title: Bright green upconversion fluorescence of Yb3+, Er(3+)-codoped NaYF4 nanocrystals.
abstract: Uniform hexagonal NaYF4: Yb3+, Er3+ nanocrystals (NCs) with bright green upconversion fluorescence were prepared. The nanocrystals were highly hydrophobic and dispersed in cyclohexane forming a transparent colloidal solution due to the use of oleic acid as a capping ligand. Temperature dependence for emission of Er3+ ions in this sample was also studied. The green emission intensity of Er3+ ions had a maximum at 160 K under 980 nm excitation, which was attributed to the thermally activated distribution of electrons and the thermal quenching effect. The transparent colloidal solution is expected to be a good candidate for research in biological imaging or display applications.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
authors.forename: Weiping
authors.initials: W
authors.lastname: Qin
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Guofeng
authors.initials: G
authors.lastname: Wang
authors.forename: Chunyan
authors.initials: C
authors.lastname: Cao
authors.forename: Guodong
authors.initials: G
authors.lastname: Wei
authors.forename: Ryongjin
authors.initials: R
authors.lastname: Kim
authors.forename: Daisheng
authors.initials: D
authors.lastname: Zhang
authors.forename: Fuheng
authors.initials: F
authors.lastname: Ding
authors.forename: Chunfeng
authors.initials: C
authors.lastname: He