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Ultrastable Luminescent Hybrid Bromide Perovskite@MOF Nanocomposites for the Degradation of Organic Pollutants in Water
摘要： Hybrid bromide perovskites (HBPs) have emerged as promising candidate in optoelectronic applications, although instability of the materials under working conditions has retarded the progress towards commercialization. As a rational approach to address this core issue, we herein report the synthesis of a series of ultrastable composite materials, wherein HBP nanocrystals (NCs) have been stabilised within a well-known chemically stable metal-organic framework (MOF) viz. zeolitic imidazolate framework (ZIF-8) via pore-encapsulated solvent directed (PSD) approach. The composites maintain their structural integrity as well as photoluminescence (PL) properties upon dipping into a wide range of polar solvents including water (even in boiling conditions), prolonged exposure to UV irradiation and elevated temperature for longer period of time. Further on the basis of high stability, HBP@MOF composites have been demonstrated as heterogeneous photocatalyst to degrade toxic organic pollutants directly in water.
关键词： photocatalysis,porous coordination polymer,stability of hybrid perovskite,Hybrid bromide perovskite,nanocomposites,luminescence properties
更新于2025-09-19 17:15:36
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Synthesis and Luminescence properties of Lithium Aluminium Phosphate Glasses Doped with Nd <sup>3+</sup> Ion for Laser Medium
摘要： Nd3+ ion doped lithium aluminium phosphate glasses were synthesized and studied their properties for laser medium application. The density and the refractive index of the glass samples were carried out at the room temperature. The optical and luminescence properties were studied by investigating absorption and NIR emission spectra of the glass samples. The glasses absorbed photons in ultraviolet (UV), visible light (VIS) and near-infrared (NIR) regions are clearly observed from absorption spectra. For the photoluminescence properties, the glass samples showed the strongest emission at 1063 nm when it were excited by 581 nm which assigned to the energy transitions of Nd3+. The three phenomenological Judd-Ofelt parameters (?2, ?4, ?6) were determined from the spectral intensities of absorption band in order to calculate the radiative transition possibility (AR), stimulated emission cross section (σ(?p)) and branching ratio (?R) of the 4F3/2?4I9/2, 4I11/2 and 4I13/2 transitions. From the obtained results the conclusions made about the possibility of using these glasses as laser material.
关键词： luminescence properties,laser medium,lithium aluminium phosphate glasses,Nd3+ ion,Judd-Ofelt parameters
更新于2025-09-19 17:13:59
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Orange-red-emitting CaTi4(PO4)6:Eu3+ phosphor for white LEDs: synthesis and luminescence properties
摘要： CaTi4(PO4)6:xEu3+ phosphors are successfully synthesized under air condition by high-temperature solid-state method. The crystal structure, morphology, energy spectrum, atomic percentage, elemental mapping, and luminescence properties are investigated, respectively. Monitored at 594 nm, the excitation spectral bands of CaTi4(PO4)6:Eu3+ phosphor in the range of 210–550 nm are assigned to the O2?–Eu3+ charge transfer band (CTB) and the 7F0 → 5H3, 5L7, 5L6, 5D1, 5D2, 5D3, and 5D4 transitions of Eu3+ ion. With excitation at 394 nm, CaTi4(PO4)6:Eu3+ phosphor emits orange-red light with the chromaticity coordinates (0.548, 452), and the emission spectral bands in the region from 575 to 720 nm are attributed to the 5D0 → 7F1, 7F2, 7F3, and 7F4 transitions of Eu3+ ion. The optimal doping concentration of Eu3+ ion is ~ 8 mol%. The lifetime of CaTi4(PO4)6:Eu3+ phosphors decreases from 1.87 to 0.97 ms with increasing Eu3+ concentrations from 1 to 10 mol%. CaTi4(PO4)6:Eu3+ phosphor has a good thermal stability. The experimental results indicate that CaTi4(PO4)6:Eu3+ phosphor has an application prospect in white light-emitting diodes (LEDs) based on the near ultraviolet (~ 394 nm) LED chip.
关键词： Phosphors,Eu3+ ion,CaTi4(PO4)6,Luminescence properties,Orange-red emission
更新于2025-09-19 17:13:59
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Near infrared emitting quantum dots: synthesis, luminescence properties and applications
摘要： Near-infrared (NIR) luminescent quantum dots (QDs) have been studied very intensively. These QDs have excellent optical properties. Their emitting wavelength can be adjusted by their size and composition, and falls in the telecommunication window, making these QDs promising materials for telecommunication. NIR light has small background interference and large penetration depth, which make NIR QDs advantageous in bio-imaging applications. This paper reviews the synthesis and optical properties of several representative NIR QDs, including traditional cadmium, mercury, lead, silver, and indium based QDs, as well as I–III–IV ternary QDs. Typical applications of QDs with NIR luminescence properties, such as light-emitting diodes (LEDs), in biology, luminescent solar concentrators (LSCs), doped glasses/fibers, and optical sensing, are also discussed.
关键词： applications,synthesis,Near-infrared,quantum dots,luminescence properties
更新于2025-09-16 10:30:52
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Luminescent properties of calcium-alumino-silicate glasses (CaAlSi) doped with Sm2O3 and co-doped with Sm2O3?+?Eu2O3 for LED glass applications
摘要： A new glass system of calcium-alumino-silicate doped with Sm2O3 and co-doped with Sm2O3 ± Eu2O3 was fabricated in order to improve the efficiency of the red emission for phosphor glass materials. The optical properties of the glass samples were studied by measurements using UV–vis absorption spectra and excitation energy. The results showed that 403 nm of photon energy is effective to elevate the electron in a ground state to an excited state. This photon energy was used to study the emission spectra and energy transfer. The luminescence intensity O/R ratio of the glass samples showed a stronger red shift colour with an increase in the dopants. Moreover, the quantum yield (QY) of the glass samples was measured, and the results showed that Eu2O3 can increase the QY by acting as activator. These results indicate that the glass samples are a good potential candidate for LED applications.
关键词： Sm3+,Glass,Decay times,Luminescence properties,Eu3+
更新于2025-09-12 10:27:22
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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 - Synthesis and characterization of GO coupled SrS material with a study of luminescence properties
摘要： In recent times the production of Graphene Oxide (GO) nanoparticles has drawn an enormous attention of the scientists because of its wide applications and potential candidature in the band gap engineering. Keeping the above facts in mind, the authors have prepared GO with modified Hummer’s method and then prepared a coupled product using annealing and cold freezing method with a phosphorescent material (Strontium Sulfide). The synthesis of GO was confirmed using XRD and Raman techniques. The luminescence properties of pure GO and the coupled product were studied with the help of Thermoluminescence glow curves. The glow curves clearly suggest the formation of trapping centres in the forbidden energy gap, in both the samples with interesting and substantial changes in trapping centres in case of coupled product as compared to pure GO sample. The results can directly be applied for the preparation of new optical materials.
关键词： Strontium Sulfide,optical materials,luminescence properties,thermoluminescence,Graphene Oxide
更新于2025-09-11 14:15:04
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Luminescence properties of Ce3+ and Eu2+ doped M3MgSi2O8 (M = Ca, Sr) phosphors for potential detecting applications
摘要： A series of phosphors M3–xLnxMgSi2O8 (M = Ca, Sr; Ln = Ce, Eu; x = 0.005, 0.01, 0.03, 0.05, 0.07, 0.10, 0.15) were synthesized. The luminescence properties in the vacuum ultraviolet-ultraviolet visible spectral range and the X-ray excited radioluminescence were investigated in detail. The results reveal that the M3–xLnxMgSi2O8 (M = Ca, Sr; Ln = Ce, Eu) phosphors exhibit typical broad excitation and emission bands, which are ascribed to the 4f–5d transitions of the Ce3+ and Eu2+ ions. Finally, X-ray excited luminescence (XEL) spectra were measured to evaluate the possibility of Sr3MgSi2O8:Ce3+ and Sr3MgSi2O8:Eu2+ as scintillation materials.
关键词： Scintillation materials,M3MgSi2O8,Luminescence properties
更新于2025-09-11 14:15:04
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Investigation of luminescence mechanism of Nd3+-doped calcium aluminate glasses: Effect of glass-formers
摘要： The relationship between the luminescence properties and the glass structure of Nd3+-doped CaO-Al2O3-(B2O3, SiO2, or Ga2O3) glasses are investigated. The luminescence properties of CaO-Al2O3-B2O3 system are twice as much as that of the CaO-Al2O3-(SiO2 or Ga2O3) system. The glass structure and the coordination environment of the Nd3+ ions were investigated using nuclear magnetic resonance, Raman and electron paramagnetic resonance spectroscopy. All Al, Ga, and Si atoms are four coordinated. The B atoms have three- and four-coordinated boron units, however, most of them are three coordinated. The hyper?ne sublevel correlation spectra reveal that the Al and B nuclei are in the coordination sphere of Nd3+ ions for aluminoborate glasses; however, only 27Al signals could be observed for aluminosilicate and aluminogallate glasses. Owing to the increased number of AlO4-BO3 connections and 11B nuclei around the Nd3+ ions, B has a signi?cant e?ect on the luminescence properties of the Nd3+ ions. The increase in GaO4 or SiO4 does not change the three dimensional-tetrahedral network, and the coordination environment of Nd3+ ions varies slightly. Thus, the e?ect of Ga2O3 and SiO2 on the luminescence properties of the Nd3+ ions is not as great as that of B2O3.
关键词： Glass structure,Local environments of rare-earth ions,EPR,Luminescence properties,NMR
更新于2025-09-10 09:29:36
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Mesoporous silica modified luminescent Gd2O3:Eu nanoparticles: physicochemical and luminescence properties
摘要： Highly colloidal Gd2O3:Eu nanoparticles (core-NPs) were synthesized by thermal decomposition via weak base at low temperature. The sol–gel chemical process was employed for silica layer surface coating to increase solubility, colloidal stability, biocompatibility, and non-toxicity at the ambient conditions. XRD results indicate the highly puri?ed, crystalline, single phase, and cubic phase Gd2O3 nanocrystals. TEM image shows that the mesoporous thick silica layer was effectively coated on the core nanocrystals, which have irregular size with nearly spherical shape and grain size about 10–30 nm. An absorption spectra and zeta potential results in aqueous media revealed that solubility, colloidal stability, and biocompatibility character were enhanced from core to core–shell structure because of silica layer surface encapsulation. The samples, demonstrated excellent photoluminescence properties (dominant emission 5D0 → 7F2 transition in the red region at 610 nm), indicated to be used in optical bio-detection, bio-labeling, etc. The photoluminescence intensity of the silica shell modi?ed core/shell NPs was suppressed relatively core-NPs; it indicates the multi-photon relaxation pathways arising from the surface coated high vibrational energy molecules of the silanol groups. The core/nSiO2/mSiO2 nanocrystals display strong emission (5D0 → 7F2) transition along with excellent solubility and biocompatibility, which may ?nd promising applications in the photonic based biomedical ?eld.
关键词： silica,Gadolinium oxide,Biocompatible,Luminescence properties,Zeta potential,Mesoporous
更新于2025-09-09 09:28:46
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Heterometallic Organic Frameworks Built from Trinuclear Indium and Cuprous Halide Clusters: Ligand-Oriented Assemblies and Iodine Adsorption Behavior
摘要： Two novel heterometallic organic frameworks built from trinuclear indium and cuprous halide clusters, [(In3O)2(Cu2I2)3(ina)12(H2O)6](NO3)2·7DMA·10H2O (1) and [NH2(CH3)2][In3(OH)2(H2O)2(ina)8(Cu4I4)2]·5DMA·8H2O (2), where Hina = isonicotinic acid, have been successfully constructed with the orientation of the ina ligand. 1 shows a fascinating highly porous honeycomb-like 3D cationic framework with a trigonal-bipyramid-type cage based on a planar [In3O(CO2)6]+ trimer and a rhombohedral Cu2I2 cluster. Comparably, 2 displays a 3D negative network with irregular hexagonal channels constructed from a [In3(OH)2(CO2)8]? trimer and a cubane-like Cu4I4 cluster. Especially, 1 displays a reversible I2 adsorption/release performance with high adsorption capacity, whose mechanism has been disclosed by theoretical simulation. Also, the green/red emission of 2 stems from iodocuprate centers with quenched indium-centered emission.
关键词： I2 adsorption,cuprous halide clusters,luminescence properties,heterometallic organic frameworks,trinuclear indium
更新于2025-09-04 15:30:14