Mirror-image magnetic circularly polarized luminescence (MCPL) from optically inactive EuIII and TbIIItris(β-diketonate)

Abstract

Five optically inactive Eu^III(hfa)₃, Tb^III(hfa)₃, Eu^III(acac)₃·Phen, Tb^III(acac)₃·Phen and Eu^III(hfa)₃·BDPB (hfa: hexafluoroacetylacetonate, acac: acetylacetonate, BDPB: 2,2′-bis(diphenylphosphino)biphenyl and Phen: phenanthroline) complexes showed clear mirror-image magnetic circularly polarised luminescence (MCPL) spectra in CHCl₃, acetone, and DMF solutions, in a poly(methyl methacrylate) film, a KBr pellet and bulk powder at room temperature under 1.6 T as an external magnetic field with Faraday geometry. The signs of the MCPL signals were determined via N-up and S-up geometries. The g_MCPL values of Eu^III(hfa)₃ and Tb^III(hfa)₃ were ±(0.046–2.0) × 10⁻² T⁻¹ at the ⁵D₀ → ⁵F_J transitions (J = 1–4) in the range of 590 nm and 703 nm and ±(0.0081–1.0) × 10⁻² T⁻¹ at the ⁵D₄ → ⁷F_J transitions (J = 3–6) in the range of 480 nm and 630 nm, respectively. Interestingly, the photoluminescence spectra of Eu^III(hfa)₃ and Tb^III(hfa)₃ in CHCl₃ and acetone under 1.6 T considerably redshifted by 10–114 cm⁻¹, while those of Eu^III(acac)₃·Phen and Tb^III(acac)₃·Phen did not reveal detectable redshifts.