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Electrochemiluminescent biosensor with DNA link for selective detection of human IgG based on steric hindrance
摘要： A highly selective DNA-based electrochemiluminescence (ECL) based biosensor is described for the detection of human IgG. It is exploiting the effect of steric hindrance that affects the strength of the ECL signal in the presence of IgG. Digoxin-linked signalling DNA was specifically bound to IgG, and this causes steric hindrance which limits the ability of DNA to hybridize with capturing DNA attached to a gold electrode. Europium (II) doped CdSe quantum dots were covalently linked to the DNA in order to generate the ECL signal. Using this steric hindrance hybridization method, the ECL signal of the biosensor were proportional to the concentration of IgG with a wide linear range and a 14 pM detection limit. Conceivably, the method can be expanded to the detection of a wide range of proteins for which homologous recognition elements are available.
关键词： Digoxin-linked signalling DNA,Electrochemiluminescence,Human IgG,Steric hindrance effects,Biosensor,Europium (II) doped CdSe quantum dots
更新于2025-09-23 15:21:01
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Synthesis of Calcium Aluminate-Based Luminophores by the Citrate Nitrate Sol–Gel Process
摘要： Microwave-assisted sol–gel process was used to synthesize calcium aluminate and luminescent materials based on it, which find wide use in the manufacture of construction materials, catalysts, optical emission sources, and display devices. The major processes involved in the formation of crystalline calcium aluminate were identified resorting to powder X-ray diffraction, thermal analysis, scanning electron microscopy, and IR spectroscopy data. Synthetic steps have moderate activation energies in the 44–260 kJ/mol range. Luminescence characteristics of the obtained crystal phosphors were measured. The increase in the synthesis temperature to 1200°C and the increase in the activator concentration to 5 mol % enhance the luminescence of the Eu3+-activated calcium aluminate-based luminophore. Further increase in the concentration of the activator ions leads to luminescence quenching caused by the concentration effect.
关键词： calcium aluminate,sol–gel process,microwave treatment,europium(III) ions,crystal phosphor
更新于2025-09-23 15:21:01
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Europium and terbium lanthanide ions co-doping in TiO2 photoanode to synchronously improve light-harvesting and open-circuit voltage for high-efficiency dye-sensitized solar cells
摘要： In this study, we explore the effects on the incorporation of europium (Eu3+) and terbium (Tb3+) rare-earth ions into titanium dioxide (TiO2) photoanodes in dye-sensitized solar cells (DSSCs). X-ray photoelectron spectroscopy (XPS) studies affirm that the Eu3+ ions are arranged at the cationic locales of Ti4+ in the matrix whereas the site inhabitance was remunerated by Tb3+ ions, supporting that the anatase phase stays unaltered without generating any new deformities. Additionally, the Eu3+ ions decidedly changed the conduction band minimum of TiO2, actually, Tb3+ ions contrarily conversion because of various vacant trap states in the band gap. Besides, the photoinduced electron transfer estimations show an efficient interfacial charge transfer for co-doped TiO2 (kET = 3.1 ns) contrasted with the bare TiO2 (2.6 ns). DSSCs based on Eu3+/Tb3+ co-doped TiO2 display higher efficiency (9.11%) than those for the bare TiO2 (7.20%) and the exclusively Eu3+ (8.01%) or Tb3+ (7.10%) doped samples, which is ascribed to the joined impact of a faster electron transportation and longer electron lifetime in the co-doped TiO2 film. This work may open another approach to further improve the performance of DSSCs by Eu3+/Tb3+ co-doping technique, advancing the development of DSSCs toward commercial applications.
关键词： Co-doping process,Europium (Eu3+)/terbium (Tb3+) lanthanide ions,Stability,Photoanodes,DSSCs,Titanium dioxide (TiO2) nanopowders
更新于2025-09-23 15:21:01
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Efficiency enhancement of silicon solar cells covered by GeO2-PbO glasses doped with Eu3+ and TiO2 nanoparticles
摘要： An objective of the solar industry is to improve the efficiency of the light-electricity conversion process of photovoltaic solar cells. An alternative to achieve this purpose is to manage the solar spectrum that is absorbed by the solar cell in order to match it with the solar cell responsivity. It can be done, for example through the downconversion process, covering the solar cell with photonic materials that can convert photons of the UV region to photons with energy close to the band gap energy of the solar cell. This process can be observed, for example, through the UV excitation of transparent glasses with low phonon energy hosting luminescent ions with energy levels in the VIS region. The luminescence from these energetic levels can be improved siting the luminescent ions in places with low symmetry. In the present study the optical response to the solar spectrum of GeO2-PbO glasses containing Eu3t ions and titanium dioxide nanoparticles was explored to enhance the efficiency of polycrystalline silicon solar cells. Results revealed a maximum efficiency enhancement of 15.92% for the silicon solar cell covered with GeO2-PbO glass doped with 1% of Eu2O3 and 0.5% of TiO2 heat treated for 24 h. This efficiency enhancement was attributed to the location of the Eu3t ions in sites of low symmetry of TiO2 nanoparticles.
关键词： TiO2 nanoparticles,Photovoltaic cells,Europium,Luminescent glasses,Down-conversion
更新于2025-09-23 15:19:57
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The effect of templates on the morphological and optical properties of BaMgAl10O17:Eu2+ phosphors
摘要： Blue light emitting BaMgAl10O17:Eu2+ phosphors were prepared by solution combustion synthesis method using urea as a fuel. Water-soluble templates, β-cyclodextrin and thioglycerol were used for the synthesis process. The main aim of the present work is to study the effect of these templates on morphology and optical properties of BaMgAl10O17:Eu2+ phosphor. The inclusion of templates prevents agglomeration, hence improving crystallinity and photoluminescence emission intensity. β-cyclodextrin and thioglycerol modified the morphology of BaMgAl10O17:Eu2+ phosphor by transforming its multifaceted plate-like to rod-like morphology. It is observed that the addition of β-cyclodextrin and thioglycerol in the synthesis of BaMgAl10O17:Eu2+ phosphor not only increased the photoluminescence emission of BaMgAl10O17:Eu2+ phosphor but also enhanced the thermal stability of the BaMgAl10O17:Eu2+ phosphor. Hence the use of β-cyclodextrin and thioglycerol was beneficial in improving the crystallinity, photoluminescence characteristics and the thermal stability of BaMgAl10O17:Eu2+ phosphor.
关键词： blue emission,photoluminescence,thermal stability,europium,polymer
更新于2025-09-23 15:19:57
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Eu <sup>3+</sup> luminescence in high charge mica: an in situ probe for the encapsulation of radioactive waste in geological repositories
摘要： Isolation of high-level radioactive waste (HLW) in deep geological repositories (DGR) through a multi-barrier concept is the most accepted approach to ensure long-term safety. Clay minerals are one of the most promising materials to be used as engineered barriers. In particular, high charge micas, as components of the engineered barrier, show super-selectivity for some radioactive isotopes and a large adsorption capacity, which is almost twice as the other low charge aluminosilicates. In addition, high charge micas are optimum candidates for decontamination of nuclear waste through two different mechanisms; namely an ion exchange reaction and a non-reversible mechanism involving the formation of new stable crystalline phases under hydrothermal conditions. In this paper we report a new in situ optical sensor based on the incorporation of Eu3+ in these high charge micas for tracking the long-term physical-chemical behaviour of HLW contaminants in DRG under mild hydrothermal conditions. The incorporation of Eu3+ into the interlayer space of the mica originates a well resolved green and red luminescence, from both the 5D1 and 5D0 excited states, respectively. The formation of new crystalline phases under hydrothermal conditions involves important changes in the Eu3+ emission spectra and lifetime. The most interesting features of Eu3+ luminescence to be used as an optical sensor are: (1) the presence or absence of the Eu3+ green emission from the 5D1 excited state, (2) the energy shift of the 5D0→7F0 transition, (3) the crystal-field splitting of the 7F1 Eu3+ level, and (4) the observed luminescence lifetimes, which are directly related to the interaction mechanisms between the lanthanide ions and the silicate network.
关键词： europium luminescence,surface interaction,radioactive waste,high charge micas,europium disilicate
更新于2025-09-19 17:15:36
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Ultrasound-Assisted Synthesis and Characterization of Heparin-Coated Eu3+ Doped Hydroxyapatite Luminescent Nanoparticles
摘要： Herein, the heparin-coated Eu3+ doped hydroxyapatite luminescent nanoparticles were synthesized by an ultrasound-assisted coprecipitation method followed with steam sterilization at 121 °C. The effects of ultrasound treatment, steam sterilization, sodium heparin (SH) concentration and Eu doping content on the formation of heparin-coated Eu3+ doped hydroxyapatite nanoparticles (SH-Eu:nHAP) were investigated. The sterilized and suspended Eu-nHAP with improved luminescence and stability was simultaneously achieved in a process of about 2 h due to the combined effect of ultrasonic sonochemistry and stabilization function of SH. The obtained SH-Eu:nHAP suspension shows good stability in water and biological media. Moreover, the SH-Eu:nHAP shows no hemolysis and cytotoxicity, and can be ingested by cells and emit characteristic luminescence in cells. In summary, this study provides an improved method for the synthesis of SH-Eu:nHAP suspension that is helpful for promoting the application of rare earth doped nHAP as bioimaging agent.
关键词： Heparin,Hydroxyapatite nanoparticles,Europium,Luminescence,Bioimaging
更新于2025-09-19 17:15:36
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Efficient visible-light excitable Eu3+-complexes for red organic light-emitting diodes
摘要： Visible-light excited Eu3+-complexes have received much attention in the last years due to the rapidly increasing demand for less-harmful biomarkers and optoelectronics. Nevertheless, these complexes usually exhibit poor emission quantum yields, contrarily to the ones excited in the ultraviolet spectral region. To address this challenge, a series of complexes based on trivalent lanthanide ions, [Eu(bpyO2)(CH3OH)2(H2O)(NO3)2](NO3) (1), [Gd(bpyO2)(H2O)4(Cl)2]Cl (4), Ln(tta)3(H2O)(C2H5OH) (Ln = Eu (2), Gd (5)) and Ln(tta)3(bpyO2) (Ln = Eu (3), Gd (6)), are synthesized using 2-thenoyltrifluoroacetone (Htta) as primary ligand and 2,2′-dipyridyl N,N′-dioxide (bpyO2) as neutral donor, and characterized, with special emphasis on their crystal structures and luminescence properties. Single crystal X-ray diffraction revealed that the central metal ion has a coordination number of 9 in 1, and 8 in all other complexes. Complex 3 exhibited a broad excitation spectrum ranging from 250 to 480 nm, exhibiting, when compared to 1 and 2, higher absolute emission quantum yields of 0.46, 0.36 and 0.33, for excitation at 400, 425, and 450 nm, respectively. The theoretical intensity parameters, radiative and non-radiative decay rates, and intrinsic and absolute emission quantum yields were assessed using the LUMPAC software displaying a very good accord with the experimental values. Moreover, organic light-emitting diodes with a maximum efficiency of 5.7 × 10?2 cd·A?1 at 14 V were fabricated using 3 as an emitting layer.
关键词： Luminescence,OLED,LUMPAC,Europium,Visible-light excitation
更新于2025-09-19 17:13:59
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Enhancing Photovoltaic Performance of GaAs Single-Junction Solar Cells by Applying a Spectral Conversion Layer Containing Eu-Doped and Yb/Er-Doped Phosphors
摘要： In this study, we examined e?orts to increase the photovoltaic performance of GaAs single-junction solar cells using spectral conversion layers, respectively, composed of europium-doped (Eu-doped) phosphors, ytterbium/erbium-doped (Yb/Er-doped) phosphors, and a combination of Eu-doped and Yb/Er-doped phosphors. Spin-on ?lm deposition was used to apply the conversion layers, all of which had a total phosphor concentration of 3 wt%. The chemical compositions of the phosphors were examined by energy-dispersive X-ray spectroscopy. The ?uorescence emissions of the phosphors were con?rmed by using photoluminescence measurements. Under laser diode excitation at 405 nm, we observed green luminescent downshift (LDS) emissions by Eu-doped phosphors at wavelengths of 479 nm to 557 nm, and under excitation at 980 nm, we observed red up-conversion (UC) emissions by Yb/Er-doped phosphors at wavelengths of 647 nm to 672 nm. The spectral conversion layers were characterized in terms of optical re?ectance, external quantum e?ciency, and photovoltaic current and voltage under AM 1.5 G simulations. The conversion e?ciency of the cell combining Eu-doped and Yb/Er-doped phosphors (23.84%) exceeded that of the cell coated with Yb/Er-doped phosphors (23.72%), the cell coated with Eu-doped phosphors (23.19%), and the cell coated without phosphors (22.91%).
关键词： ytterbium/erbium-doped (Yb/Er-doped),europium-doped (Eu-doped),up-conversion,phosphors,GaAs solar cell,luminescent downshift
更新于2025-09-16 10:30:52
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On the development of a new approach to the design of lanthanide-based materials for solution-processed OLEDs
摘要： The targeted design of lanthanide-based emitters for solution-processed organic light-emitting diodes (OLEDs) resulted in obtaining an NIR OLED with one of the highest efficiencies among ytterbium-based solution-processed OLEDs (30 μW W?1). The design was aimed at the combination of high luminescence efficiency with solubility and charge carrier mobility. The latter was achieved thanks to the introduction of the purposefully selected neutral ligands, which combine electron mobility and the ability to sensitize lanthanide luminescence. Besides, the HOMO and LUMO energies and charge carrier mobility of solution-processed thin films of coordination compounds were measured experimentally for the first time, and novel highly luminescent europium-based materials with PLQYs of up to 80% and purely NIR luminescent ytterbium complexes were obtained.
关键词： NIR OLED,europium complexes,lanthanide-based materials,solution-processed OLEDs,ytterbium complexes
更新于2025-09-16 10:30:52