Beta irradiation-induced thermoluminescence: Glow curve analysis and kinetic parameters in combustion-synthesized undoped Ca4YO(BO3)3

This study examines the thermoluminescent (TL) properties of undoped Ca4YO(BO3)3 phosphor, focusing on how it behaves under a variety of experimental conditions. The IRSL-TL 565 nm was chosen as the appropriate detection filter among various optical detection filter combinations. During the preheating trials conducted at a rate of 2 °C/s, the TL peak exhibited increased intensity, particularly around 200 °C. The experimental outcomes demonstrated a reliable linear relationship (R2 = 0.996 and b = 1.015) in the dose response of undoped preheated Ca4YO(BO3)3 within the range of 1-200 Gy. The investigation encompasses a range of techniques, including the TM-Tstop method, computerized glow curve deconvolution (CGCD) analysis, and theoretical modelling. The application of the TM-Tstop method to samples irradiated with a 5 Gy dose revealed distinct zones on the TM versus Tstop diagram, signifying the presence of at least two discernible components within the TL glow curve, specifically, a single general order kinetics peak and a continuous distribution. The analysis of activation energy versus preheated temperature exhibited a stepwise curve, indicating five trap levels with depths ranging between 1.13 eV and 1.40 eV. The CGCD method also revealed the superposition of at least five distinct TL glow peaks. It was observed that their activation energies were consistent with the Tm-Tstop experiment. Furthermore, the low Figure of Merit (FOM) value of 1.18% indicates high reliability in the goodness-of-fit measure. These findings affirm the reliability and effectiveness of the employed methods in characterizing the TL properties of the Ca4YO(BO3)3 phosphor under investigation. Theoretical models, including the semi-localized transition model, were introduced to explain anomalous observations in TL glow peak intensities and heating rate patterns. While providing a conceptual framework, these models may require adjustments to accurately capture the specific characteristics uncovered through CGCD analysis. As a potential application, the study suggests that the characterized TL properties of Ca4YO(BO3)3 phosphor could be utilized in dosimetric applications, such as radiation dose measurements, owing to its reliable linear response within a broad dose range.

Temperature-responsive insights: Investigating Eu3+ and Dy3+ activated yttrium calcium oxyborate phosphors for structure and luminescence

An investigation into the luminescent behavior of YCOB (Yttrium Calcium Oxyborate) doped with Eu3+ and Dy3+ ions, synthesized via the combustion method, is presented. The study, employing X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS) analyses, confirms the structural integrity and purity of the synthesized nanophosphors. An XRD pattern exhibiting distinct crystalline peaks indicates that the dopant ions were successfully integrated into the YCOB lattice. The photoluminescence (PL) response of YCOB with Eu3+ and Dy3+ ions is thoroughly examined, uncovering distinct excitation and emission spectra. In the case of Eu3+ doping, excitation spectra reveal a significant charge transfer (CT) band at 254 nm, indicative of electron transfer between oxygen and europium ions. This CT transition enhances our understanding of the excitation behavior, with the dominant and Laporte-forbidden 5D0 → 7F2 transition. Characteristic peaks at 345 nm in the excitation spectra efficiently stimulate YCOB:Dy3+ when Dy3+ is used as a dopant. The primary emission peak at 585 nm corresponds to the hypersensitive electric dipole transition 4F9/2-6H13/2. Concentration quenching phenomena are observed, with a maximum Eu3+ concentration of 7 wt % attributed to the dipole-quadrupole interaction. Dy3+ doping, with a maximum concentration of 2 wt % primarily shows multipolar interactions, especially dipole-dipole interactions. The study extends to CIE chromaticity analysis, emphasizing Eu3+ doping's suitability for white light-emitting diode (WLED) applications and ensuring color stability. Conversely, varying Dy3+ concentrations do not yield consistent chromaticity coordinates. These findings have significant implications for the development of advanced phosphor materials across diverse applications, offering a roadmap for optimizing their optical performance.

Europium-doped strontium gadolinium oxide phosphor: Investigating structural and photoluminescence characteristics via sol-gel combustion synthesis

SrGd2O4 phosphors doped with Eu3+ were successfully synthesized through a sol-gel combustion method, covering a range of dopant concentrations from 0.25 mol% to 3 mol%. The structural analysis of these phosphor materials was comprehensively conducted utilizing various techniques, including X-ray powder diffraction analysis (XRD), Energy Dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR). In addition to unveiling the structural characteristics, these analyses provide valuable insights into the compositional aspects, enhancing our understanding of the synthesized SrGd2O4:Eu3+ phosphors across different doping levels. XRD analysis findings validate the successful generation of the intended SrGd2O4 host, demonstrating orthorhombic system structures consistent with JPCD card number 98-019-3592. FTIR analyses conducted on the phosphor samples not only identify bending modes but also reveal intricate details about small vibration bonds within the material. When excited by the 349 nm laser, SrGd2O4:xEu3+ phosphors exhibit distinct photoluminescence (PL) properties like red emission at 614 nm from Eu3+. From the emission spectra, one can clearly observe that Eu3+ with an ionic radius close to the Gd3+ ion preferentially occupies the symmetry sites of the host lattice. The optimal doping concentration was determined to be 0.5 mol%, as revealed by the data in our study. Additionally, a deeper understanding of the luminescence quenching mechanism was attained, pinpointing the involvement of dipole-dipole (d-d) energy transfer in this intriguing phenomenon. This optimal concentration not only enhances the material's properties but also underscores the pivotal role of d-d interactions in governing the luminescence behavior within the doped system.

Novel Sm3+ doped YCa4O(BO3)3 phosphors: Structural and, low and room temperature luminescent insights

Inorganic phosphors, known for their ability to capture energy from various sources and emit visible light, have become essential in the development of advanced lighting and display technologies. This study explores YCa4O(BO3)3 (YCOB) as a potential host material for phosphors, focusing on the luminescent properties of YCOB phosphors doped with Sm3+ ions. The successful integration of Sm3+ ions into the YCOB host lattice is confirmed through structural characterization using X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS). Photoluminescence (PL) studies reveal distinct emission spectra with Stark energy level splitting, indicating a cooperative effect between Y3+ and Sm3+ ions. Concentration quenching, mainly attributed to dipole-dipole (d-q) interactions, is observed at higher Sm3+ concentrations. Temperature-dependent PL measurements demonstrate thermal quenching at lower temperatures and increased emission intensity with higher laser power. Thermal quenching is explained by reduced lattice vibrations and electron-phonon interactions, leading to decreased radiative recombination of charge carriers. The CIE chromaticity data position the samples in the orange-red region, emitting vibrant orange-red light. This comprehensive investigation provides insights into the synthesis and luminescent properties of YCOB:Sm3+ phosphors, highlighting their potential applications in luminescent devices.

Bioresource Polymer Composite for Energy Generation and Storage: Developments and Trends

The ever-growing demand of human society for clean and reliable energy sources spurred a substantial academic interest in exploring the potential of biological resources for developing energy generation and storage systems. As a result, alternative energy sources are needed in populous developing countries to compensate for energy deficits in an environmentally sustainable manner. This review aims to evaluate and summarize the recent progress in bio-based polymer composites (PCs) for energy generation and storage. The articulated review provides an overview of energy storage systems, e. g., supercapacitors and batteries, and discusses the future possibilities of various solar cells (SCs), using both past research progress and possible future developments as a basis for discussion. These studies examine systematic and sequential advances in different generations of SCs. Developing novel PCs that are efficient, stable, and cost-effective is of utmost importance. In addition, the current state of high-performance equipment for each of the technologies is evaluated in detail. We also discuss the prospects, future trends, and opportunities regarding using bioresources for energy generation and storage, as well as the development of low-cost and efficient PCs for SCs.

Tb-doped MgAl2O4 phosphors: A study of structural and luminescence characteristics

In the MgO-Al2O3 system, magnesium aluminate spinel (MgAl2O4) is a technologically significant compound due to its unique properties, including a high melting point, low thermal conductivity, excellent thermal shock resistance, chemical inertness, and robust mechanical strength. This compound has diverse applications in refractory materials, catalyst supports, moisture sensors, nuclear techniques, insulating materials, and even military applications. While rare-earth elements are commonly used as dopants in luminescent materials, limited research exists on doping of Tb3+ ions in magnesium aluminate. This study investigates the luminescence properties of Tb3+ doped synthesis magnesium aluminate materials, shedding light on this underexplored area. The combustion method is employed for synthesis, known for producing nano-sized powders with exceptional luminescent properties. Additionally, this study explores Sm3+ ion doping in magnesium aluminate materials and their luminescence properties. Using the combustion synthesis method, structural attributes of Tb3+-doped MgAl2O4 nanophosphors are meticulously examined. Through X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses, coupled with excitation and emission spectra, a comprehensive investigation of the luminescent provide behavior at room temperature is provided. The XRD data reveal Tb3+ doped MgAl2O4 phosphors exhibit a single phase with face centred cubic structure belonging to the Fd3m‾ space group, consistent with the standard JCPDS files (No. 21-1152). Excitation and emission spectra offer valuable insights into the energy transitions within the Tb3+-doped MgAl2O4 phosphors. Furthermore, the study explores the effects of varying Tb3+ ion concentrations on the luminescent properties, revealing an optimal doping concentration of 5 wt% Tb for maximizing emission intensity. Concentration quenching, primarily attributed to dipole-dipole (d-q) interactions, is observed at higher Sm3+ concentrations. In conclusion, this research enhances our understanding of rare-earth ion doping in luminescent materials and highlights the potential applications of Tb3+-doped MgAl2O4 nanophosphors, which offer promise for various technological applications, including lighting and displays.

Efficient Detection of 2,6-Dinitrophenol with Silver Nanoparticle-Decorated Chitosan/SrSnO3 Nanocomposites by Differential Pulse Voltammetry

Herein, an ultra-sonication technique followed by a photoreduction technique was implemented to prepare silver nanoparticle-decorated Chitosan/SrSnO₃ nanocomposites (Ag-decorated Chitosan/SrSnO₃ NCs), and they were successively used as electron-sensing substrates coated on a glassy carbon electrode (GCE) for the development of a 2,6-dinitrophenol (2,6-DNP) efficient electrochemical sensor. The synthesized NCs were characterized in terms of morphology, surface composition, and optical properties using FESEM, TEM, HRTEM, BET, XRD, XPS, FTIR, and UV-vis analysis. Ag-decorated Chitosan/SrSnO₃ NC/GCE fabricated with the conducting binder (PEDOT:PSS) was found to analyze 2,6-DNP in a wide detection range (LDR) of 1.5~13.5 µM by applying the differential pulse voltammetry (DPV) approach. The 2,6-DNP sensor parameters, such as sensitivity (54.032 µA µM^-1 cm^-2), limit of detection (LOD; 0.18 ± 0.01 µM), limit of quantification (LOQ; 0.545 µM) reproducibility, and response time, were found excellent and good results. Additionally, various environmental samples were analyzed and obtained reliable analytical results. Thus, it is the simplest way to develop a sensor probe with newly developed nanocomposite materials for analyzing the carcinogenic contaminants from the environmental effluents by electrochemical approach for the safety of environmental and healthcare fields in a broad scale.

Effect of counterions on the micellization and monolayer behaviour of cationic gemini surfactants

The effect of various inorganic and organic counterions on the aggregation behavior of gemini surfactants was examined to investigate the dominant influence of the anions on their micellization and aggregation behavior.