Optical Absorption Properties Research Articles

Structural, optical, luminescent and magnetic properties of Gd2O3 nanoparticles: A comparative study on the effect of different green fuels in the sol–gel synthesis tactics

In this study, five samples of Gd2O3 NPs (size range: 4–33 nm) were synthesized by five different green facile and diverse natural products acting as reducing & stabilizing agents such as: fresh juices of sugarcane, lemon, tomato & orange fruits and citric acid via self combustion sol–gel tactics. Powder X-ray diffraction (PXRD), High resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) and Raman analysis affirmed cubic-C type crystal structure of Gd2O3 NPs prepared using citric acid, lemon juice and sugarcane juice. Mixed cubic and monoclinic phases were observed in Gd2O3 NPs prepared using tomato and orange juices. Notably, NPs of Gd2O3 in quantum dot regime (size: 6 ± 2 nm) were produced in the fresh sugarcane juice mediated synthesis protocol. Fresh lemon juice and sugarcane juice were appeared to be the most efficient green fuel for producing quality samples of Gd2O3 NPs. Optical absorption studies showed that bandgap in these Gd2O3 NPs is strongly dependent on the preparation protocol and type of green fuel. Interestingly, highest and lowest band gap of 4.91 eV and 4.43 eV were obtained for Gd2O3 NPs fabricated with orange and lemon juices, respectively. Photoluminescence (PL) and electron spin resonance (ESR) analysis affirmed formation of Schottky and Frenkel surface defects along with self trapped excitons and oxygen vacancies in these Gd2O3 NPs. Paramagnetic character of these Gd2O3 NPs at 300 K is validated by dc-magnetization and ESR studies. Present study demonstrated that microstructural, optical absorption and photoluminescence properties of Gd2O3 NPs can be easily customized by choice of natural products in the synthesis tactics.

Engineering the third-order nonlinear optical absorption properties of two-dimensional layered materials

Engineering the third-order nonlinear optical absorption properties of two-dimensional layered materials

Mo2TiAlC2 as a Saturable Absorber for a Passively Q-Switched Tm:YAlO3 Laser.

Owing to their remarkable characteristics, two-dimensional (2D) layered, MAX phase materials have garnered significant attention in the field of optoelectronics in recent years. Herein, a novel MAX phase ceramic material (Mo2TiAlC2) was prepared into a saturable absorber (SA) by the spin-coating method for passively Q-switching (PQS), and its nonlinear optical absorption properties were characterized with a Tm:YAlO3 (Tm:YAP) nanosecond laser. The structure characteristics and composition analysis revealed that the Mo2TiAlC2 material exhibits a well-defined and stable structure, with a uniform thin film successfully obtained through spin coating. In this study of a PQS laser by employing a Mo2TiAlC2-based SA, an average output power of 292 mW was achieved when the absorbed pump power was approximately 4.59 W, corresponding to a central output wavelength of 1931.2 nm. Meanwhile, a stable pulse with a duration down to 242.9 ns was observed at a repetition frequency of 47.07 kHz, which is the narrowest pulse width recorded among PQS solid-state lasers using MAX phase materials as SAs. Our findings indicate that the Mo2TiAlC2 MAX phase ceramic material is an excellent modulator and has promising potential for ultrafast nonlinear photonic applications.

Copper Versatility in Hydroxyapatite: Valence States, Clusters, and Optical Absorption Properties.

The solid-state reaction between a stoichiometric hydroxyapatite (HA) and CuO at temperatures above 1100 °C produces pure Cux-HA phases for x ≤ 0.7 with the general formula Ca10CuIx(PO4)6(OH)2-xOx. The Cu atoms are located at the center of the hexagonal tunnels between two hydroxyl ligands, as determined by Fourier analysis based on XRD data. During heat treatment, the reduction of Cu2+ ions into Cu+ is concomitant with the stabilization of copper in HA in the hexagonal tunnel. The incorporation of monovalent copper within the apatite, as revealed by XANES spectroscopy, explains the violet color of the samples. The incorporation of Cu+ ions, by substitution of a hydrogen atom by copper(I), results in the formation of linear O-Cu-O chains where the majority of which are isolated for x ≤ 0.3. In addition, the EXAFS investigation showed, thanks to the linear geometry of these clusters that results in multiple diffusion effects, the existence of [CuO]n chains with n ≥ 2, which only appear clearly for higher copper contents x ≥ 0.5. The strong covalency of the Cu-O bond in such a dumbbell configuration would lead to strong hybridization between the 3d and 4s orbitals of copper and the 2p orbitals of oxygen, as illustrated by ESR signals. In the case of Cu-doped HA prepared by coprecipitation and annealed at a lower temperature (T ≤ 600 °C), copper substitutes calcium according to the theoretical formula Ca10-xCux(PO4)6(OH)2, mainly at the Ca(2) site. This local environment is in line with the Jahn-Teller distortion induced by the Cu2+ ion (as evidenced by UV-vis-NIR, XPS, and XANES-EXAFS spectroscopy analyses) and also allows copper-copper interactions from one site to another, as observed by ESR spectroscopy. This versatility of copper in HA gives it optical properties that change from a violet color with near-IR absorption to a blue hue. In all cases, Cu-O-Cu interactions persist whatever the valence state, and heat treatment induces a redox phenomenon, with copper exchanging between two sites close to each other.

Growth and spectroscopy characteristics of Er, Ce:BGSO crystal: A promising material for eye-safe laser applications

Er, Ce co-doped BGSO single crystals were successfully grown by the Bridgman method. The growth parameters, including temperature gradient and growth rate, were optimized to achieve high-quality crystals. The crystal structure and morphology were characterized using X-ray diffraction and scanning electron microscopy. The optical absorption properties of Er, Ce co-doped BGSO single crystals were studied using UV–Vis absorption spectroscopy. The absorption spectrum revealed the absorption edge and the presence of absorption bands related to the presence of Ce dopant, providing valuable insights into the energy transfer processes occurring within the crystal lattice. Furthermore, the luminescence mechanism of BGSO crystals was analyzed using the Judd-Ofelt (J-O) theory, with detailed investigation into the role of ligands in spectral parameters. The photoluminescence spectra and emission decay time of Er, Ce co-doped BGSO single crystals were characterized. A comparative analysis with Er, Ce:BGSO crystals was conducted to investigate the sensitization mechanism of Ce ions on Er emission at 1.5 μm, demonstrating their potential for use as eye-safe laser materials in various applications.

Dye Induced Luminescence Properties of Gold(I) Complexes with near Unity Quantum Efficiency

AbstractTo study the effect of a dye on the photoluminescence (PL) properties of metal complexes, a series of gold(I) complexes were synthesized, containing a 7‐amino‐4‐methylcoumarin luminophore. The complexes are comprised of a coumarin moiety featuring different ancillary ligands, specifically N‐heterocyclic carbenes, triphenylphosphine, and diphenyl‐2‐pyridylphosphine. The synthesized gold(I) complexes are luminescent both in solution and the solid state at room temperature and 77 K. Complexes of different nuclearity, i.e., mono‐, di‐ and trinuclear compounds were synthesized. A clear trend between the nuclearity and the quantum yields can be seen. The coumarin dye not only improves the PL properties, but also enhances the luminescence of trinuclear clusters, which are otherwise known to be weak emitters in solution. The optical absorption properties were investigated in detail by quantum chemical calculations.

Dye induced luminescence properties of gold(I) complexes with near unity quantum efficiency.

To study the effect of a dye on the photoluminescence (PL) properties of metal complexes, a series of gold(I) complexes were synthesized, containing a 7-amino-4-methylcoumarin luminophore. The complexes are comprised of a coumarin moiety featuring different ancillary ligands, specifically N-heterocyclic carbenes, triphenylphosphine, and diphenyl-2-pyridylphosphine. The synthesized gold(I) complexes are luminescent both in solution and the solid state at room temperature and 77 K. Complexes of different nuclearity, i.e., mono-, di- and trinuclear compounds were synthesized. A clear trend between the nuclearity and the quantum yields can be seen. The coumarin dye not only improves the PL properties, but also enhances the luminescence of trinuclear clusters, which are otherwise known to be weak emitters in solution. The optical absorption properties were investigated in detail by quantum chemical calculations.

Bismuth-based nanocomposites as potential materials for indoor air treatment

Air pollution is a worldwide health hazard; thus, improving air quality is a demanding need. Photocatalysis is a robust strategy for air treatment. The boosted activity of the photocatalytic system depends on tuning their properties for the particular application. BiOX (X: Cl, I) compounds are emergent photocatalytic systems with numerous advantages for air treatment. However, their optical properties (Eg) and fast recombination of active species (e−/h+) limit their practical applications. In this study, we remark on the properties of BiOX-GO systems for indoor air purification. We use a microwave-activated solvothermal technique to synthesize the nanomaterials (NMs). BiOX NMs exhibit hierarchical 3D structures, crystallinity, and tunable optical absorption properties. BiOX-GO composites present an enhanced visible-light photocatalytic activity due to the electron acceptor capacity of GO and modification of Eg. The indoor air disinfection capacity of the NMs ranked as follows: BiOCl-GO (96.7%) > BiOI-GO (96.2%) > BiOI (89.2%) > BiOCl (79%). The higher efficiency under visible light of BiOCl-GO can be related to the presence of oxygen vacancies, strong oxidation potential, and single crystalline phase of the materials. Due to the abundance and biocompatibility of bismuth-containing compounds, together with their enhanced visible light activity, BiOX become potent candidates for environmentally sustainable remediation technologies.

Enhanced optical and structural traits of irradiated lead borate glasses via Ce3+ and Dy3+ ions with studying Radiation shielding performance

Lead borate glass is the best radiation shielding glass when lead is in high concentration. However, it has low transparency after radiation exposure. Radiation decreases transparency due to chemical and physical changes in the glass matrix, such as creating or healing defects in the glass network. The addition of rare earth elements like cerium and dysprosium oxides to lead borate glasses can improve their transparency and durability as radiation shielding barriers. The newly manufactured glasses’ optical absorption, structural, and radiation shielding properties were measured. The optical characteristics of the generated samples were examined to determine the effect of the cerium/dysprosium ratio on the structural alterations, specifically in the presence of bridging oxygen (BO) and non-bridging oxygen (NBO). Incorporating Ce3+ results in peaks at 195 nm for borate units, 225 nm for Ce3+, and a broadened peak at 393 nm due to overlapping peaks for Ce3+ and Ce4+ in the UV region. By adding Dy, multiple peaks are observed at 825, 902, 1095, 1275, and 1684 nm, corresponding to the transition from 6H15/2 ground state to 6F5/2, 6F7/2, 6F9/2, 6F11/2, and 6H11/2. The samples were also tested before and after exposure to gamma irradiation from a 60Co source at a dose of 75 kGy to assess their stability against radiation. The energy gap value during irradiation shows decreased non-bridging oxygen. The energy gap difference before and after irradiation for the M4 sample shows higher NBO to BO conversion, reducing radiation damage and improving structural stability. Furthermore, X-ray photoelectron spectroscopy was utilized to get insight into the coordination chemistry of the created glass samples. The half-value layer (HVL), radiation protection efficiency (RPE), neutron removal cross-section (FRNCS), mean free path (MFP), mass attenuation coefficients (MAC), and effective atomic numbers (Zef) of the glassy structure were calculated theoretically to assess its radiation shielding qualities. The linear attenuation coefficient order for the prepared samples was M1 > M2 > M3 > M4. The FRNCS values were 0.090, 0.083, 0.081, and 0.079 cm−1 for samples M1, M2, M3, and M4, respectively.

Structural, optical absorption and electrical characteristics of sol-gel synthesized chromium-doped bismuth ferrites

Multiferroic materials have remarkable and several technical uses such as random-access multi-state memories, solar cell devices, data storage recording technologies, etc. An attempt has been made here to synthesize chromium-doped Bi(Fe1-xCrx)O3 (x = 0–0.10) oxides via citrate based sol-gel route and characterized with regards to structural, optical absorption and electrical properties. It depicts a rhombohedral structure with space group R3c for BiFeO3 and Bi(Fe0.98Cr0.02)O3 compositions. The lattice parameters for BiFeO3 on rhombohedral axes are aR ∼5.796 Å, α ∼59.34° which decreases linearly with chromium (x). Similarly, the parameters on hexagonal axes also decrease as aH ∼5.739–5.730 Å, and cH ∼14.269–14.262 Å. However, chromium doping causes a drop in crystallite size and rise in dislocation density. The absorption spectra show a broad peak at λ = 392 nm (for x = 0) and a broader as well as high intense peak for x = 0.02 (λ∼ 393 nm) which is attributed to charge transfer transitions from O2− (2p) valence band to Fe -3d (eg and t2g split levels) conduction band. Band at λ ∼310 nm is associated to the band gap (Eg) of material. Composition Bi(Fe0.98Cr0.02)O3 (x = 0.02) exhibits the highest values of the dielectric constant (εr ∼ 1102), loss (tan δ ∼ 1.1), and least value of impedance. The Cole-Cole plot depicts a depressed semi-circle and indicates presence of loss due to grains only. The room temperature P–E hysteresis loop with remanent polarization (Pr = 0.11439 μC/cm2) and leakage current density (J = 1.1 μA/cm2) are found maximum for Bi(Fe0.98Cr0.02)O3 (x = 0.02). The I-E loop and frequency-dependent P-E loops depict ferroelectric nature of all compositions. The analysis of leakage current density and slope values infer the presence of space charge limited conduction (SCLC) mechanism. These findings suggest materials applications in recent technologies.

Anchoring TiO2 and CuO nanoparticles on SnO2 nanotube arrays to construct ternary heterostructure for visible-light-driven photocatalytic degradation of green malachite dye

Designing and constructing heterostructure photocatalysts is necessary to facilitate the long-term separation of photogenerated charge carriers and enhance photocatalytic efficiency. Herein, a ternary nanocomposite photocatalyst based on SnO2, TiO2 and CuO semiconductors was successfully synthesized and employed as a highly effective photocatalyst for the malachite green (MG) dye degradation under visible light irradiation. According to the results, the ternary SnO2/TiO2/CuO nanocomposite demonstrated impressive photocatalytic activity (98.4 %) compared to pristine SnO2 nanotubes (40.3 %), binary SnO2/TiO2 (76 %) and SnO2/CuO nanocomposites (88 %), when exposed to 90 min of visible illumination. The photoreaction rate constant of SnO2/TiO2/CuO nanocomposite (0.0482 min−1) was found to be ∼8.5 times faster than SnO2 nanotubes (0.0057 min−1) against MG dye. This enhancement in photocatalytic performance can be attributed to the introduction of TiO2 and CuO which effectively suppress the recombination of photogenerated electron-hole pairs, accelerate the transfer of charge carriers, increase the active sites, and improve the optical absorption properties. Scavengers were used to elucidate the photocatalytic mechanism, exhibiting the pivotal role of •O2− and h+ in the photodegradation process. Besides, recyclability tests showed acceptable results after four cycles, confirming the stability and durability of the SnO2/TiO2/CuO nanocomposite against RhB dye degradation.

Effect of replacing B2O3 with CuO on the structural, optical absorption, thermal, mechanical, and gamma-ray shielding properties of B2O3–Bi2O3–K2O glass

This paper delves into the effect of replacing B2O3 with CuO on the structural, optical absorption, thermal, mechanical, and gamma(γ)-ray shielding properties of four CKB glasses formulated as (65-y)B2O3–15Bi2O3–20K2O-yCuO (where y = 0, 0.3, 0.6, and 1.2 mol%). The glasses were created using the melt-quenching technique, and their non-crystalline structure was verified by X-ray diffraction (XRD) analysis. Fourier-transform infrared (FTIR) spectroscopy identified several structural groups, predominantly consisting of BO3, BO4 units, and B–O–B linkages. Thermal properties, assessed via Differential Scanning Calorimetry (DSC), indicated that the glass transition temperature was highest for the 0.3 mol% CuO sample (CKB0.3), demonstrating enhanced thermal stability in comparison to other compositions. Density measurements correlated positively with CuO concentration, peaking at 1.2 mol%, while molar volume, boron molar volume, oxygen packing density, and boron-boron separation distances showed a decreasing trend with increased CuO concentration. UV–Vis absorption spectroscopy indicated a decline in the optical energy gap and an increase in Urbach energy, attributed to the conversion of BO3 into BO4 units in the glass matrix. Mechanical properties, evaluated using the Makishima-Mackenzie model, demonstrated enhancements in elastic moduli and micro-hardness with rising CuO concentration. The γ-ray shielding properties (γ-RPs) were examined at energies of 0.662, 1.173, and 1.333 MeV, revealing that both the linear attenuation coefficient and effective atomic number reached their maximum values at 1.2 mol% CuO (CKB1.2). While CKB1.2 exhibited excellent mechanical and γ-ray shielding performance, CKB0.3 excelled in thermal stability and demonstrated γ-ray shielding efficiency comparable to CKB1.2. This suggests that CKB0.3 is a promising candidate for radiation shielding applications requiring a balanced combination of thermal stability and effective γ-ray attenuation properties, particularly at 0.662 MeV.

Spectroscopic Properties of TmF3-Doped CaF2 Crystals.

In this study, we report the growth and comprehensive spectroscopic analysis of TmF3-doped CaF2 crystals, grown using the vertical Bridgman method. The optical absorption and photoluminescence properties of both trivalent (Tm3+) and divalent (Tm2+) thulium ions were investigated. Optical absorption spectra in the UV-VIS-NIR range reveal characteristic transitions of Tm3+ ions, as well as weaker absorption bands corresponding to Tm2+ ions. The Judd-Ofelt (JO) formalism was applied to determine the intensity parameters Ω2, Ω4, and Ω6, which were used to calculate radiative transition probabilities, branching ratios, and radiative lifetimes for the Tm3+ ions. The emission spectra showed concentration-dependent quenching effects, with significant emissions observed for the concentration of 0.1 mol% TmF3 under excitation at 260 nm and 353 nm for Tm3+ ions and at 305 nm for Tm2+ ions. A new UV emission associated with divalent Thulium is reported. The results indicate that higher TmF3 concentrations lead to increased non-radiative energy transfer, which reduces luminescence efficiency. These findings contribute to the understanding of the optical behavior of Tm-doped fluoride crystals, with implications for their application in laser technologies and radiation dosimetry.

Synthesis, optical absorption, luminescence, chromaticity, and catalytic properties of undoped CuO and Gd-doped CuO nanostructures for LED devices and waste water treatment applications

The first objective of this present investigation is the co-precipitation synthesized of undoped and various concentrations of Gd-doping in the CuO material as a photocatalyst and methylene blue dye under passing solar light radiation, followed by obtaining their photocatalytic degradation efficiency of 88–96%. Using photoluminescence (PL) data of synthesized undoped and 1%, 3%, and 5 wt% Gd-doped CuO to make a chromaticity diagram for identifying the colour coordinates to scrutinize the applications of light-emitting devices. To trace the diffraction peaks, related crystal system, and vibrational bond of undoped and Gd-doped CuO materials by XRD and FT-IR studies. The morphological structure has been varied in each Gd-dopant concentration when compared to undoped CuO nanostructures through SEM studies. The aforementioned material has a narrow band gap and strong visible emission, as identified by UV–visible and PL spectra.

Synthesis of multifunctional NiFe2O4-Zns-Ag nanocomposite for sunlight driven photocatalytic dye degradation and solar cells applications: Structural, magnetic and optical properties

This article focuses on the fabrication and investigation of the novel multifunctional NiFe2O4-Zns-Ag core-bi-shell nanocomposite and their magnetic optical properties. The nanocomposite was prepared by a simple co-precipitation method and characterized using various techniques such as XRD, SEM, TEM, UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and VSM. The results showed that the nanocomposite had a spinel cubic structure with an average crystallite size of 29 nm. The SEM and TEM images revealed that the nanocomposite had a spherical shape with an average particle size of 61 nm. The optical study demonstrated that the nanocomposite had high absorption in the visible region, indicating its potential for photocatalytic applications. The magnetic study showed that the nanocomposite was superparamagnetic in nature, which could be useful in magnetic separation processes. Furthermore, the potential application of the nanocomposite in solar cells was explored by studying its optical absorption properties. Finally, the photocatalytic activity of the nanocomposite was evaluated using two different azoic dyes under sunlight irradiation. The results showed that the nanocomposite exhibited excellent photocatalytic activity, with a degradation efficiency of 96.22 % within 90 min. Overall, this study provides insights into the potential use of NiFe2O4-Zns-Ag nanocomposite as an efficient photocatalyst for environmental remediation.

Prediction of a novel two-dimensional superatomic Cd6S2 monolayer for photocatalytic water splitting.

Two-dimensional transition metal dichalcogenides possess a significant specific surface area, adjustable bandgaps, and excellent optical absorption properties, rendering them highly conducive to photocatalytic applications. Herein, a MoS2-like 2D superatomic Cd6S2 monolayer is predicted, wherein the octahedral Cd6 superatom unit connects with S atoms via six vertices. Chemical bonding analysis reveals that the remarkable dynamic, thermal, and mechanical stability of the Cd6S2 monolayer results from the covalent Cd-S bonds and the 6-center 8-electron (6c-8e) delocalized bond within the Cd6 core, which ensures the chemical octet rule for both the S atom and the Cd6 superatom. Demonstrating notable optical absorption coefficients and a strain-tuned energy band structure, the Cd6S2 monolayer emerges as a viable candidate for catalyzing the solar-powered splitting of water. This work offers an alternative avenue to modify or improve the properties of 2D materials for photocatalytic applications through superatomic assembly.

Effect of low concentrations of WO3 on synthesis, structural, physical, optical, neutron attenuation, and charged particle absorption properties of B2O3+Na2O+BaO glassy composites

This study presents the physical, optical, and radiation shielding attributes of 75B2O3+5Na2O+(20-x)BaO + xWO3 glasses, with the aim of producing effective transparent and light shields. The well-known melting-and-quenching technique was used to prepare the transparent glasses for x = 0; 03; 10 mol%). The glasses were characterized by determining their density, molar volume, optical transmittance, bandgap, refractive index, dielectric constant, reflection loss, molar refraction charged radiation stopping powers, projected range, fast neutron removal cross section and thermal neutron total cross-section. All the estimated parameters showed variations with glass stoichiometry. The addition of WO3 triggered the BO4 → BO3 unit transformation which prompted the variations in the physical and optical parameters of the glasses. The optical transparency in the visible region and density of the glasses decreased with WO3 concentration while the molar volume increased. For electrons, the stopping powers were in the range, 1.436–11.76 cm2/g, 1.433–11.66 cm2/g, and 1.426–11.44 cm2/g, for BNB-W00, BNB-W03, and BNB-W10, respectively. For protons, alpha particles, and carbon ions, the mass stopping powers increased with WO3 content. Based on projected range data, particles with greater energy per nucleon penetrated the glasses deeper and the WO3- rich glasses had higher transmissivity for charged radiation. Compared to some existing neutron moderators, the investigated glasses displayed higher fast neutron cross-sections. The studied glasses can function well as barriers to moderate fast neutrons, attenuate thermal neutrons, and absorbed charged radiation.

Fabrication, surface characterization and optical behavior of flexible PVA/Nd2O3 polymer nanocomposites materials for optoelectronics applications

The nanocomposite PVA/Nd2O3 with novel properties, that composed of Neodymium (III) oxide (Nd2O3) and polyvinyl alcohol (PVA), was synthesized by the casting preparation method for applied as flexible films for optoelectronic. The techniques of the FTIR, XRD, SEM and EDX showed that the PVA/Nd2O3 were successfully synthesized. The successful inclusion of Nd2O3 into PVA is indicated by a reduction in PVA/Nd2O3 peak intensities as observed by the FTIR and XRD. Additionally, the UV/Vis technique was used to record the optical behavior at wavelengths between 200 and 1100 nm. The measurements of carbon clusters, band gap, absorption edge, and band tail were determined. The band gap decreases from 5.01 eV to 4.60 eV and the band tail changes from 1.8 eV to 2.85 eV when the Nd2O3 is raised from 5 % to 20 %. In addition, the absorption edge reduced from 5.06 eV for PVA to 4.92, 4.81, 4.72, and 4.49 eV, accordingly, when 5 %, 10 %, 15 %, and 20 % of Nd2O3 are introduced in the composite. The result showed the composites made with PVA and Nd2O3 have excellent optical characteristics, especially in the UV–visible spectrum, where they are highly reflective and absorbent. The study emphasizes the fabricated composites enhanced optical transparency and absorption properties, which make it a good materials for uses in photonic devices, sensors, and optical instruments.

Transparent MXene Microelectrode Arrays for Multimodal Mapping of Neural Dynamics.

Transparent microelectrode arrays have proven useful in neural sensing, offering a clear interface for monitoring brain activity without compromising high spatial and temporal resolution. The current landscape of transparent electrode technology faces challenges in developing durable, highly transparent electrodes while maintaining low interface impedance and prioritizing scalable processing and fabrication methods. To address these limitations, we introduce artifact-resistant transparent MXene microelectrode arrays optimized for high spatiotemporal resolution recording of neural activity. With 60% transmittance at 550 nm, these arrays enable simultaneous imaging and electrophysiology for multimodal neural mapping. Electrochemical characterization shows low impedance of 563 ± 99 kΩ at 1 kHz and a charge storage capacity of 58 mC cm⁻² without chemical doping. In vivo experiments in rodent models demonstrate the transparent arrays' functionality and performance. In a rodent model of chemically-induced epileptiform activity, we tracked ictal wavefronts via calcium imaging while simultaneously recording seizure onset. In the rat barrel cortex, we recorded multi-unit activity across cortical depths, showing the feasibility of recording high-frequency electrophysiological activity. The transparency and optical absorption properties of Ti₃C₂Tx MXene microelectrodes enable high-quality recordings and simultaneous light-based stimulation and imaging without contamination from light-induced artifacts.

(Invited) In-Situ Observation of Silicon Solution Growth: Observation Principle and Effect of Al Addition to Si-Cr Solvent

The in-situ interface observation of silicon carbide (SiC) solution growth effectively elucidates various phenomena occurring at the growth front. To investigate this observation technique from the perspective of the optical transmission properties of SiC, the optical absorption properties of 3C-, 4H-, and 6H-SiC were measured over a wide range of temperatures. The obtained absorption properties indicate the optical conditions necessary for in-situ observation and the possibility of identifying different polytype inclusions. Furthermore, the effect of Al addition to the Si-Cr solvent on the SiC growth interface, where Al addition is known to be effective for growing high-quality SiC, was investigated by in situ observations. It was clarified that the presence of Al suppressed the formation of step pinning, resulting in preventing the formation of bunching steps and subsequent roughening of the growth interface.