Search Results (736)

High electrostrain, excellent thermal stability, and low hysteresis are critical requirements for advanced high-precision actuators. However, simultaneously achieving these synergistic properties in lead-free ferroelectric ceramics remains a significant challenge. In this work, a targeted B-site doping strategy was employed to develop novel lead-free (0.99-x)BaTiO₃-xBaZrO₃-0.01Bi(Zn_2/3Nb_1/3)O₃ (BT-xBZ-BZN, x = 0–0.2) ceramics. Systematic investigation identified optimal Zr⁴⁺ substitution at x = 0.1, which yielded an outstanding combination of electromechanical properties. For this optimal composition, a high unipolar electrostrain (S_max = 0.11%) was achieved at 50 kV/cm, accompanied by an ultra-low hysteresis (H_S = 1.9%). Concurrently, a large electrostrictive coefficient (Q₃₃ = 0.0405 m⁴/C²) was determined, demonstrating excellent thermal robustness with less than 10% variation across a broad temperature range of 30–120 °C. This superior comprehensive performance is attributed to a composition-driven evolution from a long-range ferroelectric to a pseudocubic relaxor state. In this state, the dominant electrostrictive effect, propelled by reversible dynamics of polar nanoregions (PNRs), minimizes irreversible domain switching. These findings not only present BT-xBZ-BZN (x = 0.1) as a highly promising lead-free candidate for high-precision, low-loss actuator devices, but also provide a viable design strategy for developing high-performance electrostrictive materials with synergistic large strain and superior thermal stability. Full article

Supercapacitors based on mixed metal oxides are being developed as potential devices for large-scale energy storage applications with physical flexibility, thanks to their low cost and good electrochemical performance. This work demonstrates a novel approach to enhancing the electrochemical performance of bismuth–cerium oxide BiCeO₃ (BC) through thiourea doping. The incorporation of sulfur, confirmed by EDS, induced significant structural modifications, including a reduction in crystallite size from 42.5 nm to 34.8 nm and the emergence of new diffraction planes (002) and (222) in XRD patterns. These changes, indicative of successful lattice doping, yielded a more nanostructured morphology with increased active surface area and a 20% reduction in the optical band gap. Electrochemically, the thiourea-doped BiCeO₃ (BCT) electrode delivered a marked improvement, exhibiting a specific capacitance of 150 F·g⁻¹ at 25 mV·s⁻¹, a 17.2% increase over the pure BiCeO₃ (128 F·g⁻¹). Furthermore, BCT demonstrated superior rate capability and a 43% reduction in overall impedance, underscoring enhanced charge transfer kinetics and ionic conductivity. The synergy between sulfur-induced structural defects, increased electroactive surface area, and improved electronic structure establishes thiourea doping as an effective strategy for developing high-performance BiCeO₃-based supercapacitors. Full article

A novel Z-scheme Dy₂TmSbO₇/BiHoO₃ heterostructure photocatalyst was synthesized with the ultrasound-assisted solvothermal method. The Dy₂TmSbO₇/BiHoO₃ heterojunction photocatalyst (DBHP) reflected wonderful separation efficiency of photogenerated electrons and photogenerated holes owing to the efficient direct Z-scheme heterojunction structure characteristic. The lattice parameter and the bandgap energy of the Dy₂TmSbO₇ were 10.52419 Å and 2.58 eV, simultaneously, the lattice parameter and the bandgap energy of the BiHoO₃ were 5.42365 Å and 2.25 eV, additionally, the bandgap energy of the DBHP was 2.32 eV. Above results indicated that DBHP, Dy₂TmSbO₇ or BiHoO₃ possessed an excellent ability for absorbing visible light energy, therefore, DBHP, Dy₂TmSbO₇ or BiHoO₃ owned superior photocatalytic activity for degrading the sulphamethoxypyridazine (SMP) under visible light irradiation. The removal rate of the SMP after visible light irradiation of 135 min with the DBHP was 99.47% for degrading the SMP during the photocatalytic degradation (PADA) process, correspondingly, the removal rate of the total organic carbon (TOC) concentration after visible light irradiation of 135 min with the DBHP was 98.02% for degrading the SMP during the PADA process. The removal rate of the SMP after visible light irradiation of 135 min with the DBHP was 1.15 times, 1.29 times or 2.60 times that with Dy₂TmSbO₇, BiHoO₃ or nitrogen-doped TiO₂ (N-T). Therefore, the DBHP displayed higher photocatalytic activity for degrading the SMP under visible light irradiation compared with Dy₂TmSbO₇, BiHoO₃ or N-T. Specifically, the mineralization rate for removing the TOC concentration during the PADA process of the SMP with the DBHP was 1.18 times, 1.32 times or 2.79 times that with Dy₂TmSbO₇, BiHoO₃ or N-T. In addition, the stability and reusability of the DBHP were systematically evaluated, confirming that the DBHP owned potential applicability for degrading the antibiotic pollutant, which derived from the practical industrial wastewater. Trapping radicals experiments and the electron paramagnetic resonance measurement experiments were conducted for identifying the reactive radicals, such as the hydroxyl radicals (•OH), the superoxide anions (•O₂⁻) and the photogenerated holes (h⁺), which were generated with the DBHP for degrading the SMP during the PADA process under visible light irradiation, as a result, the •O₂⁻ possessed the maximal oxidative capability compared with the •OH or the h⁺. Above results indicated the degradation mechanism and the degradation pathways which were related to the SMP. In conclusion, this study makes a significant contribution for the development of the efficient Z-scheme heterostructure photocatalysts and provides a key opinion to the development of the sustainable remediation method with the view of mitigating the antibiotic pollution. Full article

This study demonstrates the complete transformation of almond shell waste into a high-performance carbon material for carbon paste electrode (CPE) fabrication. The biocarbon was synthesized via carbonization at 800 °C and subsequently activated with CO₂, resulting in a semicrystalline structure rich in carbonyl groups—consistent with its lignocellulosic origin (34.25% cellulose, 13.48% hemicellulose, 48.03% lignin). Carbonization increased the total pore volume of carbonized almond (CAR_ALD) by nearly 13-fold and the specific surface area by over two orders of magnitude compared to raw almond (RAW_ALD), while CO₂ activation further enhanced activated almond’s (ACT_ALD) surface area (~19%) and pore volume (~35%). To improve electrochemical performance, Bi₂O₃ doped with Sm was applied as a surface modifier. Comprehensive characterization (N₂ physisorption X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopic Analysis (FTIR), X-Ray Photoelectron Spectroscopic Analysis (XPS), Thermogravimetric and Differential Thermal Analysis (TG-DTA), Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS)) confirmed the material’s structural integrity, graphitic features, and successful modifier incorporation. Electrochemical testing revealed the highest current response (48 µA) for the CPE fabricated from CAR_ALD/Bi₂O₃-Sm, indicating superior electrocatalytic activity and reduced charge transfer resistance. Notably, this is the first report of a fully functional CPE working electrode fabricated entirely from waste material. Full article

Organic field-effect transistors (OFETs) require reliable micro- and nanoscale patterning of semiconducting layers, yet conjugated polymers have long been considered incompatible with photolithography due to dissolution and chemical damage from photoresist solvents. Here, we present a photolithography-compatible strategy based on doping-induced solubility conversion (DISC), demonstrated using poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT). AuCl₃ doping reversibly modulates the benzoid/quinoid resonance balance, lamellar stacking, and π–π interactions, suppressing solubility during lithographic exposure, while dedoping restores the intrinsic electronic properties. Using this approach, micropatterns with linewidths as small as 2 µm were fabricated in diverse geometries—including line arrays, concentric rings, dot arrays, and curved channels—with high fidelity; quantitative analysis of dot arrays yielded mean absolute errors of 48–66 nm and coefficients of variation of 2.0–3.9%, confirming resolution and reproducibility across large areas. Importantly, OFETs based on patterned PBTTT exhibited charge-carrier mobility, threshold voltage, and on/off ratios comparable to spin-coated devices, despite undergoing multiple photolithography steps, indicating preservation of transport characteristics. Furthermore, the same DISC-assisted lithography was successfully applied to other representative p-type conjugated polymers, including P3HT and PDPP-4T, confirming the universality of the method. This scalable strategy thus combines the precision of established lithography with the functional advantages of organic semiconductors, providing a robust platform for high-density organic electronic integration in flexible circuits, biointerfaces, and active-matrix systems. Full article

The optimization of BiVO₄-based structures significantly contributes to the development of a global system towards clean, renewable, and sustainable energies. Enhanced photocatalytic performance has been reported for numerous doped BiVO₄ materials. Bi³⁺-based compounds can be easily doped with rare earth (RE³⁺) ions due to their equal valence and similar ionic radius. This means that RE³⁺ ions could be regarded as active co-catalysts and dopants to enhance the photocatalytic activity of BiVO₄. In this study, a simple microwave-assisted approach was used for preparing nanostructured Bi_1−xEu_xVO₄ (x = 0, 0.03, 0.06, 0.09, and 0.12) samples. Microwave heating at 170 °C yields a bright yellow powder after 10 min of radiation. The materials are characterized through X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible–near-infrared diffuse reflectance spectroscopy (UV-Vis-NIR DRS), photoluminescence spectroscopy (PL), and micro-Raman techniques. The effects of the different Eu³⁺ ion concentrations incorporated into the BiVO₄ matrix on the formation of the monoclinic scheelite (ms-) or tetragonal zircon-type (tz-) BiVO₄ structure, on the photoluminescent intensity, on the decay dynamics of europium emission, and on photocatalytic efficiency in the degradation of Rhodamine B (RhB) were studied in detail. Additionally, microwave chemistry proved to be beneficial in the synthesis of the tz-BiVO₄ nanostructure and Eu³⁺ ion doping, leading to an enhanced luminescent and photocatalytic performance. Full article

Environmentally friendly materials with superior structural, physical, optical, and shielding capabilities are of great technological importance and are continually being investigated. In this work, novel multicomponent borate glasses with the composition xTiO₂-10BaO-5Al₂O₃-5WO₃-20Bi₂O₃-(60-x) B₂O₃, where 0 ≤ x ≤ 15 mol%, were produced via the melt-quenching technique. The increase in TiO₂ content results in a decrease in molar volume and a corresponding increase in density, indicating the formation of a compact, rigid, and mechanically hard glass network. Elastic constant measurements further confirmed this behavior. FTIR analysis confirms the transformation of BO₃ to BO₄ units, signifying improved network polymerization and structural stability. The prepared glasses exhibit an optical absorption edge in the visible region, demonstrating their strong ultraviolet light blocking capability. Incorporation of TiO₂ leads to an increase in refractive index, optical basicity, and polarizability, and a decrease in the optical band gap and metallization number; all of these suggest enhanced electron density and polarizability of the glass matrix. Radiation shielding properties were evaluated using Phy-X/PSD software. The outcomes illustrate that the Mass Attenuation Coefficient (MAC), Effective Atomic Number (Z_eff), Linear Attenuation Coefficient (LAC) increase, while Mean Free Path (MFP) and Half Value Layer (HVL) decrease with increasing TiO₂ at the expense of B₂O₃, confirming superior gamma-ray attenuation capability. Additionally, both TiO₂-doped and undoped samples show higher fast neutron removal cross sections (FNRCS) compared to several commercial glasses and concrete materials. Overall, the incorporation of TiO₂ significantly enhances the optical performance and radiation-shielding efficiency of the environmentally friendly glass system, making these potential candidates for advanced photonic devices and radiation-shielding applications. Full article

Second harmonic generation measurements for neodymium-doped bismuth–tellurium borate (Bi₃TeBO₉:Nd³⁺) powders are shown for the first time. Using undoped and low-content Nd³⁺-doped samples associated with the strongest nonlinear optical response, studies of temperature-dependent second-harmonic generation near the absorption edge were conducted. Spectroscopic measurements of the investigated powders revealed characteristic Nd³⁺ absorption bands and helped to estimate the corresponding energy band gaps for the chosen samples. The influence of low Nd³⁺-content on the absorption edge shift, as well as on the enhancement of second-harmonic generation and its temperature attenuation, is discussed. Temperature-dependent X-ray diffraction measurements enabled researchers to calculate the thermal expansion coefficients for undoped and Nd³⁺-doped Bi₃TeBO₉ and to assess the impact of this phenomenon on its acentricity. Thermogravimetric studies demonstrated the absence of phase transitions for the chosen samples up to their incongruent melting points. Energy Dispersive X-ray Spectroscopy measurements verified the uniformity of Nd³⁺ distribution in doped Bi₃TeBO₉ powders. The suitability of polycrystalline Bi₃TeBO₉:Nd³⁺ as media for the self-frequency doubling devices for potential optoelectronic and biomedical applications was assessed. The finest fractions of deagglomerated and suspended powders were extracted and demonstrated near-nanostructural morphology of separated particles, as revealed by means of atomic force microscopy. Full article

Doping lead-free halide perovskite nanocrystals with trivalent lanthanide ions has emerged as a promising strategy for engineering their optical properties in various photonic applications. Here, we report the design and synthesis of a series of lead-free double halide perovskite (Cs₂Na(In/Y/Gd)Cl₆) nanocrystals co-doped with a pair of different lanthanides (e.g., Tb³⁺, Dy³⁺, and Eu³⁺) as emission centers, and ns² ions (Sb³⁺ or Bi³⁺) as sensitizers. The tunability of the delayed photoluminescence spectral density was achieved through the selective excitation of lanthanide dopants either via ligand-to-metal charge transfer (e.g., Eu³⁺) or via ns² ion s-p transitions (e.g., Dy³⁺ or Tb³⁺). The intensities of the narrow lanthanide f-f emission bands can, therefore, be tuned by modulating the excitation wavelength and/or dopant ratio, allowing for the accurate engineering of the emission color coordinates and spectral density. We also demonstrated time-resolved tuning of the photoluminescence spectral density for the investigated nanocrystal host lattices co-doped with transition-metal (Mn²⁺) and lanthanide ions, owing to a large difference between the decay dynamics for Mn²⁺ d-d and lanthanide f-f transitions. The rational co-doping of double halide perovskite nanocrystals reported in this work provides a new strategy for generating pre-designed multilevel luminescent signatures for protection against counterfeiting. Full article

Lead halide-based perovskite solar cells have gained significant attention from academia and the photovoltaic industry due to their exceptional optical and electrical characteristics. The primary problem with Pb-based perovskite pertains to its toxicity and solubility in water within the external environment. These concerns regarding hazards to the environment are constraining the application of lead-based perovskite in both consumer and industrial contexts. To offer a viable alternative to lead-based hazardous perovskite solar cells, we examined an inverted (p-i-n) perovskite structure with three distinct absorber layers based on cesium bismuth halides (Cs₃Bi₂I₉, Cs₃Bi₂Cl₉, Cs₃Bi₂Br₉) and conducted a comparative analysis utilizing SCAPS-1D software (version 3.3.08). The comparison analysis of our design against starting parameters indicated that the optimal power conversion efficiency (PCE) of 10.01% was recorded for Cs₃Bi₂I₉, 7.56% for Cs₃Bi₂Br₉, and 4.34% for Cs₃Bi₂Cl₉. Following careful optimization of the thickness of charge-transport layers (CTLs), doping concentrations of CTLs, and all three absorber layers, the overall efficiencies of the three inverted structures were enhanced from 10.01% to 14.08% for Cs₃Bi₂I₉, from 4.34% to 5.28% for Cs3Bi2Cl9, and from 7.56% to 11.05% for Cs₃Bi₂Br₉, respectively. The other performance enhancement, open-circuit voltage, increased from 1.08 V to 1.37 V for Cs₃Bi₂I₉, from 1.26 V to 1.47 V for Cs₃Bi₂Cl₉, and from 1.20 V to 1.47 V for Cs₃Bi₂Br₉. This comparative analysis of proposed perovskite devices demonstrates that Cs₃Bi₂X-based perovskite devices possess significant potential to replace conventional hazardous solar cells in the renewable and clean energy sectors. Full article

DFT calculations have been employed to investigate the impact of Sm dopant(s) on the structure and stability of periodic CeO₂(111) slab and Ce₁₄₀O₂₈₀ nanoparticle systems. We found that substituting Ce ion(s) with Sm ion(s) in the surface layer yields the most favorable doped configurations in both systems. Further, we evaluated how Sm ion(s) modify the reducibility of the systems—a key process in the catalytic applications of ceria. It has been found that a substantial reduction in oxygen vacancy formation energy occurs due to the presence of Sm ion(s), with values of 1.24 and 0.29 eV for mono- and bi-doped CeO₂(111), respectively, which are considerably lower than 2.43 eV obtained for the pristine ceria slab. As the system changes from slab to nanoparticle, mono-doping reduces this energy to 0.25 eV—about four times lower than that calculated for the pristine Ce₁₄₀O₂₈₀ nanoparticle. The presence of a second Sm ion within the nanoparticle leads to a dramatic decrease in E_vac, making the reduction process exothermic. In either slab or nanoparticle models, the Sm³⁺ ions prefer to be in close proximity to each other, and the formation of oxygen vacancies is most energetically favorable in the vicinity of Sm³⁺ ions. Full article

A novel series of Gd₂O₃-doped Pb₃O₄–Sb₂O₃–B₂O₃–Bi₂O₃ glasses was synthesized via the conventional melt-quenching technique to explore their structural, thermal, and optical properties for potential photonic and medical phototherapy applications. X-ray diffraction and SEM analyses confirmed the amorphous and homogeneous nature of the samples, while their FTIR spectra revealed characteristic Pb–O, Sb–O, Bi–O, and B–O vibrational bands indicative of a stable glass network. Differential scanning calorimetry (DSC) demonstrated good thermal stability, suitable for high-temperature optical applications. Optical absorption and emission studies indicated the presence of prominent Gd³⁺ ion transitions, with a strong and sharp ultraviolet emission at 311 nm (⁶P_7/2→⁸S_7/2) when excited at 274 nm. The emission intensity and lifetime increased with Gd₂O₃ concentrations of up to 1.0 mol%, beyond which concentration quenching was observed. The optimized composition exhibited a reduced optical band gap and enhanced NB-UVB emission efficiency, suggesting efficient energy transfer with minimal non-radiative losses. These results establish the designed glass system as a promising multifunctional material for NB-UVB-based phototherapy, UV-laser generation, scintillation, and other next-generation photonic devices. Full article

KY₃F₁₀:Yb³⁺, Tm³⁺ upconversion microparticles (UCMPs) with varying Mn²⁺ doping concentrations were synthesized via a hydrothermal method. Under 980 nm laser excitation, the sample with 3 mol% Mn²⁺ doping demonstrated markedly enhanced luminescence performance, exhibiting a significant intensity increase compared to undoped samples. The as-synthesized UCMPs were successfully incorporated into an anti-counterfeiting ink. Target information was encrypted using a hash function to generate a QR code, which was then screen-printed onto substrate materials. Under 980 nm laser irradiation, the printed QR code exhibited visible blue fluorescence with high stability, confirming its anti-counterfeiting capability. Furthermore, an image recognition system for anti-counterfeiting, based on a hybrid Convolutional Neural Network-Bidirectional Long Short-Term Memory (CNN-BiLSTM) architecture, was developed on the Matlab platform. The system achieved 100% recognition accuracy for the luminescent QR code patterns, providing valuable insights for the development of deep learning-based image anti-counterfeiting technologies. Full article

A-site-ordered quadruple perovskite manganites, AMn₇O₁₂, show many interesting physical phenomena, including orbital and spin modulations, spin-induced multiferroic properties, and competitions between different magnetic ground states. Doping with Cu²⁺ can result in colossal magnetoresistance properties, ferrimagnetism, and additional structural modulations producing electric–dipole helicoidal textures. Many previous works have focused on large-concentration doping, reaching ACu₃Mn₄O₁₂ compositions. Small-concentration doping has been investigated in a limited number of systems, e.g., in BiCu_xMn_7−xO₁₂. In this work, we investigated solid solutions of NdCu_xMn_7−xO₁₂ with x = 0.1, 0.2, and 0.3, prepared at 6 GPa and 1500 K. Specific heat measurements detected three magnetic transitions at x = 0 (at T_N3 = 9 K, T_N2 = 12 K, and T_N1 = 84 K) and two transitions at x = 0.1 (at T_N2 = 10 K and T_N1 = 78 K), while only one transition was found at x = 0.2 (T_N1 = 72 K) and x = 0.3 (T_N1 = 65 K). Differential scanning calorimetry (DSC) measurements showed sharp and strong peaks near T_OO = 664 K at x = 0, corresponding to an orbital-order (OO) structural transition from I2/m to Im-3 symmetry. DSC anomalies were significantly broadened and their intensities were significantly reduced at x = 0.1–0.3, and structural transitions were observed near T_OO = 630 K at x = 0.1, T_OO = 600 K at x = 0.2, and T_OO = 570 K at x = 0.3. The x = 0.1 sample clearly showed double-peak features on the DSC curves near T_OO because of the presence of two close phases. High-resolution synchrotron powder X-ray diffraction studies gave strong evidence that phase separation phenomena took place in the x = 0.1–0.3 samples, where two I2/m phases with an approximate ratio of 1:1 were present (e.g., a = 7.47143 Å, b = 7.36828 Å, c = 7.46210 Å, and β = 90.9929° for one phase and a = 7.46596 Å, b = 7.37257 Å, c = 7.45756 Å, and β = 90.9328° for the second phase at x = 0.3). The Curie–Weiss temperature changed from negative (for x = 0, 0.1, and 0.2) to positive (for x = 0.3). T_OO, T_N1, the Curie–Weiss temperature, and magnetization (at 5 K and 70 kOe) changed almost linearly with x. Full article

In this study, a novel photocatalytic nanomaterial BiTmFeSbO₇ was successfully synthesized for the first time by using the solvothermal method. On account of the effective Z-scheme mechanism, the BiTmFeSbO₇/BiTmO₃ heterojunction photocatalyst (BTBTHP) could effectively separate the photoinduced electrons and the photoinduced holes, concurrently, the high oxidation potential and reduction potential of the BiTmFeSbO₇ and the BiTmO₃ were retained. Additionally, a Z-scheme BTBTHP was synthesized by using an ultrasound-assisted solvothermal approach. As a result, the BTBTHP exhibited excellent photocatalytic performance during the degradation process of the sulfathiazole (STZ). The morphological features, composition distribution, photochemistry properties and photoelectric properties of the prepared samples were investigated by using the comprehensive characterization techniques. Under the condition of visible light irradiation, the BTBTHP demonstrated an excellent removal efficiency of 99.50% for degrading the STZ. Contrastive analysis results indicated that the removal efficiency of the STZ by using the BTBTHP was substantially higher than that by using the BiTmFeSbO₇, the BiTmO₃, and the N-doped TiO₂. The removal rate of the STZ by using the BTBTHP was 1.14 times that by using the BiTmFeSbO₇, 1.28 times that by using the BiTmO₃, and 2.71 times that by using the N-doped TiO₂. Moreover, the stability and the reusability of the BTBTHP were verified through five successive photocatalytic cyclic degradation experiments, indicating that the BTBTHP owned potential for the practical application. The active species which was produced by the BTBTHP were identified as hydroxyl radicals (•OH), superoxide anions (•O₂⁻), and photoinduced holes (h⁺) by capturing radicals experiments and electron paramagnetic resonance testing experiments. Therefore, the degradation mechanism and the pathway of the STZ could be more comprehensively elucidated. In summary, this study lays a solid foundation for the development and further research of high efficient Z-scheme heterojunction photocatalysts and offers novel insights into sustainable remediation strategies for the STZ pollution. Full article