Core/shell NaGdF4:Nd3+/NaGdF4nanocrystals with efficient near-infrared to near-infrared downconversion photoluminescence for bioimaging applications

Guanying Chen, Tymish Y. Ohulchanskyy, Sha Liu, Wing Cheung Law, Fang Wu, Mark T. Swihart, Hans Ågren, Paras N. Prasad

Research output: Journal article publicationJournal articleAcademic researchpeer-review

327 Citations (Scopus)

Abstract

We have synthesized core/shell NaGdF4:Nd3+/NaGdF4nanocrystals 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 ∼900, ∼1050, and ∼1300 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. NaGdF4:Nd3+/NaGdF4nanocrystals, 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 ∼900 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.
Original languageEnglish
Pages (from-to)2969-2977
Number of pages9
JournalACS Nano
Volume6
Issue number4
DOIs
Publication statusPublished - 24 Apr 2012
Externally publishedYes

Keywords

  • bioimaging
  • lanthanide
  • nanocrystals
  • near-infrared
  • photoluminescence

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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