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Energy transfer and luminescence quenching of Cr3+-doped LiGaW2O8
摘要： Luminescence properties of the Cr3+-doped LiGaW2O8 crystals are investigated by laser excitation spectroscopy. The powder samples for various Cr3+ concentration were prepared by high-temperature solid state reaction. The temperature behaviors of the emission intensity and the decay time of the self-activated LiGaW2O8 host are discussed. The emission spectra and decay times of LiGa1-xW2O8:xCr3+ are measured under UV excitation in the temperature range 10 - 300 K. The luminescence quenching of LiGaW2O8:Cr3+ as functions of temperature and Cr3+-concentration is explained by structural and spectral characteristics.
关键词： luminescence quenching,temperature dependence.,energy transfer
更新于2025-09-19 17:15:36
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Highly Erbium-Doped Nanoplatform with Enhanced Red Emission for Dual-Modal Optical-Imaging-Guided Photodynamic Therapy
摘要： Generally, luminescence quenching at high doping concentrations typically limits the concentration of doped ions in the lanthanide material to less than 0.05?20 mol %, and this is still a major hindrance in designing nanoplatforms with improved brightness. In this research, a nanoplatform capable of dual-modal imaging and synergetic antitumor cells therapy was designed. NaYF4:x%Er@NaXF4 (x = 5, 25, 50, and 100; X = Lu and Y) core@shell nanoparticles with Er3+ ion concentration up to 100 mol % were synthesized, and the luminescence properties under near-infrared (NIR) excitation were detected. The results show the strong coupled of surface and concentration quenching effects in upconversion nanoparticles (UCNP). Upconversion luminescence (UCL) and NIR-II emission intensity increased with negligible concentration quenching effect under 980 and 800 nm NIR lasers because of the growth of epitaxial shells. Therefore, the enhanced red luminescence transfers energy to photosensitizer ZnPc as the photodynamic therapy (PDT) agent for tumor inhibition efficacy.
关键词： photodynamic therapy,upconversion nanoparticles,luminescence quenching,nanoplatform,synergetic antitumor cells therapy,NaYF4:x%Er@NaXF4,dual-modal imaging
更新于2025-09-10 09:29:36
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Two new luminescent ternary Cd(II)-MOFs by regulation of aromatic dicarboxylate ligands used as efficient dual-responsive sensors for toxic metal ions in water
摘要： Two new Cd(II) metal-organic frameworks (MOFs) formulated as [Cd(L)(atpa)]n (1) and [Cd(L)(tbta)(H2O)]n (2) [H2atpa = 2-aminoterephthalic acid, H2tbta = tetrabromoterephthalic acid, L = 1,4-bis(benzimidazol-1-yl)-2-butene] were hydrothermally synthesized. 1-2 were characterized by IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. 1 displays a 3D framework with five-fold interpenetrating dia topology. 2 holds a 2D corrugated sql layer. Both MOFs were confirmed to be dual-responsive luminescent sensors (Cu2+ and Cr2O7 2- for 1, Hg2+ and Cr2O7 2- for 2) in water through the luminescence quenching experiments. The detection limits for these species were 1.2 μM (Cu2+) and 0.29 μM (Cr2O7 2-) of 1, 0.043 μM (Hg2+) and 0.13 μM (Cr2O7 2-) of 2, respectively. The luminescence quenching mechanism was investigated.
关键词： Hydrothermal synthesis,Luminescence quenching,Semi-rigidity bis(benzimidazole),Crystal structure,Cadmium(II) MOF
更新于2025-09-10 09:29:36
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Two Zn(II) coordination polymers based on 5-substituted isophthalic acid: syntheses, crystal structures, luminescence sensing properties
摘要： Two new Zn(II) coordination polymers (CPs), {[Zn(L)(5-nip)]2·5.5H2O}n (1) and {[Zn(L)(5-mip)]·EtOH}n (2) [L = 1,3-bis(benzimidazol-1-yl)-2-propanol, 5-H2nip = 5-nitroisophthalic acid, 5-H2mip = 5-methyisophthalic acid] were solvothermally synthesized and characterized by elemental analyses, IR spectra, thermogravimetric analyses, and single-crystal X-ray diffraction. CP 1 possesses a 1D ladder-like chain structure and further packed into 2D supramolecular architectures by π-π stacking interactions. CP 2 exhibits a 2D 63 layer, which is finally extended into 3D supramolecular network via the weak C–H···O hydrogen bond interactions. CP 1 and CP 2 can be used as luminescent sensors for Hg2+ and Cr2O7 2- ions in water.
关键词： Znic(II),Bis(benzimidazole),Luminescence quenching,Supramolecular architecture,Coordination polymer
更新于2025-09-09 09:28:46