Low-lying electronic states of [Rh(bpy)3]3+, [Pt(bpy)2]2+, and [Ru(bpy)3]2+. A comparative study based on highly resolved and time-resolved spectra

Photophysical Properties and OLED Applications of Phosphorescent Platinum(II) Schiff Base Complexes

“…[12] Therefore, it is of great interest to determine this important parameter for the complexes described in this work. Besides the direct determination of the ZFS parameters from highly resolved emission and excitation spectra, [12,16,17] it is possible to obtain these values from the temperature dependence of the emission decay time. Under the assumption of fast thermalization, the occupation dynamics of the excited states (triplet substates) involved in the emission process are governed by Equation (1), [12,[19][20][21] in which n i denotes the Boltzmann occupation number of state i, k i is the total rate constant for depopulation of state i. N is the total number of occupied excited states and k therm = 1/t therm is the rate constant for depopulation of the equilibrated system of excited states, that is, the inverse of the measured decay time.…”

“…A high degree of MLCT character has also been calculated for [IrA C H T U N G T R E N N U N G (ppy) 3 ] in the theoretical works of Hay [26] and Nozaki. 2 + , with zero-field splittings of the lowest triplet state being 60, [17,18] 76, [28] and 211 cm À1 , [17,18] respectively. In contrast, complexes such as [PdA C H T U N G T R E N N U N G (thpy) 2 ] (thpy = 2-(2'-thienyl)pyridyl), [16,29] [Pd(q) 2 ] (q= 8-quinolinato), and [Pt(q) 2 ], [30] as well as [RhA C H T U N G T R E N N U N G (bpy) 3 ] 3 + [31] and [PtA C H T U N G T R E N N U N G (bpy) 2 ] 2 + [17,18] , are characterized by ZFS values significantly below 1 cm À1 .…”

Quasi-epitaxial Growth of [Ru(bpy)3]2+by Confinement in Clay Nanoplatelets Yields Polarized Emission

“…To probe the quality of orientation of the intercalated transition metal complex, the polarization degree of emitted light was studied with macroscopic meso-crystals of the [Ru(bpy) 3 ]-fl uorohectorite. [Ru(bpy) 3 ] 2+ was chosen because its electronic structure has been well characterized [17][18][19][20] and because it has been shown to adopt well defi ned patterns in the interlayer of a clay host. [ 21 ] The emission properties of [Ru(bpy) 3 ] 2+ are essentially determined by the electronic structures of the lowest excited states.…”

“…It turns out that above T ≈ 10 K and up to ambient temperature, one triplet sub-state (of group theoretical E character in a trigonal point group with a totally symmetric ground state) essentially emits while being polarized with the electric fi eld vector E perpendicularly to the molecular 3 C -axis. [17][18][19][20]22 ] For the sake of completeness it should be mentioned that it has been shown by Yersin et al that at ambient temperature a higher lying singlet state (of group theoretical 1 A 2 character) is thermally populated and leads to a weak thermally activated delayed fl uorescence (TADF). According to the selection rules, the emission E corresponding to this TADF sub-state is polarized parallel to the 3 C -axis.…”

Exploring the Photodeactivation Pathways of Pt[O^N^C^N] Complexes: A Theoretical Perspective

“…Yersin et al reportedt hat the value of the total zero-field splitting (ZFS) can reflect the extent of the MLCT perturbation in the emitting state, [12] and the k r value. Yersin et al reportedt hat the value of the total zero-field splitting (ZFS) can reflect the extent of the MLCT perturbation in the emitting state, [12] and the k r value.…”