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pH Mediated Control Synthesis of Lanthanide-Doped YPO4 Upconversion Nano/Microcrystals
摘要： A pH-mediated rational control over the phase transformation, morphology and size of lanthanide doped YPO4 nano/microcrystals has been accomplished using a hydrothermal route. The morphology of the resulting particles evolves from the spheres, to the nanoflakes and finally to the nanorods when increasing the pH value of the reaction solution from 1 to 9, while the induction of crystal phase transformation from a tetragonal structure to a hexagonal structure takes place at pH = 5. When excited at 980 nm, the hexagonal phase YPO4?0.8H2O: 18%Yb3+, 2%Er3+ nanoflakes prepared at pH = 7 exhibit the strongest UC emission intensity among investigated samples of varying size, phase and morphologies. This work provides a paradigm on the controlled synthesis of lanthanide doped upconverting orthophosphates, which hold great promise for various photonic and biophotonic applications.
关键词： Orthophosphate,Morphology,Upconversion
更新于2025-09-23 15:21:01
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LED&Paper-based Analytical Device for Phosphatemia/Calcemia Diagnostics
摘要： In this communication a prototype of paper-based analytical device designed for simultaneous determination of orthophosphate and calcium ions, which levels are significant for hyperphosphatemia diagnostics, is presented. The laboratory-on-paper structure for two analytes detection was wax-printed on the surface of filter paper. These two-analyte disposable paper strips are combined with two paired LED-based fluorescence detectors and simple voltmeter used as recorder of analytical signal, what makes the developed device miniature, extremely low-cost, portable and user-friendly. Thus the developed device allows usage at the patient’s bed or by patients themselves. Moreover, each paper strip is disposable and its utilization is easy and fast and, additionally, burnt strip tests ensure waste non-infectious. The presented LED&Paper-based analytical device provides low detection limits: 1.4 μM and 7.4 μM for orthophosphate and calcium ions, respectively. The practical utility of the developed device for calcemia/phosphatemia diagnostics is demonstrated using control serum standards and real human serum.
关键词： Paper-based device,Orthophosphate,Fluorescence,LEDs,Calcium
更新于2025-09-23 15:19:57
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Luminescence varied by selective excitation in Eu3+,Tb3+-doped LiSrPO4 phosphors for W-LEDs applications
摘要： Tb3+ and Eu3+-doped LiSrPO4 (LSPO) were produced via a modified sol-gel route. Structural and optical characterization was performed by X-ray diffraction (XRD) and photoluminescence spectroscopy (PL), respectively. The results reveal that the presence of dopants has an effect on the LSPO structure. PL spectra of the LSPO:Tb, Eu (LSPOTE) phosphor consisted of major emission lines associated with 5D3,4-7FJ (J = 3, 4, 5 and 6) and 5D0-7FJ (J = 0, 1, 2, 3 and 4) transitions of Tb3+ and Eu3+ ions, respectively. A change in emission spectra was observed when the excitation wavelength was changed. Under middle-ultraviolet excitation (227 nm), the Tb3+ and Eu3+-doped LiSrPO4 phosphor exhibited white emission. The results suggest that the LiSr0.97PO4:Tb0.01,Eu0.02 phosphors prepared in the present work could be used in combination with AlGaN chips to fabricate white LEDs.
关键词： Terbium,Lithium strontium orthophosphate,Europium,White LEDs
更新于2025-09-16 10:30:52
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Enhancement of the red emission in Ba <sub/>3</sub> (PO <sub/>4</sub> ) <sub/>2</sub> :Eu3+ by addition of charge compensator Na+
摘要： Ba2.96(PO4)2:0.04Eu3+ (S1) and Ba2.92Na0.04(PO4)2:0.04Eu3+ (S2) were prepared by solid state reaction. The phases and luminescent properties of the obtained phosphors were characterized. The results demonstrate that the phosphors particles emit an intensive red light under excitation at 395 nm. Both phosphors can be efficiently excited by ultraviolet and blue light, and the emission spectra mainly consist of two emission peaks at 591 nm and 611 nm. The crystallographic sites of Eu3+ ions in Ba3(PO4)2 host were discussed on the base of emission spectra and its host crystal structure. By introducing the charge compensator Na+ into the S1 phosphor, its emission intensity was enhanced, indicating that S2 could serve as a promising red-emitting phosphor for UV LED applications.
关键词： charge compensator,barium orthophosphate,Phosphors,luminescence,photoluminescence
更新于2025-09-09 09:28:46