A novel upconversion luminescence derived photoelectrochemical immunoassay: ultrasensitive detection to alpha-fetoprotein

A upconversion luminescence derived photoelectrochemical Immunoassay for ultrasensitive detection to Alpha-fetoprotein under near infrared lights illumination.

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Nano-Crystallization of Ln-Fluoride Crystals in Glass-Ceramics via Inducing of Yb3+ for Efficient Near-Infrared Upconversion Luminescence of Tm3+

Nanomaterials ◽

10.3390/nano11041033 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1033

Author(s):

Jianfeng Li ◽

Yi Long ◽

Qichao Zhao ◽

Shupei Zheng ◽

Zaijin Fang ◽

...

Keyword(s):

Crystal Structures ◽

Near Infrared ◽

Upconversion Luminescence ◽

Glass Ceramics ◽

Upconversion Emission ◽

Ceramic Composites ◽

Wide Range ◽

Transmission Window ◽

Optical Applications ◽

Upconversion Emissions

Transparent glass-ceramic composites embedded with Ln-fluoride nanocrystals are prepared in this work to enhance the upconversion luminescence of Tm3+. The crystalline phases, microstructures, and photoluminescence properties of samples are carefully investigated. KYb3F10 nanocrystals are proved to controllably precipitate in the glass-ceramics via the inducing of Yb3+ when the doping concentration varies from 0.5 to 1.5 mol%. Pure near-infrared upconversion emissions are observed and the emission intensities are enhanced in the glass-ceramics as compared to in the precursor glass due to the incorporation of Tm3+ into the KYb3F10 crystal structures via substitutions for Yb3+. Furthermore, KYb2F7 crystals are also nano-crystallized in the glass-ceramics when the Yb3+ concentration exceeds 2.0 mol%. The upconversion emission intensity of Tm3+ is further enhanced by seven times as Tm3+ enters the lattice sites of pure KYb2F7 nanocrystals. The designed glass ceramics provide efficient gain materials for optical applications in the biological transmission window. Moreover, the controllable nano-crystallization strategy induced by Yb3+ opens a new way for engineering a wide range of functional nanomaterials with effective incorporation of Ln3+ ions into fluoride crystal structures.

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Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Materials ◽

10.3390/ma14040937 ◽

2021 ◽

Vol 14 (4) ◽

pp. 937

Author(s):

Katarzyna Halubek-Gluchowska ◽

Damian Szymański ◽

Thi Ngoc Lam Tran ◽

Maurizio Ferrari ◽

Anna Lukowiak

Keyword(s):

Energy Transfer ◽

Near Infrared ◽

Upconversion Luminescence ◽

Sol Gel ◽

Emission Spectra ◽

Transmission Electron ◽

Characteristic Emission ◽

Diffraction Patterns ◽

Size Of Particles ◽

Average Size

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

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