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Preparation and luminescence properties of Dy3+-doped Na3Gd(PO4)2 nanophosphor for solid state white LEDs
摘要： White emitting Na3Gd(PO4)2 nanocrystalline phosphors doped with trivalent dysprosium (Dy3+) ions were synthesized by using citrate gel combustion technique. The structure of the compound is found to be orthorhombic with a particle size is 10 nm. Luminescence properties have been characterized using photoluminescence (PL), excitation, emission spectra and decay time measurements. In emission spectrum sharp emission peaks were observed 4F9/2 → 6H15/2 (blue) and 4F9/2 → 6H13/2 (yellow) transition of Dy3+ ions. From the concentration dependent PL studies, the optimum concentration of Dy3+ ions in Na3Gd(PO4)2 is found to be 1.0 mol %, where intense near white light for 352 nm pump wavelength. The yellow to blue intensity ratios, CIE chromaticity coordinates and correlated color temperature studies has shown the possibility of using this phosphor for W-LEDs.
关键词： Spectroscopic,Dy2O3,Color coordinates,Lifetime,White light emission
更新于2025-09-12 10:27:22
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Bright Cool White Emission from Ultrasmall CdSe Quantum Dots
摘要： In this work we employ a post-synthesis ligand treatment of ultrasmall CdSe quantum dots (QDs) with citric acid to increase the quantum yield (QY) of the of the as-synthesized CdSe from an average of 5.7% to a maximum of 61.3%. This is the highest reported value for a single component white-light emitting QD. The white-light emission of the ultrasmall CdSe quantum dots is derived from three surface states: pinned emission at a trap state associated with the phosphonic acid surface ligand, a surface Se state, and conventional deep trap states. The citric acid treated CdSe QDs were found to recover band gap emission from the phosphonic acid ligand trap state emission, exhibiting behavior . This band gap emission peak also becomes more prominent, resulting in a cooler white, as indicated by the shift in the CIE coordinates from an average of (0.30, 0.36) to (0.26, 0.32). Comparing to a previous method of increasing the QY by a post-synthesis treatment of formic acid, the citric acid treated CdSe QDs are brighter as well as more stable in solution over time, which opens the possibility for use in multiple applications.
关键词： white-light emission,quantum yield,quantum dots,citric acid,CdSe
更新于2025-09-12 10:27:22
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Multicolor emission from non-conjugated polymers based on a single switchable boron chromophore
摘要： Multicolor emissive and responsive materials are highly attractive due to their potential applications in various fields, and polymers are preferred for their good processability and high stability. Herein, we report a series of new polymers based on a methacrylate monomer containing a switchable boron chromophore. In spite of the unconjugated nature, interestingly, the homopolymers from this monomer display rare multicolor fluorescence in solution that is highly dependent on the degree of polymerization (DP). With an ascending DP, the local concentration of the chromophore increases, leading to a higher propensity for switching the blue emitting tricoordinate boron chromophore to the red emitting tetracoordinate one. The homopolymers also display temperature and solvent-dependent emission colour change. Furthermore, pure white-light emission could be achieved in various solvents by precisely tuning the homopolymer molecular weight, or in films/solid state by copolymerizing the emissive boron monomer with non-emissive monomers in an appropriate ratio.
关键词： Multi-responsiveness,Non-conjugated Polymer,Single Chromophore,White Light Emission,Multicolor Emission
更新于2025-09-10 09:29:36
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White-Light Emitting Di-Ureasil Hybrids
摘要： White-light emitting materials have emerged as important components for solid state lighting devices with high potential for the replacement of conventional light sources. Herein, amine-functionalized organic-inorganic di-ureasil hybrids consisting of a siliceous skeleton and oligopolyether chains codoped with lanthanide-based complexes, with Eu3+ and Tb3+ ions and 4,4'-oxybis(benzoic acid) and 1,10-phenanthroline ligands, and the coumarin 1 dye were synthesized by in situ sol–gel method. The resulting luminescent di-ureasils show red, green, and blue colors originated from the Eu3+, Tb3+, and C1 emissions, respectively. The emission colors can be modulated either by variation of the relative concentration between the emitting centers or by changing the excitation wavelength. White light emission is achieved under UV excitation with absolute quantum yields of 0.148 ± 0.015, 0.167 ± 0.017, and 0.202 ± 0.020 at 350, 332, and 305 nm excitation, respectively. The emission mechanism was investigated by photoluminescence and UV–visible absorption spectroscopy, revealing an efficient energy transfer from the organic ligands to the Ln3+ ions and the organic dye, whereas negligible interaction between the dopants is discerned. The obtained luminescent di-ureasils have potential for optoelectronic applications, such as in white-light emitting diodes.
关键词： lanthanide complexes,di-ureasil organic–inorganic hybrids,in situ sol–gel synthesis,white light emission,coumarin 1
更新于2025-09-10 09:29:36
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The Remote Light Emission Modulated by Local Surface Plasmon Resonance for the CdSe NW-Au NP Hybrid Structure
摘要： CdSe nanowire (NW)–Au nanoparticle (NP) compounds are synthesized successfully using the method of physical vapor deposition, and the modulated remote emission is realized in the hybrid structure with strong metal–semiconductor coupling. The well-crystallized, uniform morphology, smooth surface CdSe NW is attached with an Au NP on the terminal, which forms the integration structure with direct plasmon–exciton coupling of semiconductor–metal hybrid system. When the CdSe terminal or Au NP terminal of the hybrid structure is excited by the laser with wavelength of 633 nm, the remote light emission at another terminal is greatly modulated. To reveal the physical mechanism of energy conviction between plasmon and exciton, finite-difference time-domain simulations are performed for the CdSe NW–Au NP hybrid structures. The calculated results confirm that the modulation of remote light emission is attributed to the competing of the quench of photoluminescence and the electric field enhancement of local surface plasmon resonance. These works can provide deeper understanding of physical mechanism of plasmon and exciton coupling, and open up new application for the remote light sensing and detection.
关键词： localized electromagnetic field enhancement,remote light emission,CdSe NW,Au NP,photoluminescence
更新于2025-09-10 09:29:36
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Ultrawide strain-tuning of light emission from InGaAs nanomembranes
摘要： Single-crystal semiconductor nanomembranes provide unique opportunities for basic studies and device applications of strain engineering by virtue of mechanical properties analogous to those of flexible polymeric materials. Here, we investigate the radiative properties of nanomembranes based on InGaAs (one of the standard active materials for infrared diode lasers) under external mechanical stress. Photoluminescence measurements show that, by varying the applied stress, the InGaAs bandgap energy can be red-shifted by over 250 nm, leading to efficient strain-tunable light emission across the same spectral range. These mechanically stressed nanomembranes could therefore form the basis for actively tunable semiconductor lasers featuring ultrawide tunability of the output wavelength.
关键词： strain-tuning,nanomembranes,photoluminescence,light emission,InGaAs
更新于2025-09-10 09:29:36
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Novel blue light emitting poly(arylene ether)s under the influence of guest concentrations in host-guest systems: Synthesis, electrochemical and photophysical properties
摘要： A series of novel blue (poly-arylene ether)s polymers based on the anthracene derivatives as the guest material, and the hole transfer carbazole dervatives as the host material have been successfully synthesized by nucleophilic polycondensation. The obtained polymers exhibited high glass transition temperatures (Tg) ranging from 180 to 255 °C and decomposition temperatures (Td) ranging from 358 to 477 °C. Number average molecular weight (Mn) ranged from 3.12 × 104 to 7.20 × 104, and polydispersity indices (PDI) ranged from 1.25 to 2.10. Cyclic voltammetry investigation inform that these polymers possess LUMO energy levels ranging from ?2.29 to ?2.46 eV. In case of thin films state, all the polymers emit blue luminance with the emission maximum peaks ranging from 442 to 448 nm. The electroluminescent devices based on the these polymers with a configuration of ITO/PEDOT:PSS/polymer/TmPyPB/LiF/Al emitted blue light with CIE chromaticity coordinates of (0.15, 0.10).
关键词： Polymer Light Emitting Diodes,Ether Linkage,Blue Light Emission,Anthracene,Carbazole
更新于2025-09-04 15:30:14
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Rare earth phosphors based on spherical infinite coordination polymers
摘要： A novel luminescent infinite coordination polymer (Tb-M), constructed by the interaction between Tb3+ ions and 3,5-pyrazoledicarboxylate and malonate linkers, was prepared by water microwave-assisted synthesis. The material self-assembles into amorphous microspherical particles. Under UV excitation, a very intense green luminescence is observed by the naked eye at room temperature for Tb-M. A Gd3+ analogue compound (Gd-M) was also synthesized. Successful attempts at codoping Tb-M and Gd-M samples with Eu3+ and Dy3+ ions were carried out and different emission colors were obtained, including white-light emission.
关键词： infinite coordination polymers,rare earth phosphors,microwave-assisted synthesis,luminescence,white-light emission
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe) - Palermo (2018.6.12-2018.6.15)] 2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe) - Simplified Assessment of Blue Light Emissions based on Photometric Measurements
摘要： The human-luminous environment interaction is a topic of interest to the scientific community from the perspectives of comfort and health. The widespread introduction of innovative lighting sources, often justified by energy-saving reasons, poses new challenges for evaluating their emissions and estimating their photobiological effects. In this paper, the results of a measurement campaign to characterize the artificial optical radiation emitted by LED sources suitable for replacing traditional sources used in general lighting are discussed and compared with similar results obtained for fluorescent tubes. The evaluation methods described and the measurement results shown in this paper can be useful for those who regularly perform risk assessments of work environments.
关键词： General lighting systems,Risk group classification,Artificial optical radiation,LED sources,Blue light emission
更新于2025-09-04 15:30:14
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Eu <sup>3+</sup> /Tb <sup>3+</sup> functionalized Bi-based metal–organic frameworks toward tunable white-light emission and fluorescence sensing applications
摘要： The rational design strategy to construct lanthanide ion functionalized metal organic frameworks (MOFs) has attracted tremendous attention as they are promising candidates for developing novel long-lived and tunable luminescence materials and optical sensors owing to their intense, luminescence performances. In this work, a series of Eu3+/Tb3+ singly doped or codoped bismuth-based MOFs were prepared under in situ facile solvothermal conditions using BiOBr nanoplates as bismuth resources. A red-green-blue-based trichromatic white-light emission can be finely achieved by modulating the doping ratio of Eu3+/Tb3+ in the blue-emitting Bi-MOF host material and such photoluminescence tuning can also be realized by controlling the excitation wavelength. In addition, the Eu3+/Tb3+ singly incorporated Bi-MOF can serve as a multifunctional fluorescent probe for sensing Fe3+ and Cr2O7 2? ions in aqueous solution, as well as small organic pollutants of acetone molecules, and their sensing mechanisms have also been analyzed. These lanthanide ion functionalized Bi-MOF materials exhibit great potential in exploring white-light emitting devices and construction of supersensitive multifunctional sensors.
关键词： Eu3+/Tb3+ doped Bi-MOF,solvothermal synthesis,lanthanide ion functionalized MOFs,white-light emission,fluorescence sensing
更新于2025-09-04 15:30:14