Urbach Energy Research Articles

Exploring optical and electrochemical studies on thulium selenite (TmSeO3)

Abstract Thulium selenite (TmSeO3) has been synthesized by precipitation method. It shows interesting smooth surface with nearly non-symmetric texture similar to water droplets spreading on hydrophobic surface. TmSeO3 is found to be monoclinic structure with lattice parameters a = 5.919±0.01 Å, b = 12.422±0.01 Å, c = 8.717±0.01 Å, α = γ = 90°, β = 106.01° and V = 616.1 Å3. Fourier transform infrared spectroscopy confirms the presence of Tm–Se bonding. X-ray photo emission spectrum confirmed the presence of thulium, selenium and oxygen in the samples in oxide form. Magnetic study between 300 and 20 K, shows decrease of magnetic moment with temperature, then reaches saturation and aligns all thulium spins. This results cooperative interaction of thulium spins. M–H curve at 300 K confirms the paramagnetic nature of sample. Cyclic voltammogram of three electrode system, manifests electric double layer capacitance with a potential window of 0.55 V. Specific capacitance is 102 F/g. Chronopotentiometry analysis shows 75 F/g specific capacitance, 11 Wh kg−1 energy density, and 275 W kg−1 power density. Impedance analysis confirms electric double layer capacitor behavior. Hence, TmSeO3 electrode based symmetric supercapacitor device was successfully fabricated and tested by two electrode configuration in aqueous electrolyte of KOH. A specific capacitance of 64.60 F/g at 1 A/g within a potential window of 1.85 V was achieved. Impedance analysis also confirms electric double layer capacitor nature with low series resistance of 0.2596 Ω and charge transfer resistance of 1.6352 Ω. The improved cycling performance after 4000 cycles is 51.5 % specific capacitance retention. Thus, symmetric supercapacitor electrodes based TmSeO3 materials are expected to have good electrochemical properties and good stability for energy storage and conversion applications. Furthur, optical parameters 5.28 eV energy gap, 0.4924 eV Urbach energy value and 1.959 refractive index are determined.

First-principles calculations to investigate impact of doping by chalcogen elements on the electronic, structural, and optical properties of SrTiO3 compounds

Doping techniques are commonly utilized to effectively modify the physical properties of a desired compound. In this study, we employed the first-principles DFT calculations with a GGA + TB-mBJ approach as implemented by the Wien2k code, by investigating the effects of oxygen group element concentrations on the structural, electronic, and optical properties of the perovskite substance SrTiO3. We calculated the formation energies of each doped structure to assess the viability of synthesis. The band gap is equal to 1.355 eV, 0.653 eV, and 0.632 eV for 12.5 % S, Se, and Te doped SrTiO3, respectively. For the pure SrTiO3, the band gap is 2.584 eV. According to our findings, raising the chalcogen concentrations resulted in a considerable decrease in band gaps and an improvement in the ability to absorb light in the visible range (380–790 nm), exceeding 105 cm−1 for Te doped SrTiO3 (STO). At zero frequency, the dielectric constant was found (ε1 (0)) to be 4.432 for SrTiO3 pure and 6.332 for SrTiO3 doped with Te (12.5 %) in GGA-PBE and (ε1 (0)) = 4.432 and 12.217 for GGA + mBJ. The optical conductivity of SrTO3 doped with Te is determined to be 0.322 * 104 /Ω.cm, in comparison to a value of 0.377 * 104/Ω.cm for mBJ. Our research revealed that raising the chalcogen concentrations significantly enhanced the electrical conductivity, as predicted, along with improvements in optical conductivity and reflectivity. SrTiO3-xYx (Y = S, Se, or Te) represents one of our quaternary alloys, demonstrating substantial potential as a promising material for advanced photovoltaic and solar cell applications. Our findings revealed that the doped materials exhibited significantly high absorption rates and productivity. We also examined additional optical parameters, including optical band gap, Urbach energy, and optical conductivity.

Auger-limited minority carrier lifetime in GeSn/SiGeSn quantum well

A minority carrier lifetime of 2.7 ns is measured at 77 K for a GeSn/SiGeSn single quantum well using time-resolved photoluminescence, and subsequent analyses indicate that the lifetime is Auger-limited. The 77 K lifetime is evaluated as a function of stepwise dose of 63 MeV proton irradiation up to a fluence of 1.5 × 1012 p+/cm2 with no discernable reduction in the observed lifetime, which implies that the lifetime damage factor slope to 63 MeV proton irradiation is not greater than 2 × 10−5 cm2/s. Steady-state photoluminescence is used to evaluate the total luminescence output as a function of excitation, yielding a 2/3 power law slope consistent with Auger-limited recombination. The observed Auger-limited behavior is consistent with reports of high p-type background carrier concentration in these alloys. The temperature dependence of the steady-state photoluminescence spectra also provides the Einstein single oscillator model parameters for the ground state transition energy and Urbach energy of the GeSn quantum well.

Influence of low temperature annealing time on CdS thin films

In this work, a low temperature annealing process is shown to improve the photoresponse time of CdS thin films. The films were deposited on glass substrates by chemical bath deposition. The samples were annealed in air for different times (0, 2, 4 and 6 h) at 200 °C. The morphology, optical and electrical properties of the CdS thin film was studied. The films were characterized by scanning electron microscope, X-ray diffraction, spectroscopic ellipsometry, 3D optical profilometry and UV–vis spectroscopy. The CdS thin films presented a compact structure with a grain size of approximately 80–100 nm. The average thickness of the films was 200 nm. All films exhibited a cubic CdS phase with preferred orientation along the (111) direction. The average value of the crystallite size was 30 nm. The refractive index varied from 2.40 to 2.64 as the annealing time increased. The optical bandgap for the samples showed a decreasing trend as the annealing time increased from 2.36 eV to 2.24 eV while the Urbach's energy had an inverse behavior from 0.160 eV to 0.270 eV. The annealing time was studied in the photoresponse of CdS films under ultraviolet and blue light. The fastest rise and fall times were 190 ms and 90 ms respectively for the 4 h annealing under blue light. We show that a low annealing temperature is possible to improve the photoresponse by 2 orders of magnitude.

Recyclable CS/r‐GO Polymer Nanocomposites: Green Synthesis and Characterizations

The study herein is directed toward the tuning of various properties of recyclable and biocompatible polymer: chitosan (CS) via incorporating the variable wt% of r‐GO in the polymer. The CS/r‐GO polymer nanocomposites (PNCs) are prepared in the form of free‐standing film by solution mixing and casting technique. To search the potential applications, the prepared PNCs are characterized in terms of structural, photoluminescence (PL), surface morphology, optical, and Raman spectra. The crystalline size and microstrain both are enhanced with rise in wt% of r‐GO nanofiller. Raman spectra confirm that as the wt% of r‐GO increases, there is a minor shift toward a smaller wavenumber in the locations of the D, G, and 2D bands, while the intensity ratios ) increase. Field‐emission scanning electron microscopy results are capable of offering details regarding the surface quality for the interface purposes. The characteristic peaks and their broadening in PL spectra, chromaticity coordinates, dominant wavelength, and correlated color temperature are altered with variation of r‐GO wt.%. The optical bandgap, refractive index, and Urbach energy are found to tune with varying the nanofiller wt.%. These results suggest that CS/r‐GO PNC may be the potential candidate for possible application in fabricating the tunable optoelectronic devices.

Understanding the effects of annealing induced structural transformations on the UVC absorbance and other optical properties of RF sputter deposited Ga2O3 thin films

Gallium oxide (Ga2O3) is a transparent material with high absorption in the UVC region of the electromagnetic spectrum and hence is a very important candidate in the field of short wavelength optical device fabrication. A proper understanding of the different optical parameters is necessary for developing more efficient coatings and devices. In this work, changes in the optical behavior of Ga2O3 thin films due to post-deposition annealing (at temperatures 300 °C–900 °C) are discussed in detail. Structural, surface morphological and compositional modifications of the films are identified using the x-ray diffractometer, scanning electron microscopy and x-ray photoelectron spectrometer techniques, respectively. At 900 °C, a highly stable monoclinic β phase of Ga2O3 is obtained. The optical transmittance spectra acquired using UV–Vis spectroscopy indicate an improved UVC absorbance of the β-Ga2O3 films with an excellent visible transmittance (>80%). The structural transformation from amorphous to crystalline β-Ga2O3 phase and the associated reduction in defect density is found to modify other optical attributes, like the bandgap energy, Urbach energy, dispersion parameters, etc.

Ni-doped ZnO nanoparticles derived by the sol–gel method: structural, optical, and magnetic characteristics

A simple sol–gel route was used for preparation of Ni doped ZnO nanoparticles (Ni:ZnO) with 0, 3, 5, 7 and 9 wt% of Ni to Zn precursor salts. Structural, optical and room temperature magnetic properties were studied. The prevailing structural arrangement that observed in all the examined samples is the wurtzite structure of ZnO. Nevertheless. The orderly development of NiO rock-salt phase on at the surfaces of ZnO nanoparticles upon Ni doping is confirmed by Rietveld refinements. The ZnO wurtzite structure is dominant in all the samples as confirmed by both XRD and Raman results. The average crystallite size showed almost no change upon Ni doping. RTFM behavior is being exhibited for all Ni:ZnO nanoparticles that is demonstrating using of ZnO as the host structure allowed for the efficient formation of DMS. The Near-infrared solar reflectance (RNIR) and the visible solar reflectance (RVis) values reduced with increasing of the Ni content as a result of the rising in density of trap states upon Ni doping of the samples. Kubelka-Munk method was used to determine the energy band gap (Eg) and band Urbach energy (EU) tails from diffused reflectance (DRS) results. The obtained energy gap values were very close in all studied samples with an average value of energy gap is 3.164 eV. The EU values raise from 123 to 173 meV upon increasing of Ni content in the samples in agreement with lower values of RNIR and RVis and their effect on optical performance of the investigated samples in applications.

Cross-linking tendency and photo-oxidation degradation in Silane-grafted LDPE insulation under accelerated cyclic weathering aging

Si-g-LDPE (Silane-grafted LDPE) is the based material of silane-crosslinked polyethylene (Si-XLPE) nominated to be used in renewable energy (photovoltaic) structures for the reason of its good behavior under weathering circumstances. The present study has an attempt to follow up the cross-linking process of Si-g-LDPE under cyclic accelerated weathering aging and to track its photo and thermo-oxidative degradation at both microscopic and macroscopic scales. The realized experiments consist to carry out cyclic accelerated weathering aging of 1152 hours, using QUV chamber, on films of Si-g-LDPE. The process of cross-linking is checked by using Hot-Set-Test measurements and Fourier Transform Infrared (FTIR) spectroscopy. Evolution of mechanical properties and carbonyl index are used as relevant precursors of photo and thermo-oxidation degradation. Additional information on the microstructural changes (crystallinity) and on the optical properties is gained by using X-ray difractometry and UV-visible measurements. Our findings lead to a result that Si-g-LDPE has a big ability to crosslink under cyclic weathering aging. The elastic behavior of the material was enhanced gradually with increasing aging time. The elastic behavior enhancement is a consequence of crosslink network density increase. FTIR results support perfectly the Hot-Set-Test results by the increase of single or multi-siloxane linkages absorption bands. These linkages modify the digital fingerprint of the material. Our results ascertained also that we can relate the elongation at break and tensile strength changes to the changes in the carbonyl index. Both characteristics are related to the photo and thermo-oxidation degradation. Photo-oxidation degradation leads to the decrease of mechanical properties and to the increase of carbonyl index. An abrupt and sharp increase at the beginning of aging in the crystallinity of the material followed by a level-off state was observed. Finally, the optical properties (band gaps, Urbach energy and dielectric constant) are greatly affected by the weathering aging process.

Nd-doped CdS nano-particles: optical band gap and Urbach energy investigations

Nd-doped CdS nano-particles: optical band gap and Urbach energy investigations

Visible-light optical limiting of vanadia–polyvinylpyrrolidone nanofibers

In this work, vanadium pentoxide (V2O5) nanoparticles-filled electrospun polyvinylpyrrolidone (PVP) nanofibers were investigated systematically at various nanofiller weight percentages (8 and 10 wt%) and input intensities to reveal the effective optical limiting feature in the visible spectrum. XRD analysis demonstrated the purity of the produced V2O5 nanoparticles. According to SEM findings, V2O5 nanoparticles were effectively integrated into the PVP nanofibers. Two distinct absorption bands were observed at around 400 and 217 nm. These bands were related to PVP and V2O5 nanoparticles in linear absorption measurements, respectively. Moreover, an increased Urbach energy value was obtained with an increase in V2O5 nanofiller content within PVP. Open-aperture Z-scan measurements were taken at 532 nm considering the band gap energy of the V2O5 nanofillers in PVP composite nanofibers. In 8 wt% V2O5 nanofilled PVP nanofibers, one-photon absorption (OPA) was the main nonlinear absorption (NA) mechanism, and the defect states of the V2O5 nanoparticles had no contribution to NA. On the other hand, sequential two-photon absorption was the main NA mechanism, and the defect states of the nanoparticles caused more efficient NA behavior in 10 wt% V2O5 nanofilled PVP nanofibers. The effective optical limiting behavior was obtained for this composite nanofiber with lower limiting threshold as 1.49 × 10–5 J/cm2. The V2O5 nanofilled PVP nanofibers presented strong potential optical limiters in the visible wavelength region. This was attributed to their high linear transmittance at low input intensities and their robust NA behavior at higher input intensities.

A new non-centrosymmetric material (C5H9N3)[ZnBr4]·H2O : Molecular structure, characterization, optical properties and biological activities

The use of 2,3-diaminopyridine as an aromatic organic molecule in the synthesis of a new hybrid halogenometallate compound by the slow evaporation method afforded an unexpected non-centrosymmetric structure type. The obtained material with the formula (C5H9N3)[ZnBr4]·H2O (1) crystallizes in the triclinic space group P1. The compound was characterized by UV–visible measurements, differential thermal analysis (TG-DTA), single crystal X-ray diffraction and nonlinear optical activity. The structure consists of isolated tetrahedral [ZnBr4]2− anions, 2-amino-3-ammoniopyridinium [C5H9N3]2+ cations and water molecules, which are connected via NH…O/Br and OH…Br hydrogen bonds leading to the formation and strengthening of a three-dimensional supramolecular assembly. The optical band gap and Urbach energy were obtained through Tauc's equation. The direct and indirect band gap values are found to be 3.23 and 3.55 eV, respectively. The bioassay results showed that the compound exhibits modest antibacterial and antifungal activities.

Spectroscopic and thermal investigations on Zn2+ and Ba2+ ions modified 30TeO2-39.5B2O3-(30-x)ZnO-xBaO-0.5V2O5 (0 ≤ x ≤ 30 mol %) glass system

Melt quenching technique was employed to prepare glasses with compositional formula 30TeO2-39.5B2O3-(30-x)ZnO-xBaO-0.5V2O5 (0 ≤ x ≤ 30 mol%). Various characterization tools viz., X-ray diffraction (XRD), Energy dispersive X-ray (EDX) includes color mapping images, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Raman, Differential scanning calorimetry (DSC), UV–Vis absorption and Electron paramagnetic resonance (EPR) were used in this investigation for the characterization of these glasses. The XRD patterns together with DSC thermograms asserted the amorphous nature of all glasses. FTIR and Raman vibrational analyses has unveiled the formation of B-O--Ba2+-O− and Te-O−--Ba2+-O− wherein the bonds with Ba2+ ions are mostly ionic. DSC investigations disclosed that the increase of BaO at the cost of ZnO declined the crystal phases and favored the amorphosity and this behavior causes these glasses more advantageous for fiber drawing. The Urbach energy (ΔE) lies in between 0.28 and 0.57 eV and suggested the glasses containing high ZnO has less defects. EPR data validated that Ba2+ ions might surround V4+ ions as Ba2+-O-V4+=O by replacing Zn2+-O-V4+=O linkages. The other optical properties were discussed in detail by correlating the structural variations noticed from both FTIR and Raman data analyses.

The violet laser irradiation influence on the dispersive properties of the PVA/MO composite thick

Polyvinyl alcohol (PVA) polymer, methyl orange (MO) and their composite was dissolved in water in order to prepare films with different thickness by casting method. The films were irradiated by a violet laser with a wavelength 405 nm for different times (0, 10, 20, 30 and 40) minute. The dispersion parameters were calculated before and after exposure to the laser using the Wemple–DiDomenico method. Dispersion energy (E d) and the single oscillator energy of electronic transition (E o) were increased with increasing the irradiating time for PVA, MO and PVA/MO thick films. This is useful to modify geometrical and optical specifications for materials which has many applications especially in the medical field. The Urbach energy also can be controlled by the irradiation times since it decreased with increasing the laser irradiation time which can be used to enhance the structure of the material.

Elucidating the impact of Dy2O3 substitution on structure, optical, photoluminescence and mechanical properties of borosilicate glass

This work aims to investigate the changes in characteristics seen in the composition 60B2O3+ (30–x) BaO + 10SiO2 + xDy2O3 where x is 0.0, 1.0, 2.0, and 3.0 mole% glass samples. Melt-quenching technique was used to prepare the glass samples. A variety of analytical techniques were employed to characterize the prepared glasses, such as x-ray, Raman, photoluminescence, and UV-vis-NIR spectroscopy. XRD spectra verified the glassy nature. The glasses’ compactness was studied using structural properties such as density, molar volume, and oxygen packing density. Makishima-Mackenzie’s (M-M) method was used to determine mechanical parameters such as elastic moduli, Poisson’s ratio, and hardness, and it was found that these properties decreased with increasing Dy2O3 concentration. Glass absorption spectra showed eleven distinct peaks in the range 300–2000 nm, resulting from Dy3+ electronic transitions. Urbach energy, refractive index, and optical band gap energy were determined. The optical parameters, such as molar refraction, molar polarizability, reflection loss, optical transmission, metallization, and optical electronegativity, were estimated. The photoluminescence spectra revealed five distinct peaks in the 400–800 nm wavelength range under excitation at 325 nm.

Spectroscopic evaluation of Nd3+ doped cadmium-boro-phosphate glasses for near-IR (1060 nm) laser applications

Neodymium-doped Cadmium-boro-phosphate glasses were synthesized using the melt quenching procedure to investigate their lasing capacities. The FTIR results reveal the different functional groups and structural units of our glass system. Physical parameters such as density (ρ), molar volume (VM), refractive index (n), Urbach energy (ΔE), and band gap (Eg) were measured, and computed. The results demonstrated that our glasses have indirect-allowed transitions with low localized states. The photoluminescence and absorption spectra were measured and the results suggest that the Nd3+ ions have a uniform distribution throughout the glass network. The Judd-Ofelt parameters (Ω2, Ω4, and Ω6) were obtained using the least-squares procedure. The spectroscopic quality factor (χ), the emission-peak-wavelength (λp), the radiative-transition-probability (Ar), the radiative lifetime (τrad), the radiative and experimental branching-ratio (βrad, βexp), the effective-bandwidth (Δλeff), the stimulated-emission-cross-section (σ(λp)), the gain-bandwidth (σ(λp), × Δλeff) and the optical-gain (σ(λp) x τrad) were measured, computed and compared with other famous reported glasses. The current glass showed low χ values (=0.45), high βexp (=0.7), and high optical gain (15.8 × 10− 24 cm2 s). According to its spectroscopic and radiative properties, our glass system shows remarkable potential for lasing around 1057 nm.

A novel approach to enhance the ionic conductivity of silver nanoparticles incorporated PVA:NaBr polymer electrolyte films via fast neutron irradiation

This study investigates the unprecedented impact of fast neutron irradiation on the structural, electrical, and morphological properties of solid polymer electrolytes (SPEs). The SPE, a poly (vinylalcohol) (PVA)-sodium bromide (NaBr) based matrix with the incorporation of silver nanoparticles (AgNPs), was prepared via a solution casting method and subjected to various time intervals of fast neutron irradiation. X-ray diffraction (XRD) analysis revealed a distinct trend in the polymer electrolyte sample's amorphous phase, with decreased levels at lower neutron fluence and augmented levels at higher fluences. Fourier transform infrared (FTIR) spectroscopy highlighted plausible interactions leading to chain scission and cross-linking. Optical investgations below 300 nm exhibited increased absorbance and a shifted position of the surface plasmon resonance peak correlated with AgNPs. Validation of structural changes in the Ag-incorporated PVA-NaBr system was supported by reduced bandgap and elevation in Urbach energy, corroborating FTIR findings. Enhanced thermal stability was confirmed using thermogravimetric (TGA) analysis. Morphological modification upon irradiation were evident via Field emission scanning electron microscope (FESEM). Transport properties evaluated by Nyquist plot fitting showcased escalating room temperature conductivity with neutron fluence, and the highest conductivity obtained was 4.38 × 10−3 S/cm, an order higher than the pristine sample. Transference number measurements (TNM) indicated that the primary charge carriers are ions rather than electrons. This novel approach confirms that neutron irradiation can be used as a potential way to obtain highly conductive polymer electrolyte films.

Nanoscale morphology, optical dynamics and gas sensor of porous silicon

We investigated the multifaceted gas sensing properties of porous silicon thin films electrodeposited onto (100) oriented P-type silicon wafers substrates. Our investigation delves into morphological, optical properties, and sensing capabilities, aiming to optimize their use as efficient gas sensors. Morphological analysis revealed the development of unique surfaces with distinct characteristics compared to untreated sample, yielding substantially rougher yet flat surfaces, corroborated by Minkowski Functionals analysis. Fractal mathematics exploration emphasized that despite increased roughness, HF/ethanol-treated surfaces exhibit flatter attributes compared to untreated Si sample. Optical approaches established a correlation between increased porosity and elevated localized states and defects, influencing the Urbach energy value. This contributed to a reduction in steepness values, attributed to heightened dislocations and structural disturbances, while the transconductance parameter decreases. Simultaneously, porosity enhances the strength of electron‒phonon interaction. The porous silicon thin films were further tested as effective gas sensors for CO2 and O2 vapors at room temperature, displaying notable changes in electrical resistance with varying concentrations. These findings bring a comprehensive exploration of some important characteristics of porous silicon surfaces and established their potential for advanced industrial applications.

Structural, optical, and impedance spectroscopy of the pseudobrookite Pb0·5Ba0·5Fe2O5 synthesized by sol–gel route

Pseudobrookite of general formula Pb0·5Ba0·5Fe2O5 was synthesized by the sol–gel route. X-ray diffraction confirms the orthorhombic Pnma space group of our sample. UV–Vis absorption spectroscopy was used to characterize this material's optical properties. We used the Tauc model and absorption measurements to estimate the direct optical band gap at 3.53 eV. We also calculate the Urbach energy, the optical extinction coefficient, and the refractive index. In addition, the skin depth, optical conductivity, and Cauchy parameters were investigated in relation to the incident photon's wavelength. Electrical conductivity data flow the Jonscher's power law and show that PBFO has two different conducts; Semiconductor behavior in the temperatures region [400 K–520 K]. Then, a metallic trend was detected beyond TS-M = 520 K. The correlated barrier hopping (CBH) model is the appropriate model to describe the conduction process in low temperature range. On the other hand, the conduction is ensured by the non-overlapping small polaron tunneling (NSPT) at high temperature zone. The scaling study shows that the conductivity spectra deviate from Summerfield and Ghosh scaling. The random barrier model (RBM) is employed to correct the Summerfield approach and we note that the conductivity isotherms are combined into a single master curve. The estimated activation energies values from dc-conductivity, hopping frequency and relaxation time are very close. The behavior of dielectric parameters was examined using the Maxwell-Wagner theory of interfacial polarization. The dielectric-relaxation phenomenon is shown by the behaviors of imaginary parts of impedance (Z″) and modulus (M″). The ideal electrical equivalent circuit for simulating the Nyquist curves (i.e. Z′′(Z′)) for our pseudobrookite is (Rg + Rgb//CPEgb). Finally, the entropy (ΔS), and enthalpy (ΔH) were established as thermodynamic parameters.

Optical and Color Modification in Polycarbonate/Polybutylene Terephthalate/Zinc sulfide-Nickel Oxide Nanocomposite Films due to Gamma Irradiation

Nanocomposites (NC) of amorphous polycarbonate (PC), semicrystalline polybutylene terephthalate (PBT), zinc sulfide (ZnS) and nickel oxide (NiO) nanoparticles (NP) were synthesized. We believe that this study is novel in the area of the effect of γ radiation on such NC. Both the synthesized NiO and ZnS had a nanonature of average particle size 4 and 18 nm, respectively, as indicated from the Rietveld refinement of the XRD records. Samples of the PC-PBT/ZnS-NiO NC films were irradiated with several γ doses (10–140 J/cm2). The resultant outcome of the γ irradiation on the optical behavior of the NC films was studied applying ultraviolet spectroscopy (UVs). Upon raising the dose up to 140 kGy, the direct bandgap decreased from 4.11 to 3.6 eV. The Urbach energy showed an opposite tendency; it increased from 0.61 to 0.95 eV. We attribute this to the dominance of chain crosslinks. Also, the optical dielectric loss (ε″) aided in detecting the nature of the microelectronic transitions. It was found that the PC-PBT/ZnS-NiO NC films had direct allowed transitions. Additionally, the γ induced alterations in the dielectric parameters and optical conductivity were studied. Moreover, the optical color changes between the pristine and the irradiated films were assessed. The pristine NC film was uncolored. It showed significant color alterations when irradiated with γ radiation up to 140 kGy. The induced enhancements in the optical properties suggest that the γ radiation is an effective means that allows the use of PC-PBT/ZnS-NiO NC in optoelectronic devices.

Citrate silver nanoparticles impregnated cellulose as a photocatalytic filter in the degradation of organic dye in the aqueous media

Photocatalysis is a clean and efficient process pursued under light irradiation with a suitable photocatalyst to degrade a contaminant. We report citrate functionalization of silver nanoparticles (SNPs) for effective immobilization on cellulosic fabric. The porous cellulosic matrix could be explored as microfiltration membranes for the photocatalytic degradation of organic dyes in the aqueous media. Where valid, the citrate functionalized SNPs and the treated cellulose fabrics were considered for optical, structural, surface chemical, thermal, textile, flowability, photocatalytic, and antibacterial attributes. The SNPs expressed the bandgap energy of 2.56 and 2.43 eV and Urbach energy of 3.38 and 5.21 eV before and after functionalization with the citrate moieties, respectively. The liquid chromatographic and FTIR analyses indicated that the crystal violet (CV) organic dye has been successfully photodegraded to environmentally safer and nontoxic species on passing the contaminated water through the SNPs-treated cellulosic filter. The spectroscopic data also supported the said outcomes. The results demonstrated that the citrate-SNPs-treated cellulose could be efficiently employed as antibacterial photocatalytic membranes for degrading organic dyes in the aqueous media for multiple cycles.