Ions In Lattice Research Articles

Electrochemical lithium extraction from hectorite ore

Electrochemical technologies add a unique dimension for ore refinement, representing tunable methods that can integrate with renewable energy sources and existing downstream process flows. However, the development of electrochemical extraction technologies has been impeded by the technological maturity of hydro- and pyro-metallurgy, as well as the electrical insulating properties of many metal oxide ores. The fabrication and use of carbon/insulating material composite electrodes has been a longstanding method to enable electrochemical activation. Here, using real hectorite ore, we employ this technical approach to fabricate hectorite-carbon black composite electrodes (HCCEs) and achieve electrochemical activation of hectorite. Anodic polarization results in lithium-ion release through a multi-step chemical and electrochemical mechanism that results in 50.7 ± 4.4% removal of lithium from HCCE, alongside other alkaline ions. This technical proof-of-concept study underscores that electrochemical activation of ores can facilitate lattice deterioration and ion removal from ores.

The commensurate state and lock-in in a holographic model

We study a holographic model in which the striped structure of charge density is spontaneously formed over an ionic lattice which breaks the translational symmetry explicitly. The effect of commensurate lock-in between the spontaneous stripes and the ionic lattice is observed when the lattice amplitude is large enough. We investigate the optical conductivity as a function of frequency in commensurate state and compare its characteristics during the phase transition from metallic phase to insulating phase. Notably, we find that the DC resistivity in lock-in state increases algebraically with lowering temperature, which is in line with the phenomenon observed in the holographic model for simulating the experimental behavior of Mott insulator in [1]. In addition, at lower temperature the pinning effect is observed for both unlock-in and lock-in states. This holographic model successfully demonstrates the commensurate lock-in signatures, and provides more information for understanding the interplay between ionic lattices and electronic lattices by holography.

A comprehensive role of co-doping (Ce, Al) in dielectric, magnetic, and optical properties of NiO for its efficient use in magneto-optical and spintronics device applications

The crystalline NiO is prepared within the configuration Ni1-xCexAlxO (x = 0.00, 0.05, and 0.1) using a hydrothermal process. XRD and SEM analyses were conducted to examine the crystal structure and morphology of samples which reveals highly crystalline nature and uniform morphology, respectively. UV-spectra confirms the optical band gap lies in the range of 1.63-3.41 eV. The pristine NiO has a band gap of 3.42 eV which lies in the insulating properties range, while the insertion of co-dopant concentration causes to reduction of the band gap up to 1.63 eV which lies in the semiconducting properties range that ensures the higher electronic conduction. The PL spectra show that the luminescence intensity is highly reduced with the insertion of co-dopant ions in the NiO lattice which is the confirmation of higher sensitivity. Raman spectra reveal the formation and purity of the samples due to the non-existence of secondary Raman modes related to the Ce and Al dopants and are well-matched with XRD results. The magnetic measurements reveal the enhancement in remanace magnetization and saturation magnetization with the reduction in coercivity and square ratio showing that the doping of Ce and Al into NiO is influencing its antiferromagnetic nature. NiO may be showing altered magnetic characteristics with the possible contribution from ferrimagnetic or ferromagnetic phases, as the dopant affects the magnetic interactions. Dielectric measurements reveal the increase in capacitance, conductance, energy dissipation, energy storage, and decrease in resistance with the increase in co-dopant concentrations. Based on the obtained results, NiO with 10 % (Ce, Al) co-doping is a suitable candidate for efficient use in magneto-optical and spintronics device applications.

Supramolecular Control of Helicene Circularly Polarized Luminescence Emitters in Molecular Solids and Bright Nanoparticles

AbstractCircularly polarized luminescence (CPL) from chiral molecules is attracting much attention due to its potential use in optical materials. However, formulation of CPL emitters as molecular solids typically deteriorates photophysical properties in the aggregated state leading to quenching and unpredictable changes in CPL behavior impeding materials development. To circumvent these shortcomings, a supramolecular approach can be used to isolate cationic dyes in a lattice of cyanostar‐anion complexes that suppress aggregation‐caused quenching and which we hypothesize can preserve the synthetically‐crafted chiroptical properties. Herein, we verify that supramolecular assembly of small‐molecule ionic isolation lattices (SMILES) allows translation of molecular ECD and CPL properties to solids. A series of cationic helicenes that display increasing chiroptical response is investigated. Crystal structures of three different packing motifs all show spatial isolation of dyes by the anion complexes. We observe the photophysical and chiroptical properties of all helicenes are seamlessly translated to water soluble nanoparticles by the SMILES method. Also, a DMQA helicene is used as FRET acceptor in SMILES nanoparticles of intensely absorbing rhodamine antennae to generate an 18‐fold boost in CPL brightness. These features offer promise for reliably accessing bright materials with programmable CPL properties.

Softening of the optical phonon by reduced interatomic bonding strength without depolarization.

Softening of the transverse optical (TO) phonon, which could trigger ferroelectric phase transition, can usually be achieved by enhancing the long-range Coulomb interaction over the short-range bonding force1, for example, by increasing the Born effective charges2. However, it suffers from depolarization effects3,4 as the induced ferroelectricity is suppressed on size reduction of the host materials towards high-density nanoscale electronics. Here, we present an alternative route to drive the TO phonon softening by showing that the abnormal soft TO phonon in rocksalt-structured ultrawide-bandgap BeO (ref. 5) is mainly induced by a substantial reduction in the short-range bonding interaction due to the Be-O bond stretching caused by an electron cloud-overlap-induced Coulomb repulsion between two adjacent oxygen ions that are arranged octahedrally around an extremely small Be ion. We further demonstrate the emergence of robust ferroelectricity in strain-induced perovskite BaZrO3 and ultrathin HfO2 and ZrO2 films6,7 grown epitaxially on lattice-mismatched SiO2/Si substrate arising from the softening of the TO phonon driven by a reduction in the short-range bonding strength of biaxial strain-induced stretching bonds. These findings shed light on developing a unified theory for ferroelectricity enhancement in ultrathin films free from depolarization fields by tailoring chemical bonds using ionic radius differences, strains, doping and lattice distortions.

Nanostructured spinel ferrites: A comprehensive study on the synthesis, characterization, and magnetic properties of Zn and Mn substituted magnetite nanoparticles produced through the co-precipitation method

Seven cubic spinel ferrite nanoparticles were successfully synthesized through the co-precipitation method. These nanoparticles include Fe3O4, Zn0.4Fe0.62+Fe23+O4, Mn0.4Fe0.62+Fe23+O4, Zn0.6Mn0.4Fe0.42+Fe1.63+O4, Zn0.4Mn0.6Fe0.42+Fe1.63+O4, Zn0.4Mn0.4Fe0.22+Fe23+O4, and Zn0.4Mn0.4Fe0.42+Fe1.83+O4. The Rietveld method was used to analyze X-ray diffraction data, confirming that all samples have a single-phase cubic spinel structure. The presence of zinc and manganese ions in magnetite lattice leads to changes in lattice parameters and crystallite size, resulting in a range of 7–12 nm crystallite sizes. Fourier transform infrared spectroscopy (FT-IR) analysis of nanoparticles reveals two significant adsorption peaks at 560-576 cm−1 and 437-449 cm−1, corresponding to metal ion stretching vibrations at tetrahedral and octahedral sites. The X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of iron, zinc, and manganese in various oxidation states. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images showed spherical, agglomerated nanoparticles. The study confirmed the elemental composition and mapping images of prepared samples using energy-dispersive X-ray spectroscopy (EDS). The magnetic properties of the synthesized nanoparticles were meticulously examined utilizing a vibrating sample magnetometer (VSM) at room temperature. A direct correlation is established between the structural alterations induced by Zn2+/Mn2+ and their subsequent effects on magnetic characteristics, specifically through the reallocation of cations and the mechanisms of electron hopping occurring at the B-sites. The structural modifications result in enhanced superparamagnetic behavior, exhibiting saturation magnetization values between 46.01 and 69.38 emu/g. The sustainable characteristics of these materials render them highly viable options for applications in environmental remediation and green technology.

Effect of incorporated transition metals on the adsorption mechanisms of radioactive cesium in Prussian blue analogs

Extensive efforts were made to remove radioactive cesium (137Cs) from the environment, with Prussian blue analogs (PBAs) emerging as highly selective and efficient materials for 137Cs removal. However, limited studies systematically compared Cs+ adsorption across different transition metals in PBA. This study investigates the influence of the choice of transition metal ion (Co, Cu, Fe, Mn, Ni, Zn) on Cs+ adsorption mechanisms and efficiency. PBAs were synthesized and characterized based on their specific surface area, ion exchange capacity, lattice parameter, and defect sites (as indicated by water molecule content). Cs+ adsorption mechanisms varied significantly with transition metals. In CoFe and FeFe PBAs, ion exchange with K+ dominated, while CuFe and MnFe PBAs, with more defect sites primarily used ion exchange between H+ and Cs+. NiFe and ZnFe exhibited enhanced Cs+ adsorption under light irradiation, likely due to their light-absorbing properties facilitating a reduction reaction. The Langmuir adsorption isotherm was applied to model the adsorption behavior, confirming that each performance of PBA depends on the transition metal used. These findings suggest that PBAs with various transition metals can efficiently remove 137Cs under diverse environmental conditions by using distinct adsorption mechanisms.

Phonon collapse and anharmonic melting of the 3D charge-density wave in kagome metals

The charge-density wave (CDW) mechanism and resulting structure of the AV3Sb5 family of kagome metals has posed a puzzling challenge since their discovery four years ago. In fact, the lack of consensus on the origin and structure of the CDW hinders the understanding of the emerging phenomena. Here, by employing a non-perturbative treatment of anharmonicity from first-principles calculations, we reveal that the charge-density transition in CsV3Sb5 is driven by the large electron-phonon coupling of the material and that the melting of the CDW state is attributed to ionic entropy and lattice anharmonicity. The calculated transition temperature is in very good agreement with experiments, implying that soft mode physics are at the core of the charge-density wave transition. Contrary to the standard assumption associated with a pure kagome lattice, the CDW is essentially three-dimensional as it is triggered by an unstable phonon at the L point. The absence of involvement of phonons at the M point enables us to constrain the resulting symmetries to six possible space groups. The unusually large electron-phonon linewidth of the soft mode explains why inelastic scattering experiments did not observe any softened phonon. We foresee that large anharmonic effects are ubiquitous and could be fundamental to understand the observed phenomena also in other kagome families.

Stability of inorganic ionic structures: the uniformity approach.

The crystal structure uniformity is numerically estimated as the standard deviation of the crystal space quantizer 〈G3〉. This criterion has been applied to explore the uniformity of ionic sublattices in 21465 crystal structures of inorganic ionic compounds. In most cases, at least one kind of sublattice (whole ionic lattice, cationic or anionic sublattice) was found to be highly uniform with a small 〈G3〉 value. Non-uniform structures appeared to be either erroneous or essentially non-ionic. As a result, a set of uniformity criteria is proposed for the estimation of the stability of ionic crystal structures.

Internal Electric Fields and Structural Instabilities in Insulating Transition Metal Compounds: Influence on Optical Properties

AbstractThis work reviews new ideas developed in the last two decades which play a key role for understanding the optical properties of insulating materials containing transition metal (TM) cations. Initially, this review deals with compounds involving d4 and d9 ions where the local structure of the involved MX6 complexes (M=dn cation, X=ligand) is never cubic but distorted, a fact widely ascribed to the Jahn‐Teller (JT) effect. Nevertheless, that assumption is often wrong as the JT coupling requires an orbitally degenerate ground state in the initial geometry a condition not fulfilled even if the lattice is tetragonal. For this reason, the equilibrium geometry of d4 and d9 complexes in low symmetry lattices, is influenced by two factors: (i) The effects, usually ignored, of the internal electric field, ER, due to the rest of lattice ions on the active electrons localized in the MX6 unit. (ii) The existence of structural instabilities driven by vibronic interactions that lead to negative force constants. As first examples of these ideas, we show that the equilibrium structure, electronic ground state of KZnF3:Cu2+, K2ZnF4:Cu2+ and K2CuF4 obey to different causes and only in KZnF3:Cu2+ the JT effect takes place. These ideas also explain the local structure and optical properties of CuF2, CrF2 or KAlCuF6 compounds where the JT effect is symmetry forbidden and those of layered copper chloroperovskites where the orthorhombic instability explains the red shift of one d−d transition under pressure. In a second step, this review explores stable systems involving d3, d5 or d9 cations, where the internal electric field, ER, is responsible for some puzzling phenomena. This is the case of ruby and emerald that surprisingly exhibit a different color despite the Cr3+‐O2− distance is the same. A similar situation holds when comparing the normal (KMgF3) and the inverted (LiBaF3) perovskites doped with Mn2+ having the same Mn2+‐F distance but clearly different optical spectra. The role of ER is particularly remarkable looking for the origin of the color in the historical Egyptian Blue pigment based on CaCuSi4O10.

The manufacture, optical properties, and mechanical aspects of europium-doped borate glasses

An investigation into the optical and mechanical properties of a novel borate glasses with the chemical composition of 70 B2O3-10 Li2O-10ZnO-5Bi2O3-5CaO-xEu2O3 was conducted. The glassy specimens of Eu3+-doped borate were prepared by the melting-quenching technique. An enhanced density from 3.0860 to 3.2176 g cm−3 and reduced molar volume from 29.27819 to 29.17447 (cm3 mol−1) are the outcome of increasing the concentration of Eu3+ in glasses. Plotting the extinction coefficient, dielectric constant (ε1, ε2), and refractive index (n) against wavelength reveals that they all rise as level of Eu3+ elements in the glass lattice increases. An increase in Eu3+ concentration results in a decrease in both the volume (VELF) and surface (SELF) energy loss functions. Also, all elastic-mechanical moduli (such as Young’s, Bulk, Shear, and Elongation) increase with increasing the quantity of Eu3+ ions in the glass lattice. The Young’s modulus (Y, GPa) of the glassy specimens was 34.512, 36.089, 36.504, 36.730 and 37.114 GPa for x equal 0, 0.25, 0.5, 0.75 and 1 mol ratio in the glass system, and coded by Eu-0.0, Eu-0.25, Eu-0.5, Eu-0.75 and Eu-1.0, respectively. Growing Eu2O3 levels resulted in an increase in Micro-Hardness from 2.050 to 2.146 GPa. Poisson’s ratio values for Eu-0.0, Eu-0.250, Eu-0.5, Eu-0.75 and Eu-1.0 were 0.273, 0.275, 0.277, 0.277 and 0.278, respectively.

Oxidative stress-modifying effects of TiO2 nanoparticles with varying content of Ti3+(Ti2+) ions

Nanoparticles (NPs) with reactive oxygen species (ROS)-regulating ability have recently attracted great attention as promising agents for nanomedicine. In the present study, we have analyzed the effects of TiO2defect structure related to the presence of stoichiometric (Ti4+) and non-stoichiometric (Ti3+and Ti2+) titanium ions in the crystal lattice and TiO2NPs aggregation ability on H2O2- and tert-butyl hydroperoxide (tBOOH)-induced ROS production in L929 cells. Synthesized TiO2-A, TiO2-B, and TiO2-C NPs with varying Ti3+(Ti2+) content were characterized by x-ray powder diffraction, transmission electron microscopy, small-angle x-ray scattering, x-ray photoelectron spectroscopy, and optical spectroscopy methods. Given the role of ROS-mediated toxicity for metal oxide NPs, L929 cell viability and changes in the intracellular ROS levels in H2O2- and tBOOH-treated L929 cells incubated with TiO2NPs have been evaluated. Our research shows that both the amount of non-stoichiometric Ti3+and Ti2+ions in the crystal lattice of TiO2NPs and NPs aggregative behavior affect their catalytic activity, in particular, H2O2decomposition and, consequently, the efficiency of aggravating H2O2- and tBOOH-induced oxidative damage to L929 cells. TiO2-A NPs reveal the strongest H2O2decomposition activity aligning with their less pronounced additional effects on H2O2-treated L929 cells due to the highest amount of Ti3+(Ti2+) ions. TiO2-C NPs with smaller amounts of Ti3+ions and a tendency to aggregate in water solutions show lower antioxidant activity and, consequently, some elevation of the level of ROS in H2O2/tBOOH-treated L929 cells. Our findings suggest that synthesized TiO2NPs capable of enhancing ROS generation at concentrations non-toxic for normal cells, which should be further investigated to assess their possible application in nanomedicine as ROS-regulating pharmaceutical agents.

3-Electrode Setup for the Operando Detection of Side Reactions in Li-Ion Batteries: The Quantification of Released Lattice Oxygen and Transition Metal Ions from NCA

Detecting parasitic side reactions is paramount for developing stable cathode active materials (CAMs) for Li-ion batteries. This study presents a method for the quantification of released lattice oxygen and transition metal ions (TMII+ ions). It is based on a 3-electrode cell design employing a Vulcan carbon-based sense electrode (SE) that is held at a controlled voltage against a partially delithiated lithium iron phosphate (LFP) counter electrode (CE). At this SE, reductive currents can be measured while polarizing a CAM working electrode (WE), here a LiNi0.80Co0.15Al0.05O2 (NCA), against the same LFP CE. In voltammetric scans, we show how the SE potential can be selected to specifically detect a given side reaction during CAM charge/discharge, allowing, e.g., to discriminate between lattice oxygen and dissolved TMs. Furthermore, it is shown via online electrochemical mass spectrometry (OEMS) that O2 reduction in the here-used LP47 electrolyte consumes ∼2.3 electrons/O2. Using this value, the lattice oxygen release deduced from the 3-electrode setup upon charging of the NCA WE is in good agreement with OEMS measurements up to NCA potentials >4.65 VLi. At higher potentials, the contributions from the reduction of TMII+ ions can be quantified by comparing the integrated SE current with the O2 evolution from OEMS.

Luminescence performance, temperature sensing characteristics and Judd-Ofelt theory analysis of Y2MoO6:Er3+/Yb3+/Li+ upconversion phosphors

A series of Y2MoO6:0.01Er3+/0.09 Yb3+ upconversion phosphors doped with different concentrations of Li + ions (0.05, 0.10, 0.15, 0.20, 0.25, and 0.30 mol) were prepared by the high temperature solid phase reaction method, and their physical phase structures and upconversion luminescence were analyzed. At the excitation wavelength of 980 nm, the addition of Li+ sharply increased the upconversion luminescence intensity. With the increase of Li+ ion content, the luminescence intensity first increases and then decreases. When the doping amount reaches 0.25 mol, the luminescence intensity reaches the maximum, and the sample emits green light in the two-photon process. Y2MoO6:0.01Er3+/0.09 Yb3+/0.25Li + exhibits excellent temperature sensing properties. Its absolute sensitivity Sa reaches up to 0.012 K-1, the relative sensitivity Sr is 0.017 K-1 and the measurement error δT is less than 0.3 K at room temperature. Its temperature sensing performance is far superior to similar materials. In addition, Judd-Ofelt theory calculations revealed that in comparison with Y2MoO6:0.01Er3+/0.09 Yb3+, its Ω2 increased from 0.56 × 10−20 cm2 to 3.68 × 10−20 cm2, and the spectroscopic quality factor Ω4/Ω6 ratio reached 4.09, which is much higher than that of the other fluorescent materials. The main reason is that Li + replaces the Y3+ ion lattice site, causing lattice distortion and reducing the lattice symmetry around the active ion. The increase in asymmetry increases the possibility of spontaneous radiative transitions. It is shown that the prepared upconversion luminescent materials have potential applications in the field of solid-state lasers and optical sensing.

Mechanism of praseodymium yttrium regulating the absorption properties of M-type strontium ferrite: From single phase to multi phase mixed system

When Pr and Y ions are added to M-type strontium ferrite, a portion of the ions will enter the main phase lattice, while the excess ions will aggregate at the grain boundaries to form a secondary phase. The occupancy of rare earth ions in the main phase lattice and the formation of secondary phases are two key factors affecting the material's absorbing properties. The difference in ultimate solid solubility between rare earth ions Pr and Y in M-type strontium ferrite is significant, and they also form different secondary phases at grain boundaries. Consequently, the synthesized SrFe12-2xPrxYxO19 (0 < x ≤ 1.5) demonstrates its potential as a microwave absorbing material across a wide range of substitutions. Moreover, the performance changes have their own characteristics at different substitution levels. XRD results show that the samples include pure M phase and the coexistence of M phase and heterogeneous phases, with the heterogeneous phases being perovskite-type and garnet-type. SEM and EDS results indicate that Pr and Y co-substitution can refine grain size and reduce oxygen content. XPS results suggest that the valence change of Pr ions leads to the generation of Fe2+ ions and oxygen vacancies (Od). PPMS results reveal that saturation magnetization and coercivity are mainly affected by anisotropy field and particle size. Co-substitution of Pr and Y increases the dielectric and magnetic losses of the M phase, and the generated heterogeneous phases also enhance the dielectric and magnetic losses through interface polarization and magnetic exchange coupling effects, both cooperatively improving the wave-absorbing performance, with the minimum reflection loss (RLmin) reaching −51.57 dB (x = 0.1, d1 = 4.0 mm, EAB = 2.57 GHz).

Regenerated spent LiFePO4 with tailored residual copper-atoms towards improved energy-storage capacity and reversibility

Large-scale recycling spent LiFePO4 (LFP) has aroused the enthusiasm of widespread studies due to its significant economic/environmental values. Restricted by the accuracy of mechanical disassembling, Cu element would be inevitably introduced into the spent samples, resulting in the existence of impurities. Exploring precise thresholds of Cu-impurities was significant in commercial promotion of LiFePO4 regeneration processes. Theory calculation proved that Cu-doping was beneficial to accelerate the diffusion process of Li ions in LFP lattice. Inspired by the theory calculation, a generation process with tailored Cu-impurities content was designed in this work. Supported by the well-designed regeneration process, Cu ions can be rationally doped into the lattice of spent LFP, contributing to the attractive electrochemical properties. Utilized as the cathode of LIBs, the capacity of samples with optimized Cu-impurities content achieved about 130 mAh/g at 2.0C, accompanied by a capacity retention of 100 % among 300 cycles. Importantly, the in-depth mechanism between the reversibility and Cu-impurities threshold is investigated by in-suit XRD, especially the irreversible phase evolution of regenerated samples with excessive Cu-impurities introducing. Given this, this work revealed the in-depth mechanism between Cu-impurities threshold and electrochemical performance, while contribute to the large-scale regeneration of spent LFP.

Influence of Host Lattice Ions on the Dynamics of Transient Multiband Upconversion in Yb-Er Codoped NaLnF4 and LiLnF4 Microcrystals (Ln: Y, Lu, Gd).

Inorganic host matrices provide a tunable luminescence environment for lanthanide ions, allowing for the modulation of upconversion luminescence (UCL) properties. AREF4 (A = alkali metal, RE = rare earth) have a low phonon energy and a high optical damage threshold, making them widely used as the host matrix for UCL materials. However, the impact mechanism of alkali metal ions and lanthanide lattice ions on transient UCL dynamics in AREF4 remains unclear. This study utilized a high-power nanosecond-pulsed laser at 976 nm to excite Yb-Er codoped NaLnF4 and LiLnF4 (Ln: Y, Lu, and Gd) microcrystals (MCs). All samples exhibit multiband emission, and the transient UC dynamics are discussed in detail. Compared with LiLnF4, NaLnF4 has higher UC efficiency and red to green (R/G) ratio. Lanthanide ions (Y, Lu, and Gd) affect the energy transfer (ET) distance in Yb-Er codoped systems, thereby altering UC efficiency and the R/G ratio. The energy level coupling between Gd3+ and Er3+ prolongs the duration of the UC emission. Specifically, the red emission lifetime of NaGdF4 is five times longer than that of NaYF4. Our research contributes to exploring excellent alternative host matrices for NaYF4 in the fields of rapid-response optoelectronic devices, micro-nano lasers, and stimulated emission depletion (STED) microscopy.

Thermoluminescence properties of β-ray irradiated LuAGG:Ce nanophosphors prepared by sol-gel method for potential applications in dosimetry

In this paper, Lu2.97Al5–xGaxO12:Ce0.03 (x = 0, 1, 2, 3) nanophosphors were synthesized using sol-gel method and calcined at 1100 °C for 3 h. The effect of Ga content on the structural, photoluminescence (PL), and notably thermoluminescence (TL) glow curve, dose response, repeatability and fading properties were investigated. X-ray diffraction (XRD) results indicated that all synthesized samples were crystallized in a pure garnet phase. The PL emission spectra exhibited a broad emission band corresponding to the 5 d → 4f (2F5/2, 2F7/2) transition of Ce3+ ions in the garnet lattice. Furthermore, a significant decrease in emission intensity was observed upon increasing Ga content. The TL characteristics of nanopowders irradiated with β-rays revealed a significant effect of Ga content on the peak position, shape and intensities of TL Glow curves, which can be explained by the reduction of the energy gap and the distribution of trap levels. The dose response linearity in the range of 0.125–100 Gy was examined for different Ga content, revealing a good linear behavior for x = 0 and 1 Ga. Additionally, samples prepared with x = 0, 1, and 2 Ga exhibited a high level of repeatability across a batch of 10 samples. Also, fading studies were performed for 128 h and revealed strong fading in samples synthesized with x = 0 and 1 Ga. These results suggest potential applications of Lu3Al5O12:Ce and Lu3Al4Ga1O12:Ce in ionizing radiation dosimetry.

Supramolecular Control of Helicene Circularly Polarized Luminescence Emitters in Molecular Solids and Bright Nanoparticles.

Circularly polarized luminescence (CPL) from chiral molecules is attracting much attention due to its potential use in optical materials. However, formulation of CPL emitters as molecular solids typically deteriorates photophysical properties in the aggregated state leading to quenching and unpredictable changes in CPL behavior impeding materials development. To circumvent these shortcomings, a supramolecular approach can be used to isolate cationic dyes in a lattice of cyanostar-anion complexes that suppress aggregation-caused quenching and which we hypothesize can preserve the synthetically-crafted chiroptical properties. Herein, we verify that supramolecular assembly of small-molecule ionic isolation lattices (SMILES) allows translation of molecular ECD and CPL properties to solids. A series of cationic helicenes that display increasing chiroptical response is investigated. Crystal structures of three different packing motifs all show spatial isolation of dyes by the anion complexes. We observe the photophysical and chiroptical properties of all helicenes are seamlessly translated to water soluble nanoparticles by the SMILES method. Also, a DMQA helicene is used as FRET acceptor in SMILES nanoparticles of intensely absorbing rhodamine antennae to generate an 18-fold boost in CPL brightness. These features offer promise for reliably accessing bright materials with programmable CPL properties.

Comparative Study of Cu Ion Adsorption by Nano-Hydroxyapatite Powder Synthesized from Chemical Reagents and Clam Shell-Derived Calcium Sources.

The increasing contamination of water sources by heavy metals necessitates the development of efficient and sustainable adsorption materials. This study evaluates the potential of nano-hydroxyapatite (HA) powders synthesized from chemical reagents (Chem-HA) and clam shells (Bio-HA) as adsorbents for Cu ions in aqueous solutions. Both powders were synthesized using microwave irradiation at 700 W for 5 min, resulting in nano-sized rod-like particles confirmed as HA by X-ray diffraction (XRD). Bio-HA exhibited higher crystallinity (67.5%) compared to Chem-HA (34.9%), which contributed to Bio-HA's superior adsorption performance. The maximum adsorption capacities were 436.8 mg/g for Bio-HA and 426.7 mg/g for Chem-HA, as determined by the Langmuir isotherm model. Kinetic studies showed that the Cu ion adsorption followed the pseudo-second-order model, with Bio-HA achieving equilibrium faster and displaying a higher rate constant (6.39 × 10⁻4 g/mg·min) than Chem-HA (5.16 × 10⁻4 g/mg·min). Thermodynamic analysis indicated that the adsorption process was spontaneous and endothermic, with Bio-HA requiring less energy (ΔH° = 39.00 kJ/mol) compared to Chem-HA (ΔH° = 43.77 kJ/mol). Additionally, the activation energy for Bio-HA was lower (41.62 kJ/mol) than that for Chem-HA (46.39 kJ/mol), suggesting better energy efficiency. The formation of a new Cu2(OH)PO4 phase after adsorption, as evidenced by XRD, confirmed that the Cu ions replaced the Ca ions in the HA lattice. These findings demonstrate that Bio-HA, derived from natural sources, offers environmental benefits as a recyclable material, enhancing heavy metal removal efficiency while contributing to sustainability by utilizing waste materials and reducing an environmental impact.