Novel Stoichiometrically Erbium−Ytterbium Cocrystalline Complex Exhibiting Enhanced Near-Infrared Luminescence

• Published in: Inorganic chemistry 2006-05, Vol.45 (11), p.4537-4543
• Main Authors: Zhong, Qi, Wang, Huaishan, Qian, Guodong, Wang, Zhiyu, Zhang, Jiahua, Qiu, Jianrong, Wang, Minquan
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic051697y

Three β-diketonate complexes of erbium and ytterbium, Er(HFA)3(TPPO)3, Yb(HFA)3(TPPO)3, and Er1/2Yb1/ 2(HFA)3(TPPO)2 (HFA = hexafluoroacetylacetonate, TPPO = triphenylphosphine oxide) are synthesized and structurally characterized, and their luminescent properties are examined in detail. Compared with monometallic complexes Er(HFA)3(TPPO)3 and Er(HFA)3(TPPO)3, the stoichiometrically Er−Yb cocrystalline complex Er1/2Yb1/2(HFA)3(TPPO)2 exhibits special indirect near-infrared (NIR) luminescence with the acceptor and sensitizer (donor) coexisting in a single crystal. Of interest is that the NIR luminescence of the erbium ion in Er1/2Yb1/2(HFA)3(TPPO)2 is significantly enhanced because of the coexistence of the ytterbium ion through the energy-transfer between the ytterbium and erbium ions. The estimated donor−acceptor energy-transfer critical radii R C,DA, obtained from the Förster model, are in good agreement with those determined from the single X-ray crystal structure, confirming the dipole−dipole character for such a Yb−Er energy-transfer process.