Up-conversion (Gd,Yb,Tb)PO(4) materials and their potential for bimodal imaging have received little attention in the literature. Herein, we report the first study on the up-conversion emission of (Gd,Yb,Tb)PO(4) nanocrystals synthesized via a hydrothermal method at 150 °C. These materials exhibit ultraviolet, blue and green up-conversion emissions upon excitation with a 980 nm continuous wave laser diode. The intensity of the blue-emission band at 479 nm, ascribed to the cooperative up-conversion emission of a pair of excited Yb(3+) ions, depends on the Yb(3+)/Tb(3+) concentration ratio, calcination temperature and particle size. Strong green up-conversion emission of Tb(3+) is observed at 543 nm for the (5)D(4)→(7)F(5) transition. Relaxometry measurements reveal that the nanocrystals are efficient T(2)-weighted (negative) contrast agents which, combined with visible-light emission generated by infrared excitation, affords them considerable potential for being used in bimodal, photoluminescence-magnetic resonance, imaging.
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http://dx.doi.org/10.1039/c2nr31226c | DOI Listing |
Phys Chem Chem Phys
December 2024
Suzhou Laboratory, Suzhou, Jiangsu, China.
Fucoxanthin is a typical carotenoid that absorbs light in the blue region of the visible spectrum, and its detailed electronic structures remain to be clarified. It is well known that carotenoids harvest energy from sunlight and transfer it to chlorophylls (Chls) and/or bacteriochlorophylls (BChls) through its excited states as the intermediate states; however, some excited states still need evidence to be definitely confirmed. Through steady-state fluorescence emission spectroscopy and femtosecond time-resolved fluorescence up-conversion technique, we provide new evidence for the identification of the excited S state in fucoxanthin, a representative of carotenoids.
View Article and Find Full Text PDFJ Fluoresc
November 2024
Department of Physics and Photonics Science, National Institute of Technology, Hamirpur, 177005, H.P, India.
Luminescence
November 2024
Department of Physics, Sri Venkateswara University, Tirupati, India.
Er and Er/Yb-doped phosphate-based glasses have been synthesized by melt quenching technique and are characterized by absorption spectra, infrared emission, decay curves, Fourier transform infrared spectrum and up-conversion studies. From the absorption spectra, intensity parameters and radiative properties have been derived utilizing the Judd-Ofelt theory. Er-doped glass is found to have larger radiative lifetime for the laser originating from I level at 1537 nm.
View Article and Find Full Text PDFFood Chem X
December 2024
Zhejiang Provincial Key Laboratory of Chemical and Biological Processing Technology for Agricultural Products, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Liuxia Street Number 318, Hangzhou 310023, PR China.
In this study, a fluorescence detection method combining aptamer-modified up-conversion nanoparticles (UCNPs) and magnetic nanoparticles (MNPs) was developed for detection of Clenbuterol (CLB). The aptamer-modified magnetic NPs captured CLB, which reacted with the aptamer-modified UCNPs and generated a sandwich complex. The aptamer-modified UCNPs acted as a fluorescence source.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2024
School of Information Science and Engineering, Dalian Polytechnic University, Dalian 116034, P.R. China.
Laser-active interference with high confidentiality and convenience opens up a cutting-edge path for releasing and hiding key targets; however, its development still faces enormous challenges owing to the difficulty of concealing objects. Herein, a novel conceptual design for laser-controlled information release and hiding (LIRH) is proposed and successfully realized. CsNaInCl:Er, Yb (CNIC:Er, Yb) perovskite microcrystal is adopted as a carrier for LIRH implementation, exhibiting excellent up-conversion (UC) emission under NIR (980 and 1530 nm) irradiation due to its ultralow phonon energy.
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