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Characterization and Photoluminescence Property of a New Eu <sup>3+</sup> -doped Phosphor of the K <sub/>2</sub> [Al(B <sub/>5</sub> O <sub/>10</sub> )] Prepared by Precursor Method
摘要： A new phosphor of the K2[Al(B5O10)]:Eu3+ was prepared by annealing of the as-prepared of the precursor of K2[Al(B5O10)]·4H2O:Eu3+ at 300–400 °C, and which has been synthesized under facile hydrothermal conditions. All the samples were characterized by the EDS, XRD, FT-IR, and SEM. A systematic study on their luminescent properties has been performed by the PL and PLE. A series of influencing factors on the luminescent properties were also investigated. The PL and PLE studies reveal that the phosphor of K2[Al(B5O10)]:Eu3+ with optimal luminescent intensity and higher red-orange ratio were obtained by sintering the precursor at 400 °C for 5.5 h, with 9% doping concentration, which suggests that it might as a potential application of the light display systems.
关键词： Precursor method,Luminescent property,Eu3+ doped phosphor,Aluminoborate
更新于2025-09-23 15:22:29
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Photocatalytic Degradation of Estriol Using Iron-Doped TiO2 under High and Low UV Irradiation
摘要： Iron-doped TiO2 nanoparticles (Fe-TiO2) were synthesized and photocatalitically investigated under high and low ?uence values of UV radiation. The Fe-TiO2 physical characterization was performed using X-ray Powder Diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Diffuse Re?ectance Spectroscopy (DRS), and X-ray Photoelectron Spectroscopy (XPS). The XPS evidenced that the ferric ion (Fe3+) was in the TiO2 lattice and unintentionally added co-dopants were also present because of the precursors of the synthetic method. The Fe3+ concentration played a key role in the photocatalytic generation of hydroxyl radicals (?OH) and estriol (E3) degradation. Fe-TiO2 accomplished E3 degradation, and it was found that the catalyst with 0.3 at.% content of Fe (0.3 Fe-TiO2) enhanced the photocatalytic activity under low UV irradiation compared with TiO2 without intentionally added Fe (zero-iron TiO2) and Aeroxide? TiO2 P25. Furthermore, the enhanced photocatalytic activity of 0.3 Fe-TiO2 under low UV irradiation may have applications when radiation intensity must be controlled, as in medical applications, or when strong UV absorbing species are present in water.
关键词： hydroxyl radical,estriol,iron-doped TiO2,photocatalytic activity,low UV irradiation
更新于2025-09-23 15:22:29
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Highly Selective Photocatalytic Reduction of o-Dinitrobenzene to o-Phenylenediamine over Non-Metal-Doped TiO2 under Simulated Solar Light Irradiation
摘要： Photocatalytic reduction and hydrogenation reaction of o-dinitrobenzene in the presence of oxalic acid over anatase-brookite biphasic TiO2 and non-metal-doped anatase-brookite biphasic TiO2 photocatalysts under solar simulated light was investigated. Compared with commercial P25 TiO2, the prepared un-doped and doped anatase-brookite biphasic TiO2 exhibited a high selectivity towards the formation of o-nitroaniline (85.5%) and o-phenylenediamine ~97%, respectively. The doped anatase-brookite biphasic TiO2 has promoted photocatalytic reduction of the two-nitro groups of o-dinitrobenzene to the corresponding o-phenylenediamine with very high yield ~97%. Electron paramagnetic resonance analysis, Transient Absorption Spectroscopy (TAS) and Photoluminescence analysis (PL) were performed to determine the distribution of defects and the fluorescence lifetime of the charge carriers for un-doped and doped photocatalysts. The superiority of the doped TiO2 photocatalysts is accredited to the creation of new dopants (C, N, and S) as hole traps, the formation of long-lived Ti3+ defects which leads to an increase in the fluorescence lifetime of the formed charge carriers. The schematic diagram of the photocatalytic reduction of o-dinitrobenzene using the doped TiO2 under solar light was also illustrated in detail.
关键词： selectivity,photocatalysis,non-metal-doped TiO2,nitroaromatic compounds,reduction
更新于2025-09-23 15:22:29
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Recent Development of Photocatalysts Containing Carbon Species: A Review
摘要： Undoubtedly, carbon-based (nano)composites can be promising photocatalysts with improved photocatalytic activity due to the coupling effect from the incorporation of carbon species. In this mini-review, we focus on the recent development of photocatalysts based on carbon-based (nano)composites. TiO2 is well-known as a typical photocatalyst. Special attention is paid to the various types of carbon–TiO2 composites such as C-doped TiO2, N–C-doped TiO2, metal–C-doped TiO2, and other co-doped C/TiO2 composites. Various synthetic strategies including the solvothermal/hydrothermal method, sol–gel method, and template-directed method are reviewed for the preparation of carbon-based TiO2 composites. C/graphitic carbon nitride (g-C3N4) composites and ternary C-doped composites are also summarized and ascribed to the unique electronic structure of g-C3N4 and the synergistic effect of the ternary interfaces, respectively. In the end, we put forward the future perspective of the photocatalysts containing carbon species based on our knowledge.
关键词： (nano)composites,synergistic effect,g-C3N4,C-doped,photocatalysts,TiO2
更新于2025-09-23 15:22:29
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Comparison of the Optical and Electrical Properties of Al-Doped ZnO Films Using a Lorentz Model
摘要： In this research, zinc oxide (ZnO) films are doped with various amounts of Al dopants, from 0 to 13 at.%, using ion-beam co-sputtering for Zn and Al metallic targets at room temperature. The Al-doped ZnO (AZO) films appear to have lower transmittances in the UV and near-IR ranges. The electrical and optical properties of each film are successfully analyzed by using the spectroscopic ellipsometry of two Lorentz oscillators for the two lower transmittances. The optimal AZO film is deposited with an Al-dopant of 1.5 at.% at an oxygen partial pressure of 0.12 mTorr; it has the smallest resistivity of 7.8 × 10?4 Ω cm and high transmittance of > 80% in the visible regions. The free carrier concentration and mobility evaluated using ellipsometry are different from those measured using the Hall effect. This phenomenon was the result of the grain boundary scattering due to the small ~20-nm grain size of the AZO film used in this study.
关键词： ellipsometry,grain boundary scattering,Hall effect,Lorentz oscillators,Al-doped ZnO,ZnO
更新于2025-09-23 15:22:29
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Plasma-Assisted Chemical Vapor Synthesis of Aluminum-Doped Zinc Oxide Nanopowder and Synthesis of AZO Films for Optoelectronic Applications
摘要： Transparent conducting oxide aluminum-doped zinc oxide (AZO) nanoparticles were synthesized by a plasma-assisted chemical vapor synthesis route using zinc nitrate and aluminum nitrate as the precursors. The injected precursors vaporized in the plasma flame, followed by vapor-phase reaction and subsequent quenching of the vaporized precursors, producing nanosized AZO powder. The amount of aluminum nitrate was varied to obtain samples with 2 at.%, 4 at.% and 8 at.% Al, designated as AZO1, AZO2 and AZO3, respectively. The XRD patterns of the AZO1 and AZO2 nanoparticles indicated the presence of a wurtzite structure without any alumina peaks except in the AZO3 sample, and scanning electron microscopy micrographs revealed spherical particles. The magnetization measurements revealed a ferromagnetic behavior at room temperature in the AZO1 sample, and the ferromagnetic order is decreased in the high field region with an increase in the Al doping amount. AZO thin films were deposited on glass substrates by spin-coating a dispersion of nanoparticles. All the AZO films had a hexagonal wurtzite structure and exhibited a c-axis preferred orientation perpendicular to the substrate. The Hall effect measurements yielded a minimum resistivity of 9.9 × 10?? Ω cm for the AZO2 film and optical transmission of 80% for both the AZO1 and AZO2 films. However, with 8 at.% Al in the AZO3 film, deterioration in crystallinity, electrical and optical properties were observed. Post-annealing of the AZO1 film in H2 atmosphere caused a significant decrease in resistivity from 1.2 × 10?3 Ω cm to 8.7 × 10?? Ω cm. The optical band gap energies of the AZO films were determined from the transmission spectra. The blue shift in the band gap from 3.2 eV to 3.28 eV, observed with an increase in Al doping, was interpreted by the Burstein–Moss effect. The photoluminescence spectra of the AZO films revealed a UV near-band edge emission and a green emission peak.
关键词： Plasma,optoelectronics,doped-zinc oxide,chemical vapor synthesis
更新于2025-09-23 15:22:29
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Ultraviolet electroluminescence from nanostructural SnO2-based heterojunction with high-pressure synthesized Li-doped ZnO as a hole source
摘要： We report an ultraviolet (UV) electroluminescence (EL) in n-SnO2/p-ZnO heterojunction light-emitting diodes with the nanostructural SnO2 as an n-type layer and the Li-doped ZnO (ZnO:Li) synthesized by high-temperature high-pressure (HTHP) method as a high hole concentration p-type layer. Two kinds of SnO2 nanostructures including nanobelts (NBs) and nanowires (NWs) were used to fabricate n-type layers in the heterojunctions. The two heterojunctions with different SnO2 nanostructures demonstrate different light-emission feature in EL measurements. The SnO2 NBs/p-ZnO heterojunction shows a blue emission band centered at 416 nm under forward-bias voltage. A strong UV emission peak located at 391 nm was observed for the SnO2 NWs/p-ZnO heterojunction. Photoluminescence (PL) spectra indicate that the difference in EL is attributed to morphology-dependent light-emission feature in nanostructural SnO2 layer. Our results suggest that the nanostructural SnO2/ZnO:Li heterojunction is a potential and promising system in the UV optoelectronic field.
关键词： High-temperature high-pressure method,Light-emitting diode,Nanobelt,Nanowire,SnO2,Li-doped ZnO
更新于2025-09-23 15:22:29
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Experimental and numerical investigation to rationalize both near-infrared and mid-infrared spontaneous emission in?Pr3+ doped selenide-chalcogenide fiber
摘要： This contribution reports on detailed experimental and numerical investigations of both near-infrared (NIR) and mid-infrared (MIR) photoluminescence obtained in praseodymium trivalent ion doped chalcogenide-selenide glass fiber. The experimental analysis allows for the identification of the radiative transitions within the praseodymium ion energy level structure to account for the photoluminescent behavior. Numerical analysis is carried out using the rate equations' approach to calculate the level populations. The numerical analysis provides further insight into the nature of the radiative transitions in the Pr3+ ion doped chalcogenide-selenide glass and allows for the identification of the electronic transitions, which contribute to the observed photoluminescence. The numerical results agree well with the experimental results.
关键词： chalcogenide glass fibers,optical fiber modelling,lanthanide doped fibers
更新于2025-09-23 15:22:29
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Synthesis and mechanoluminescent property of (Eu2+, Dy3+)-co-doped strontium aluminate phosphor by soft mechanochemistry-assisted solid-state method
摘要： (Eu2+, Dy3+)-co-doped strontium aluminate (SrAl2O4:Eu2+, Dy3+) powder as a mechanoluminescent (ML) phosphor was synthesized via soft mechanochemical pretreatment of precursor mixtures in a stirred media mill and subsequent calcination. Effect of soft mechanochemical pretreatment of precursors on the synthesis process as well as the photoluminescent (PL) and ML properties of SrAl2O4:Eu2+, Dy3+ phosphor was investigated. The precursor mixtures unground and ground at different time and the resultant phosphors were characterized by laser particle size analysis, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, Fourier transfer infrared spectroscopy and optical property measurement. The results reveal that soft mechanochemical pretreatment of precursor mixture promotes the crystal growth, and reduces the subsequent calcination temperature. SrAl2O4:Eu2+, Dy3+ phosphor can be obtained via calcining at 1200 oC for precursor mixture ground at 60 min, but formed via calcining at 1400 oC for unground precursor mixture. The phosphor synthesized with precursor mixture ground at 60 min has the maximum PL and ML intensities due to the enhancement of Eu2+ and Dy3+ ions into the crystal lattice to form more electron traps. The measurements by a designed ML instrument indicate that the ML intensity increases with increasing impact stress, and decreases with multiple applications of the same impact stress on phosphor disks.
关键词： Phosphor,Soft mechanochemistry,(Eu2+, Dy3+)-co-doped strontium aluminate,Solid-state method,Mechanoluminescence
更新于2025-09-23 15:22:29
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Ag3PO4 modified phosphorus and sulphur co-doped graphitic carbon nitride as a direct Z-scheme photocatalyst for 2, 4-dimethyl phenol degradation
摘要： Very recently, hybrid photocatalysts are gaining importance due to their unique and enhanced photocatalytic activity. In precedent study, we have successfully prepared Ag3PO4 (AP) and P and S co-doped g-C3N4 (PSGCN) based AP/PSGCN photocatalyst via facile deposition-precipitation method. The P and S co-doped g-C3N4 was prepared via thermal poly-condensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. The photocatalysts were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). The thickness of AP/PSGCN was less than 9.0 nm. The zeta potential and Tyndall effect experiments validated the formation of well dispersed suspension of AP/PSGCN in water. The co-doping resulted in lowering of optical band gap of g-C3N4. The Tyndall effect experiments ascertained the formation of well dispersed suspension of AP/PSGCN. The photoluminescence and electrochemical impedance analysis confirmed reduction in recombination of photogenerated electron and hole pairs. The photodegradation of 2,4-dimethyl phenol (DMP) followed pseudo first order kinetics. The enhanced photocatalysis was due to direct Z-scheme mechanism. Hydroxyl and superoxide radicals were the two main reactive species during DMP degradation. The COD, HPLC and LC-MS investigations ascertained mineralization of DMP. AP/PSGCN displayed high stability and recycle efficiency significant for ten catalytic cycles.
关键词： DMP,Ag3PO4,P and S Co-doped g-C3N4,Nanocomposite,Z-scheme photocatalysis
更新于2025-09-23 15:22:29