We have successfully synthesized near-infrared photoluminescent erbium-doped lithium yttrium fluoride nanocrystals using a facile coprecipitation approach. The nanocrystals are capped with oleic acid, enabling dispersion in nonpolar solvents such as toluene and cyclohexane. The relative amounts of yttrium and erbium precursors were adjusted during the synthesis to obtain different concentrations of Er between 1% and 15%. The composition and structure of the nanocrystals were studied via X-ray fluorescence spectroscopy and X-ray powder diffraction. The nanocrystals were optically characterized by extensive photoluminescence studies, including Stokes and anti-Stokes emission. When excited with 1.55-μm light, the nanocrystals displayed strong anti-Stokes emission associated with the 4I13/2 → 4I15/2 transition. These nanocrystals therefore have a high potential to be used in optical cooling applications with telecommunication-wavelength excitation.
Synthesized nanoparticles with strong luminescence in the second near-infrared window show great potential for applications in biomedical imaging and diagnosis. Nanoscale dimensions and tunable optical properties can enable nanoparticles to operate as fluorescent probes in the imaging of tumors and lymphatic tissues. Lanthanide-doped rare-earth fluoride nanoparticles with photoluminescence tuned to the second near-infrared window can circumvent many of the issues currently limiting the clinical utility of fluorescence imaging technology and show promise as tools for the early detection of cancer. We report on the synthesis and characterization of colloidal LiYF4 nanoparticles doped with erbium. The nanoparticles were synthesized through a coprecipitation method using rare-earth chlorides, LiOHꞏH2O, and NH4F as precursors. 1-octadecene was used as a high-temperature solvent, and oleic acid was used as an organic capping agent. The reaction took place under the protection of nitrogen atmosphere. The size, morphology, and colloidal stability of the nanoparticles were determined using data obtained from transmission electron microscopy, dynamic light scattering, and zeta potential techniques. Optical characterization data were collected using NIR absorption spectroscopy and fluorescence spectroscopy. The Er3+-doped LiYF4 nanoparticles show NIR-II emission peaks at 1001 nm, 1490 nm, 1531 nm, and 1558 nm upon NIR-II excitation at 972 nm. The excellent luminescence in the NIR-II range makes them a strong candidate for bioimaging applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.