Enhanced Lasing Properties of Dissymmetric Eu(III) Complex with Bidentate Phosphine Ligands

Abstract

The luminescent and lasing properties of Eu(III) complexes were enhanced by using an dissymmetric Eu(III) complex. The photophysical properties (the emission spectral shapes, the emission lifetimes, the emission quantum yields, and the stimulated emission cross section (SEC)) were found to be dependent on the geometrical structures of Eu(III) complexes. The geometrical structures of Eu(III) complexes were determined by X-ray single crystal analyses. The symmetrical group of Eu(hfa)3(BIPHEPO) (tris(hexafluoroacetylacetonato)europium(III) 1,1'-biphenyl-2,2'-diylbis(diphenylphosphine oxide)) was found to be C1, which was more dissymmetric than Eu(hfa)3(TPPO)2 (tris(hexafluoroacetylacetonato)europium(III) 1,2-phenylenebis(diphenylphosphine oxide): C2 symmetry) and Eu(hfa)3(OPPO)2 (tris(hexafluoroacetylacetonato)europium(III) 1,2-phenylenebis(diphenylphosphine oxide): C2 symmetry). The analytical data were supported by Judd-Ofelt analysis. The most dissymmetrical Eu(III) complex, Eu(hfa)3(BIPHEPO), showed large electron transition probability and large SEC (4.64 x 10(-20) cm2). The SEC of Eu(hfa)3(BIPHEPO) was superior to even the values of Nd-glass laser for practical use (1.6-4.5 x 10(-20) cm2). The lasing properties of Eu(III) complexes in polymer thin film were measured by photopumping of a Nd:YAG laser (355 nm). The threshold energy of lasing oscillation was found to be 0.05 mJ. The increasing rate of the lasing intensity of Eu(hfa)3(BIPHEPO) as a function of the excitation energy was much larger than that of Eu(hfa)3(TPPO)2 and Eu(hfa)3(OPPO)2. The dissymmetrical structure of Eu(hfa)3(BIPHEPO) promoted the enhancement of the lasing property.

Stereochemistry and solid-state circular dichroism spectroscopy of eight-coordinate chiral lanthanide complexes

“…The single-crystal structural measurements of 1-3 were performed on a Rigaku R-AXIS SPIDER IP diffractometer with graphite monochromated Mo Kα radiation (λ= 0.71073 Å) at 296 K. Crystal data [25] for [Tb(dbm) 3 (14), which indicates that the absolute configurations of 3 can be determined. The crystal data for 1 and 2 are almost the same as the literature [24] .…”

“…Reducing the symmetry of eight-coordinate Eu(III) complexes with a square anti-prism (SAP) geometry by means of reasonable design and synthesis could effectively improve their luminescent properties [9,14] . However, besides SAP polyhedron of eight-coordinate complexes, there are also other stereoisomers [1] , such as triangular dodecahedron (DD), cube, bi-capped triangular prism (TPR) and hexagonal bipyramid (HBP), among which the SAP and DD geometries are particularly the most common ones [15] .…”

Spectroscopic and photoluminescence characterization of Eu3+-doped monoclinic KY(WO4)2 crystal

“…Room-temperature (RT) lasing was obtained with Eu:GaN [8] and Eu:polymer [9] thin films. Recently, 25 at% Eu-doped potassium gadolinium DT, KGd(WO 4 ) 2 , was introduced as novel bulk dielectric material for pulsed room-temperature Eu 3 þ lasing [10].…”

Metal‐Ion Sensing Europium(III) Complexes with Bidentate Phosphine Oxide Ligands Containing a 2,2′‐Bipyridine Framework

“…) show relatively high emission quantum yields (F > 60% in (D 6 )acetone) [13] [14]. The LVF phosphine oxides with attached chemosensing units are expected to be promising ligands for luminescent lanthanide complexes having high emission quantum yields and effective chemosensing properties.…”

“…The radiative (k r ) and nonradiatve (k nr ) rate constants estimated from the emission lifetimes and the emission quantum yields are also summarized in the Table. The radiative and nonradiative rate constants of [Eu(hfa) 3 In our previous study, we have reported that the coordination geometry of [Eu(hfa) 3 (BIPHEPO)] is characterized as a square-antiprism structure (SAP) with eight coordinating O-atoms (8-SAP), and the two phosphine oxides of the BIPHEPO ligand are located on one square of the 8-SAP (Fig. 3) [14]. The two phosphine oxide sites in the BIPYPO and Me-BIPYPO ligands might also be located on one square of the 8-SAP.…”