TY  - JOUR
A1  - López de Guereñu Kurganova, Anna
A1  - Klier, Dennis Tobias
A1  - Haubitz, Toni
A1  - Kumke, Michael Uwe
T1  - Influence of Gd3+ doping concentration on the properties of Na(Y,Gd)F-4
BT  - Yb3+, Tm3+ upconverting nanoparticles and their long-term aging behavior
JF  - Photochemical & photobiological sciences / European Society for Photobiology
N2  - We present a systematic study on the properties of Na(Y,Gd)F-4-based upconverting nanoparticles (UCNP) doped with 18% Yb3+, 2% Tm3+, and the influence of Gd3+ (10-50 mol% Gd3+). UCNP were synthesized via the solvothermal method and had a range of diameters within 13 and 50 nm. Structural and photophysical changes were monitored for the UCNP samples after a 24-month incubation period in dry phase and further redispersion. Structural characterization was performed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as dynamic light scattering (DLS), and the upconversion luminescence (UCL) studies were executed at various temperatures (from 4 to 295 K) using time-resolved and steady-state spectroscopy. An increase in the hexagonal lattice phase with the increase of Gd3+ content was found, although the cubic phase was prevalent in most samples. The Tm3+-luminescence intensity as well as the Tm3+-luminescence decay times peaked at the Gd3+ concentration of 30 mol%. Although the general upconverting luminescence properties of the nanoparticles were preserved, the 24-month incubation period lead to irreversible agglomeration of the UCNP and changes in luminescence band ratios and lifetimes.
KW  - Upconversion luminescence
KW  - Lanthanides
KW  - Near infra-red
KW  - Ultra-low
KW  - temperature
KW  - Time-resolved spectroscopy
Y1  - 2022
U6  - https://doi.org/10.1007/s43630-021-00161-4
SN  - 1474-905X
SN  - 1474-9092
VL  - 21
IS  - 2
SP  - 235
EP  - 245
PB  - Springer
CY  - Heidelberg
ER  -