TY - JOUR
T1 - Single-nanocrystal sensitivity achieved by enhanced upconversion luminescence
AU - Zhao, Jiangbo
AU - Jin, Dayong
AU - Schartner, Erik P.
AU - Lu, Yiqing
AU - Liu, Yujia
AU - Zvyagin, Andrei V.
AU - Zhang, Lixin
AU - Dawes, Judith M.
AU - Xi, Peng
AU - Piper, James A.
AU - Goldys, Ewa M.
AU - Monro, Tanya M.
PY - 2013/10
Y1 - 2013/10
N2 - Upconversion nanocrystals convert infrared radiation to visible luminescence, and are promising for applications in biodetection1-3, bioimaging4-7, solar cells8-10 and three-dimensional display technologies8,9,11. Although the design of suitable nanocrystals has improved the performance of upconversion nanocrystals10,12-14, their emission brightness is limited by the low doping concentration of activator ions needed to avoid the luminescence quenching that occurs at high concentrations15,16. Here, we demonstrate that high excitation irradiance can alleviate concentration quenching in upconversion luminescence when combined with higher activator concentration, which can be increased from 0.5 mol% to 8 mol% Tm31 in NaYF4. This leads to significantly enhanced luminescence signals, by up to a factor of 70. By using such bright nanocrystals, we demonstrate remote tracking of a single nanocrystal with a microstructured optical-fibre dip sensor. This represents a sensitivity improvement of three orders of magnitude over benchmark nanocrystals such as quantum dots17.
AB - Upconversion nanocrystals convert infrared radiation to visible luminescence, and are promising for applications in biodetection1-3, bioimaging4-7, solar cells8-10 and three-dimensional display technologies8,9,11. Although the design of suitable nanocrystals has improved the performance of upconversion nanocrystals10,12-14, their emission brightness is limited by the low doping concentration of activator ions needed to avoid the luminescence quenching that occurs at high concentrations15,16. Here, we demonstrate that high excitation irradiance can alleviate concentration quenching in upconversion luminescence when combined with higher activator concentration, which can be increased from 0.5 mol% to 8 mol% Tm31 in NaYF4. This leads to significantly enhanced luminescence signals, by up to a factor of 70. By using such bright nanocrystals, we demonstrate remote tracking of a single nanocrystal with a microstructured optical-fibre dip sensor. This represents a sensitivity improvement of three orders of magnitude over benchmark nanocrystals such as quantum dots17.
UR - http://www.scopus.com/inward/record.url?scp=84885453035&partnerID=8YFLogxK
U2 - 10.1038/nnano.2013.171
DO - 10.1038/nnano.2013.171
M3 - Article
C2 - 23995455
AN - SCOPUS:84885453035
VL - 8
SP - 729
EP - 734
JO - Nature Nanotechnology
JF - Nature Nanotechnology
SN - 1748-3387
IS - 10
ER -