Doping Level Research Articles

Unveiling the Pockels coefficient of ferroelectric nitride ScAlN

Nitride ferroelectrics have recently emerged as promising alternatives to oxide ferroelectrics due to their compatibility with mainstream semiconductor processing. ScAlN, in particular, has exhibited remarkable piezoelectric coupling strength (K2) comparable to that of lithium niobate, making it a valuable choice for RF filters in wireless communications. Recently, ScAlN has sparked interest in its use for nanophotonic devices, chiefly due to its large bandgap facilitating operation in blue wavelengths coupled with promises of enhanced nonlinear optical properties such as a large second-order susceptibility (χ(2)). It is still an open question whether ScAlN can outperform oxide ferroelectrics concerning the Pockels effect—an electro-optic coupling extensively utilized in optical communications devices. In this paper, we present a comprehensive theoretical analysis and experimental demonstration of ScAlN’s Pockels effect. Our findings reveal that the electro-optic coupling of ScAlN, despite being weak at low Sc concentration, may be significantly enhanced and exceed LiNbO3 at high levels of Sc doping, which points the direction of continued research efforts to unlock the full potential of ScAlN.

Germanium surface segregation in highly doped Ge:β-Ga2O3 grown by molecular beam epitaxy observed by synchrotron radiation hard x-ray photoelectron spectroscopy

We present a study of Ge segregation at the surface of highly germanium-doped gallium oxide (2.5 × 1020 cm−3 nominal doping level) grown by molecular beam epitaxy. We probed the dopant concentration as a function of depth by hard x-ray photoelectron spectroscopy and standard laboratory photoemission spectroscopy. We notably found that there is germanium segregation within the top 2 nm where its concentration is 3 times the nominal doping level. This increased dopant concentration leads to a threefold enhancement of surface conductivity. The results suggest a reliable method for delta doping for power electronics applications.

Achieving 34 % efficiency with a dual-absorber solar cell design using CaRbCl3 and Ca3NCl3 perovskites

This study’s DFT calculations show that the direct bandgaps of perovskite CaRbCl3 and Ca3NCl3 are 1.386 eV and 1.430 eV, respectively, confirming their semiconducting nature. The study also provides density of states and dielectric constant data for these materials. In photovoltaic (PV) technology, perovskites are highly valued as solar absorber materials for their exceptional optical properties, low cost, high efficiency, and lightweight design. This study presents a structure (Al/FTO/CdS/dual absorber (CaRbCl3/Ca3NCl3)/V2O5/Au) incorporating a CdS electron transport layer (ETL) and a V2O5 hole transport layer (HTL) with a double perovskite absorber layer (DPAL) of CaRbCl3 and Ca3NCl3 using SCAPS-1D. The results show that the DPAL-based perovskite solar cell (PSC) outperforms single-layer PSCs, with significant efficiency gains when HTL is included. The study thoroughly examines the effects of layer thickness, doping levels, and defect densities on key electrical parameters such as VOC, JSC, FF, and PCE. It also explores J-V and QE characteristics and the impact of temperature. The ideal absorber thickness for achieving the highest PCE is 500 nm for CaRbCl3 and 600 nm for Ca3NCl3, combined with a doping density of 1 × 1017 cm−3, a defect density of 1 × 1011 cm−3 and interface defect density of 1 × 1010 cm−2. While single-absorber solar cells achieve maximum efficiencies of 24.40 % (CaRbCl3) and 24.02 % (Ca3NCl3), the DPAL setup reaches an optimized efficiency of 27.66 %, further increasing to 34.39 % with a VOC of 1.295 V, FF of 83.95 %, and JSC of 31.63 mA/cm2 when using V2O5 HTL. This research provides valuable insights and a practical strategy for developing cost-effective CaRbCl3/Ca3NCl3 thin-film solar cells.

Enhancement of luminescence and thermal stability in Eu3+-doped K3Y(BO2)6 with Li+ and Na+ co-doping

Eu3+-doped and Li+/Na+ co-doped K3Y(BO2)6 (KYBO) phosphors were synthesized through a microwave-assisted sol–gel method, and their structural and photoluminescent (PL) characteristics were examined. X-ray diffraction (XRD) and Rietveld refinement confirm effective dopant incorporation and preservation of the crystalline structure. Fourier Transform Infrared (FTIR) spectroscopy indicates the maintenance of the borate structure, confirming the structural integrity of the phosphors upon doping. The addition of Li+ and Na+ co-dopants notably enhances luminescent efficiency and thermal stability, making these phosphors promising candidates for solid-state lighting (SSL) applications. PL analysis reveals strong red emission peaks at 612 nm, attributed to the 5Do → 7F2 transition of Eu3+ ions. The study indicates that electric dipole-quadrupole interactions are the primary mechanism for energy migration, with a critical distance of approximately 22.68 Å. This mechanism contributes to concentration quenching at higher doping levels. High temperature PL measurements indicated an activation energy of 0.1389 eV for thermal quenching in the Li+ co-doped sample. Additionally, the Na+ co-doped sample exhibited an abnormal thermal stability behavior, with an even higher activation energy of 0.2536 eV. This suggests that Na+ co-doping significantly enhances the thermal resilience of the phosphor, making it more suitable for high-power light-emitting applications that operate under extreme conditions. CIE chromaticity diagrams highlight the potential for optimizing Eu3+ doping levels, combined with Li+ and Na+ co-doping, to improve luminescent performance and thermal stability for advanced SSL applications.

Molecular dynamics simulation of friction in DLC films with different Cr doping levels

This study systematically investigates the impact of varying Cr doping levels on the friction properties of DLC films using molecular dynamics simulations. The results demonstrate that under identical friction velocities and load conditions, the friction force of DLC films significantly decreases when the Cr doping content reaches 16.5 %. High Cr doping levels lead to the formation of Cr atomic clusters at the interface, hindering contact and reducing the number of interface bonds. These clusters act as lubricants, filling the interface gaps and thereby reducing the friction force. Internal stress calculations indicate that Cr doping effectively reduces the average internal stress of DLC films. For DLC films with lower Cr doping levels, the friction force exhibits similar trends under different friction velocities, while films with higher Cr doping levels show a more pronounced response, with friction force increasing at higher velocities. Increasing the load significantly raises the friction force, especially for DLC films with higher Cr doping levels. Furthermore, high Cr doping levels under high loads lead to significant structural damage and adhesive wear. This study provides theoretical and technical references for optimizing the friction performance of DLC films.

Photoluminescence and afterglow of Yb2+ doped CaAl2O4

The photoluminescence (PL) and afterglow properties of Yb2+ doped CaAl2O4 phosphors (0–2.0×104 ppm) are investigated. The 4f14–4f135d1 transitions of Yb2+ dopant are evidenced by a number of sharp lines in the excitation and emission spectra of Yb2+ doped CaAl2O4. As a contrast, the host emission of Yb2+ doped CaAl2O4 is characteristic of a broadband PL spectrum which can be deconvoluted into three overlapped subbands: an ultraviolet subband peaking at 3.30 eV (375.8 nm), a blue subband peaking at 2.81 eV (441.3 nm) and a green subband peaking at 2.35 eV (527.7 nm). The afterglow spectrum of Yb2+ doped CaAl2O4 consists of three discrete subbands: an ultraviolet subband centered at around 3.54 eV (350 nm), a blue subband centered at around 2.82 eV (440 nm) and a green subband centered at about 2.30 eV (540 nm). Depending on their intensities of the afterglow subbands, the perception color of the afterglow of Yb2+ doped CaAl2O4 evolves from blue to green, and the afterglow of Yb2+ doped CaAl2O4 lasts for 86 min at the optimal doping level of 20 ppm. Our results demonstrate that: (i) the ultraviolet and the blue afterglow subband of the phosphor originate from oxygen and cation vacancies in CaAl2O4; (ii) the green afterglow (PL) subband of Yb2+ doped CaAl2O4 originates from Mn2+ impurity in CaAl2O4; and (iii) instead of a luminescence center of afterglow, Yb2+ works as a luminescence center of PL and sensitizes CaAl2O4 by enhancing the ultraviolet light harvesting efficiency of the host.

Silver doping effect on the electrochromic performance of the WO3 thin films produced by thermal evaporation in vacuum

Ag doped WO3 thin films are successfully fabricated by thermal evaporation method in vacuum as precursor, and then annealed at 450 °C in nitrogen gases atmosphere. Cyclic voltammetry, repeating chronoamperometry, chronocolumetry and optical transmittance are recorded in 1 M LiClO4/propylene carbonate electrolyte. The color of the WO3 thin films changes from transparent to the blue under the applied potential of -1.8 and +1.9 V. XRD studies show that all the films have a polycrystalline structure of WO3. The molecular formation is also confirmed by Raman and X-Ray photoelectron spectroscopy (XPS). The EDS elemental mappings clearly confirm the homogeneous distribution of Ag, W and O elements into the WO3 network. From the optical studies, indirect band gap energy of the WO3 decreases as Ag doping level increases. The best coloration and bleaching times (2.33 and 1.25 s) are obtained for the Ag(2%):WO3 thin films, compared to the pure WO3 (3.79 and 1.96 s). The produced WO3 films exhibit high reversibility (39.6/69.1%), high coloration efficiency values (26.3/141.2 cm2/C), and good cycling stability. From the EIS measurements, the charge-transfer resistance is Ag(2%):WO3 < the pure WO3 < Ag(5%):WO3 < Ag(8%):WO3, which means that Ag(2%):WO3 has the biggest electrochemically active surface area. Electronic energy levels of the pure WO3 and the Ag:WO3 thin films are also given. From the Mott-Schottky studies, it is determined that the donor concentration of the materials is of the order of 1014-1015 cm−3. In the literature, there are very limited studies related to electrochromic thin films by thermal evaporation in vacuum. In this sense, the reported results in this study are promising for the electrochromic applications.

13 μm emission InAs/AlSb quantum cascade lasers with high slope efficiency and peak output power enabled by diagonal transition design

Long wavelength InAs/AlSb quantum cascade lasers (QCLs) emitting at 13 μm, based on a diagonal transition scheme design through band structure engineering, have been grown and fabricated. This band structure engineering focuses on enhancing transition efficiency and suppressing carrier leakage. Our 3-mm-long, 25-μm-wide InAs/AlSb QCL has achieved a slope efficiency of 210 mW/A and a maximum peak power of 515 mW, despite encountering a substantial waveguide loss of 27 cm−1 and a relatively high threshold of 4.8 kA/cm2, due to the elevated residual doping level. Our InAs/AlSb QCL devices have demonstrated record-breaking performance in terms of slope efficiency, maximum peak power, and injection efficiency. Cavity length analysis suggests that reducing the residual doping by half could pave the way for achieving continuous wave output power in the realm of hundreds of milliwatts at room temperature for our designed 13 μm QCLs.

Numerical Modelling of Carrier Transport in Organic Field Effect Transistors

Background: Organic field effect transistors (OFETs), used in the fabrication of nanosensors, are one of the most promising devices in organic electronics because of their lightweight, flexibility, and low fabrication cost. However, the optimization of such OFETs is still in an early stage due to the minimal analytical and numerical models presented in the literature. Objective: This research presses to demonstrate a numerical carrier transport model based on the finite element method (FEM) to investigate the I-V characteristic of OFETs. Methods: Two various organic semiconductor materials have been included in the study, polyaniline and pentacene, where micro-scale, as well as nano-scale models have been presented. OFETs regarding channel length, dielectric thickness, and doping level impact have been studied. We nominated the threshold voltage, the on/off current ratio, the sub-threshold swing, and the field effect mobilities as the primary output evaluating parameters. Results: The numerical model has shown the criticality of the doping effect on tuning the device flowing drain current to exceed 300 μA saturation current, along with a threshold voltage of -0.1 V under a channel length of 30 nm. Conclusion: The study highlights the effectiveness of polyaniline over pentacene as nano-channel length OFET due to the boosted conductivity of polyaniline concerning pentacene.

A Comprehensive Modeling on MoS2 Interface and Defect Engineering in CZTS Thin Film Solar Cells

This work uses the SCAPS-1D modeling program to examine the effects of faults in the molybdenum Disulfide (MoS2) layer and the MoS2 interface on the electrical performance of CZTS solar cells. To get an ideal energy gap (Eg) of 1.3 eV and a carrier concentration (CC) of 1014 cm⁻³, the research attempts to optimize the CZTS absorber layer. By maintaining a consistent doping level with 1016 cm-3 ≤ CC and an Eg within 1.6 eV < Eg ≤ 1.8 eV for the MoS2 film, the work also investigates the possibility of increased efficiency in CZTS/MoS2 devices. The study results indicate that open circuit voltage (VOC) and Efficiency (Eta-η) parameters are improved by a p-type MoS2 interface, indicating a promising development for CZTS solar systems. Nonetheless, n-type MoS2 suggests a compromise with a reduction in the fill factor. The study emphasizes the stability benefits of a p-type MoS2 interface as well as the importance of surface recombination velocity. The study also considers phase transitions that occur during the manufacture of devices, highlighting the intrinsic n-type character of MoS2 and the importance of experimental methods in CZTS device optimization. After analyzing the effects of defects on carrier density, depletion width, and quantum efficiency, the study concludes that enhancing the performance of CZTS solar cells requires an acceptor-type interface with p-type MoS2. With recombination resistances of 443.92 Ω cm2, 1530.33 Ω cm2, 81.54 Ω cm2, and 93.82 Ω cm2, the SCAPS model shows zero series resistance at a particular site for the fundamental, optimized design using n-MoS2 and p-MoS2. In the end, the work sheds light on the possibilities for additional experimental studies to advance the technology of CZTS solar cells.

Microwave Absorption and Magnetic Properties of M-Type Hexagonal Ferrite Ba0.95Ca0.05Fe12−xCoxO19 (0 ≤ X ≤ 0.4) at 1–18 GHz

In order to improve the microwave-absorption performance of barium ferrite and broaden its microwave-absorption band, BaFe12O19, Ba0.95Ca0.05Fe12O19, and Ba0.95Ca0.05Fe12−xCoxO19 (x = 0.1, 0.2, 0.3 and 0.4, respectively) hexaferrites were synthesized by the solid-state reaction method, and the influence of Co ion substitution on the phase composition, microstructure, magnetic properties, and microwave-absorption ability of the ferrites in this system was studied. Introducing minor Co ions (x &lt; 0.2) facilitated sintering and grain growth. At x ≥ 0.2, XRD revealed the emergence of the Co2X phase alongside the BaM phase. Increasing Co ion concentration and the secondary X-phase led to slight reductions in saturation magnetization (69 to 63.5 emu/g) and substantial decline in coercivity (2107.02 to 111.21 Oe), attributed to grain size growth and Co2X’s soft magnetic nature. Notably, Co2X incorporation significantly enhanced the microwave absorption and provided a tunable absorption band from the Ku to the C band. For a sample with a thickness of 2.0 mm and a doping level of x = 0.2, a minimum reflection loss of −59.5 dB was achieved at 8.92 GHz, with an effective absorption bandwidth of 3.31 GHz (7.07–10.38 GHz). The simple preparation method and good performance make Ba0.95Ca0.05Fe12−xCoxO19 (x = 0.1, 0.2, 0.3 and 0.4, respectively) hexaferrites promising microwave-absorbing materials.

Optimization of electrochromic Mo doping WO3 films: A study on dual-phase stacked structures for energy-efficient smart windows

Amorphous tungsten trioxide (a-WO3) films were prepared on ITO conductive glass via electrodeposition and subsequently crystallized to obtain crystalline WO3 (c-WO3) films by heating a-WO3. A dual-phase stacked WO3 film was fabricated by covering Mo-a-WO3 film onto c-WO3/ITO substrate using electrodeposition and thermal-assisted electrodeposition methods, respectively. Optimization of electrochromic performance was achieved by varying Mo doping levels (0∼5 atom%). Results demonstrate that appropriate Mo doping (3 atom%) enhances the electrochromic properties of a-WO3 films. Mo doping introduced structural distortions that reduced energy barriers and enhanced ion mobility, leading to improved electrochemical and electrochromic properties. The intermediate c-WO3 layer improves adhesion between a-WO3 top film and ITO glass substrate, while the porous structure of a-WO3 layer increases the number of active sites for electrochromic reactions. Mo3-a-WO3/c-WO3 dual-phase stacked film with doping 3 atom% Mo shows an optical modulation range of 83.4 % at 633 nm, a coloration efficiency of 74.3 cm2/C, rapid response time (bleaching/coloration: 3.4 s/6.1 s), and 86.6 % retention of its maximum current density after 2000 cycles, respectively. The high oxidation ion diffusion coefficient (3.53 × 10−10 cm2/s) and reduction diffusion coefficient (1.55 × 10−10 cm2/s) were also observed. This dual-phase stacked film shows significant improvements in electrochromic performance due to the synergistic effects between the dual phases and Mo-doping. Electrochromic device (ECD) assembled with Mo3-a-WO3/c-WO3 dual-phase films as the working electrode, ITO glass as the counter electrode, and 1 mol/L LiClO4/PC solution as the electrolyte exhibited an optical modulation range of 74.2 % and response time (bleaching/ coloring) of 6.8 s/3.7 s. These findings confirm that ECD with Mo-a-WO3/c-WO3 dual-phase films offer excellent electrochromic performance.

Transmission of an optical wave through a multilayer structure with dispersive chiral layers

Background. The using of mirror asymmetric chemical compounds for doping quartz makes it possible to metamaterial creation that has the chirality property. In such a compositional structure, unusual effects may arise when interacting with an optical wave. Aim. We calculate the transmission and reflection of a linearly polarized optical wave through a multilayer structure consisting of two doped quartz glasses separated by two air gaps. Methods. Based on a homogeneous mathematical model of a chiral metamaterial, taking into account the dispersion of the dielectric constant and the chirality parameter based on the matrix method, a system of linear algebraic equations is obtained for the complex reflection and transmission coefficients of an electromagnetic wave of linear polarization. Results. An analysis of the frequency and angular characteristics of the modules of the reflection and transmission coefficients was carried out at various values of the quartz doping level. It is theoretically predicted that at some wavelengths, most of the incident optical energy can be concentrated in the air gaps of the multilayer structure. Conclusion. The data obtained as a result of calculations can be used in the development of planar structures for frequency-selective concentration of energy in the visible and infrared spectrum based on quartz glasses doped with chiral chemical compounds.

Heavy electron doping in monolayer MoS2 on a freestanding N-face GaN substrate

Abstract This study explores how gallium nitride (GaN) surface polarity affects the optical properties and surface potential of MoS2. Using Raman spectroscopy, photoluminescence, and Kelvin force microscopy (KFM), significant electron doping (~1014 cm-2) was observed in MoS2 on N-face GaN compared to Ga-face. PL spectra and the small contact potential difference of ~30 mV measured by KFM provided evidence for polarity-dependent different doping levels. Additionally, KFM measurements also suggested a small band bending difference between Ga- and N-face GaN, likely due to interactions at the GaN/MoS2 interface. This heavy doping contributes to the improved valley polarization of N-face GaN.

Optical control of multiple resistance levels in graphene for memristic applications

Neuromorphic computing has emphasized the need for memristors with non-volatile, multiple conductance levels. This paper demonstrates the potential of hexagonal boron nitride (hBN)/graphene heterostructures to act as memristors with multiple resistance states that can be optically tuned using visible light. The number of resistance levels in graphene can be controlled by modulating doping levels, achieved by varying the electric field strength or adjusting the duration of optical illumination. Our measurements show that this photodoping of graphene results from the optical excitation of charge carriers from the nitrogen-vacancy levels of hBN to its conduction band, with these carriers then being transferred to graphene by the gate-induced electric field. We develop a qualitative model to describe our observations. Additionally, utilizing our device architecture, we propose a memristive crossbar array for vector-matrix multiplications.

Impedance Spectroscopy of Lanthanum-Doped (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3 Ceramics

This study examines the effects of La3+ doping on (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3(PBZT) ceramics, which were synthesized using the conventional solid-state reaction method. X-ray diffraction analysis confirmed that the PBZT structure, including PBZT doped with La3+ at concentrations x = 1 at.% and x = 2 at.%, exhibited a rhombohedral (R3c) space group, while higher doping levels of x = 3 at.% and x = 4 at.% led to a dominant cubic (Pm-3m) phase with approximately 30% of a remnant rhombohedral component. Scanning electron microscopy (SEM, JEOL JSM-7100F TTL LV, Jeol Ltd., Tokyo, Japan) and energy dispersive X-ray spectroscopy (EDS) were utilized to investigate the structure and morphology of these ceramics. The findings indicated that the chemical composition of the ceramic samples closely corresponded to the initial stoichiometry of the ceramic powder. An increase in the amount of lanthanum results in a decrease in the average grain size of the ceramics. The electrical properties were further evaluated using complex impedance spectroscopy (IS) over a range of temperatures and frequencies, as well as temperature dependence of DC conductivity. The similarity in the changes in activation energy for DC conductivity and grain boundary conductivity, caused by lanthanum ion modification, allows for the conclusion that grain boundaries are the primary microstructural element responsible for conductivity in these materials.

Amorphous Exsolution of Fe3O4 Nanoparticles in SrTiO3: A Path to High Activity and Stability in Photoelectrochemical Water‐Splitting

Exsolution creates metal nanoparticles embedded within perovskite oxide matrices, promoting optimal exposure, even distribution, and robust interactions with the perovskite structure. Fe3O4, an oxidized form of Fe, is an attractive catalyst for photoelectrochemical (PEC) water‐splitting due to its strong light absorption, excellent electrical conductivity, and chemical stability. However, exsolving Fe is challenging, often requiring harsh reduction conditions that can decompose the perovskite. Herein, hybrid composites are fabricated for PEC water‐splitting by reductively annealing a solution of SrTiO3 photoanode and Fe cocatalyst precursors. In situ transmission electron microscopy reveals uniform, high‐density Fe particles exsolving from amorphous SrTiO3 films, followed by film‐crystallization at elevated temperatures. This innovative process extracts entire Fe dopants while maintaining structural stability, even at doping levels exceeding 50%. Upon air exposure, the embedded Fe particles oxidize to Fe3O4, forming a Schottky junction and enhancing light absorption. These conditions yield a high activity of 5.10 mA cm−2 at 1.23 V versus reversible hydrogen electrode (an 11.86‐fold improvement over SrTiO3) from the 30% Fe‐doped SrTiO3, with excellent stability (97% retention) over 24 h. Theoretical calculations indicate that in the amorphous state, FeO bonds weaken while TiO bonds remain strong, promoting selective exsolution. The mechanisms driving amorphous exsolution versus crystal exsolution are elucidated.

Enhancing Superconductor Critical Temperature Prediction: A Novel Machine Learning Approach Integrating Dopant Recognition.

Doping plays a crucial role in determining the critical temperature (Tc) of superconductors, yet accurately predicting its effects remains a significant challenge. Here, we introduce a novel doping descriptor that captures the complex influence of dopants on superconductivity. By integrating the doping descriptor with elemental and physical features within a Mixture of Experts (MoE) model, we achieve a remarkable R2 of 0.962 for Tc prediction, surpassing all published prediction models. Our approach successfully identifies optimal doping levels in the Bi2-xPbxSr2Ca2-yCuyOz system, with predictions closely aligning with experimental results. Leveraging this model, we screen compounds from the Inorganic Crystal Structure Database and employ a generative approach to explore new doped superconductors. This process reveals 40 promising candidates for high Tc superconductivity among existing and hypothetical doped materials. By explicitly accounting for doping effects, our method offers a powerful tool for guiding the experimental discovery of new superconductors, potentially accelerating progress in high-temperature superconductivity research and opening new avenues for material design.

Defect-Enabled Superior Negative Thermal Quenching in Palmierite Ba9La(VO4)7:Eu3+ for WLED In Situ Temperature Measuring.

Negative thermal quenching (NTQ) of the phosphors is critically important for both scientific research and practical applications, but the design of efficient NTQ phosphors is still a challenging task. Herein, we report a new strategy for developing NTQ materials by cation-vacancy engineering. Specifically, a new color-tunable Ba9La1-x(VO4):xEu3+ (BLVO:xEu3+) phosphor with abundant intrinsic cation vacancy was developed, exhibiting superior NTQ behavior under 365 nm excitation. The NTQ performance can be modulated via adjusting Eu3+ doping levels, and the emission intensity of Eu3+ ions in the BLVO:0.20Eu3+ phosphor increased by 275% at 473 K compared to room temperature. Furthermore, the reported material emitting bright white light under 365 nm excitation was well-suited for use in white light-emitting diode (WLED) phosphor and fluorescent temperature sensors, exhibiting outstanding color-rendering index (90.1) in lighting and high sensitivity (Sa = 11.83% K-1, Sr = 2.33% K-1) in temperature detecting. Lastly, the operating temperature of WLED at different currents can be monitored and displayed in real time through emission spectroscopy. All of the results demonstrated that the designed NTQ BLVO:xEu3+ can be used as a single-phase white phosphor and optical thermometry. This work provides a fresh perspective for designing high-efficient NTQ phosphors and expands the application of phosphors in WLED in situ temperature detection.

TiO2 Catalysts Co-Modified with Bi, F, SnO2, and SiO2 for Photocatalytic Degradation of Rhodamine B Under Simulated Sunlight

The organic pollutants discharged from industrial wastewater have caused serious harm to human health. The efficient photocatalytic degradation of organic pollutants under sunlight shows promise for industrial applications and energy utilization. In this study, a modified TiO2 photocatalyst doped with bismuth (Bi) and fluorine (F) and composited with SnO2 and SiO2 was prepared, and its performance for the degradation of Rhodamine B (RhB) under simulated sunlight was evaluated. Through the optimization of the doping levels of Bi and F, as well as the ratio of SnO2 and SiO2 to TiO2, the optimal catalyst reached degradation efficiency of 100% for RhB within 20 min under simulated sunlight, with a first-order reaction rate constant of 0.291 min−1. This value was 15, 41, 6.5, and 3.3 times higher than those of TiO2/SnO2, Bi/TiO2, Bi-TiO2/SnO2, and F/Bi-TiO2/SnO2, respectively. The active species detection showed that h+ was the most crucial active species in the process. The role of Bi and F addition and SnO2-SiO2 compositing was investigated by characterization. Bi formed a chemical bonding with TiO2 by doping into TiO2. The absorbance intensity in the UV and visible light regions was improved by SnO2 and F modification. Composite with SiO2 led to a larger surface area that allowed for more RhB adsorption sites. These beneficial modifications greatly enhanced the photocatalytic activity of the catalyst.