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Analogous Anti-Ferroelectricity in Y2O3-Coated (Pb0.92Sr0.05La0.02)(Zr0.7Sn0.25Ti0.05)O3 Ceramics and Their Energy-Storage Performance
摘要： Antiferroelectric analogous (Pb0.92Sr0.05La0.02)(Zr0.7Sn0.25Ti0.05)O3 (PSLZSnT) ceramics were prepared by the solid-state sintering method by introducing a Y2O3-coating via the self-combustion method. The synthesized Y2O3-doped PSLZSnT ceramics present pseudo-cubic structure and rather uniform microstructural morphology accompanied by relatively small grain size. Excellent energy-storage performance is obtained in the Y2O3-doped PSLZSnT ceramics, in which the value of the energy-storage density presents a linearly increasing trend within the electric field measurement range. Such excellent performance is considered as relating to the rather pure perovskite structure, high relative density accompanied by relatively small grain size, and the antiferroelectric-like polarization-electric field behavior.
关键词： oxide doping,self-combustion method,energy-storage density,perovskite structure,PSLZSnT antiferroelectric-like ceramics
更新于2025-09-23 15:23:52
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Preparation and photocatalytic performance of Cu-doped CeO <sub/>2</sub> by citrate combustion method
摘要： Cu-doped cerium oxides were successfully prepared by nitrate combustion method. The crysatlline phase evolution, micro morphology and photocatalytic performance of the products are systematically studied by XRD, SEM/EDX and degradation rate of methylene blue. The results show that at relative low temperature (<600°C), 20 mol% copper can be dissolved into CeO2 fluorite type cubic structure, however, at high temperature of 700°C, CuO phase desolution from CeO2 solid solution is detected by XRD, and confirmed by DTA for 5% Cu-doped sample. The as prepared photocatalysts show agglomeration of ultra fine particles with porous structure. Degradation results of methylene blue indicate that better photocatalytic performance is obtained for 5% Cu-doped CeO2 under the stimulated visible light than UV light irradiation (both 254 nm and 365 nm), even the power of former is half of the later. The loss of photocatalytic activity for higher doping samples (>5% Cu) is believed to be the serious agglomeration of the particles and desolution of CuO from CeO2 solid solution.
关键词： doping,citrate combustion method,copper,photocatalytic,Ceria
更新于2025-09-23 15:23:52
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Effects of Heat-Treatment on Photoluminescence Spectra and Photocatalytic Properties of Solution-Combusted ZnO Nanopowders
摘要： ZnO nanopowders were prepared by a solution combustion method (SCM). The SCM ZnO nanopowders were heat-treated at 200, 400, 500, or 700 °C for 30 min in air and the photoluminescence (PL) of the nanopowders was evaluated. Two strong PL emission peaks are generally recognized as the unique PL signature of ZnO, one is from the band-edge emission and the other corresponds to green emission. The green emission is derived from crystalline defects, and is a critical obstacle for the electrooptical applications of ZnO. Surprisingly, the PL spectra of the SCM ZnO powders showed a single sharp peak near 390 nm. Furthermore, the intensity of this blue emission doubled when the synthesized ZnO powder was heat-treated at 400 °C. The green emission appeared for the sample treated at 500 °C, and was the highest for that treated at 700 °C. To confirm the photocatalytic activity of the ZnO powder heat-treated at 400 °C, the removal of Ag ions from a used photofilm developer was evaluated, with complete removal within 10 min. The removal of the Ag ions by the ZnO powder heat-treated at 400 °C was more than two orders of magnitude faster than that achieved with the SCM ZnO powder. The relation between PL and photocatalytic activity was explained in terms of recombination of the photogenerated electrons. These results might be very useful for highly efficient photocatalyst applications.
关键词： Heat-Treatment,ZnO Nanopowder,PL Spectra,Solution Combustion Method
更新于2025-09-23 15:22:29
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Photoluminescence properties of Ca3B2O6: RE3+ (RE = Dy and Eu) phosphors for ecofrindly solid state lighting
摘要： The phosphors Ca3B2O6:Dy3+ and Ca3B2O6:Eu3+ were prepared by a combustion method. The phosphor was characterized for X- ray diffraction and photoluminescence. The XRD is well matched with the standard JCPDS. Ca3B2O6:Dy3+ phosphor shows two emission bands centered at 481nm and 577nm corresponding to transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 respectively. Eu3+ doped Ca3B2O6 phosphor gives emission centered at 588nm, 597nm, 614nm and 627 nm having excitation at 396nm. Concentration quenching effect was observed in both the phosphors. Photoluminescence results suggest that phosphor could be used as ecofriendly solid state lighting applications.
关键词： Combustion method,Borate,solid state lighting
更新于2025-09-23 15:21:01
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Low-temperature synthesis and characterisation of its photocatalytic properties of BiNbO<SUB align="right">4 by combustion method using polyvinyl alcohol
摘要： BiNbO4 nanopowders were synthesised by polyvinyl alcohol sol-gel combustion method using freshly starting material Nb2O5. nH2O. The prepared samples were characterised by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and thermal gravimetric and differential thermal analysis. The orthorhombic single phase calcined at 750°C for 2 h in the air was thoroughly studied with the highest photocatalytic properties in 25 nm average size. Methyl orange was used to evaluate the photocatalytic properties of BiNbO4 under the visible light irradiation which was degraded by 98%. The regeneration ability of the catalyst was reduced by only 1.65% from 98.85% to 97.20% after using four-times without recovery.
关键词： polyvinyl alcohol,BiNbO4 nanopowders,methylene orange degradation,combustion method
更新于2025-09-19 17:15:36
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Effect of Bi <sup>3+</sup> ion on upconversion-based induced optical heating and temperature sensing characteristics in the Er <sup>3+</sup> /Yb <sup>3+</sup> co-doped La <sub/>2</sub> O <sub/>3</sub> nano-phosphor
摘要： The upconversion-based optical heating and temperature sensing characteristics are investigated in the Er3+/Yb3+/Bi3+ tri-doped La2O3 nano-phosphor synthesized through a solution combustion method. The structural measurements reveal an increase in lattice parameters and particles size of the phosphor on increasing the concentrations of Bi3+ ions. The energy dispersive spectroscopic (EDS) measurements confirm the presence of La, Er, Yb, Bi and O elements in the tri-doped phosphor. The absorption spectra show the large number of bands due to Er3+, Yb3+ and Bi3+ ions. The Er3+/Yb3+ co-doped phosphor gives strong green emission bands at 523 and 548 nm upon 976 nm excitation due to 2H11/2 / 4I15/2 and 4S3/2 / 4I15/2 transitions of Er3+ ion, respectively. The emission intensity of these bands is enhanced upto 15 times in the presence of Bi3+ ions. The emission intensities of the 523 and 548 nm bands vary non-linearly with the pump power. The fluorescence intensity ratio (FIR) of the thermally coupled 523 and 548 nm emission bands shows efficient optical heating in the tri-doped phosphor. The FIR of the 523 and 548 nm emission bands further varies with the increase in temperature of the phosphor. The relative temperature sensing sensitivity has been calculated to be 71 × 10?4 K?1 at 450 K for the tri-doped phosphor. Thus, the Er3+/Yb3+/Bi3+ tri-doped La2O3 nano-phosphor may provide a platform to use it in the photonic devices, as an optical heater and temperature sensor.
关键词： La2O3 nano-phosphor,temperature sensing,optical heating,solution combustion method,Er3+/Yb3+/Bi3+ tri-doped,upconversion
更新于2025-09-19 17:15:36
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AIP Conference Proceedings [AIP Publishing DAE SOLID STATE PHYSICS SYMPOSIUM 2018 - Hisar, Haryana, India (18–22 December 2018)] DAE SOLID STATE PHYSICS SYMPOSIUM 2018 - Mixed fuel approach for the fabrication of TiO2:Dy3+(1-11?mol%) nanophosphors: Applications towards wLED and latent finger print detection
摘要： The pure and Dy3+(1-11 mol%) ions doped TiO2 nanophosphors (NPs) were prepared by solution combustion method using grouping of fuels; glycine and ammonium acetate. PXRD studies establishes that the pure and doped samples show rutile and anatase phases respectively. The Raman spectra illustrates that the absorption peaks noticed at ～ 142, 446 and 609 cm-1 were due to the active vibrational optical phonon modes pertaining to B1g, Eg and A1g respectively of the pure tetragonal rutile phase, whereas the peaks at ～ 395, 513 and 639 cm-1 were attributed due the active modes B1g, A1g and Eg respectively of anatase phase of TiO2. The active mode observed at ～ 142 cm-1 was a characteristic mode whereas the mode at ～ 229 cm-1 was attained due to second order effect [SOE] of pure rutile phase of TiO2. The Raman studies validate the PXRD studies. The CIE and CCT outcomes show that NPs can be used for wLED and household applications. The optimized product TiO2:Dy3+(9 mol% ) was utilized for the visualization of latent finger prints (LFPs). The results reveal that, all the levels (I to III) of ridge feature were clearly visualized under normal light indicating that the powder was a reliable and promising labeling agent for LFPs.
关键词： TiO2:Dy3+,latent finger print detection,wLED,solution combustion method,nanophosphors
更新于2025-09-19 17:13:59
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Kerala, India (12–14 June 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Photoluminescence study of (Sm0.95 Ce0.05)2O3 nanoparticles for LED applications
摘要： Nanophosphors are a blazing area which has gained momentum in the present day research due to the fabulous unique properties of nanoparticles from their respective bulk. The rare earth doped sesquioxides have received considerable attention due to its unique properties like high chemical and thermal stabilities, intense UV absorption and also its use in solid state lightings, LASERS and so on. Here, we have synthesized (Sm0.95 Ce0.05)2O3 nanocrystalline powder using combustion method. Powder X-ray diffraction was used to study the structural characterization of the synthesized sample and the result confirmed that the synthesized nanoparticles had a nanocrystalline structure with a cubic phase and ? space group. The crystal structure and the shape of the particles have a tremendous effect on the photoluminescent properties. The surface morphology and the size of the particles were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM micrographs showed that the synthesized particles appear to be spherical. The TEM results confirmed that the particles formed were spherical and in nano regime. Phosphors with spherical morphology will surely enhance the photoluminescent properties of the materials. Hence the synthesized sample will have good luminescent characteristics. The optical properties of the sample were studied using ultraviolet –visible (UV-Vis) data analysis and photoluminescence (PL) studies. The absorption peaks obtained are at 364nm, 376, 405, 464 nm and 476nm which correspond to 6H5/2 → 4D3/2, 6H5/2 → 4D1/2, 6H5/2 → 6F7/2, 6H5/2 → 4I13/2 and 6H5/2 → 4I11/2 transitions respectively. On excitation, these particles showed a strong emission at 605 nm which corresponds to 4G5/2 →6H7/2 transition and other emissions at 563 nm and 647nm correspond to 4G5/2 →6H5/2 and 4G5/2 →6H5/2 transitions revealing that it is an orange-red emissive phosphor. This novel nanophosphor can offer new possibilities for the development of white light-emitting diodes (WLEDs) which can be excited by the near-UV chips and also in solid state lightings.
关键词： combustion method,LED applications,photoluminescence,Nanophosphors,(Sm0.95 Ce0.05)2O3
更新于2025-09-11 14:15:04
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Comparative study of photoluminescence of single and mixed phase ZrTiO4 prepared by solution combustion and polymeric precursor method
摘要： This work aims to study synthesis methods and photoluminescence properties of ZrTiO4. Wet chemical routes used for synthesis are solution combustion method and polymeric precursor method. Urea and glycine are two different fuels used in solution combustion synthesis. Scanning Electron Microscope studies con?rms that morphology of the nanoparticles depends on synthesis method. Photoluminescent property depends on the phase of the material, rather than the method of synthesis. Characterization such as X-ray diffraction, SEM, Re?ectance and Photoluminescence studies prove the role of synthesis methods on the properties of the ZrTiO4. Both upconversion and down conversion luminescence have been achieved by synthesizing ZrTiO4 from solution combustion method using urea as fuel, where ZrTiO4 exists in mixed phase.
关键词： Polymeric precursor method, (PPM),Photoluminescence,Single phase,Mixed phase,ZrTiO4,Solution combustion method, (SCS)
更新于2025-09-09 09:28:46
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Effect of B2O3 Content on Eu3+?Surrounding in The System SrO?x.B2O3 Containing Eu3+ Ions Prepared by Combustion Method
摘要： The change of Eu3+? surrounding in the system SrO?x.B2O3 with various x values (x = 0.33, 0.5, 1) synthesized by combustion method was investigated via photoluminescence (PL) spectra and phonon sideband (PSB) spectra. From the analysis of PSB spectra, it is reasonable to suggest that when increasing B2O3 content the electron?phonon coupling strength increases due to the increase in the number of B?O? non?bridging bond. By using Judd?Ofelt (JO) theory for PL spectra of Eu3+ ion, the ?2 intensity parameter was calculated and it also shows the asymmetry of Eu3+? surrounding increase corresponding to the B2O3 content.
关键词： Eu3+,Judd?Ofelt theory,Combustion method,electron-phonon coupling,B2O3,phonon sideband
更新于2025-09-09 09:28:46