Doping Content Research Articles

Balancing Graphitic Nanodomains and Heteroatom Doping in Hard Carbons Toward High Capacity and Durable Potassium‐Ion Battery Anodes

AbstractHard carbons (HCs) have emerged as promising candidates for commercial anodes in potassium‐ion batteries (PIBs). However, a thorny challenge remains in achieving high reversible capacities at high charge/discharge rates, which significantly hinders the development of HCs for PIBs. Here, a temperature‐controlled strategy is proposed to effectively balance graphitic nanodomains and heteroatom doping content in HCs, resulting in widened carbon layer spacing, high conductivity, and abundant K‐ion intercalation sites. The optimized NO‐HC600 electrode exhibits a high reversible capacity of 315.0 mAh g−1 at 0.2 A g−1, and exceptional cyclic stability (235.0 mAh g−1 after 1200 cycles at 2.0 A g−1 with a capacity retention rate of 98.82%). Furthermore, systematic in /ex situ experiments unveil a highly reversible “adsorption–intercalation” mechanism governing potassium‐ion storage, confirming the origin of the superior performance. This work offers valuable insights into the facile preparation of HC anodes with high reversible capacity and fast charge/discharge capability for PIBs.

Slightly Li-enriched chemistry enabling super stable LiNi0.5Mn0.5O2 cathodes under extreme conditions.

High voltage/high temperature operation aggravates the risk of capacity attenuation and thermal runaway of layered oxide cathodes due to crystal degradation and interfacial instability. A combined strategy of bulk regulation and surface chemistry design is crucial to handle these issues. Here, we present a simultaneous Li2WO4-coated and gradient W-doped 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 cathode through modulating the content of the exotic dopant and stoichiometric lithium salt during lithiation calcination. Benefiting from the slightly Li-enriched chemistry induced by the hetero-epitaxially grown Li2WO4 surface, the 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 cathode demonstrates superior electrochemical performance to W-doped LiNi0.49Mn0.49W0.02O2 and WO3 coated 0.98LiNi0.5Mn0.5O2·0.02WO3 cathodes without a Li-enriched phase. Specifically, when cycled in the potential range of 2.7-4.5 V at 30 °C, the 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 cathode possesses a high discharge capacity of 199.2 and 156.5 mA h g-1 at 0.1 and 5C and a capacity retention of 92.88% after 300 cycles at 1C. Even at a high cut-off voltage of 4.6 V, it still retains a capacity retention of 91.15% after 200 cycles at 1C and 30 °C. Compared with LiNi0.5Mn0.5O2, the enhanced performance of 0.98LiNi0.5Mn0.5O2·0.02Li2WO4 can be attributed to its robust bulk and stable interface, inhibited lattice oxygen release, and improved Li+ transport kinetics. Our work emphasizes the significance of the slightly Li-enriched chemistry and bulk modulation strategy in stabilizing cathodes and hence unlocks vast possibilities for future cathode design.

Wettability of anatase TiO2 surface: Effect of niobium doping

The effect of niobium doping on the hydrophilic behavior of anatase TiO2 surface was demonstrated on a series of x-Nb-TiO2 nanocoatings with dopant concentrations in the range of 0.0 - 1.0 at.% Nb. Thin films prepared on glass substrates from sols by dip-coating were characterized by tensiometric, work function and isoelectric point measurements along with FT-IR spectroscopy in situ method. Using macroscopic and microscopic techniques, it was found that, at low doping level, it is the functionalization of the anatase surface with niobium ions that leads to a drastic change in its surface acid-base as well as electronic properties and, as a consequence, to a sharp increase in the initial surface hydrophilicity. The rearrangement in the hydroxyl‑hydrated layer with the formation of additional hydroxyl groups as a result of surface functionalization has an increased effect on wettability only at low levels of niobium inclusion, whereas with increasing dopant content the electronic factor plays a significant role on the properties of titanium dioxide, including its wettability. The kinetic dependencies of the photoinduced superhydrophilic conversion for all Nb-doped titanium dioxide surfaces were obtained and discussed in terms of proposed mechanism. Both the initial hydrophilic state and the initial rate of photoinduced hydrophilic conversion depend on the Nb concentration in titanium dioxide, while the final UV-induced superhydrophilic state is achieved for all Nb-doped TiO2 regardless of the dopant content.

Phase and defect structures of MnO2‐doped 75BiFeO3–25BaTiO3 ceramics and their effects on electrical properties

AbstractBismuth ferrite (BiFeO3)‐based high‐temperature piezoelectric ceramics have high Curie temperatures and excellent thermal stability; however, their applications are limited by inadequate piezoelectric performance due to large coercive fields and high leakage conduction. This study investigates the impact of MnO2 doping on the phase transition, defect structure, domain morphology, as well as the dielectric, ferroelectric, and electrical conduction behaviors of 75BiFeO3–25BaTiO3 ceramics sintered under an oxygen atmosphere. A structural transformation from distorted rhombohedral to pseudo‐cubic symmetry was observed with increasing MnO2 content, accompanied by domain fragmentation. MnO2 doping at an appropriate level inhibited defects such as and . Regarding electrical properties, the reduction in rhombohedral distortion and enhancement in the pseudo‐cubic phase after MnO2 doping resulted in decreased remanent polarization and electrostrain, which could potentially hinder piezoelectric response. However, appropriate MnO2 doping effectively reduced leakage conduction, significantly enhancing the poling efficiency of the ceramics. The maximum d33 value of 107 pC/N and kp of 0.36 were achieved at an MnO2 doping content of 0.1 wt.%. Excessive MnO2 addition may generate defect dipoles, as indicated by increased coercive field (Ec) and dielectric loss. The observed increase in high‐temperature resistivity with MnO2 content is primarily attributed to reduced grain size and increased concentration of mobile defects. This study provides valuable insights for further research on the application of 75BiFeO3–25BaTiO3 systems in high‐temperature piezoelectric devices.

Influence of Rare-Earth Doping Content and Type on Phase Transformation and Transport Properties in Highly Doped CeO2.

Rare-earth doped CeO2 materials find extensive application in high-temperature energy conversion devices such as solid oxide fuel cells and electrolyzers. However, understanding the complex relationship between structural and electrical properties, particularly concerning rare-earth ionic size and content, remains a subject of ongoing debate, with conflicting published results. In this study, we have conducted comprehensive long-range and local order structural characterization of Ce1-xLnxO2-x/2 samples (x ≤ 0.6; Ln = La, Nd, Sm, Gd, and Yb) using X-ray and neutron powder diffraction, Raman spectroscopy, and electron diffraction. The increase in the rare-earth dopant content leads to a progressive phase transformation from a disordered fluorite structure to a C-type ordered superstructure, accompanied by reduced ionic conductivity. Samples with low dopant content (x = 0.2) exhibit higher ionic conductivity in Gd3+ and Sm3+ series due to lower lattice cell distortion. Conversely, highly doped samples (x = 0.6) exhibit superior conductivity for larger rare-earth dopant cations. Thermogravimetric analysis confirms increased water uptake and proton conductivity with increasing dopant concentration, while the electronic conductivity remains relatively unaffected, resulting in reduced ionic transport numbers. These findings offer insights into the relationship between transport properties and defect-induced local distortions in rare-earth doped CeO2, suggesting the potential for developing new functional materials with mixed ionic oxide, proton, and electronic conductivity for high-temperature energy systems.

Insight into the Role of Rb Doping for Highly Efficient Kesterite Cu2ZnSn(S,Se)4 Solar Cells.

Various copper-related defects in the absorption layer have been a key factor impeding the enhancement of the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Alkali metal doping is considered to be a good strategy to ameliorate this problem. In this article, Rb-doped CZTSSe (RCZTSSe) thin films were synthesized using the sol-gel technique. The results show that the Rb atom could successfully enter into the CZTSSe lattice and replace the Cu atom. According to SEM results, a moderate amount of Rb doping aided in enhancing the growth of grains in CZTSSe thin films. It was proven that the RCZTSSe thin film had the densest surface morphology and the fewest holes when the doping content of Rb was 2%. In addition, Rb doping successfully inhibited the formation of CuZn defects and correlative defect clusters and promoted the electrical properties of RCZTSSe thin films. Finally, a remarkable power conversion efficiency of 7.32% was attained by the champion RCZTSSe device with a Rb content of 2%. Compared with that of un-doped CZTSSe, the efficiency improved by over 30%. This study offers new insights into the influence of alkali metal doping on suppressing copper-related defects and also presents a viable approach for improving the efficiency of CZTSSe devices.

Structural and Optical Properties of Magnetron-Sputtered Chromium Oxynitride Thin Films

Doping non-metal elements into Cr2O3 can tailor its properties, making it more efficient for applications like sensors or photocatalysis. For this purpose, the current research work presents the impact of nitrogen doping on the structural and optical properties of Cr2O3 thin films. Pure and N-doped Cr2O3 (Cr2O3−xNx) thin films were synthesized using the DC reactive magnetron sputtering approach. The stoichiometry was obtained by raising values of x, where x = 0, 0.125, 0.25, and 0.50. X-ray diffraction analysis confirmed the rhombohedral crystal structure without the presence of any other secondary phase in undoped and N-doped Cr2O3 thin films. Furthermore, crystallinity and average crystallite size have enhanced by doping. Field emission scanning electron micrographs disclosed that the surface morphology of the prepared samples changed considerably with doping. A thorough optical investigation was carried out by spectroscopic ellipsometry. Several optical properties significantly changed with dopant content. The reduction in the optical bandgap from 2.50 eV to 1.82 eV, with N-doping was observed. The study demonstrated that N-doping improves the structural and optical properties that make it a promising candidate for optoelectronic applications.

Ruthenium-doped ZnO nanostructures: Growth, characterization, and applications in waveguides and light-emitting devices

ZnO based materials are gaining importance due to its potential applications. In many of these applications, the size, shape and dopability of the structures grown play a determinant role. In the present work, ZnO nano- and microstructures doped with Ru have been grown using the Vapour-Solid (VS) method. Among the different growth parameters, gas flux and initial dopant content seem to play the major role to determine both shape and size of the structures. The main morphologies obtained are self-arranged triangular grids and elongated structures. Based on microscopic observations a simplified growth model is proposed for the grids. An exhaustive characterization has been performed. X-Ray diffraction (XRD) investigations demonstrate good crystallinity and texturing related to preferential growth direction changes due to doping. Luminescence characterization through photo- and cathodoluminescence (PL and CL) techniques reveals typical ZnO near band edge and deep level emission bands at 3.2 and 2.3 eV, respectively. The potential use of elongated structures as waveguides and optical cavities, Fabry-Pèrot resonators, is explored.

The corrosion resistance, biocompatibility and antibacterial properties of the silver-doped dicalcium phosphate dihydrate coating on the surface of the additively manufactured NiTi alloy

Additive manufacturing (AM) of NiTi alloys has attracted significant attention for its exceptional forming precision and suitability for processing complex medical implant structures. However, challenges such as the excessive release of Ni2+, bioinertness, and insufficient antibacterial ability have emerged as primary factors impeding the application of NiTi alloy in the medical field. To address these issues, the silver-doped dicalcium phosphate dihydrate (Ag-DCPD) coating is electrochemically deposited on the LPBF-NiTi alloy surface for the first time. The study investigates the effects of varying Ag doping content (2 %, 4 %, and 6 %) on morphology, corrosion resistance, biomineralization, and long-term stability of DCPD coating using scanning electron microscopy (SEM), electrochemical analysis, and immersion tests. Results show that the 4Ag-DCPD coating exhibits the most uniform and dense surface morphology, excellent corrosion resistance, and biomineralization. The corrosion current density (Icorr) is two orders of magnitude lower than that of the LPBF-NiTi alloy matrix (from 1.1 × 10−6 to 1.4 × 10−8), and a dense hydroxyapatite (HA) layer forms after immersion testing. In vitro cell experiments indicate that the 4Ag-DCPD coating maintains high cell viability, favorable cell morphology, and excellent biocompatibility. Additionally, the 4Ag-DCPD coating demonstrates effective antibacterial activity against Escherichia coli (79.75 %) and Staphylococcus aureus (69.33 %), which reduces the risk of implantation infection. Overall, the 4Ag-DCPD coated LPBF-NiTi alloy shows promising clinical application potential as a medical implant.

The influence of Gd3+ion substitution on the microstructure and magnetic properties of NiZnMgGd ferrite

Nowadays, the rapid development and demand of electronic products have prompted electronic components to develop towards miniaturisation and even thin film, high integration and modularisation, high performance and ultra-high frequency applications. With the rapid development of electronic information technology and electronic field, NiZn ferrite material as a representative material in the soft magnetic material, through the optimisation of process technology to develop soft magnetic ferrite material with excellent performance is of great practical significance. In this study, Ni0.3Zn0.5Mg0.2GdxFe1.96-xO4 (x = 0, 0.02, 0.04, 0.06, 0.08) ferrite materials were prepared by an economical solid phase method. The XRD patterns show that NiZnMgGd ferrite materials can be successfully prepared at low doping content of Gd. However, when x ≥ 0.06, the excess Gd3+ reacts with Fe3+ and O2− in the raw material to produce the heterogeneous phase GdFeO3. From the SEM images, it can be seen that the higher the Gd content, the higher the number of small grains in the sample. A small amount of Gd3+ doping has a contributing effect on reducing the Pcv of ferrite. The quality factor of the ferrite sample with x = 0.02 is 11.92 when the frequency is 1000 kHz, which is an improvement of 100.67 % compared to the ferrite without Gd doping. From the M−H curves, Ms decreases with the increasing content of Gd replacing Fe, and NiZnMgGd ferrite is more likely to reach saturation under the action of external magnetic field. Ms, Mr and Hc indicate that NiZnMgGd ferrite material has typical soft magnetic properties.

Phase evolution and chemical durability of Ca2Nd8(SiO4)6O2 glass-ceramics derived from CFA via microwave heating designed to immobilize trivalent actinides

Oxyapatite (Ca2Nd8(SiO4)6O2) glass-ceramics (GCs) derived from coal fly ash (CFA) via microwave heating were fabricated to immobilize trivalent actinides (An3+). The effects of the Nd content and sintering temperature on the phase evolution of Ca2Nd8(SiO4)6O2 GCs were systematically investigated. The chemical durability of the Ca2Nd8(SiO4)6O2 GCs waste forms was examined under different leaching conditions (pH 4.0, 6.7, and 10.0). Results demonstrated the transformation of phase from glassy to Ca2Nd8(SiO4)6O2 GCs, when the doping content of Nd2O3 was 10, 15, and 20 wt.% at 1100, 1200, and 1300 °C, respectively, and the maximum solid solution was more than 30 wt.%. Prior to this solid solubility limit, all the Nd(Ⅲ) was incorporated to the glassy phase, whereas when the limit was exceeded, the Nd(Ⅲ) was immobilized into Ca2Nd8(SiO4)6O2 GCs. Moreover, the bulk density of the solidified sample increased with increasing of Nd-doped amount in the temperature range of 1100-1300 °C. The sample that was doped with 30 wt.% Nd2O3 and sintered at 1300 °C, exhibited the maximum bulk density (3.24 g·cm-3). Importantly, the GC waste forms exhibited superior leaching resistance, and the leaching rate of Nd element was in the order of 10-7 - 10-6 g·m-2·d-1. The NLNd values of the samples doped with 30 wt.% Nd2O3 and sintered at 1100 and 1300 °C were 8.57×10-8 g·m-2·d-1 and 4.29×10-8 g·m-2·d-1, respectively, after 28 d. In particular, the leachability of Nd element under different leaching conditions followed the order of acidic ＞ alkaline ＞ neutral. Therefore, Ca2Nd8(SiO4)6O2 GCs derived from CFA via microwave heating are promising immobilization substrates for the immobilization An3+ nuclear waste.

Confining Iodine into Metal-Organic Framework Derived Metal-Nitrogen-Carbon for Long-Life Aqueous Zinc-Iodine Batteries.

Aqueous zinc-iodine batteries (AZIBs) are highly appealing for energy requirements owing to their safety, cost-effectiveness, and scalability. However, the inadequate redox kinetics and severe shuttling effect of polyiodide ions impede their commercial viability. Herein, several Zn-MOF-derived porous carbon materials are designed, and the further preparation of iron-doped porous carbon (Fe-N-C, M9) with varied Fe doping contents is optimized based on a facile self-assembly/carbonization approach. M9, with atomic Fe coordinated to nitrogen atoms, is employed as an efficient cathode host for AZIBs. Functional modifications of porous carbon hosts involving the doping species and levels are investigated. The adsorption tests, in situ Raman spectroscopy, and in situ UV-vis results demonstrate the adsorption capability and charge-discharge mechanism for the iodine species. Furthermore, experimental findings and theoretical analyses have proven that the redox conversion of iodine is enhanced through a physicochemical confinement effect. This study offers basic principles for the strategic design of single-atom dispersed carbon as an iodine host for high-performance AZIBs. Flexible soft-pack battery and wearable microbattery applications also have implications for future long-life aqueous battery designs.

[formula omitted] leaves mediated combustion synthesis of Tb[formula omitted] doped Zn2V2O7 nanoparticles: Color tunable photoluminescence and electrochemical studies for display and supercapacitor applications

A new series of Tb3+ doped Zn2V2O7 (ZV) nanoparticles (NPs) at different concentration from 1 to 9 mol% was synthesized by Menthaspicata leaves extract mediated solution combustion method. On Tb3+ doping, the diffraction pattern matches well with the monoclinic crystal structure with the C2/c(2/m) space group of ZV host matrix. The surface morphology tuned from irregular shaped NPs to hexagonal shaped NPs with variation in dopant concentration. The crystallite size estimated from Scherrer’s method matches well with the transmission electron microscopy analysis. The optical band gap determined from Tauc’s plot utilizing UV–Visible absorption was tuned from 3.061 to 3.035 eV with increase in dopant concentration. Under 266 nm excitation, the emission of Tb3+ ions from Tb3+-doped ZV NPs is observed, with the intensity of emission showing sensitivity to the concentration of Tb3+ ions. The optimal doping content is determined to be 7 mol %. The CIE coordinates clearly indicates the tuning of the emission color from green to blue region with increase in dopant concentration. The average color coordinated temperature was found to be 7895 K showing the cooler appearance. Further, cyclic voltammetry analysis offers valuable insights into redox reactions, electrode kinetics, and overall electrochemical behavior, while Electrochemical Impedance Spectroscopy (EIS) provides information on ion transport kinetics. Galvanostatic Charge–Discharge (GCD) analysis revealed supercapacitance values ranging from 79.43 to 133.26 F/g at 10 mV/s with increasing dopant concentration. These findings underscore the potential of this material for use in energy storage and display technology applications.

Synergistic vacancy defects and the surface hydrophobic-to-superhydrophilic wetting engineering in W/S co-doped BiOI for enhanced photocatalytic hydrogen evolution

Bismuth oxyhalide (BiOI) has been used for photoelectrochemical catalysis in the field of catalytic hydrogen evolution, but it in a single-phase form has hardly been reported for photocatalytic hydrogen evolution reaction (PHER). Herein, we designed a W/S co-doped BiOI-based superhydrophilic catalyst with oxygen vacancy-rich defects and heterovalent valence states for efficient PHER under visible light. The W/S doping in BiOI not only adjusts the energy band structure and expands the visible light response range, but also transforms its hydrophobicity into superhydrophilicity, with which the gas bubble amount can be reduced and PHER activity enhanced. The introduction of sulfur regulates the content of oxygen vacancies which enhance the active surface sites for capturing water molecules and activating the H-O-H bond. The added tungsten exists in different valence states of W6+ and W5+ which is beneficial for electron hopping and PHER activity. The W/S-BiOI-3 with the suitable W/S doping content exhibits the highest visible-light PHER rate of 9.46 mmol·g−1·h−1, with an apparent quantum efficiency (AQE) of 9.7 % at 420 nm. W/S-BiOI-3 shows excellent PHER activity, stability, and durability, which provides a feasible scheme for other bismuth-based halogen oxides to be used in PHER.

Long‐Durability, Surfactant‐Free, and Bifunctional Ir‐Doped Pt3Co/MWCNTs Electrocatalysts towards ORR and OER in Acidic Media

AbstractDeveloping cost‐effective, high‐performance, and durable electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is pivotal for advancing hydrogen energy conversion and storage technologies. Simultaneously, establishing scalable methods for their production is essential for the widespread adoption of these renewable energy solutions. In this study, we present a successful large‐scale synthesis of surfactant‐free iridium‐doped Pt−cobalt nanoparticles supported on multiwalled carbon nanotubes (Ir−Pt3Co/MWCNTs). This composite demonstrates significantly enhanced ORR and OER activity compared to commercial Pt/C and IrO2 in acidic environments. The Ir−Pt3Co/MWCNTs catalyst composite exhibits a low overpotential of 357 mV at 10 mA cm−2 and a remarkable mass activity of 0.594 A/mgPt. Investigating the influence of Ir doping content on ORR and OER, we found that Pt3Co0.6Ir0.4/MWCNTs showcased the most superior activity in both reactions. We present a reproducible protocol for the synthesis of surfactant‐free Ir−Pt3Co nanoparticles supported on MWCNTs, yielding a bifunctional catalyst capable of efficiently catalyzing both ORR and OER with outstanding efficiency and stability in acidic media. Detailed X‐ray photoelectron spectroscopy (XPS) analysis elucidates the electron transfer between atoms, optimizing the electronic structure and adjusting the position of the d‐band. This optimization enhances the electrocatalytic activity and structural stability of the catalysts, contributing to their superior performance in ORR and OER.

Enhanced dielectric response and non-Ohmic properties of Cd-doped Na1/3Ca1/3Bi1/3Cu3Ti4O12 ceramics

In this study, Na1/3(Ca1−xCdx)1/3Bi1/3Cu3Ti4O12 (x = 0, 0.2, 0.4, 0.8, and 1.0) ceramics were prepared via solid-state method. Effects of substitution of Ca2+ with Cd2+ on the microstructure, dielectric response, and non-Ohmic properties of Na1/3Ca1/3Bi1/3Cu3Ti4O12 ceramics were studied systematically. Results showed that all samples possessed single perovskite phase, in which grain size increased with the increase in Cd2+ doping content. Energy band gaps and activation energy first increased and then decreased, achieving their maxima (4.22 and 0.642 eV, respectively) at x = 0.2. Besides, dielectric constant of doped samples increased with the decrease in dielectric loss in frequency range of 40–106 Hz. Moreover, improvement in non-Ohmic properties was also observed with Cd2+ doping. The optimal dielectric properties (dielectric constant of ∼12,500, dielectric loss of ∼0.032 at 10 kHz, nonlinear coefficient of ∼3.42, and breakdown strength of ∼2.7 kV·cm−1) were achieved at x = 0.2. Dielectric response mechanism of ceramics followed internal barrier layer capacitor model while nonlinear ohmic properties were derived from Schottky barrier structure. Dielectric relaxation peaks at high temperatures (120 °C–220 °C) were associated with grain boundaries. Therefore, partial substitution of Ca2+ with Cd2+ can improve simultaneously dielectric and non-Ohmic properties of Na1/3Ca1/3Bi1/3Cu3Ti4O12 ceramics, which is conducive to their application in high-energy-density storage capacitors and varistors.

A high effciency (11.06 %) CZTSSe solar cell achieved by combining Ag doping in absorber and BxCd1-xs/caztsse heterojunction annealing

Many literatures have demonstrated that a smaller amount of Ag doping in Cu2ZnSn(S, Se)4 (CZTSSe) can elevate the open-circuit voltage (Voc) and fill factor (FF) of CZTSSe solar cells, but decrease short-circuit current density (Jsc) due to the increase in bandgap (Eg) of the CAZTSSe by Ag doping. The decreased Jsc limits the enhancement in PCE through Ag doping. In this paper, to compensate for the deficit in Jsc and further increase Voc and FF, a strategy is proposed to substitute CdS/CAZTSSe in CAZTSSe solar cells with annealed B-doped CdS/CAZTSSe. It is found that B doping can increase the electron density of CdS (ne) and decrease the lattice mismatch between CdS and CAZTSSe. Annealing can decrease the hole density of CAZTSSe (np) and passivate the surface of CAZTSSe by diffusing B towards the surface of CAZTSSe. The increased ne and reduced np widen the depletion region, leading to an increase in photogenerated carrier density (JL), resulting in an increase in Jsc. The surface passivation and decreased lattice mismatch can reduce interfacial recombination, resulting in decrease in the reverse saturation current density (J0), so further increases in Voc and FF. By optimizing the Ag doping content, B doping content, as well as the annealing temperature and time of the BxCd1-xS/CAZTSSe, the power conversion efficiency (PCE) increases from 8.96 % to 11.06 %. This study not only advances a deeper understanding of the mechanisms behind various parameters in CZTSSe solar cells but also proposes a method to boost the PCE of CZTSSe solar cells.

Se-dopant Modulated Selective Co-Insertion of H+ and Zn2+ in MnO2 for High-Capacity and Durable Aqueous Zn-Ion Batteries.

MnO2 is commonly used as the cathode material for aqueous zinc-ion batteries (AZIBs). The strong Coulombic interaction between Zn ions and the MnO2 lattice causes significant lattice distortion and, combined with the Jahn-Teller effect, results in Mn2+ dissolution and structural collapse. While proton intercalation can reduce lattice distortion, it changes the electrolyte pH, producing chemically inert byproducts. These issues greatly affect the reversibility of Zn2+ intercalation/extraction, leading to significant capacity degradation of MnO2. Herein, we propose a novel method to enhance the cycling stability of δ-MnO2 through selenium doping (Se-MnO2). Our work indicates that varying the selenium doping content can regulate the intercalation ratio of H+ in MnO2, thereby suppressing the formation of ZnMn2O4 by-products. Se doping mitigates the lattice strain of MnO2 during Zn2+ intercalation/deintercalation by reducing Mn-O octahedral distortion, modifying Mn-O bond length upon Zn2+ insertion, and alleviating Mn dissolution caused by the Jahn-Teller effect. The optimized Se-MnO2 (Se concentration of 0.8 at.%) deposited on carbon nanotube demonstrates a notable capacity of 386 mAh g-1 at 0.1 A g-1, with exceptional long-term cycle stability, retaining 102 mAh g-1 capacity after 5000 cycles at 3.0 A g-1.

Microstructure, optical, dielectric, and nonlinear properties of Cd1-xBi2x/3Cu3Ti4O12 ceramics

Microstructure features along with optical, dielectric and nonlinear properties of Cd1-xBi2x/3Cu3Ti4O12 (x = 0, 0.3, 0.6, 0.9, and 1.0) ceramics were investigated systematically. With increase in Bi3+ doping content, Cd1-xBi2x/3Cu3Ti4O12 structure sightly distorted and eventually formed more stable configuration. Bi3+ doping also caused grain refinement and increased compactness of ceramics, whereas Bi-rich phase appeared at grain boundaries. Optical band gap (Eg) decreased due to increase in defect concentration. Dielectric loss (tanδ) dropped with increase in Bi3+ doping content while dielectric constant (ɛ′) remained high. The most optimal dielectric characteristics (the lowest tanδ of ∼0.033, giant ɛ′ of ∼10028 at 10 kHz and room temperature, the highest nonlinear coefficient (α of 4.62) and breakdown field strength (Eb of up to ∼9.23 kV/cm) were achieved at x = 0.9. Impedance spectra revealed semiconducting grains and insulating grain boundaries. Dielectric response evolution in Cd1-xBi2x/3Cu3Ti4O12 ceramics was described using internal barrier layer capacitor model. Electric modulus values indicated that low-frequency relaxation originated from grain boundaries. High energy barrier of grain boundaries was beneficial for enhancement of nonlinear properties of ceramics. Thus, Bi3+ doping improved both dielectric and nonlinear characteristics of Cd1-xBi2x/3Cu3Ti4O12 ceramics.

Synthesis of Up-Conversion CaTiO3: Er3+ Films on Titanium by Anodization and Hydrothermal Method for Biomedical Applications.

The present study investigates the effects of Er3+ doping content on the microstructure and up-conversion emission properties of CaTiO3: Er3+ phosphors as a potential material in biomedical applications. The CaTiO3: x%Er3+ (x = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0%) films were synthesized on Ti substrates by a hydrothermal reaction at 200 °C for 24 h. The SEM image showed the formation of cubic nanorod CaTiO3: Er3+ films with a mean edge size value of (1-5) μm. When excited with 980 nm light, the CaTiO3: Er3+ films emitted a strong green band and a weak red band of Er3+ ions located at 543, 661, and 740 nm. The CaTiO3: Er3+ film exhibited excellent surface hydrophilicity with a contact angle of ~zero and good biocompatibility against baby hamster kidney (BHK) cells. CaTiO3: Er3+ films emerge as promising materials for different applications in the biomedical field.