Direct Identification of Surface Defects and Their Influence on the Optical Characteristics of Upconversion Nanoparticles

Wenjuan Bian, Yue Lin, Ting Wang, Xue Yu, Jianbei Qiu, Meng Zhou, Hongmei Luo, Siu Fung Yu, Xuhui Xu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

65 Citations (Scopus)


Core-shell structure is an obvious concept to suppress surface-related deactivations in lanthanide-doped upconversion nanoparticles (UCNPs). However, no direct observation of atomic-scale surface restoration, which can improve the upconversion photoluminescence, has been reported. Here, we use aberration-corrected high-angle annular dark field scanning transmission electron microscopy to study the surface condition of KLu2F7:Yb3+,Er3+ bare core UCNPs. Due to the very thin and uniform thickness of the UCNPs, we observe unambiguously that the recovery from surface defects enhances upconversion photoluminescence. Furthermore, the realization of dominant green lasing emission under pulsed laser excitation confirms the high crystallinity of the UCNPs.

Original languageEnglish
Pages (from-to)3623-3628
Number of pages6
JournalACS Nano
Issue number4
Publication statusPublished - 24 Apr 2018


  • energy back transfer
  • lasing
  • surface defect
  • surface restoration
  • upconversion

ASJC Scopus subject areas

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

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