title: Eu3+ doped KYF4 nanocrystals: synthesis, electronic structure, and optical properties.
abstract: Monodisperse cubic-phase KYF(4) : Eu(3+) nanocrystals (NCs) were synthesized via a modified thermal decomposition method. The optical properties of Eu(3+) in KYF(4) NCs including multiple luminescence centers, site symmetry, luminescence dynamics, as well as crystal-field levels of Eu(3+) were investigated in detail based on high-resolution photoluminescence (PL) spectroscopy at low temperature (10 K). Different from Eu(3+) in bulk counterparts, multiple sites of Eu(3+) in KYF(4) NCs were revealed by using the luminescence of Eu(3+) as a sensitive structural probe. The highest site symmetry of Eu(3+) at new near-surface site was deduced to be distorted from O(h) to D(2) (or C(2v)). Due to a small filling factor (0.45) of NCs, the PL lifetime of (5)D(0) of Eu(3+) in KYF(4) NCs was much longer than that in bulk counterparts, which was found to be significantly affected by the surrounding medium around the NCs.
authors.affiliation: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wang
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Xiao
authors.forename: Haomiao
authors.initials: H
authors.lastname: Zhu
authors.forename: Renfu
authors.initials: R
authors.lastname: Li
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Chen