Dopant Ions Research Articles

Putting Charge Transfer Degree as a Bridge Connecting Surface-Enhanced Raman Spectroscopy and Photocatalysis.

To date, few systematic approach has been established for predicting catalytic performance by analyzing the spectral information of molecules adsorbed on photocatalyst surfaces. Effective charge transfer (CT) between the semiconductor photocatalysts and surface-absorbed molecules is essential for enhancing catalytic activity and optimizing light energy utilization. This study aimed to validate the surface-enhanced Raman spectroscopy (SERS) based on the CT enhancement mechanism in investigating the CT process during semiconductor photocatalytic C-C coupling model reactions. A copper ion doping strategy was employed to simultaneously enhance the SERS effect and catalytic activity of zinc oxide (ZnO) derived from metal-organic framework (MOF). By analyzing molecular fingerprint SERS spectra, we calculated the degree of CT (ρCT), revealing that SERS enhancement is attributed to the CT mechanism. In-situ SERS spectra confirmed a high correlation between the catalytic activity and ρCT of ZnO with varying copper ion doping levels. A range of photoelectric and spectroscopic tests validated the effectiveness of SERS in linking CT to photocatalytic performance, consistent with first-principles density functional theory (DFT) simulations. This finding is also validated in other semiconductor materials and catalytic reactions, demonstrating the broad applicability of ρCT for predicting and evaluating SERS and catalytic activity.

Microwave-assisted synthesis of dual responsive luminomagnetic rare earth metal ions (Nd3+, Dy3+) co-doped nanohydroxyapatite for biomedical applications.

The existing demand for the development of innovative multimodal imaging nanomaterial probes for biomedical applications stems from their unique combination of dual response modalities, i.e., photoluminescence (PL) and magnetic resonance imaging (MRI). In this study, for the first time, neodymium (Nd3+) and dysprosium (Dy3+) rare earth (RE) metal ions were co-doped into a hydroxyapatite (HAp) crystal lattice using a simple microwave-assisted synthesis technique to incorporate the essential properties of both the lanthanides in HAp. Theoretical as well as experimental studies were performed on novel Nd:Dy:HAp nanoparticles (NPs) to understand their photoluminescence and magnetic behaviour. Through co-precipitation, RE (Nd3+, Dy3+) ions were effectively integrated into the HAp crystal lattice, where they preferentially occupied the calcium ion (Ca2+) sites. The as-synthesized HAp, Nd:HAp, Dy:HAp, and Nd:Dy:HAp samples were characterized using different analytical tools. The PL and magnetic characteristics of Nd:Dy:HAp were dependent on the RE dopant ion type and concentration. In comparison with the pure HAp, the RE co-doped (Nd:Dy:HAp) NPs displayed multimodal features due to efficient energy transfer from the Nd3+ (sensitizer) to the Dy3+ (activator) ions. Furthermore, Nd:Dy:HAp NPs had good antimicrobial properties and they also displayed low cell toxicity effects. Hence, Nd:Dy:HAp NPs are attractive biomaterials for PL and MRI applications (e.g. permanent bone and tooth implants) and they can effectively be utilized in the biomedical industry for target-specific drug delivery, bioimaging, functional antimicrobial coatings etc. due to their tunable PL, magnetic, antimicrobial, and biocompatible capabilities.

Phonon Involved Photoluminescence of Mn2+ Ions Doped CsPbCl3 Micro-Size Perovskite Assembled Crystals.

Mn2+ ions doped CsPbCl3 perovskite nanocrystals (NCs) exhibit superiority of spin-associated optical and electrical properties. However, precisely controlling the doping concentration, doping location, and the mono-distribution of Mn2+ ions in the large-micro-size CsPbCl3 perovskite host is a formidable challenge. Here, the micro size CsPbCl3 perovskite crystals (MCs) are reported with uniform Mn2+ ions doping by self-assembly of Mn2+ ions doped CsPbCl3 perovskite NCs. The electron-phonon coupling strength is enhanced in the perovskite self-assembled CsPbCl3 MCs, which remarkably accelerates the PL decay of Mn2+ ions in room temperature. Furthermore, the phonon-involved PL emission splits to two peaks at low temperature of 80 K, due to the phonon emission and absorption-induced energy exchange for exciton recombination in Mn2+ ions. These findings not only demonstrate a novel material system but also introduce a new theoretical framework for phonon-modulated PL manipulation in Mn2+-doped perovskite materials.

Advances on Defect Engineering of Niobium Pentoxide for Electrochemical Energy Storage.

The reasonable design of advanced anode materials for electrochemical energy storage (EES) devices is crucial in expediting the progress of renewable energy technologies. Nb2O5 has attracted increasing research attention as an anode candidate. Defect engineering is regarded as a feasible approach to modulate the local atomic configurations within Nb2O5. Therefore, introducing defects into Nb2O5 is considered to be a promising way to enhance electrochemical performance. However, there is no systematic review on the defect engineering of Nb2O5 for the energy storage process. This review systematically analyzes first the crystal structures and energy storage mechanisms of Nb2O5. Subsequently, a systematical summary of the latest advances in defect engineering of Nb2O5 for EES devices is presented, mainly focusing on vacancy modulation, ion doping, planar defects, introducing porosity, and amorphization. Of particular note is the effects of defect engineering on Nb2O5: improving electronic conductivity, accelerating ion diffusion, maintaining structural stability, increasing active storage sites. The review further summarizes diverse methodologies for inducing defects and the commonly used techniques for the defect characterization within Nb2O5. In conclusion, the article proposes current challenges and outlines future development prospects for defect engineering in Nb2O5 to achieve high-performance EES devices with both high energy and power densities.

Transcriptomic modifications across the genome and potential hazards of pulmonary fibrosis caused by metal-organic frameworks.

Metal-Organic Frameworks (MOFs) have shown great promise in environmental protection, owing to their exceptional properties including ultrahigh surface area and porosity, tunable pore size, and easy chemical functionalization. However, emerging evidence from experimental studies indicates that MOFs have side effects on human health due to metal ions doping, resulting in excessive reactive oxygen species (ROS) production, pro-inflammatory responses, and liver fibrosis. In this study, we investigated the impact of MOF-199 on human bronchial epithelial (HBE) cells by using transcriptome sequencing analysis. The results indicated that the stimulation of MOF-199 enhanced ROS generation, upregulated cytoplasmic Ca2+ levels, then activated the Grb2/SOS/Ras/Raf pathway, induced cell apoptosis, and ultimately resulted in lung fibroblasts through TGF-β secretion. The results were validated in vitro and in vivo. Therefore, it is necessary to carefully evaluate the nanosafety of MOF-199 in environment treatments.

Tunable luminescence in Eu3+/Sm3+ doped Na2YMg2V3O12 for WLEDs and optical thermometry.

In recent years, it has become a development trend to design multi-application luminescent materials with rare earth ion doping. In this work, a series of Eu3+/Sm3+ doped self-activated Na2YMg2V3O12 (NYMVO) phosphors were synthesized through a simple high-temperature solid-state reaction method. Interestingly, due to the energy transfer (ET) from the matrix to the activators, the luminescence color of the phosphors changed from turquoise to orange-red and yellow-green under near-ultraviolet (n-UV) 365nm excitation. Based on the fluorescence intensity ratio of the matrix to Eu3+/Sm3+, the optical thermometry performances of the NYMVO:0.20Eu3+ and NYMVO:0.06Sm3+ phosphors were described. Notably, the maximum absolute sensitivity (Sa) values for NYMVO:0.20Eu3+ and NYMVO:0.06Sm3+ phosphors were 0.30K-1 and 0.032K-1, respectively. Correspondingly, the maximum relative sensitivity (Sr) values were 2.17%K-1 and 1.22%K-1, respectively. Moreover, the light-emitting devices based on NYMVO:0.20Eu3+ and NYMVO:0.06Sm3+ phosphors had excellent optical properties, with correlated color temperature (CCT) of 4552 K and 4470 K, and color-rendering index (CRI) of 84.6 and 88.5. These results suggested that the two vanadate phosphors prepared had potential applications in both warm white light-emitting diodes (WLEDs) and optical thermometry.

Data-Driven Machine Learning Strategy for Designing Metal-Ion-Doped γ-Bi2MoO6 Photocatalysts to Enhance Degradation Performance.

Doped semiconductors are often used to improve photocatalytic efficiency and address the challenges of easy recombination of electron-hole pairs and poor photoluminescence. However, the reproducibility and complexity of experimental studies result in time-consuming and less cost-effective studies, and it is difficult to gain insights into the intrinsic properties of doped photocatalysts to control their performance. Introducing a machine learning approach, we constructed a photocatalytic model of transition-metal- and rare earth metal-ion-doped γ-Bi2MoO6. We selected 18 factors of preparation conditions and dopant ion properties, and constructed 806 data sets through literature collection for correlation analysis, paving the way for a more efficient and cost-effective research process. The results of our study are promising. The trained and improved XGboost model demonstrated high resistance to the variability caused by data segmentation, with a cross-validated model showing a coefficient of determination of 0.942. Through the combination of characteristic importance and Shapley additive explanation analysis, the importance and correlation trends of preparation conditions and dopant ion properties are obtained, especially the positive correlation trend of excitation time and preparation time and the negative correlation trend of atomic mass and bandwidth. Model prediction and experimental validation are used to demonstrate the effectiveness and behavioral prediction ability, and the Zn and Cd elements are successfully predicted for doping modification means. This study contributes to the modification and preparation of γ-Bi2MoO6 materials and provides a solid foundation for the efficient design of photocatalysts.

Technical Routes to Achieve High Circular Polarized Luminescence in Chiral Perovskites: A Mini‐Review

AbstractChiral hybrid organic‐inorganic perovskites (HOIPs) have emerged as promising materials for optoelectronic and spintronic applications, leveraging unique properties such as circularly polarized luminescence (CPL), circularly polarized nonlinear optical (NLO) emission, and chiral‐induced spin selectivity (CISS). However, challenges remain in stabilizing these materials under environmental stresses and precisely controlling chirality for scalable use. This review summarizes five main strategies to induce chirality in HOIPs, i.e., direct incorporation of chiral cations, surface modification with chiral ligands, ion doping, template‐induced chirality, and chiral metasurfaces. Each approach offers distinct advantages for optimizing CPL efficiency and device stability, paving the way for next‐generation applications in CPL detectors, information encryption, spintronic devices, etc.

Synthesis, Structure, and Electrochemical Performance of Bi-induced Stabilization of MnO2 Cathodes for Use in Highly Acidic Aqueous Electrolytes (pH

MnO2 cathode materials are widely studied in alkaline and neutral aqueous electrolytes. In these mediums, the MnO2 cathode shows suboptimal performance limited by dissolution and electrochemically inactive compound formation, leading to capacity fading. This study explores the enhancement of MnO2 cathode performance through Bi3+ ion doping (0, 1, 2.5, 5, and 10mol%) in a highly acidic electrolyte (pH < 2). By incorporating up to 10mol% Bi ions into the MnO2 structure, we significantly improved specific capacity and capacity retention stability. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed a uniform dispersion of Bi3+ ions throughout the MnO2 cathode after electrochemical cycling, contributing to performance enhancements. X-ray photoelectron spectroscopy (XPS) results indicated that Bi3+ ion concentration from 1 to 10mol% stabilises Mn3+ within the MnO2 lattice. Also, Bi3+ ion doping promotes the formation of a 2×2 tunnel structured α-MnO2 phase. Electrochemical impedance spectroscopy results demonstrated a reduction in double-layer and overall bulk capacitance. These findings suggest that Bi3+ ion doping effectively enhances MnO2 electrochemical performance and could enhance its use in aqueous metal-ion batteries.

Gd3+ doped CoCr2O4 nanoparticles: tuning of physical properties and optimizing the hyperthermia efficacy

Tuning the physical properties of nanomaterials is essential to enhance their capabilities for modern technological applications. Incorporating appropriate dopant ions is expected to modify the physical properties of nanomaterials significantly....

Strong near-infrared upconversion luminescence of the Er3+/Y3+ co-doped YbVO4 phosphor for multimode optical temperature measurement

This study explored the enhancement of near-infrared emissions in YbVO4: Er3+ through Y3+ ion doping under a 980 nm laser excitation. The phosphor exhibits weak green emissions at 527 nm (2H11/2 → 4I15/2) and 553 nm (4S3/2 → 4I15/2), red emissions at 654 nm (4F9/2 → 4I15/2), and a strong near-infrared emission at 803 nm (4I9/2 → 4I15/2). Optimal doping concentration of Y3+ ion in YbVO4: 0.02 Er3+ was determined to be 0.1, resulting in a 7.6-fold enhancement of near-infrared luminescence. This enhancement is attributed to defect bands facilitating energy transfer from green and red levels to the near-infrared levels. Furthermore, a multi-mode temperature sensor based on YbVO4: Er3+/Y3+ was developed, offering four distinct temperature sensing modes: TCEL of 2H11/2/4S3/2, NTCEL of 2H11/2/4F9/2 and 4S3/2/4F9/2, and single luminescence emission intensity of 4I9/2 energy level. The sensor demonstrates maximum relative sensitivities of 1.17 % K−1 at 298 K, 0.66 % K−1 at 298 K, 0.41 % K−1 at 298 K and 1.29 % K−1 at 673 K. YbVO4: Er3+/Y3+ phosphor exhibits high temperature sensitivity, showcasing significant potential for optical temperature sensing applications.

Impact of Cs+ ion doping on the Physical, Microstructural and electrochemical characteristics of LiNi0.5Mn1.5O4 cathode for high voltage Li-ion batteries

Impact of Cs+ ion doping on the Physical, Microstructural and electrochemical characteristics of LiNi0.5Mn1.5O4 cathode for high voltage Li-ion batteries

Synthesis and luminescence of Al based double perovskite quantum dots

The direct-bandgap AgIn based non-lead double perovskite quantum dots (DPQDs) are challenged by their low photoluminescence quantum yields (PLQYs). To address this issue, approaches such as ion doping and surface...

Enhanced microwave performance in spinel dielectric ceramics using entropy strategy for 5G/6G communication devices

Microwave dielectric ceramics are favored materials for microwave devices because of their stable dielectric properties. However, balancing the interdependent relationships among the dielectric constant (εr), quality factor (Q × f), and temperature coefficient of resonant frequency (τf) to meet the technical specifications of microwave dielectric components (low εr, high Q × f, and near-zero τf) remains a significant challenge. This paper reports a type of high-entropy spinel ceramic Mg3AlGaTi0.5Sn0.5O8. The relationships between configuration entropy, mechanical properties, and microwave dielectric properties (MDPs) of the ceramic were systematically investigated. Adjusting configuration entropy enhances phase stability, attributed to the high disorder in the ceramic caused by Ga3+ ion doping. With an entropy value of 1.56R, the ceramic achieved optimal MDPs, including a low εr of 9.87, a high Q × f of 132,564 GHz, and a near-zero of τf –10.8 ppm/°C. Designing a dielectric resonant antenna with high-entropy ceramic Mg3AlGaTi0.5Sn0.5O8 as the resonator can meet 5G/6G communication requirements. This study demonstrates that a high-entropy strategy can significantly improve the MDPs of spinel ceramics, expanding the materials suitable for microwave device applications.

Oral multistage nanomedicine for synergistic chemo/chemodynamic/near-infrared-II photothermal cancer therapy.

The oral administration of drugs for cancer therapy can maintain optimal blood concentrations, is biologically safe and simple, and is preferred by many patients. However, the complex lumen environment, mucus layer, and intestinal epithelial cells are biological barriers that hinder the absorption of orally administered drugs. In this study, sea urchin-like manganese-doped copper selenide nanoparticles (Mn-Cu2-xSe NPs) were designed using an anion exchange method and coated with calcium alginate and chitosan (AC) to form Mn-Cu2-xSe@AC capsules. The pH-responsive swelling behavior of the AC protective layer aided doxorubicin (DOX)-loaded Mn-Cu2-xSe NPs in overcoming multiple biological barriers, maintained their stability in gastric acid, and facilitated the release of the NPs in the small intestine. The intestinal epithelial cell permeability of DOX/Mn-Cu2-xSe NPs was confirmed using a monolayer absorption model involving Caco-2 human epithelial cells. The released DOX/Mn-Cu2-xSe NPs smoothly passed through the mucus layer, and were absorbed by intestinal epithelial cells. In mice, the NPs circulated in the blood and passively targeted the tumors through blood circulation by enhancing the permeability and retention effect to achieve significant tumor suppression and reduce damage to normal tissues. In addition, the unique sea urchin-like morphology of Mn-Cu2-xSe NPs enhanced the absorption in the near-infrared-II (NIR-II) window for photothermal therapy, realized the near-infrared-stimulated response release of DOX for increased chemotherapy, and promoted the Fenton-like effect because of the doping of manganese ions for chemodynamic therapy. These effects could permit the development of various synergistic cancer treatments. The use of DOX/Mn-Cu2-xSe@AC capsules as a multistage oral drug delivery system may overcome the sequential absorption barriers that currently hinder chemotherapy, chemodynamic, and photothermal therapies.

Role of divalent doping at A-sites (A=Ca2+, Sr2+, Ba2+ & Pb2+) on thermoelectric and magnetoresistive properties in La0.67(Bi0.0835Na0.0835) A0.165MnO3

The present work reports on the effect of divalent ion doping (Ca2+, Sr2+, Pb2+ & Ba2+) ions at A-site in the compound with compositional formula La0.67(Bi0.0835Na0.0835)A0.165MnO3 on structural, magnetic, magneto-transport and thermoelectric properties. X-ray diffraction reveals orthorhombic structure for calcium and barium doped with no peak splitting observed at ~ 32o whereas rhombohedral structure for strontium and lead dopants with a peak splitting in the main intensity. Doping with divalent ions at A-site in La0.67(Bi0.0835Na0.0835)A0.165MnO3 manganites has introduced Mn2+ ions, changing the ratio of Mn3+/Mn4+ in octahedral site and this has been confirmed from X-ray photospectroscopy studies. The field emission scanning electron microscope images confirm different grain sizes and morphologies for different doping elements and distinguished variation is noticed for strontium doped manganites with a grain size of 1.08µm. Room temperature ferromagnetic behavior was observed in the samples at room temperature except for calcium doped sample and magnetic behavior has been discussed on the basis of the various interactions between mixed valence manganese ions and Mn3+/Mn4+ ratio. Electrical resistivity (ρ) as a function of temperature (T) without magnetic field indicates the double peak behavior and with the application of external magnetic fields, the double peak disappears, in all the investigated samples. Highest MR% at their respective transition temperatures (TP1) has been obtained for lead doped samples when compared to barium, strontium and calcium samples. Activation energies (EP) estimated decreases initially for calcium and strontium whereas it increases for lead and barium dopants i.e. for further increases in ionic radii. The change of sign from positive to negative in Seebeck coefficient (S) was noticed with increasing ionic radii suggesting the variation in the nature of charge carriers. The electron-electron, electron-magnon, magnon-magnon scattering mechanism contributes to the temperature dependent resistivity and thermopower in the low temperature region while in the paramagnetic insulating region is governed by a small polaron hopping mechanism.

Near-standard white light emission in one matrix with solo ion doping: the case of β-Li2TiO3: Ce4+

Near-standard white light emission in one matrix with solo ion doping: the case of β-Li2TiO3: Ce4+

Study of a fiber laser based on bismuth ion doping in the 1300-1350 nm band

Study of a fiber laser based on bismuth ion doping in the 1300-1350 nm band

Bimetallic doped carbon dot nanozymes for enhanced sonodynamic and nanocatalytic therapy.

Conventional inorganic semiconductors are not suitable for acting as nanozymes or sonosensitizers for in vivo therapeutic nanomedicine owing to the lack of excellent biocompatibility. Biocompatible carbon dots (CDs) exhibit a variety of biological activities due to their adjustable size and surface chemical modification; however, the simultaneous sonodynamic activity and multiple enzyme-mimicking catalytic activity of a single CD have not been reported. Herein, we report the development of bimetallic doped CDs as a high-efficiency nanozyme and sonosensitizer for enhanced sonodynamic therapy (SDT) and nanocatalytic therapy (NCT). By selecting metal-organic complexes like EDTA-FeNa as the carbon source, we ensure that the coordination environments of metal atoms are preserved throughout the low-temperature calcination process. Compared with the single metal doped CDs including Fe-CDs or Ni-CDs, the obtained Fe and Ni co-doped CDs (Fe-Ni-CDs) not only exhibit enhanced sonodynamic activity owing to the decreased bandgap, but also possess augmented dual enzyme-mimicking catalytic activities due to the synergistic effect of bimetallic ions. The Fe-Ni-CD-mediated cascade amplification of ROS generation could lead to the production of 1O2 and O2˙- through SDT, the generation of ˙OH through POD-mimicking catalytic activity, and the provision of more O2 for SDT through CAT-mimicking catalytic activity. Through the integrated multifunctionality of Fe-Ni-CDs, we successfully enhanced the effectiveness of antitumor treatment with a single drug injection and a single US irradiation for enhanced SDT and NCT. This work provides a distinct paradigm of endowing CDs with sonodynamic and multiple enzyme-mimicking catalytic activities for enhanced SDT and NCT through bimetallic ion doping.

Characterization of structure and photoluminescence properties for LiZn(B1-xAlx)O3 (x=0-1) oxides

LiZn(B1-xAlx)O3 (x=0-1) oxide was prepared by calcining at 750 ℃ for 5h using a solid-state reaction method. Due to the difference in the ionic radii of B3+ and Al3+ ions, the lattice is distorted, and a bi-phase composed of ZnO and γ-LiAlO2 oxides are formed for x=1. As the Al3+ ion doping contents increasing, the bi-phase oxide powder particles transform from agglomerated irregular to flaky structure. Under an excitation wavelength of 367nm, two broad luminescence bands located at blue and yellow-green light regions are observed. The CIE chromaticity coordinates are located in the light blue light region for LiZnBO3, whereas the CIE coordinates are located in the white light region (x=0.33, y=0.34) for the bi-phase oxides, and it is quite close to the NTSC standard white light coordinates (x=0.33, y=0.33).