnson & Johnson Vision, Santa Ana, CA, USA), and MX60 (Bausch & Lomb, Rochester, NY, USA), and the hydrophilic lens MI60 (Bausch & Lomb, Rochester, NY, USA). We analyzed the incidence of Nd:YAG laser capsulotomy according to the type of IOL used. Results: The incidence of Nd:YAG laser capsulotomy was significantly higher with MI60 lenses (31.70%, 175/552 eyes) compared to SN60WF (7.90%, 113/1431 eyes), ZCB00 (10.06%, 64/636 eyes), and MX60 (10.57%, 13/123 eyes; p < 0.001) lenses. The incidence of Nd:YAG laser capsulotomy was significantly lower with the hydrophobic IOLs (8.68%, 190/2190 eyes) than with the hydrophilic IOL (31.70%, 175/552 eyes; p < 0.001). Over time, the rate of increase in the cumulative number of Nd:YAG laser capsulotomy cases was the highest with MI60. The cumulative rate of Nd:YAG laser capsulotomy during the first 3 years was 4.90% with SN60WF (70/1431 eyes), 6.76% with ZCB00 (43/636 eyes), 8.94% with MX60 (11/123 eyes), and 26.10% with MI60 (144/552 eyes) lenses. Conclusions: The incidence of PCO is influenced by the material of the IOLs. The hydrophilic IOL was associated with a higher rate of Nd:YAG laser capsulotomy than the hydrophobic IOLs, with a shorter time to Nd:YAG laser capsulotomy. Full article

For the first time, a new composite voltammetric sensor based on yttria-stabilized zirconia doped with neodymium-carbon black-Nafion glassy carbon electrode (YSZNd-CB-Nafion/GCE) for the determination of metoprolol (MET) has been developed. The instrumental parameters and supporting electrolyte were optimized. For 105 s accumulation time, linearity was achieved in the range of 0.01 to 0.2 µM. The limit of detection (for 105 s accumulation time) was equal to 2.9 nM (2 µg/L), and was the best result in comparison to other voltametric sensors. The reproducibility of the metoprolol signal presented as relative standard deviation (RSD) was equal to 1.9% (n = 7). Additionally, our electrode is characterized by high stability, is easy to use, and has a short preparation time. The proposed sensor was found useful for MET determination in plasma and urine, as well as for pharmaceutical samples, with a good recovery parameter (96–108%). Flow injection analysis (FIA) with amperometric detection was also performed for MET determination. The recovery was calculated and was in the range 101–103%, suggesting that the proposed material may be applied in flow injection analysis. Full article

Materials known as Nd:YAG are crystalline materials of the cubic system made from the neodymium-doped yttrium aluminum garnet, which, among others, have excellent optical properties. Nd:YAG four-level laser devices are frequently used in both the health and industrial sectors. In this study, a simple and inexpensive alternative to manufacturing Nd:YAG materials through solid state reactions following powder processing routes was proposed. For this, an intense mixture of the precursor materials (Al₂O₃ and Y₂O₃) was carried out, followed by the addition of neodymium atoms to improve the optical properties of the resulting material. High-energy mechanical mixing of the precursor powders resulted in submicron particles with good size distributions of the powders. The advance of YAG formation was monitored by intermediate phase formation during heat treatment through interrupted tests at different temperatures and analysis by X-ray diffraction. From this analysis, it was found that reaction for the formation of the desired YAG is completed at 1500 °C. Fourier transform infrared spectroscopy analyses determined the presence of functional groups corresponding to the YAG. Finally, the study employing optical emission spectroscopy showed wavelengths in agreement with those of the electronic structure of the elements of the synthesized Nd:YAG. Full article

The Microbial Desalination Cell is a novel method for desalinating water that also generates energy via substrate oxidation. The MDC comprises three chambers: the anode chamber, the desalination chamber, and the cathode chamber. The fundamental problem with the technology is that it generates very little power during the oxygen reduction reaction (ORR). One solution to this issue is to use a highly active cathode catalyst, which effectively increases the ORR rate. Neodymium-doped ZnO nanoparticles were produced and employed as a cathode catalyst in the three-chambered MDC1 to improve performance. Zn_1−xNd_xO nanocrystalline samples containing x = 0.0, 0.03, 0.6, and 0.10 were synthesized efficiently through the cost-efficient sol-gel method. Transmission electron microscopy (TEM) and X-ray diffraction techniques revealed the nanocrystalline nature and the phase purity of the Zn_1−xNd_xO samples. The structural properties of ZnO nanostructured materials were elucidated by Rietveld refinement of the XRD patterns, which showed displacement of Zn and O ions and revealed changes in the electron density around the Zn-O bond with Nd substitution. The local features of light emission from Zn_1−xNd_xO samples have been studied with photoluminescence. The UV and green-yellow emissions originate from the exciton transition and the transition between the Nd³⁺ deep level, oxygen vacancy and interstitial oxygen. The results were compared to MDC-2, which did not have a catalyst on the cathode. Both MDCs were tested using a saline water solution containing 15 g/L of NaCl to measure their desalination performance. The better reduction kinetics was confirmed by cyclic voltammetry of the MDC-1 cathode. MDC-1 had a higher desalination efficiency (77.02% ± 2.0%) due to the presence of an Nd-doped ZnO catalyst than MDC-2 (59.3% ± 8.3%). MDC-1’s maximum power density of 3.65 W/m³ was 2.78 times greater than MDC-2’s (0.78 W/m³). Furthermore, the coulombic efficiency of MDC-1 was found to be (8.8 ± 0.3%), which was much higher than that of MDC-2 (4.56 ± 0.2%). As a result, the Nd-doped ZnO-based catalyst developed in this study can potentially improve ORR in MDC cathodes, enabling them to generate more power. Full article

Random lasers have been studied using many materials, but only a couple have used glass matrices. Here, we present a study of zinc tellurite and aluminum oxide doped with different percentages of neodymium oxide (4 wt.%, 8 wt.%, and 16 wt.%) and demonstrate for the first time random laser action at 1337 nm. Laser emission was verified and the laser pulse’s rise time and input–output power slope were obtained. A cavity composed of the sample’s pump surface and an effective mirror formed by a second, parallel layer at the gain-loss boundary was probably the main lasing mechanism of this random laser system. The reason for the absence of emission at 1064 nm is thought to be a measured temperature rise in the samples’ active volume. Full article

The following investigation presents the thermal treatment of geopolymer at 300 °C, 600 °C and 900 °C. We investigated what happens to the geopolymer base when incorporated with 1% and 5% of neodymium in the form Nd₂O₃. A total of six samples were synthesized. Geopolymer 1 contained 1% and geopolymer 2 contained 5% Nd₂O₃, and these samples were treated at 300 °C; then, samples geopolymer 3 and geopolymer 4 also had the same percentage composition of Nd₂O₃ and were treated at 600 °C, while samples geopolymer 5 and geopolymer 6were treated at 900 °C. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers; however, with increased temperatures, these materials show even more unusual properties. Diffuse reflectance infrared Fourier transform (DRIFT) analysis showed that the intensity of the vibrational band decreases with the increase in temperature during thermal treatment, suggesting alterations in the chemical structure of the geopolymers. Transmission electron microscopy (TEM) analysis showed that the diameter of the nanoparticles containing Al₂O₃ is in the range 5–10 nm, while larger crystallites range from 30 to 80 nm. Scanning electron microscopy (SEM) analysis revealed that the temperature of the thermal treatment increases to 300 °C and 600 °C; the porosity of geopolymer increases in the form of the appearance of large pores and cracks in material. X-ray photoelectron spectroscopy (XPS) analysis was used to investigate the surface chemistry of geopolymers, including the chemical composition of the surface, the oxidation state of the elements, and the presence of functional groups. The UV/Vis spectra of the synthesized geopolymers doped with Nd³⁺ show interesting optical properties at 900 °C; the geopolymer matrix completely disintegrates and an amorphous phase with a rare-earth precipitate appears. Full article

Lead-containing piezoelectric materials typically show the highest energy conversion efficiencies, but due to their toxicity they will be limited in future applications. In their bulk form, the piezoelectric properties of lead-free piezoelectric materials are significantly lower than lead-containing materials. However, the piezoelectric properties of lead-free piezoelectric materials at the nano scale can be significantly larger than the bulk scale. This review looks at the suitability of ZnO nanostructures as candidate lead-free piezoelectric materials for use in piezoelectric nanogenerators (PENGs) based on their piezoelectric properties. Of the papers reviewed, Neodymium-doped ZnO nanorods (NRs) have a comparable piezoelectric strain constant to bulk lead-based piezoelectric materials and hence are good candidates for PENGs. Piezoelectric energy harvesters typically have low power outputs and an improvement in their power density is needed. This review systematically reviews the different composite structures of ZnO PENGs to determine the effect of composite structure on power output. State-of-the-art techniques to increase the power output of PENGs are presented. Of the PENGs reviewed, the highest power output belonged to a vertically aligned ZnO nanowire (NWs) PENG (1-3 nanowire composite) with a power output of 45.87 μW/cm² under finger tapping. Future directions of research and challenges are discussed. Full article