Insights into Nd<sup>III</sup> to Yb<sup>III</sup> Energy Transfer and Its Implications in Luminescence Thermometry
Mariangela Oggianu, Valentina Mameli, Miguel A. Hernández‐Rodríguez, Noemi Monni, Manuel Souto, Carlos D. S. Brites, Carla Cannas, Fabio Manna, Francesco Quochi, Enzo Cadoni, Norberto Masciocchi, Albano N. Carneiro Neto, Luís D. Carlos, Maria Laura Mercuri
Abstract
High Resolution Image Download MS PowerPoint Slide This work challenges the conventional approach of using Nd III 4 F 3/2 lifetime changes for evaluating the experimental Nd III → Yb III energy transfer rate and efficiency. Using near-infrared (NIR) emitting Nd:Yb mixed-metal coordination polymers (CPs), synthesized via solvent-free thermal grinding, we demonstrate that the Nd III [ 2 H 11/2 → 4 I 15/2 ] → Yb III [ 2 F 7/2 → 2 F 5/2 ] pathway, previously overlooked, dominates energy transfer due to superior energy resonance and J -level selection rule compatibility. This finding upends the conventional focus on the Nd III [ 4 F 3/2 → 4 I 11/2 ] → Yb III [ 2 F 7/2 → 2 F 5/2 ] transition pathway. We characterized Nd 0.890 Yb 0.110 (BTC)(H 2 O) 6 as a promising cryogenic NIR thermometry system and employed our novel energy transfer understanding to perform simulations, yielding theoretical thermometric parameters and sensitivities for diverse Nd:Yb ratios. Strikingly, experimental thermometric data closely matched the theoretical predictions, validating our revised model. This novel perspective on Nd III → Yb III energy transfer holds general applicability for the Nd III /Yb III pair, unveiling an important spectroscopic feature with broad implications for energy transfer-driven materials design.