Spectroscopic aspects for the Yb3+ coordination compound with a large energy gap between the ligand and Yb3+ excited states

Sensitization of lanthanide complexes through direct spin-forbidden singlet → triplet excitation

“…Surprisingly, the emission intensity of luminescence increases from 298 to 402 K, suggesting that the ligand-to-Yb III energy transfer is favored as the temperature rises from 298 K. The energy transfer mechanisms in Yb III complexes are not so well understood yet since such complexes usually feature a large energetic mismatch between the ligand and Yb III excited states. Kasprzycka and coworkers, 34 for instance, concluded that in a Yb III complex with N -phosphorylated sulfonamide, the S 1 → LMCT → T 1 → Yb III pathway is more likely than the S 1 → T 1 → Yb III one. Yet, in our [Yb 2 (3,5-bbza) 6 (H 2 O) 2 ] complex, LMCT states barely contribute according to DRS measurements, while upon 360 nm excitation, the S 1 state is not populated.…”

Enhancing the Luminescence of Eu(III) Complexes with the Ruthenocene Organometallic Unit as Ancillary Ligand

“…Thus, the population of the Ln­(III) emitting level is given by analytical expressions. ,− On the other hand, the system of rate equations, with its respective initial conditions, can be numerically solved using several methods such as 4th order Runge–Kutta with a fixed-step or adaptive step-size, Radau, and Adams–Bashforth among others . The Radau method was adopted in the simulations once it was successfully applied in other Ln-based complexes, providing very consistent results. ,,− Each simulation was done in a time interval from 0 to 10 ms, with a step-size of 2 μs. See Supporting Information for further details.…”

“…The overall quantum yield (or emission quantum yield) Q Ln L is defined by the ratio of the numbers of photons emitted and absorbed ,,, where P 0 is the population of the ground level, and ϕ is the pumping rate of the populations from this level (e.g., S 0 → S 1 absorption). The latter can be estimated by , where σ is the absorption cross-section of the ligand (in the order of ∼10 –16 cm 2 ), ρ is the power density in units of W·cm –2 , λ exc is the excitation wavelength, h is Planck’s constant, and c is the speed of light. ,,, …”

Single-center LnIII ratiometric luminescent temperature probes based on singlet → singlet and singlet → triplet sensitizations

“…This thermally dependent ligand to Ln III energy transfer has already been reported for Eu III and Tb III complexes, 34,35 yet, contrary to such systems, the energy transfer pathways in Yb III complexes are not so well elucidated in the literature due to the large energetic mismatch between Yb III excited states and ligand donor states. For instance, Kasprzycka and coworkers 36 recently showed that in a Yb III complex with N-phosphorylated sulfonamide ligands, the S 1 → LMCT → T 1 → Yb III path displays larger contribution than the S 1 → T 1 → Yb III one.…”