A series of NaYF4: Yb3+/Tm3+@NaYF4: Yb3+/Er3+ nanoparticles doped with Tm3+ and Er3+ were successfully prepared by the solvothermal method. Under a 980 nm laser excitation, intense upconversion emission peaks of...
The solvothermal method prepared a series of Yb3+/Tm3+/Ca2+ co-doped NaYF4 nanoparticles with different Ca2+ contents. Strong upconversion blue fluorescence could be observed under 980 nm laser excitation of the samples....
The core–shell NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ upconversion nanoparticles
were
successfully prepared by a solvothermal method, and a layer of mesoporous
silica (mSiO2) was successfully coated on the periphery
of the core–shell nanoparticles to transform their surface
from lipophilic to hydrophilic, further expanding their applications
in biological tissues. The physical phase, morphology, structure,
and fluorescence properties were characterized by X-ray diffraction
(XRD), field emission transmission electron microscopy (TEM), Fourier
infrared spectroscopy (FT-IR), ζ potential analysis, and fluorescence
spectroscopy. It was found that the material has a hexagonal structure
with good hydrophilicity and emits intense fluorescence under 980
nm pump laser excitation. The non-contact temperature sensing performance
of nanoparticles was evaluated by analyzing the upconversion fluorescence
of Tm3+ (1G4 → 3F4 and 3F3 → 3H6) in the temperature range of 284–344 K. The absolute and
relative sensitivities were found to be 0.0067 K–1 and 1.08 % K–1, respectively, with high-temperature
measurement reliability and good temperature cycling performance.
More importantly, its temperature measurement in phosphate-buffered
saline (PBS) solution is accurate. In addition, the temperature of
the cells can be increased by adjusting the laser power density and
laser irradiation time. Therefore, an optical temperature sensing
platform was built to realize the application of real-time monitoring
of cancer cell temperature and the dual function of photothermal therapy.
Non-contact optical temperature sensors are highly sought after by researchers due to their satisfactory temperature resolution (δ(T) < 0.1℃), high relative thermal sensitivity (S_r>1%/℃), fast temporal response (t<0.1s), and...
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