Ultrasmall Monodisperse NaYF4:Yb3+/Tm3+ Nanocrystals with Enhanced Near-Infrared to Near-Infrared Upconversion Photoluminescence
2010 (English)In: ACS NANO, ISSN 1936-0851, Vol. 4, no 6, 3163-3168 p.Article in journal (Refereed) Published
Photoluminescent NaYF4:Yb3+/Tm3+ nanocrystals are ideally suited for in vitro and in vivo photoluminescence (PL) bioimaging due to their virtue of near-infrared to near-infrared (NIR-to-NIR) upconversion (UC); they display PL with a peak at similar to 800 nm if excited at similar to 980 nm. Here, we report the synthesis of monodisperse NaYF4:Yb3+/Tm3+ nanocrystals of ultrasmall size (7-10 nm) with high UC efficiency. The intensity of their NIR UC emission was demonstrated to increase by up to 43 times along with an increase in the relative content of Yb3+ ions from 20 to 100%, with a corresponding decrease in the Y3+ content from 80 to 0%. The achieved ultrasmall NaYbF4:2% Tm3+ nanocrystals manifest NIR PL emission, which is 3.6 times more intense than that from 25-30 nm sized NaYF4:20% Yb3+/2% Tm3+ nanocrystals, previously synthesized and used for in vitro and in vivo bioimaging. An optimization of both size and UC PL efficiency of NIR-to-NIR nanocrystals provides us with highly efficient optical imaging probes for bioapplications.
Place, publisher, year, edition, pages
2010. Vol. 4, no 6, 3163-3168 p.
near-infrared, upconversion photoluminescence, nanocrystals, rare-earth ions
IdentifiersURN: urn:nbn:se:kth:diva-27312DOI: 10.1021/nn100457jISI: 000278888600026ScopusID: 2-s2.0-77955860620OAI: oai:DiVA.org:kth-27312DiVA: diva2:376037
QC 201012092010-12-092010-12-092010-12-09Bibliographically approved