Observation of Ligand-Centred Fluorescence and Intramolecular Relaxation at Sub-Vibrational Time Scales

Using broadband photoluminescence upconversion, we observe fluorescence from a high-lying ligand-centred state in Ir(ppy)3. This result allows us to clock the electronic relaxation to the lowest 3MLCT state, occurring at sub-vibrational time scales.