Doped Oxide Research Articles

A comprehensive study on the sandwich stacking structures of antiferroelectric/ferroelectric doped hafnium oxide

In this paper, the combinations of sandwich stacking structures of antiferroelectric/ferroelectric doped hafnium oxide are systematically explored. The sandwich stacking ferroelectric capacitors with the optimal structure (2 nm ferroelectric HZO/4 nm antiferroelectric HZO/2 nm ferroelectric HZO) exhibit high remanent polarization (2Pr = 48 μC/cm2), low coercive field (1.15 MV/cm), and excellent retention ability (8% degraded Pr after 105 s) at a low operating voltage of 1.8 V. The endurance of this structure has also been enhanced to over 1010 cycles, compared with the control group of 8 nm ferroelectric HZO (∼109 cycles). This study provides a promising solution for the application of the embedded FeRAM and advanced silicon technology nodes with low-power consumption.

Spontaneous Donor Defects and Voltage-Assisted Hole Doping in Beta-Gallium Oxides under Multiple Epitaxy Conditions

Spontaneous Donor Defects and Voltage-Assisted Hole Doping in Beta-Gallium Oxides under Multiple Epitaxy Conditions

Machine-learning for discovery of descriptors for gas-sensing: A case study of doped metal oxides

Machine-learning for discovery of descriptors for gas-sensing: A case study of doped metal oxides

Developing innovative PVA@TiO2-based adsorbents for CO2 capture via multiple metal oxide dopants for sustainable development

Developing innovative PVA@TiO2-based adsorbents for CO2 capture via multiple metal oxide dopants for sustainable development

La3+ Doped Nickel-Manganese Oxide as High-Capacity Cathode for Sodium-Ion Batteries Guided by Bayesian Optimization.

In sodium-ion batteries, the layered transition metal oxides used as cathode often experience interlayer sliding of interlayer spacing and lattice variations during charge/discharge, leading to structural damage and capacity degradation. To address this challenge, a La3+ doping strategy guided by Bayesian optimization has been employed to prepare the high-performance O3-NaNi0.39Mn0.50Cu0.06La0.05O2 (NMCL) cathode material. Density functional theory calculations reveal that the O2p orbital overlaps with the t2g orbital of transition metals in NMCL, facilitating the formation of Na-O-La bonds and promoting the oxygen redox reaction kinetics. During the Na+ (de)intercalation process, NMCL exhibits significant negative lattice expansion, characterized by an increase in the c lattice parameter and exceptionally low volume expansion of 1.8 % and 3.1 %, respectively. Consequently, it delivers an excellent specific capacity of 243.3 mAh g-1 over a wide voltage range of 2.0 V to 4.5 V, which can be attributed to La3+ doping that promotes oxidation of O2- to peroxide O2 n- (n<2) during charge.

Investigation on Physical, Structural and Luminescence Properties of Nickel Oxide Doped Lithium Strontium Borate Glasses

Nickel oxide doped lithium strontium borate glasses were prepared by conventional melt-quench method. X-ray diffraction studies confirmed the amorphous nature of the sample. Density increases whereas molar volume decreases with the addition of nickel oxide. Glass bond density, boron-boron separation and oxygen packing density were estimated using standard formulae. Polaron radius, inter ionic distances and field strength exhibit composition dependent trends. Fourier transform infrared spectroscopic studies revealed the presence of short-range structural units such as diborate (B4O7 2–), dipentaborate (B5O17 2–), pyroborate (B2O5 4–) and metaborate units (BO2O–) in the borate glasses. Photoluminescence studies revealed four emission bands centered at 486, 521, 547 and 623 nm. An intense emission peak was observed at 487 nm. Commission internationale de l’éclairageand correlated colour temperature studies suggested that the investigated glasses emit blue light at 1741-1809 K.

Synthesis, characterization, and thermal conductivity properties of graphene oxide doped chromium-titanium oxide structures

This study investigates synthesis and characterization of graphene oxide (GO) undoped and doped chromium-titanium oxide structures, along with their thermal conductivity properties in detail. The importance of low or high thermal conductivity varies depending on the type of material intended, and it is known that thermal conductivity, which determines the ability of materials to conduct heat, plays a crucial role in energy, electronics, and thermoelectric applications. Materials with low thermal conductivity are widely used in various industrial fields due to their ability to isolate heat effectively. For experimental studies, GO-undoped(T1), 1%-GO-doped(T2), and 3%-GO-doped(T3) samples were produced via sol-gel method, followed by calcination, pelletization, and sintering processes. Characterization of these pellets was performed using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform-Infrared Spectroscopy (FTIR). Thermal conductivity was measured using Physical Properties Measurement System (PPMS). No structural or peak changes were detected in the XRD and FTIR results, but differences in peak intensities were observed. SEM images revealed that reductions in structural dimensions occurred with GO doping, and this was explained by changes in thermal conductivity data. The thermal conductivity values of T1, T2, and T3 samples were measured as 6.49, 3.45, and 1.50 W/K·m, respectively. These findings indicate that GO-doping reduces thermal conductivity and differences in the material structure are effective. Additionally, it was observed that the reduction of the structure to the nanoscale also led to a decrease in thermal conductivity data. These materials could play an important role in developing next-generation material designs.

Dielectric relaxation studies of Eu3+ doped graphene oxide nano layers

A bulk of graphene oxide nanosheets was prepared using the modified Hummers’ method. Rare earth materials, such as europium nitrate pentahydrate compounds, are added to graphene oxide in varying percentages to study the dielectric behavior of graphene oxide. The morphological analysis revealed a nanosheet-like pattern in pure graphene oxide, while for europium-doped graphene oxide, a cluster of europium atoms seemed trapped between layers of graphene. The electron diffraction rings are indexed using multiphase analysis, and the hexagonal carbon structure remains unaltered in the doped samples. Electrochemical impedance spectroscopy (EIS) studies were conducted on pure and Europium-doped graphene oxide. The frequency variations with respect to the real and imaginary parts of the dielectric constants are studied for both the composite material and pure graphene oxide. Additionally, photoluminescence (PL) studies were performed. The emission spectrum of Eu3+-doped graphene oxide was used to study the Judd–Ofelt parameters, and the allowed transition probability was determined.Graphical

Seebeck coefficient and thermal properties of graphene oxide doped calcium cobalt copper oxide nanoceramics

In this study, graphene oxide undoped and doped Ca3Co3.8Cu0.2Ox nanoceramic materials were produced using the sol–gel method. After achieving gelation of the mixtures produced via this method, calcination was carried out to remove organic structures. The nanoceramic powders obtained from calcination were compressed as pellets, which were sintered to ensure the fusion of the structures. Graphene oxide undoped and doped pellets were characterized, and the Seebeck coefficient and thermal conductivity as a function of temperature were determined for these samples using a physical properties measurement system device. Upon examining the characterizations, it was generally observed that the crystallite sizes decreased with the addition of graphene oxide, which was consistent with the XRD and SEM results. When the peaks in the FTIR results were compared with the compound bond structures in the XRD results, they were found to be compatible in both samples. Additionally, when the EDX and mapping results were examined, the elements were found to be consistent with the XRD, FTIR and TGA results. TGA analysis demonstrated that graphene oxide doping shifted decomposition temperatures and enhanced combustion efficiency by reducing carbon content. BET results demonstrated that graphene oxide doping significantly increased the surface area and alters the pore structure. In the Seebeck coefficient results, the addition of graphene oxide provided a 1.3-fold advantage at room temperature, and a 10-fold advantage in thermal conductivity was observed with the addition of graphene oxide.

Quantitative Identification of Dopant Occupation in Li-Rich Cathodes.

Elemental doping is widely used to improve the performance of cathode materials in lithium-ion batteries. However, macroscopic/statistical investigation on how doping sites are distributed in the material lattice, despite being a key prerequisite for understanding and manipulating the doping effect, has not been effectively established. Herein, to solve this predicament, a universal strategy is proposed to quantitatively identify the locations of Al and Mg dopants in lithium-rich layered oxides (LLOs). Solid evidence confirms that Al prefers to occupy the transition metal (TM) layer, while Mg evenly occupies both TM and Li layers. As a result, Mg significantly reduces the thickness of LiO2 slabs at room temperature, which will increase the energy barrier of oxygen activation and enhance the structure stability of LLOs. The suppressed oxygen activity in Mg-doped LLO can be kinetically unlocked at 55°C. The different characteristics of Al and Mg enlighten an Al/Mg co-doping strategy to optimize LLOs, which significantly improves the cycle performance while lifting the capacity. These insights from the quantitative identification of doping sites shed light on the manipulation of doping effects toward better cathodes.

Effect of Bi Doping on the Kinetics of Nickel Oxides-Based Electrocatalyst in Alkaline Oxygen Evolution Reaction

As a generation process of hydrogen fuel, an alkaline water electrolysis is considered as one of the most promising pathway. The water electrolysis is able to divide into two half-cell reaction: hydrogen evolution reaction (HER) in cathode and oxygen evolution reaction (OER) in anode. However, high activation energy of OER is regarded as a major bottleneck for utilization of water electrolysis, therefore it is necessary to use an electrocatalyst to improve the reaction rate. Currently, commercially used electrocatalysts of OER is precious metal such as platinum (Pt), ruthenium (Ru), and iridium (Ir) based compound which have critical drawback for high cost and low stability in alkaline electrolyte.As a substitute of platinum group materials for electrocatalyst of oxygen evolution reaction (OER), the development of cost-effective and high-active nickel oxide catalyst has attracted intense research interest. Alkaline OER is composed by five states: M, M-OH, M-O, M-OOH, and M + O2, and the gibbs free energy of final state is 4.92 eV higher than the first state. Thus, the free energy difference between each states equally becomes 1.23 eV to minimize the activation energy of rate determining step (RDS). In this point, nickel oxide shows a remarkable catalytic activity because a rapid and reversible electrochemical oxidation on the surface of nickel oxide triggers reconstructions to form hydroxide which is suitable structures for intermediate of OER. However, the nickel oxide still has high activation energy of reaction step from nickel(II) oxide to nickel(III) oxyhydroxide (3rd step of OER, Ni-O à Ni-OOH), which becomes RDS of OER. Because the catalytic activity seriously reduces without the balanced rate between each step of reaction, it is necessary to control the electric structure of nickel oxide to optimize adsorption energy of intermediates.In this context, bismuth doped nickel oxide is synthesized for electrocatalyst of OER. Because bismuth has higher electronegativity than nickel, the adsorption energy of positively charged nickel with proton decreases and the adsorption energy of positively charged nickel oxide with hydroxide ion increases. Therefore, the activation energy of RDS of OER is expected to reduce than the pristine nickel oxide.In practice, the bismuth doped nickel oxide is synthesized by hydrothermal process and the composition of bismuth is controlled by the concentration of precursors. The crystal structure of nickel oxide is maintained after the addition of bismuth, but the inter-planar spacing of overall plane of nickel oxide structure decreases according to selected area electron diffraction (SAED) pattern of transmission electron microscopy (TEM). In this context, the bismuth additive does not form the bi-metal oxide with nickel, but it substitutes the nickel site of nickel oxide structure. According to the nickel 2p3/2 spectra of x-ray photoelectron spectroscopy (XPS), a binding energy of nickel oxide peak positively shifts when the composition of bismuth additive increased due to the shifted electron from nickel to bismuth atom. As electrochemical measurement for evaluation of catalytic activity, the bismuth doped nickel oxide shows 59 mV lower overpotential at 20 mA cm-2 in alkaline OER, respectively, than the nickel oxide. In particular, the addition of bismuth is especially influenced to intrinsic activity, the bismuth doped nickel oxide catalyst shows higher turnover frequency than the pristine nickel oxide although it has similar active surface area. Figure 1

Understanding and Optimizing Inactive Doping in P2-Type Sodium Layered Oxides for Sodium Ion Batteries

Sodium ion batteries are promising alternatives to complement lithium ion batteries in the modern energy storge market. Among sodium-based cathodes, layered oxides (NaxTMO2, TM = transition metal) are one of the most attractive candidates. P2 and O3 are two of the most studied structures in the NaxTMO2 system. Regarding Na+ conductivity, P2 is believed to be preferable over O3 as it provides open prismatic pathways with a lower energy barrier for Na diffusion.[1] However, a drawback for P2 materials is that they are typically synthesized with low Na content, often close to x = 2/3, and can rarely reach beyond 3/4, which is not ideal when building full cells.[2] The other major issue of P2 is the P2–O2 phase transition taking place at high voltage during electrochemical cycling, which is not well reversible and limits its cycling stability and capacity retention.[3,4] Our work aims to improve the Na inventory by doping inactive elements in pristine cathode materials while maintaining their cycling stability.In this presentation, we would first focus on a family of Li doped P2 materials with nominal compositions of Na5/6LiyNi5/12-3y/2Mn7/12+y/2O2 (y = 2/18, 3/18, 4/18, 5/18). We report on the characterizationsof the crystal structures of these materials, as well as the temperature-resolved in situ XRD during their solid-state synthesis. These studies provide guidance for further synthesis of desired phases and compositions of the P2 materials.Electrochemically, this family of materials show an increasing trend of polarized hysteresis in the first charge and discharge cycle, which suggests the capacity contribution from oxygen redox. We coupled semi-simultaneous operando XRD and x-ray absorption near edge structure (XANES) to understand the structural evolution and redox behavior during this process. In particular, we observed that Li in the TM site mitigates phase transitions at high voltage, with a threshold likely between 0.15 and 0.18 Li per formula unit (f.u.). An increasing Li amount facilitates the activation of the O-redox starting at lower voltages (in attached Figure). To further understand the contribution by TM- and O-redox, we studied the gassing behavior using online electrochemical mass spectrometry (OEMS) to detect the amount and onset of oxygen release depending on the materials composition.We studied rate performance and cycling stability of these materials in half cells against sodium metal reference. The 0.15 and 0.18 f.u. Li stoichiometric compositions prove to deliver the best balance of cycling stability and capacity. We further applied these two compositions against hard carbon in exploration of their possibility in full cells. We also compared the electrochemical characteristics of similar compositions with distinct morphology. Finally, we would share the ongoing progress of other inactive element doping beyond TM layer, e.g., Ca in the alkali layers in the P2 materials.

(Invited) Atomic Layer Deposition of (Semi)Conductive Oxides for Photovoltaics and Mo(o)Re

(Semi)conductive oxides are a peculiar class of materials that combine optical transparency and (tunable) electrical conductivity, and are typically composed of combinations of In, Zn, Sn or Ga. These materials play a profound role in solar cells, but are also more and mo(o)re considered in memory, logic, photonics and sensing. When they are highly (degenerately) doped, these materials can act as transparent conductive window layers (e.g. in solar cells), and are often referred to as Transparent Conductive Oxides (TCOs). Conversely, for lowly-doped (non-degenerate) semiconductive oxides, the Fermi level is susceptible to external influences. The electrical conductivity can then be modulated, for example by gating in a transistor or gas exposure in a sensor. Often amorphous alloys such as InGaZnO are used, and the more common term is hence amorphous oxide semiconductors (AOS).Especially since the early 2000s, many ALD processes for doped and compound (semi)conductive metal oxides have been developed. The interest in ALD for preparing these oxides can most likely be attributed to the distinct merits of ALD, such as low-temperature processing, excellent uniformity and conformality, and accurate control over the doping level and composition. Moreover, as device dimensions shrink the need for high-quality ultrathin materials becomes ever more important. These merits of ALD stem directly from the self-limiting nature of the surface chemistry that drives the ALD growth. On the other hand, the strong role that surface chemistry has in the growth mechanism brings in many intricacies, and detailed understanding of these aspects has been vital for the development of high-quality doped and compound oxides by ALD. Examples of growth effects that can occur during ALD of compound oxides include growth delays, clustering of dopants and interruption of grain growth by doping. Such effects often need to be accounted for or mitigated, while on the other hand there are also clear cases where such growth effects can be leveraged to achieve enhanced or new functionality.Recently, we have reviewed these aspects, focusing on how such underlying ALD mechanisms relate to the resulting performance of the (semi)conductive oxide.[1] In this contribution, we apply these learnings to the application side, specifically looking at silicon and perovskite (tandem) solar cells and back end of line-compatible transistors for nanoelectronics. While these application areas are seemingly distinct, many learnings and parallels can be drawn from an ALD point of view. Topics that will be covered include (1) isotropic doping vs. nanolaminates, (2) advanced ALD (super)cycles, (3) soft deposition, (4) crystallinity control, (5) ultrathin films and more. We will highlight these aspects through case studies, drawing from our own recent work as well as examples from the field.[1] B. Macco, W.M.M. Kessels, Atomic layer deposition of conductive and semiconductive oxides, Appl. Phys. Rev. 9 (2022) 041313. Figure 1

Insights into Crystallography and Electrochemical Performance of Doped Li-Rich Layered Oxides for Lithium-Ion Batteries

The development of new materials is imperative to meet the growing demand for systems delivering higher capacity, energy density, cycle life stability, and safety. Lithium-Rich Layered Oxides (LRLOs) are at the forefront of enabling high-capacity and high energy density positive electrodes for Lithium-Ion Batteries, addressing the challenges of green and safe transportation and sustainable stationary energy storage from renewable sources [1]. LRLOs, with the general formula Li1+xTM1-xO2 (where TM represents a blend of transition metals such as Mn, Co, Ni...), belong to the layered material family but their crystal structure remains elusive [2]. On the other hand, they exhibit excellent reversible performance in aprotic lithium-metal and lithium-ion batteries over numerous charge/discharge cycles. Their higher specific capacity compared to commercial cathodes can be attributed to cumulative cationic and anionic redox processes, wherein anionic redox reactions involve lattice oxygen, balancing lithium extraction with the activation of the O2-/O- redox couple. However, inadequate cycle life stability and capacity retention hinder their commercial adoption, owing to structural rearrangements and phase transitions upon cycling. Moreover, reducing costs and toxicity of raw materials such as cobalt is crucial for large-scale production [3].In this communication, we elucidate the significant influence of extensive defectivity on the description of LRLOs crystal structure. Specifically, we illustrate how the utilization of supercells or defects (antisite defects, stacking faults ...) contribute to a more accurate structural description. Additionally, doping strategies were used to enhance the electrochemical behavior and mitigate the structural rearrangements. Our findings showcase optimized layered materials boasting exceptional electrochemical performance, enhanced environmental compatibility, and reduced manufacturing costs relative to the current state-of-the-art.

Mixed Protonic and Electronic Conduction in N-Type Oxide Semiconductor MgIn2O4 Under Hydrogen Atmosphere

There is an emerging interest in mixed protonic-electronic conductors for use as hydrogen-permeable membranes and electrodes of fuel cell and water electrolyzer working at 300–500℃. Up to now, the research for mixed protonic-electronic conductors has been limited to a common approach: an acceptor cation is doped to a perovskite-type oxide, creating positively charged compensating defects, notably oxygen vacancy, then hydrate these1;H2O(g) + VO •• + OO × → 2OHO •.Since the doped acceptor has an effective negative charge relative to the species they replace, the introduced protons are plausibly trapped surrounding the acceptors (proton trapping). Therefore, to achieve mixed protonic-electronic conductors with high proton conductivity at intermediate temperatures. In n-type oxide semiconductors, such as In2O3, SnO2, and ZnO, hydrogen is a ubiquitous impurity that acts as an electron donor. Hydrogen is incorporated into interstitial sites and forms a shallow donor state2, according toH2(g) → 2H i • + 2e’. Here, we reveal that the interstitial proton introduced via this mechanism conducts through n-type conducting MgIn2O4 3 at intermediate temperatures. We show that hydrogen is incorporated into MgIn2O4 in a hydrogen atmosphere, leading to an increase in the electronic conductivity. To assess the partial proton conductivity of hydrogen-incorporated MgIn2O4, we prepared an electron-blocking cell. A MgIn2O4 thin film was deposited by RF magnetron sputtering on a proton-conducting phosphate glass4. We conducted chronoamperometry and electrochemical impedance spectroscopy for the electron-blocking cell. The proton partial conductivity of MgIn2O4 was determined as 1.1×10−6 Scm−1 at 250℃. In the presentation, the proton mobility of MgIn2O4 will be discussed in comparison with perovskite-type proton conductors, showing that n-type conducting oxides are promising for mixed protonic-electronic conductors. References Kreuer, K.-D. Proton Conductivity: Materials and Applications. Chem. Mater. 8, 610–641 (1996).Kılıç, Ç. & Zunger, A. n-type doping of oxides by hydrogen. Appl. Phys. Lett. 81, 73–75 (2002).Ueda, N. et al. New oxide phase with wide band gap and high electroconductivity, MgIn2O4. Appl. Phys. Lett. 61, 1954–1955 (1992).Ishiyama, T. et al. Transport properties of proton conducting phosphate glass: An electrochemical hydrogen pump enabling the formation of dry hydrogen gas. Int. J. Hydrog. Energy 44, 24977–24984 (2019).

First-Principles Analysis of the Influence of the Valence on the Optical Spectra of Uranium Ions in Oxide Crystals

Recently U6+-doped oxide green phosphors are attracting attentions for the white LED application. However, the absorption and emission mechanisms in some of these materials are still unclear. For the development of the novel uranium-doped phosphors, clarification of the origins of the peaks in the absorption and emission spectra of these materials is indispensable.In our previous research, we investigated the origin of the peaks in the optical spectra of uranium ions in some oxide crystals by comparing the experimental spectra with the theoretical ones obtained by first-principles calculations. The results indicated that there is a U-doped phosphor whose spectrum seems to originate from 5f-6d transitions of U3+ instead of LMCT transitions of U6+. In this work, in order to investigate the influence of the valence of uranium ions, we created some hypothetical model clusters representing uranium ions in oxides and performed first-principles calculations for the LMCT transitions of U6+ and the 5f-6d transitions of U3+ using the relativistic discrete-variational multi-electron (DVME) code which is a configuration-interaction calculation program based on the four-component fully relativistic wave functions obtained by the relativistic discrete-variational Xα (DV-Xα) molecular orbital method. The effects of coordination numbers and bond distances on valence of uranium ions were also investigated in detail by performing calculations using model clusters with coordination numbers from 6 to 12.

Functionalized Graphene via a One-Pot Reaction Enabling Exact Pore Sizes, Modifiable Pore Functionalization, and Precision Doping.

Functionalizing graphene with exact pore size, specific functional groups, and precision doping poses many significant challenges. Current methods lack precision and produce random pore sizes, sites of attachment, and amounts of dopant, leading to compromised structural integrity and affecting graphene's applications. In this work, we report a strategy for the synthesis of functionalized graphitic materials with modifiable nanometer-sized pores via a Pictet-Spengler polymerization reaction. This one-pot, four-step synthesis uses concepts based on covalent organic frameworks (COFs) synthesis to produce crystalline two-dimensional materials that were confirmed by PXRD, TEM measurements, and DFT studies. These new materials are structurally analogous to doped graphene and graphene oxide (GO) but, unlike GO, maintain their semiconductive properties when fully functionalized.

Low Dimensional vanadium pentoxide nanomaterial: Experimental and theoretical characterization on enhancing LED performance

Comprehensive understanding about the novel approach of sysnthesis of hierarchically structured pure and doped vanadium oxides using hydrothermal route. Delocalization electron transition appears the strong absorption band at 361.31 nm in the Photoluminescence (PL) signals. In dual doped samples this absorption increases the optical absorption in visible region (blue-green). Cyclic Voltammetry (CV) results obtained for pure and doped materials shows the expanded anodic and cathodic peaks of pure substance. The quantum chemical calculations analysis gives prominent molecular geometry. The confirmation analysis, Molecular Electrostatic Potential (MEP) reveals that cation doped substance has minimum energy. The biological activities of selected samples are characterized.

Enhancement of Photocatalytic Removal of 4-Chlorophenol from Aqueous Solutions by Manganese Oxide Doped ZnO Nanoparticles Using RSM

Background: Phenol and its derivatives as a toxic and dangerous substance produce by many industries. This pollutant must be removed from contaminated streams or fluids before discharging. The aim of this study was to enhancement of nano-photocatalytic removal of 4-chlorophenol (4- CP) from aqueous solutions applying manganese oxide doped ZnO nanoparticle (MnO₃-doped ZnO) catalyst via experimental designing of surface-response method. Methods: In this study, MnO₃-doped ZnO NPs were fabricated using hydrothermal technique and ratio of Mn-doped ZnO NPs consisted of 0 (pure), 0.5, 1 and 1.5%. The characteristics of the synthesized NPs was studied by scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and atomic force microscopy (AFM) analyses. For determined the doped ZnO quality, variables such as pH, initial 4-CP concentration, NPs dose and contact time were probed in 4-CP removal. Results: Results demonstrate that the removal efficiency are significantly affected by the varied Mn-doped ZnO ratio. The ratio of 1% was optimal. The hexagonal shape of NPs confirmed by XRD and SEM analysis. The SEM indicated that no agglomeration of NPs observed. The sharp edges peaks in XRD indicate a proper crystallized ZnO NPs. Regression analysis showed a quadratic polynomial model was obtained for efficiency prediction. The data providing an acceptable model assumption for analyzing the variance. It was also realized that increasing the nanoparticles dose and the contact time led to reduce the removal rat. Conclusion: Comparing the 4-CP removal efficiency of bare ZnO and Mn-doped ZnO showed that the Mn-doped ZnO have larger efficiency and improve up to 84%.

Low‐Coordination Crystallographic Lattice Engineering to Discover Ce3+‐Activated Ultra‐Wide Visible‐to‐Near‐Infrared Luminescent Materials

AbstractDevelopment of ultra‐broadband visible‐to‐near‐infrared (VIS‐NIR) luminescent materials is a challenging but rewarding endeavor, as they are highly desirable for a number of applications in photonics, optoelectronics, and biological sciences. Nevertheless, to date, rare earth‐doped phosphors that can be efficiently excited by blue light and produce broadband emission in the VIS‐NIR regions remain scarce. In this study, a series of Ce3+‐doped Ba3M4O9 (M = Sc, Lu, Y) broadband luminescent materials are designed based on low‐coordination crystallographic lattice engineering. Among these materials, Ba3Y4O9:Ce3+ produces a continuous ultra‐wide VIS‐NIR emission (λem = 660 nm) in the range of 500–950 nm under 410 nm light excitation. This emission wavelength is the longest among those observed in Ce3⁺‐doped oxide materials. Structural refinement, theoretical calculation, and spectral analysis demonstrate that this VIS‐NIR broadband emission is attributed to the occupying multiple distorted octahedral lattice sites by Ce3+ in Ba3Y4O9. Several strategies are employed to enhance the luminescence intensity and thermal stability of this material, including the use of carbon paper coating, the incorporation of co‐solvents, and the addition of GeO₂ or ZrO₂. Furthermore, the as‐prepared materials demonstrate multifunctional applications in white light‐emitting diodes (WLED), night vision, and fluorescent thermometers. This study offers insights into the design of Ce3+‐doped ultra‐wide VIS‐NIR light‐emitting materials.