Synthesis and Characterization of Europium Complex Nanoparticles with Long-Wavelength Sensitized Luminescence

Luminescent nanoparticles (dav=35 nm) of Eu(tta)3dpbt (dpbt=2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine, tta=thenoyltrifluoroacetonato) protected by bovine serum albumin (BSA) were prepared by a precipitation method.These particles disperse well in aqueous solutions to form stable and transparent colloidal solutions.The BSA-protected Eu(tta)3dpbt nanoparticles exhibit high photostability and excellent long-wavelength sensitized EuIII luminescence properties.The quantum yield of EuIII luminescence is 0.20 (λex=415 nm, 25 ℃), and the excitation band for the EuIII luminescence centers at 415 nm and extends to 470 nm.Upon two-photon excitation, the prepared nanoparticles emit pure-red light with a two-photon excitation action cross section of 2.4×105 GM (λex=830 nm, 1 GM=10-50 cm4·s·photo-1·particle-1).The prepared nanoparticles and the reported preparation method are promising for the development of luminescent bionanoprobes with excellent biocompatibility and luminescent properties.