Core/shell NaGdF 4:Nd 3+/NaGdF 4 nanocrystals with efficient near-infrared to near-infrared downconversion photoluminescence for bioimaging applications
2012 (English)In: ACS Nano, ISSN 1936-0851, Vol. 6, no 4, 2969-2977 p.Article in journal (Refereed) Published
We have synthesized core/shell NaGdF 4:Nd 3+/NaGdF 4 nanocrystals with an average size of 15 nm and exceptionally high photoluminescence (PL) quantum yield. When excited at 740 nm, the nanocrystals manifest spectrally distinguished, near-infrared to near-infrared (NIR-to-NIR) downconversion PL peaked at âˆŒ900, âˆŒ1050, and âˆŒ1300 nm. The absolute quantum yield of NIR-to-NIR PL reached 40% for core-shell nanoparticles dispersed in hexane. Time-resolved PL measurements revealed that this high quantum yield was achieved through suppression of nonradiative recombination originating from surface states and cross relaxations between dopants. NaGdF 4:Nd 3+/NaGdF 4 nanocrystals, synthesized in organic media, were further converted to be water-dispersible by eliminating the capping ligand of oleic acid. NIR-to-NIR PL bioimaging was demonstrated both in vitro and in vivo through visualization of the NIR-to-NIR PL at âˆŒ900 nm under incoherent lamp light excitation. The fact that both excitation and the PL of these nanocrystals are in the biological window of optical transparency, combined with their high quantum efficiency, spectral sharpness, and photostability, makes these nanocrystals extremely promising as optical biomaging probes.
Place, publisher, year, edition, pages
2012. Vol. 6, no 4, 2969-2977 p.
bioimaging, lanthanide, nanocrystals, near-infrared, photoluminescence
IdentifiersURN: urn:nbn:se:kth:diva-98575DOI: 10.1021/nn2042362ISI: 000303099300013ScopusID: 2-s2.0-84860378153OAI: oai:DiVA.org:kth-98575DiVA: diva2:538274
FunderSwedish e‐Science Research Center
QC 201206292012-06-292012-06-282013-04-08Bibliographically approved