Decrease In Optical Band Gap Research Articles

Influence of morphology, crystal structures on the enhanced photoluminescence dynamics, zeta potential, and AC resistance of disc shaped cesium oxidex@cobalt oxide nanostructures

In the present study, cesium oxidex@cobalt oxide (Cs2Ox@Co3O4) (x = 5, 10 and 12 wt%) nanostructures (NS) were successfully synthesized by chemical precipitation method and characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), EDX (energy dispersive X-ray), XPS (X-ray photoelectron spectroscopy), BET (Brunauer-Emmett-Teller), Raman, and UV–visible analytical techniques. XRD studies revealed the formation of the mixed phase of orthorhombic/monoclinic crystal structure. Disc shaped morphology of the cesium oxidex@cobalt oxide NS was noticed from SEM images. Redshift in optical absorbance and decrease in optical band gap (Eg) resulted in increase in Cs1+ concentration. Room temperature photoluminescence (RTPL) studies of cesium oxidex@cobalt oxide NS at various excitation wavelengths showed sharp and broad emission peaks located at 668.2 nm (red), 675.1 nm (red), 561.8 nm (yellow-green), 834.5 nm (near infrared region), 594 nm (yellow). Steady state photoluminescence (SSPL) studies revealed a sharp emission peak at ∼ 428.0 nm (violet) with large stoke’s shift (21.1 to 590.0 eV). The zeta potential studies showed a decrease in conductance from 62 to 57 μs with an increase in mobility of the charge carriers (0.4 to 1.08 μ/s V/cm) and an increase in zeta potential (31.90 to 82.92 mV). AC resistance studies at various temperatures showed inducting coupling phenomenon in cesium oxidex@cobalt oxide NS with DC resistance of cesium oxide5 wt.%@cobalt oxide was found to be 8.2 × 10–4 Sm–1. The relaxation frequency of cesium oxide12 wt.%@cobalt oxide NS was found be 1.2 × 105 Hz. The synthesized NS is a promising candidate for optoelectronics and photonic applications.

Influence of Transition Metal (Cu) and Rare Earth Metal (Dy) Co-doping on Spinel Zinc Ferrite (Cu0.1Dy0.08Zn0.9Fe1.92O4) for Improved Photocatalytic Degradation of Industrial Effluents

In the present era, design and development of novel, highly stable, easily and magnetically separable, cost effective, and visible light driven catalytic material for the removal of harmful industrial effluents is of great importance. In this context, facile co-precipitation route was adopted for the synthesis of ZnFe2O4 (ZFO), Cu0.1Zn0.9Fe2O4 (CZFO), Dy0.08ZnFe1.92O4 (DZFO), and Cu0.1Dy0.08Zn0.9Fe1.92O4 (CDZFO) and their fabrication was confirmed by XRD, FTIR, SEM, and UV-Visible spectroscopy. The phase analysis of all designed materials exhibits that there is an increment in the crystallite size of co-doped zinc ferrite (CDZFO) i.e. 11.51nm as compared to ZFO (10.74nm), CZFO (10.92nm), and DZFO (11.41nm). The optical study shows a significant decrease in bandgap of CDZFO i.e. 1.82eV as compared to DZFO (1.89eV), CZFO (2.0eV), and ZFO (2.14eV). This decrease in optical bandgap and increase in crystallite size of the CDZFO is due to the quantum confinement effect. The photocatalytic efficiency of pure, doped, and co-doped samples was investigated against organic dye (Congo red), pharmaceutical drug (ibuprofen), and colorless organic compound (benzoic acid). The photocatalytic results reveal that CDZFO showed about ~90% degradation of Congo red while ZFO, CZFO, and DZFO showed only 59%, 70%, and 79% respectively. Moreover, CDZFO also showed highest photocatalytic removal efficiency against ibuprofen (88%) and benzoic acid (74%) out of all other synthesized materials. The remarkable photodegradation ability of CDZFO for all targeted pollutants could be attributed to the generation of crystal defects in its lattice, its small bandgap, and higher absorption in visible region. Furthermore, the recyclability experiment confirmed the stability and reusability of the prepared sample.

Perylene-3,4,9,10-tetracarboxylic dianhydride dye intercalated liquid crystal molecules: Synthesis, spectroscopic characterizations and photoluminescence dynamics

The present research explores the interaction between perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA)-dye (PD) and 3b {(E)-1-[3-fluoro-4-(pentyloxy)phenyl]-2-(4-methylphenyl)diazene} liquid crystal (LC) mesophase, 3c{(E)-1-[3-fluoro-4-(hexyloxy)phenyl]-2-(4-methylphenyl)diazene} nematic liquid crystal (NLC) molecule. Spectroscopic characterizations of 3b@PD LC mesophase and 3c@PD NLC molecule were carried out using scanning electron microscopy (SEM), polarizing optical microscope (POM), Raman, Fourier transform infrared spectroscopy (FT-IR), and UV–visible analytical methods. The UV–visible studies revealed a red shift in absorption bands (348.0 nm to 374 nm) with a decrease in optical band gap from 2.43 eV to 2.25 eV. Room temperature photoluminescence (RTPL) spectra of 3b@PD LC mesophase exhibited blue light emission characteristics centred at 453.1 nm and 3c @PD NLC molecule showed broad emission peaks located at 400.7 nm and 324.8 nm. Steady-state photoluminescence (SSPL) spectra showcased indigo-purple emission bands corresponding to the wavelengths 303–353 nm, 420.5 nm, 418 nm, 418.3 nm, and 347.0 nm, however, for the 3c@PD NLC molecule, emission intensity peaks appeared at 429.6 nm, 418.0 nm and 329.0 nm. The stoke’s shift for 3b@PD LC mesophase varied between 0.01 eV to 0.613 eV while for 3c@PD NLC molecule it was found in between 0.317 eV to 0.453 eV. POM analysis unveiled distinct fan-like textures with varied colour interfaces. Time-resolved photoluminescence (TRPL) decay studies unveiled average lifetime of 3b@PD LC mesophase was 1.80 ns, 0.98 ns, 0.308 ns and for 3c@PD NLC molecule, the average lifetime was found to be 0.98 ns, 0.82 ns, and 0.306 ns at various excitation wavelengths. However, phosphorescence decay studies showed faster decay characteristics for 3c@PD NLC molecule (1.40 ns to 4.00 ns) compared with 3b@PD LC mesophase (1.65 to 5.42 ns) when excited at various wavelengths. The interaction between LC molecules and PTCDA demonstrated a significant enhancement in RTPL, TRPL, and SSPL properties, suggesting promising applications in photonics and optoelectronics.

On the response of the CR-39 NTD to low doses of gamma rays using optical and photoluminescence spectroscopy

In this work, the response of the CR-39 nuclear track detector (NTD) exposed to different low doses of gamma rays was investigated using UV–Vis and photoluminescence spectroscopy. Five NTDs of CR-39 were irradiated with low gamma-ray doses ranging from 10 to 120 kGy using a60Co source. The dose of gamma rays correlates with red shift in the absorption spectra of a gamma-irradiated CR-39 detector. As the gamma dose increases, the indirect and direct energy band gaps, as well as Urbach energy, decrease gradually. However, the decrease in the indirect optical band gap is greater than the decrease in the direct band gap. The observed spectra of the CR-39 detector after being irradiated with different doses of γ-rays showed an acceptable variation in photoluminescence (PL) emission spectra generated by a well-defined excitation wavelength of 290 nm. Starting at 45 kGy dose, the integrated area of the photoluminescence peak increases and tends to saturate, whereas the photoluminescence peak height is linearly correlated with the gamma dose with high sensitivity, which is 53.1 ± 6.3 CPS. kGy−1. According to the current findings, photoluminescence (PL) spectroscopy has a greater sensitivity than UV–Vis spectroscopy for measuring the response of the CR-39 detector to gamma rays in the dose range of 10–120 kGy. The results reflected a potential possibility of using the CR-39 detector in dosimetric applications of low gamma ray doses through the high resolution achieved by photoluminescence (PL) and UV–Vis spectroscopy.

Improved electrochemical performance of Fe3O4/TiO2 composite thin film electrode for energy storage applications

This study is the first attempt to examine the electrochemical properties of TiO2 composite with Fe3O4 thin film. In our analysis, X-Ray diffraction (XRD) confirms the formation of Fe3O4 on TiO2. Fourier Transform Infrared Spectroscopy (FT-IR) and Raman spectroscopy confirmed the functional groups. The UV–Vis spectroscopy analysis shows that the addition of Fe3O4 results in decrease in optical band gap. Our Cyclic Voltammetry (CV) results demonstrate that, under steady state conditions, the behaviors of TiO2 and Fe3O4/TiO2 electrodes regarding ion adsorption and charge transmission vary. Pseudocapacitive effects and charge transfer affects the functionality of the TiO2 electrode, whereas two-layer capacitance effects primarily control the response of the Fe3O4/TiO2 electrode. Numerous factors, including ion diffusion, rate capability, charge transfer, and series resistance, can be directly determined using electrochemical impedance spectroscopy (EIS). The experimental results and analysis presented in this work brings to light the significance of Fe3O4 in the electrochemical response of an electrode-electrolyte interface.

Influence of Ni2+ on OER kinetics and photoluminescence properties of ZnSnO3 nanoparticles

Ni2+ doped ZnSnO3 nanoparticles (NPs) were synthesized using Aloe vera mediated solution combustion method, followed by an investigation into their luminescence and oxygen evolution reaction properties. The Bragg reflections of ZnSnO3: Ni(1–9 mol%) NPs revealed a cubic structure, with the addition of the dopant inducing lattice strain and resulting in peak shifting towards higher angles. No impurity-related peaks were observed. The estimated crystallite size and optical band gap decrease (3.1–2.94 eV) with an increase in dopant concentration. The surface morphology consists of irregular-sized and shaped NPs with hallows. The EDAX spectra show the purity of the sample. Photoluminescence emission spectra were recorded at a 230 nm excitation wavelength, where intense blue emission observed at 482 nm was attributed to a direct transition between the conduction band edge and the valence band edge, corresponding to the direct recombination of free excitons. Another satellite peak observed at 525 nm can be attributed to oxygen deficiency. Moreover, the nanoparticles exhibited outstanding performance in oxygen evolution reaction studies, showing low over potentials between 300 and 318 mV, a minimal Tafel slope of range 63–72 mV dec−1, and stable electrochemical behavior over 12 h at a current density of 23 mA/cm2. These results highlight their effectiveness as electrocatalysts.

Design and characterization of borosilicate glass modified with TiO2 for enhanced optical and radiation shielding applications

This work investigates the potential of borosilicate glass doped with titanium dioxide (TiO2) for radiation shielding applications. The study explored the impact of varying TiO2 concentrations on the glass structure, optical properties, and radiation shielding effectiveness. X-ray diffraction (XRD) and Raman spectroscopy confirmed the amorphous nature of the glasses. The addition of TiO2 affected the glass network structure, as evidenced by changes in the Raman spectra and density measurements. UV–Vis spectroscopy revealed a red shift in the absorption edge (416–481 nm) and a decrease in the indirect optical band gap (2.91–2.70 eV) with increasing TiO2 content. The refractive index also increased from 2.54 to 3.54 with TiO2 concentration. The mass attenuation coefficient (MAC) and linear attenuation coefficient (LAC) increased significantly with TiO2 addition, indicating enhanced radiation attenuation capability. The inclusion of TiO2 reduced the half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP), while increasing the effective atomic number (Zeff). The effective electron density (Neff) and effective conductivity (Ceff) showed a slight increase with TiO2 content. Energy build-up factors (EBF and EABF) indicated a higher rate of radiation intensity increase and energy absorption within the glass due to the presence of TiO2. Finally, the incorporation of TiO2 into borosilicate glass offered a promising approach to developing improved optical and radiation shielding glasses.

Structural, optical, and morphological properties of PVC-BaTiO3 nanocomposite films

This work aims to fabricate barium titanate (BaTiO3) nanoparticles and study the effect of adding different contents of BaTiO3 nanoparticles on the structural, optical, and electrical properties of PVC polymer matrices. The PVC/BaTiO3 nanocomposite films were characterized by X-ray diffraction, FT-IR spectroscopy, and SEM. In addition, dielectric properties were studied within the frequency range of 0.1 KHz–6 MHZ. The XRD analysis reveals an amorphous nature of pure PVC with two characteristic peaks at 2θ = 17.09° and 2θ = 23.25°, and it reveals that BaTiO3 has sharp and narrow peaks. In PVC/BaTiO3 nanocomposite films, all XRD peaks of BaTiO3 appeared in all the samples with an increase in the average particle size from ∼46 nm to 55 nm. There is no shift of IR position in PVC bands, but the decreased intensity of some bands suggests complexation between PVC and BaTiO3. The UV–visible absorption spectrum of pure PVC has a band at λ = 278 nm. This band was shifted to 252 nm after adding BaTiO3 content. UV–visible transmission spectra demonstrate a decrease in the transmittance as an increase of BaTiO3 content from 89.23 % for pure PVC to 5.23 % for 0.1 wt% of BaTiO3. The values of the optical bandgap decrease with increasing BaTiO3 contents due to defect formation in PVC matrices. The optical parameters of the prepared nanocomposite films were also enhanced. The AC conductivity shows an increase with both frequency and BaTiO3 concentration, leading to enhanced movement of charge carriers and relaxation of interface polarization.

Cerium oxide-reinforced Fe2O3–Na2O–SiO2–B2O3 glass matrix for protection against ionizing X and gamma rays

Radiation shielding glass is an interesting material in the field of radiation shielding due to its remarkable features. In the present paper, we investigated the physical properties of radiation-shielding glass materials that consist of sodium oxide (Na2O), cerium oxide (CeO2), and iron oxide (Fe2O3) incorporated into borosilicate glasses with the formula 90SiO2-(70-x)B2O3+ 20Na2O–1Fe2O3-xCeO2 (CeFeNaBS-glasses). One of the distinguishing characteristics of this glass system is its enhanced radiation shielding capabilities. The structural studies indicated a gradual rise in glass density from 1.954 to 2.658 g/cm with further CeO2 doping. Optical studies showed that the optical band gaps went down from 3.41 eV to 3.33 eV as the amount of CeO2 in the CeFeNaBS-glass matrix rose. The decrease in optical band gap has been correlated with the rising basicity. Also, the increased basicity behavior induces more conversion of Ce3+ to Ce4+ ions by losing a 4f electron. Moreover, with further CeO2 additions, the glass color changed from light brown to dark brown. The presence of Ce4+ ions with further CeO2 additions is responsible for this color transformation. The linear and non-linear refractive indices exhibit enhanced behaviors with higher CeO2 concentrations. We used declining basicity and polarizability behaviors to describe this behavior. The incorporation of larger CeO2 concentrations enhances the ability to improve radiation shielding properties, as demonstrated by the increased values of the mass attenuation coefficient and half-value layer, especially in the energy ranges of soft tissues X-ray and hard tissues X-ray. Hence, the investigated CeFeNaBS-glasses exhibit enhanced transparency and radiation shielding capabilities, rendering them highly suitable for implementation in this domain.

Ultraviolet optical absorption enhancement and bandgap decrease in PVDF matrix promoted by the addition of Nd/trans-3,4-(methylenedioxy)cinnamic complex

In this work, the UV–Vis measurements have been done to study the changes in the optical absorbance and optical bandgap of Polyvinylidene Fluoride (PVDF) caused by Nd/trans-3,4-(Methylenedioxy) cinnamic complex (Nd-MCA) addition. The UV–Vis measurements showed that adding the Nd-MCA compound to the PVDF matrix enhances its optical absorption in the UV region and increases the absorption edge. The Nd-MCA addition decreases the optical bandgap parameter by 49%, which might be associated with structural changes in the PVDF matrix. The results revealed an oscillatory behavior in the band tailing (A) and Urbach energy (ΔE). Finally,our results reveal that the PVDF/Nd-MCA sample is a potential candidate for optical and photonic devices.

Polyvinyl pyrrolidone/ carboxymethyl cellulose (PVP/CMC) polymer composites containing CuO nanoparticles synthesized via laser ablation in liquids

Polyvinyl pyrrolidone/carboxymethyl cellulose (PVP/CMC) polymer composites containing CuO nanoparticles synthesized via laser ablation in liquids were prepared. Fourier transform infrared (FTIR) spectroscopy, UV/Vis spectroscopy, and scanning electron microscopy (SEM) were used to characterize the structural, optical, and morphological properties of the polymer composites. The addition of CuO nanoparticles resulted in changes in the FTIR spectra, indicating interaction between the polymer matrix and nanoparticles. UV/Vis spectroscopy showed a red shift in absorption and a decrease in optical bandgap with increasing CuO nanoparticle content. SEM micrographs revealed increases in surface roughness with higher CuO nanoparticle loading. Antibacterial activity of the composites against Gram-positive and Gram-negative bacteria increased with greater CuO nanoparticle concentration. The results suggest these biofilms have potential for use as coating materials in biomedical applications.

Investigation of radiation-induced aromatization in high-density polyethylene and the product formations mechanism using molecular spectroscopy

The effects of 1.75 MeV N5+ ion beam irradiation of varying ion fluences, ranging from 1 × 1012 to 3 × 1014 ions/cm2, on high-density polyethylene have been done to investigate the structural, optical and chemical properties using X-ray diffraction (XRD), UV–visible spectroscopy and Fourier transform infrared (FTIR) spectroscopic techniques. XRD patterns show no significant change in crystallinity in irradiated polymer samples. The lattice plane and crystallite size of the irradiated polymer have not changed noticeably. More than 50% decrease in optical band gap were found for higher ion fluences of 3 × 1014 ions/cm2. UV–visible spectra show a red shift in absorption maxima due to the formation of extended conjugation. FTIR peaks 3646, 1707 and 2170 cm−1 in irradiated polymer were observed. The reaction mechanism chemistry of radiation-induced product formations, including chain scission, molecular crosslinking and hydroxyl, carbonyl and alkyne functional groups have been discussed.

Evaluating the reactivity of polyvinyl alcohol/graphene nanocomposites

The synthesis and characterization of polyvinyl alcohol (PVA)/graphene nanocomposite films, through the solution casting technique, were thoroughly explored and studied. The integration of varying concentrations of graphene was systematically explored to enhance the structural and optical attributes of the PVA matrix. Comprehensive characterization employing X-ray Diffraction (XRD), Fourier-Transform Infrared (FTIR) Spectroscopy, and Ultraviolet–Visible (UV–Vis) Spectrophotometry revealed significant interactions between PVA and graphene, manifesting in a decrease in crystallinity and optical bandgap with increasing graphene content. DFT:B3LYP/6-31g(d,p) quantum mechanical level, corroborated these findings by indicating a diminished HOMO/LUMO bandgap energy. Additionally, molecular electrostatic potential mapping underscored an increase in PVA's reactivity post-graphene integration. The investigation further extends to evaluating global reactivity descriptors, providing insights through PDOS plots and QSAR analysis. The outcomes of this research underscore the potential of PVA/graphene nanocomposites for next-generation applications in flexible photovoltaic cells, transistors, and diodes.

Comparative Investigation of Pressure Effect on Structural Stability, Electronic and Optical Response of LaXO<sub>3</sub> (X = Al, In, Ga) for Optoelectronic Applications

A first principle study intense on the density functional theory with Heydscuseria-Ernzerhof screened hybrid functional hybrid function (HSEO6) is used to assess the structural, Electronic, elastic, mechanical and optical responses of LaXO<sub>3</sub> (X = Al, In, Ga) perovskite materials. The compressive investigation under the external static isotropic pressure (P= 0 to 80GaP), phase stability, band structure and their important impact on the optical response of LaAlO<sub>3</sub>, LaInO<sub>3</sub> and LaGaO<sub>3</sub>. Electronic band structure shows that LaXO<sub>3</sub> (X = Al, In Ga) semiconductor with indirect band gap and an optically inactive response up to 20GPa, while the band gap becomes direct at 80GaP. There are gamma points (G-X-Q) at 80GPa and the band gap changes from indirect to direct nature. Under main desperation physical parameters of perovskite materials are well explained the response of TDOS, PDOS and EPDOS contour plots have been well understood for the full description of the band gap. It is further observed that the external pressure enhanced upto 40GPa both materials are significantly more mechanically stable compared to pristine LaXO<sub>3</sub> (X = Al, In, Ga) at 0GPa. The optical properties of LaAlO<sub>3</sub>, LaGaO<sub>3 </sub>and LaInO<sub>3</sub>, dielectric coefficient <i>(ε<sub>1</sub>, iε<sub>2</sub>)</i> have been employed along with the optical responses like absorption, energy loss function, reflectivity and reflective index are obtained in the energy scale from 0 to 60 eV. It was observed that static dielectric constant decreases with the decrease in optical band gap. The optical tunings under the effect of pressure which are good candidates in practical optoelectronic applications are extensively used and interpreted by the calculation of the dielectric function.

Tailoring of Interface Quality of MoOx/Si Solar Cells

Transition metal oxide films (TMO) as passivating contacts with improved opto-electronic characteristics play an important role in improving the silicon solar cell device efficiency. In this report, the effect of sputtering power on the optical properties of MoOx and the quality of MoOx/n-Si interface for its application in a silicon solar cell as carrier selective contacts has been reported. The optical transmittance of the film greater than 80 % in the visible and near infrared region of the spectrum is observed, which further improved with sputtering power. The creation of oxygen ion vacancies, which acts as positively charged structural defects able to capture one or two electrons led to the decrease of optical band gap from 3.70 eV to 3.23 eV at higher power. The oxygen vacancies occupied by electrons acts as donor centers, which lies close to the valence band, were responsible for modulation in electrical properties. The electrical properties of MoOx/n-Si interface was analyzed using current-voltage (I-V) measurements for its application as selective contact. A significant change in the selectivity parameters, like barrier height, I0 and series resistance of MoOx, has been observed with dc power. These extracted parameters showed that the sputtering power has a great influence on the selectivity of the charge carriers.

Magnetically separable and visible light-driven photocatalytic activity of graphene oxide based α-Fe2O3 nanocomposite

This work investigates the impact of graphene oxide (GO) on the structural, morphological, optical, and photocatalytic investigations of Fe2O3, an excellent photocatalyst for industrial wastewater treatment. Using the straightforward and inexpensive sol-gel auto-combustion, hummer's method and sonication method, Fe2O3 nanoparticle (NPs), GO nanosheet, and GO-based Fe2O3 (GO/Fe2O3) nanocomposite have been synthesized, respectively. The XRD patterns, Raman spectra, and FTIR spectroscopy were used for the structural analysis, which verifies the single phase hexagonal geometry of Fe2O3 NPs. The average size of the crystallites is seen to have reduced from 50 nm to 44 nm for Fe2O3 and GO/Fe2O3. The SEM along with EDS were applied to investigate the surface morphology and confirm the existence of the elements Fe and O in pure Fe2O3, and C, Fe and O in GO/Fe2O3. From UV–vis absorbance spectra, the decrease in optical band gap (2.5 eV–1.9 eV) caused by GO incorporation has been inferred, as clearly displayed in the Tauc plots. X-ray photoelectron spectroscopy (XPS) confirms the presence of Fe2+/Fe+3 ionic states and large oxygen vacancies in the GO/Fe2O3 nanocomposite. The photocatalytic properties of both materials for the toxic MB (methylene blue) dye photodegradation in an aqueous solution was evaluated while being exposed to sunlight. It makes an excellent choice for wastewater treatment due to the high photocatalytic activity of magnetically separable GO/Fe2O3 nanocomposite for decomposing the MB dye.

Investigation of novel, green synthesized and photocatalytic Sn-doped MoO3 nanomaterial for the degradation of methyl orange

Nowadays, water resources are being contaminated owe to the waste organic pollutants. A novel Sn-doped MoO3 nanomaterial was developed in the presence of extract from the skin of Capsicum annuum fruit to decontaminate the waste water by degrading this organic pollutant. For the preparation of these nanomaterials, a facile green synthesis approach was adopted by using Capsicum annuum extract. The as designed nanomaterials were thoroughly characterized by X-ray diffraction spectroscopy (XRD, scanning electron microscopy (SEM), ultraviolet visible spectroscopy (UV–vis) and photoluminescence spectroscopy (PL) techniques. The photocatalytic activity of as designed nanomaterials was observed against the methyl orange (MO) a model dye under the irradiation of visible light. The results obtained from the characterization of these nanomaterials have shown reduced sized particles with cone, sphere and rod like morphologies. In comparison to pure MoO3 prepared without extract (Sample-1) and MoO3 prepared with extract (Sample-2), the Sn-doped MoO3 prepared in the presence of extract (Sample-3) has shown a reduced optical energy bang gap value i.e 2.84 eV and an enhanced photocatalytic activity against MO i.e about 95%. This optimized sample has also shown a low charges recombination rates. This excellent photocatalytic performance is credited to the increased active sites owe to the development of large surface area and a significant decrease in the recombination rate of charge carriers along with a reasonable decrease in optical band gap. These results have exhibited a boosted photocatalytic performance of this material in visible light region.

Microstructure, optical, and electrical characteristics of NaBaBi2(PO4)3: Sm3+ orange-red phosphor for WLEDs

White light-emitting diodes (WLEDs) are widely used as lighting devices in daily life. However, due to the scarcity of orange-red components, they lack warm white light. Therefore, there is an urgent need for orange-red phosphors to improve the lighting quality and generate more saturated and warm white light. In this regard, NaBaBi2(PO4)3: xSm3+ orange-red phosphors were synthesized using the solid-state method. A systematic study was conducted on the microstructure, optical, and electrical properties of NaBaBi2(PO4)3: xSm3+ phosphors through various characterizations such as X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, fluorescence decay curves, and electrochemical impedance spectroscopy. The diffuse reflectance spectrum indicates that with the increase of Sm3+ doping concentration, the optical bandgap decreases. Remarkably, the NaBaBi2(PO4)3: 0.05Sm3+ phosphor has good thermal stability, and its retention rate is 84.42% at a high temperature of 428 K. Furthermore, the packaged LED manifested desirable characteristics, such as a low correlated color temperature (CCT ∼ 4280 K) and a high color rendering index (CRI ∼ 82), as evidenced by rigorous testing. These results indicate that the NaBaBi2(PO4)3: Sm3+ phosphors have a significant potential for utilization in the LED lighting industry.

Thermal, optical, dielectric and electrical transport properties of nano-structured Se95-xIn5Prx (x = 2, 4, and 6) glassy alloys

In the present study, Se95-xIn5Prx (x = 2, 4, and 6) alloys were prepared using the melt quench technique. X-ray diffraction (XRD) and Raman spectroscopy reveal that the glassy matrix of each sample consists of crystalline entities identified as a mixed phase of indium selenide (HCP) and praseodymium selenide (FCC). TEM images show that the crystalline entities are nanorods stuck to nanoparticles. The thermal stability and optical band gap (direct) decrease (1.974 eV to 1.425 eV) with Pr content. The dielectric constant and loss are maximums for x = 4 at any frequency and temperature (30°C-60 °C). AC conductivity follows the correlated barrier hopping (CBH) model (frequency exponent s<1, and decreases with temperature) with non-intimate valence alteration pairs (NVPA) for x = 2 and 6, and intimate valence alteration pairs (IVPA) for x = 4. AC activation energy decreases with Pr concentration at all frequencies in the study range.

Investigation of Structural, Dielectric and Optical Properties of Polyaniline-Magnesium Ferrite Composites.

A study on the influence of magnesium ferrite nanoparticles on the optical and dielectric attributes of Polyaniline has been conducted. Magnesium nano Ferrite powder is synthesized by the self-propagating solution combustion method. Polyaniline-Magnesium nano ferrite composites are synthesized by chemical oxidative polymerization of aniline with the addition of Magnesium nanoparticles. The samples are characterized with XRD and UV-Vis spectrometer, in the wavelength range of 200-800 nm and studied for optical properties. Dielectric properties are studied in the frequency range of 50 Hz to 5 MHz. X-ray diffraction reveals single phase formation of Magnesium ferrite, whereas Polyaniline shows an amorphous nature. In the XRD of the composites, we see the crystalline peaks of ferrite becoming more intense with the addition of ferrite and whereas the peak of Polyaniline diminishes. The crystallite size is quantified with the Debye-Scherrer formula, and it increases as the content of ferrite in the composites increases. The micro-strain decreases in the composites as the percentage of ferrite enhances in the composites. In the UV-Vis absorption spectra of composites, the peaks of Polyaniline shift to higher wavelength and there is also an absorption band in the spectra of composites corresponding to that of Magnesium ferrite particles. Both direct and indirect band gaps are calculated with the Tauc plot, and both the optical band gap decrease as the percentage of ferrite increases in the composite. The dielectric loss and dielectric constant both decrease with frequency in all the samples, and the dielectric response are in good agreement with Maxwell-Wagner model. Ferrite-polymer composites with both conducting and magnetic properties are considered useful for electromagnetic shielding and microwave absorption.