Photoluminescence Spectral Analysis Research Articles

Tailoring scintillation and luminescence through Co-doping engineering: A comparative study of Ce,Tb Co-doped YAGG and GAGG garnet crystals

The development of scintillators with co-doping mechanisms has received significant attention due to the resulting enhancements in luminescence and scintillation properties. Scintillators such as Ce-doped (Gd,Tb)3(Al,Ga)5O12 have been recognized for their improved performance, attributed to the effective energy transfer between Ce3+ and Tb3+ ions. Nevertheless, the presence of Gd3+ introduced complexities, as its absorption lines strongly overlap with those of Tb3+, thus masking the details of mechanisms of the Tb3+↔Ce3+ energy transfer. This study endeavored to elucidate this mechanism by comparing the luminescence characteristics of Ce,Tb co-doped Y3Al2Ga3O12 (YAGG) and Gd3A2Ga3O12 (GAGG) single crystals. Through detailed photoluminescence spectral analysis, it was discerned that GAGG exhibited a more robust Tb3+↔Ce3+ energy transfer, as evidenced by a marked extension in the decay time of Ce3+ luminescence. Furthermore, GAGG demonstrated superior integrated radioluminescence intensity across all compositions which is a result of efficient energy transfer from Gd3+ to the luminescence centers. Additionally, comparative thermally stimulated luminescence glow curves, revealed distinctive spectral features between YAGG and GAGG, underscoring the complexity of their luminescence mechanisms. This comparative study not only augmented our comprehension of the intricate energy transfer processes in Ce, Tb co-doped garnet scintillators but also underscored the potential for tailored scintillator development through strategic ion co-doping.

Enhanced Antibacterial Activity of Carbon Dots: A Hybrid Approach with Levofloxacin, Curcumin, and Tea Polyphenols

Bacterial infections and their increasing resistance to antibiotics pose a significant challenge in medical treatment. This study presents the synthesis and characterization of novel carbon dots (CDs) using levofloxacin (Lf), curcumin (Cur), and tea polyphenols (TP) through a facile hydrothermal method. The synthesized curcumin-tea polyphenol@carbon dots (Cur-TP@CDs) and levofloxacin-tea polyphenol@carbon dots (Lf-TP@CDs) were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, confirming their unique structural and chemical properties. Cur-TP@CDs exhibited an average particle size of 1.32 nanometers (nm), while Lf-TP@CDs averaged 1.58 nm. Both types demonstrated significant antibacterial activity, with Lf-TP@CDs showing superior effectiveness against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in broth dilution and disc diffusion assays. Biofilm inhibition assays revealed a significant reduction in biofilm formation at higher concentrations. The ultraviolet-visible (UV-vis) and photoluminescence (PL) spectral analyses indicated efficient photon emission, and electron paramagnetic resonance (EPR) analysis showed increased singlet oxygen generation, enhancing bactericidal effects. Live and dead bacterial staining followed by scanning electron microscopy (SEM) analysis confirmed dose-dependent bacterial cell damage and morphological deformities. These findings suggest that Cur-TP@CDs and Lf-TP@CDs are promising antibacterial agents, potentially offering a novel approach to combat antibiotic-resistant bacterial infections.

Crystal structure and photophysical and electrochemical properties of the first octamolybdate porphyrin

A novel molybdenum polyoxometalate (POM) porphyrinic compound, i.e. (Mo8O26)(5,10,15,20-tetra-3-H-pyridinyl-21H,23H-porphine)·2H2O (1) was synthesized via a hydrothermal reaction of MoCl5, 5,10,15,20-tetra-3-pyridinyl-21H,23H-porphine and distilled water. This is the first octamolybdate porphyrinic compound. Its crystal structure and properties have been unlocked thoroughly by virtue of single-crystal X-ray diffraction, PXRD (powder X-ray diffraction), UV/vis, FTIR, photoluminescence, CIE (Commission Internationale de I'Éclairage), CT (color temperature) and cyclic voltammetric (CV) spectral analyses. The crystal structure of this compound is characteristic of an isolated (0D) motif and it is comprised of a (Mo8O26)4− anion, a (5,10,15,20-tetra-3-H-pyridinyl-21H,23H-porphine)4+ cation and two lattice water molecues. A three-dimensional (3D) framework is formed by the π-π stacking and hydrogen bonding interactions. The solid state photoluminescence measurements show that compound 1 emits red photoluminescence which results from the (5,10,15,20-tetra-3-H-pyridinyl-21H,23H-porphine)4+ cations. Compound 1 has CIE chromaticity coordinates of (0.7236, 0.2764). The CT is 7978 K. The slow sweep CV of 1 exhibits a reversible wave with E1/2 being of 0.78 V.

Novel Ag-Bridged Z-Scheme CdS/Ag/Bi2WO6 Heterojunction: Excellent Photocatalytic Performance and Insight into the Underlying Mechanism

The construction of semiconductor heterojunction photocatalysts that improve the separation and transfer of photoinduced charge carriers is an effective and widely employed strategy to boost photocatalytic performance. Herein, we have successfully constructed a CdS/Ag/Bi2WO6 Z-scheme heterojunction with an Ag-bridge as an effective charge transfer channel by a facile process. The heterostructure consists of both CdS and Ag nanoparticles anchored on the surface of Bi2WO6 nanosheets. The photocatalytic efficiency of the CdS/Ag/Bi2WO6 system was studied by the decontamination of tetracycline (TC) and Rhodamine B (RhB) under visible light irradiation (λ ≥ 420). The results exhibited that CdS/Ag/Bi2WO6 shows markedly higher photocatalytic performance than that of CdS, Bi2WO6, Ag/Bi2WO6, and CdS/Bi2WO6. The trapping experiment results verified that the •O2− and h+ radicals are the key active species. The results of photoluminescence spectral analysis and photocurrent responses indicated that the CdS/Ag/Bi2WO6 heterojunctions exhibit exceptional efficiency in separating and transferring photoinduced electron−hole pairs. Based on a series of characterization results, the boosted photocatalytic activity of the CdS/Ag/Bi2WO6 system is mostly due to the successful formation of the Ag-bridged Z-scheme heterojunction; these can not only inhibit the recombination rate of photoinduced charge carriers but also possess a splendid redox capacity. The work provides a way for designing a Z-scheme photocatalytic system based on Ag-bridged for boosting photocatalytic performance.

Graphene oxide decorated BiOI/CdS nanocomposite: An efficient ternary heterostructure for photodegradation and adsorption study of organic pollutants

This study presents a ternary heterostructure comprising graphene oxide (GO) decorated BiOI/CdS, as a highly effective candidate for both the photodegradation and adsorption of organic pollutants. The composite materials were synthesized through a facile solvothermal method. The structural and morphological characteristics of the synthesized materials were thoroughly analyzed using various analytical techniques. Photoluminescence (PL) spectral analysis of the photocatalysts emphasises the strong charge-carrier separations in ternary composites, which is the main requirement for enhancing degradation performances. The photocatalysts were utilized to remove the methylene blue (MB) and doxycycline (DC) from aqueous suspensions. The most effective ternary composite (GO/BiOI/CdS-x, x = 0.4 mmol CdS) resulted in 99.2% degradation of MB within 25 min and 83.7 % degradation of DC within 150 min of light exposure. Trapping experiments identified O2•- and h+ as the most active species in pollutant degradation. A Z-scheme mechanism, supported by Mott-Schottky plots, VB-XPS spectra, and active species observations, was proposed to elucidate degradation processes. Additionally, the GO/BiOI/CdS-0.4 ternary composite demonstrated impressive adsorption ability for MB, indicating its robust pollutant removal capability. The composite also demonstrated remarkable stability and an impressive ability to be reused, positioning it as a highly promising material for use in wastewater treatment.

Influence of PbO content on the glass forming ability, crystallization, electrical, UV–Vis. and photoluminescence spectroscopy properties of LiF.PbO system

New glass samples were synthesized from the binary system LiF. PbO with different ratiosby the traditional melt-quenching technique. The corresponding glass-ceramics were formed by heat treating the prepared glasses. Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Transmission electron microscope (TEM) were employed to study the structure of the samples; while characterization of the glass and glass-ceramics were studied using photoluminescence (PL) spectral analysis, electrical, UV–Visible absorption, optical band gap and hardness measurements. The ability to form glass was increased with increase PbO content (1LiF:≥5PbO). Tetragonal and orthorhombic PbO, orthorhombic and monoclinic Pb2O3, α-PbF2 and traces of both Li4PbO4, PbO1.37 were crystallized under specific heat-treatment circumstances as identified by XRD analysis. The crystal size decreased with increasing the PbO content; it reaches ∼15 nm in case of 10 Pb. PL revealed concentration quenching in glass with 10 Pb, a red shift and enhancement of bands intensity were observed with decrease λex, increase heat-treatment temperature and increase PbO concentration. The UV–Visible absorption elucidated that the cutoff wavelength (λ) was shifted toward lower wavelength (blue shift) by increasing PbO content and the values of optical band gap energies recorded 2.69, 2.66 and 2.72 eV for LiF·5PbO, LiF·8PbO, and LiF·10PbO, respectively. The electrical properties recorded conductivity ∼1.2 × 10−6 S m−1 and dielectric constant ∼ 46.8. These characteristics suggests that, the prepared materials exhibited semiconducting and photoluminescence behavior nominated it to be utilized in solar cell applications.

Copper oxide modified biphasic titania for enhanced hydrogen production through photocatalytic water splitting

Recently, TiO2(B) has been extensively used in catalytic and energy fields owing to its exceptional crystal structure. But being a metastable state, TiO2(B) is transformed easily into other stable crystalline forms like anatase or rutile phase, and the low crystallinity limits the application of the material in catalysis. A combination of TiO2(B) with anatase, which is benefitted by a homojunction, is proven to be blessed with high activity. Herein, hydrogen production via photocatalytic water-splitting is presented using Cu modified biphasic titania nanotubes achieved by a facile hydrothermal procedure. The systems are well characterized using SEM, TEM, XRD analysis, N2 adsorption study, FTIR, DR-UV, Raman, Photoluminescence, and X-ray photoelectron spectral analysis. The homo-junction developed in titania due to anatase –TiO2 (B), as well as the heterojunction created by the co-catalyst, tune the photocatalytic activity of TiO2 nanotubes positively, as evident from the enhanced hydrogen production over the system.

Probing NV and SiV charge state dynamics using high-voltage nanosecond pulse and photoluminescence spectral analysis

Nitrogen-vacancy (NV) and silicon-vacancy (SiV) color defects in diamond are promising systems for applications in quantum technology. The NV and SiV centers have multiple charge states, and their charge states have different electronic, optical and spin properties. For the NV centers, most investigations for quantum sensing applications are targeted on the negatively charged NV (NV−), and it is important for the NV centers to be in the NV− state. However, it is known that the NV centers are converted to the neutrally charged state (NV0) under laser excitation. An energetically favorable charge state for the NV and SiV centers depends on their local environments. It is essential to understand and control the charge state dynamics for their quantum applications. In this work, we discuss the charge state dynamics of NV and SiV centers under high-voltage nanosecond pulse discharges. The NV and SiV centers coexist in the diamond crystal. The high-voltage pulses enable manipulating the charge states efficiently. These voltage-induced changes in charge states are probed by their photoluminescence spectral analysis. The analysis result from the present experiment shows that the high-voltage nanosecond pulses cause shifts of the chemical potential and can convert the charge states of NV and SiV centers with the transition rates of ∼MHz. This result also indicates that the major population of the SiV centers in the sample is the doubly negatively charged state (SiV2−), which is often overlooked because of its non-fluorescent and non-magnetic nature. This demonstration paves a path for a method of rapid manipulation of the NV and SiV charge states in the future.

Photochromic cellulose nanofibers-reinforced polyacrylic acid self-healable hydrogel toward dual-mode security authentication stamp

Photochromic inks have displayed various disadvantages such as poor durability, high cost and limited efficiency. The self-healing inks have shown to be more durable and photostable. In order to create an authentication stamp, UV-induced photochromic hydrogel inks with self-healable capabilities were developed. Nanoparticles of rare-earth aluminate (NREA) were synthesized and dispersed in a combination of cellulose nanofibers (CNF) and polyacrylic acid (PAA) to create an organic-inorganic hybrid ink. NREA were produced and analyzed using transmission electron microscope (TEM), revealing diameters of 1–4 nm. CNF were synthesized to act as a nanofiller and dispersing agent to improve the mechanical strength of the polyacrylic acid bulk and to prevent the agglomerates of the NREA. In order to create transparent prints, NREA must be uniformly disseminated in the CNF/PAA hybrid hydrogel ink without clumping. A paper surface was effectively stamped with the photochromic ink, and then the ink was thermofixed. Transparency was achieved by direct stamping of a consistent photochromic layer on the sheet surface, and this film was shown to become green when exposed to ultraviolet light as verified by photoluminescence spectral and CIE Lab analysis. The luminous paper sheets had an emission wavelength at 519 nm when irradiated at 368 nm. Energy-dispersive X-ray (EDX), infrared spectroscopy (FT-IR), X-ray fluorescence and scanning electron microscope (SEM) were utilized to examine the morphology of the stamped sheets. The cellulose nanofibers displayed diameters of 9–17 nm. The printed hydrogel ink displayed highly reversible photochromic emission without fatigue. Mechanical testing of the printed sheets and examination of the rheology of the luminous hydrogel was explored. The current NREA@CNF/PAA hydrogel ink offers a competent method for anticounterfeiting that can be used in a variety of authentication industries.

Facile synthesis of CuO/g-C3N4 nanolayer composites with superior catalytic reductive degradation behavior

The cupric oxide (CuO) loaded graphitic carbon nitride (g-C3N4) nanocomposites (CuO/g-C3N4) were prepared by a facile calcination method. The formation of monoclinic CuO nanocrystals along with g-C3N4 was confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic analysis. X-ray photoelectron spectral (XPS) analysis further confirms the formation of CuO/g-C3N4. Distribution of CuO stone-like crystalline nanoparticles on g-C3N4 nanosheets was observed by transmission electron microscopic images. The influence of CuO loading on the optical property of g-C3N4 was determined by ultraviolet (UV)-visible absorption and photoluminescence (PL) spectral analysis. Band gap was decreased from 2.7 to 2.3 eV by the addition of CuO nanoparticles. The catalytic performance of the synthesized samples in 4-nitrophenol (4-NP) and methyl orange (MO) reduction was evaluated. The 5 wt% CuO/g-C3N4 showed 99.5% (7 min) and 99.7% (4 min) reduction efficiency for 4-NP and MO respectively. The 5 wt% CuO/g-C3N4 could become a potential catalyst in the chemical treatment of organic pollutants.

Oxalic acid incorporated acetamide single crystal growth dynamics, characterization, NLO and antimicrobial activities via shock wave treatment

Shock waves are applied to non-linear optical materials, particularly organic materials, due to their fast responsein electro-optic switchesand high nonlinearefficiency. At room temperature, an acetamide-doped oxalic acid single crystal has been grown using the slow evaporation method among other crystal growth techniques. Single crystal oxac applies to shock waves in steps of 50 and 100 shock waves to the tail or the material properties without altering the original crystal system. The grown and shock wave treated crystals of OXAC were structurally identified by X-ray diffraction and Fourier transform infrared spectroscopy,UV–Visible and Photoluminescence spectral analysis, nonlinear optical activity (NLO) studies. The antimicrobial studies such as antibacterial and antifungal activities of the grown crystals of oxalic acid, OXAC and OXAC with 50 and 100 shocks were performed and the obtained results were discussed. From we declared results, we state that the post shock wave induced OXAC crystal is enhancing properties of NLO, antimicroibial studies relatively pre shock wave induced OXAC crystal and reflected in structural and optical studies.

Structural, Morphological, Electronic Structural, Optical, and Magnetic Properties of ZnO Nanostructures.

ZnO nanostructures were grown on a Si(111) substrate using a vapor-liquid-solid (VLS) growth procedure (pristine ZnO) and annealed via a rapid thermal-annealing process in an argon atmosphere at 1100 °C (Ar-ZnO). The synthesized ZnO nanostructures were investigated through structural, electronic structural, morphological, optical, and magnetic characterizations. X-ray diffraction and selective area electron diffraction (SAED) measurements revealed that both samples exhibited the hexagonal wurtzite phase of nanocrystalline ZnO. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy carried out at the O K-edge inferred the presence of the intrinsic-defect states. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy images displayed the formation of ZnO nanostructures. The photoluminescence (PL) spectra demonstrated an emission band in the UV region along with an additional defect band in the visible region. PL spectral analysis confirmed the presence of intrinsic defects in Ar-ZnO nanowires, contributing to the enhanced emission in the visible region. The Raman spectra showed the characteristic band (434 cm-1) corresponding to the vibrational modes of hexagonal wurtzite ZnO, with an additional band attributable to intrinsic defects. DC magnetization measurements showed a ferromagnetic response in both samples with enhanced coercivity in Ar-ZnO (~280 Oe). In brief, both samples exhibited the presence of intrinsic defects, which are found to be further enhanced in the case of Ar-ZnO. Therefore, it is suggested that intrinsic defects have played an important role in modifying the optical and magnetic properties of ZnO with enhanced results for Ar-ZnO.

Photoluminescence microscopy as a noninvasive characterization method for defects in gallium oxide and aluminum gallium oxide epitaxial films

Herein we utilize polarized photoluminescence (PL) microscopy and spectral analysis to locate and characterize many different types of µm-scale extended defects present in melt-grown bulk crystals and metal-organic vapor-phase epitaxy (MOVPE)-grown epitaxial thin films of β-Ga2O3 and β-(Al,Ga)2O3. These include pits, divots, mounds, scratches, rotation domain boundaries, stacking faults, cracks, and other defect categories. Some types of µm-scale defects simply decrease overall PL yield, while others emit different spectra than single crystal regions. We combine PL microscopy with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to provide detailed characteristics of these different types of features which can arise from both bulk crystal growth, surface preparation, and epitaxial growth processes. We show that sample quality (in terms of extended defects) can be determined by using PL and that attributing spectral features to isolated point defects is invalid unless the sample is proven to not contain extended defects.

Synthesis of ZnO and ZnS nanoparticles and their structural, optical, and photocatalytic properties synthesized via the wet chemical method

This study reports the synthesis of ZnO and ZnS and their nanocomposites with varying ratios of the two by the wet chemical method. The successful preparation of the samples was confirmed from XRD, FESEM, Raman spectroscopy, and EDX analysis showed hexagonal wurtzite phase of ZnO, cubic ZnS crystal structure, with high purity and crystallinity, coupled with nanoparticles-like morphology of the samples. The optical study reveals that the bandgap of ZnO, ZnS, and their composites, GT-1, and GT-2, was 3.23, 3.54, 3.31, and 3.36 eV, which decreases the bandgap energy after recombination of ZnO and ZnS. The photoluminescence spectral analysis demonstrates that multiple separate bands drive the broad emissions spectrum with zinc vacancies, oxygen vacancies, and surface imperfections. The photocatalytic performance of these samples was tested for degradation of a dye methylene blue under UV light exposure. Among different samples, the GT-1 composite shows a higher dye degradation efficiency (93%) than pure ZnO (55%).

Synthesis, structural characterization, and Hirshfeld surface analysis of novel NLO active 1-methyl-1,3,5,7-tetraazaadamantan-1-ium 3-carboxy-5-nitrobenzoate hydrate

Single crystals of 1-methyl-1,3,5,7-tetraazaadamantan-1-ium 3-carboxy-5-nitrobenzoate hydrate (I) were grown from an aqueous solution containing hexamethylenetetramine (HMT) and 5-nitroisophthalic acid (5NIPA) by slow evaporation solution growth technique after the mild hydrothermal process. The crystal structure is elucidated by single-crystal X-ray diffraction analysis. It crystallizes in the monoclinic system with acentric space group Cc. The cation and anion present in the adduct are bridged by a water molecule, which is interconnected with CH···O and OH···O hydrogen bonds. The relative second harmonic generation (SHG) efficiency measurements characterized by the Kurtz powder technique reveal that (I) is an active SHG material. The grown crystals were further characterized by FT-IR, UV-DRS, and photoluminescence spectral analysis. Theoretical calculations were performed using density functional theory to derive the dipole moment, polarizability, and first-order molecular hyperpolarizability (β). The intermolecular hydrogen bonding interactions are analysed by Hirshfeld surface analysis and fingerprint plots. Theoretically estimated high β rationalized by the experiment. The molecular electrostatic potential (MEP) maps and Mulliken atomic charge were calculated using density functional theory (DFT) calculations.

Effect of Neodymium substitution on the structural, morphological and optical properties of yttrium oxide nanocrystals

ABSTRACT Pure and neodymium (Nd) substituted yttrium oxide nanoparticles were synthesized by the co-precipitation technique. The synthesized materials were annealed at 350°C, 500° C, 750° C and 1000° C using a muffle furnace at an open atmosphere. X-ray diffraction patterns, FTIR spectra and XPS spectra were recorded to study the structural variations. The morphology has been studied through high-resolution SEM images. The elemental analysis was carried out using energy-dispersive spectral analysis by X-rays. The particle sizes and crystalline nature of the annealed samples were studied by transmission electron microscopic images and their corresponding SAED patterns. The photoluminescence spectral analysis indicated that the pure, as well as Nd-substituted materials have emissions in the blue and green regions. It is also observed that the substitution of Nd has enhanced the emission in the blue region. Moreover, the photoluminescence of Nd-substituted Yttrium oxide has a significant variation with respect to annealing temperatures.

Simple Preparation of Multifunctional Luminescent Textile for Smart Packaging.

Linen has been a significant material for textile packaging. Thus, the application of the simple spray-coating method to coat linen fibers with a flame-retardant, antimicrobial, hydrophobic, and anticounterfeiting luminescent nanocomposite is an innovative technique. In this new approach, the ecologically benign room-temperature vulcanizing (RTV) silicone rubber was employed to immobilize the environmentally friendly Exolit AP 422 (Ex) and lanthanide-doped strontium aluminum oxide (RESAO) nanoscale particles onto the linen fibrous surface. Both morphological properties and elemental compositions of RESAO and treated fabrics were examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), wavelength-dispersive X-ray fluorescence (WD-XRF), Fourier transform infrared (FTIR) spectroscopy, and energy-dispersive X-ray spectroscopy (EDX). In the fire resistance test, the treated linen fabrics produced a char layer, giving them the property of self-extinguishing. Furthermore, the coated linen samples’ fire-retardant efficacy remained intact after 35 washing cycles. As the concentration of RESAO increased, so did the treated linen superhydrophobicity. Upon excitation at 366 nm, an emission band of 519 nm was generated from a colorless luminescent film deposited onto the linen surface. The coated linen displayed a luminescent activity by changing color from off-white beneath daylight to green beneath UV source, which was proved by CIE Lab parameters and photoluminescence spectral analysis. The photoluminescence effect was identified in the treated linen as reported by emission, excitation, and decay time spectral analysis. The comfort properties of coated linen fabrics were measured to assess their mechanical and comfort features. The treated linen exhibited excellent UV shielding and improved antimicrobial performance. The current simple strategy could be useful for large-scale production of multifunctional smart textiles such as packaging textiles.

Red luminous ternary europium complexes: Optoelectronic and photophysical analysis

Four luminescent ternary europium complexes of general formula Eu(PBD)3L were synthesized and characterized. Here, L represents auxiliary unit (2,2′-bipyridine and its derivatives) and PBD (1-phenyl-1,3-butanedione) is an organic chromophoric ligand. Elemental composition and complexation has been estimated by elemental and spectroscopic studies. Photoluminescence emission spectra clearly indicate the chromophoric nature of diketone ligand that has effectively sensitized the energized level of Eu3+ ion through antenna effect. The detailed photophysical parameters of the complexes were evaluated theoretically and experimentally. Theoretical parameters were estimated via LUMPAC software and their outcomes were found to be in good concurrence with experimentally derived data. Luminescence decay curve were recorded by monitoring the wavelength corresponding to hypersensitive 5D0→7F2 transition. Geometry of the complexes was resolved via Avogadro software. Colorimetric and photoluminescence spectral analyses suggest the red luminous nature of ternary europium complexes. These red emissive materials might be utilized in designing display devices.

Evolution of photocatalytic activity of CeO2–Bi2O3 composite material for wastewater degradation under visible-light irradiation

The Ce-doped bismuth oxide have been fascinated significantly due to the potential applications in ecological decontamination by photodegradation of the dye pollutants and agrochemical wastewater in to ecofriendly byproducts. Ceria (CO), Bismuth oxide (BO) and Ce-modified bismuth oxide (CBO) nanocrystalline materials were synthesized and thoroughly characterized by XPS, powder XRD, SEM-EDS, FT-IR, Raman, UV–Visible diffuse reflectance (UV–vis-DRS), photocurrent measurements, electrochemical impedence spectroscopy and photoluminescence (PL) spectral analysis. The band gap energy of Bi2O3 was reduced from 3.35 to 2.64 eV, the transformation of the monoclinic (α-Bi2O3) phase to the tetragonal (β-Bi2O3) phase and increase in BET surface area was observed upon Ce4+ doping into BO. Low fluorescence intensity, lesser arc radius of the Nyquist plots, high photocurrent response of CBO specifies a reduction in the rate of recombination of photogenerated electron and hole pair. The photocatalytic activity of BO, CO and CBO were examined for photodegradation of methylene blue (MB), cotton blue (CB) and agrochemical industrial wastewater (ACIWW) under visible light treatment. CBO exhibited greater degradation of MB, CB and ACIWW whereas pristine BO was less active in the degradation of pollutants. The greater photocatalytic activity of CBO is ascribed to stronger absorption of visible-light energy because of the higher surface area and shrinking of band gap energy as well as the easy production of •OH radicals during the photocatalytic reaction evidencing from scavenger studies. Even after five cycles of photodegradation of MB, CB and ACIWW, the photocatalyst CBO is found to be consistent in photocatalytic activity and powder XRD pattern as compared to pure CBO material.

Improved photocurrent properties of La doped CuO thin films coated by nebulizer spray pyrolysis method for photosensor applications

In this study, pure and La of various concentrations (0.5, 1.0, 1.5, 2.0, and 2.5 wt.%) doped CuO thin films were produced by means of the NSP technique to be used as UV photodetection applications. Various physicochemical investigations such as XRD, SEM, PL, UV–Vis, and current-voltage (I–V) characteristics have been conducted to inspect the role of La in the grown films. X-ray diffraction data confirm the single cubic crystal structure and the size of crystallites shrinkages from 22.6 to 19.4 nm. SEM photo shows the formation of triangular prismic shape like morphology. The spectroscopic studies show that the added La impurity promotes their absorption level in the UV region and redshift the optical bandgap from 2.07 to 1.81 eV. Photoluminescence spectral analysis confirms the presence of oxygen vacancies at 413 nm. Upon exposure to a UV light source (λ = 365 nm) the fabricated La-doped CuO thin films offered a better photo-responsivity, detectivity, and external quantum efficiency value of 1.63 × 10−1 AW−1, 1.75 × 1010 Jones, and 107% respectively. Our results provide a guideline to design high-performance UV photodetectors.