Evidence for triplet-state-dominated luminescence in biicosahedral superatomic molecular Au25 clusters. Issue 22 (26th April 2022) - Mitsui, Masaaki
Abstract : Biicosahedral Au25 clusters exhibit room-temperature phosphorescence from the excited triplet state with an intersystem crossing quantum yield of almost 100%. This property allows triplet sensitization and induces triplet fusion photon upconversion. Abstract : In photoluminescence (PL) quenching and triplet fusion upconversion experiments with fluorescent organic-molecule quenchers, it was revealed that a rod-shaped, phosphine- and thiolate-protected biicosahedral Au25 cluster (a representative di-superatomic molecule) exhibits only phosphorescence, not fluorescence, at room temperature with an intersystem crossing quantum yield of almost 100%. By virtue of these photophysical properties, this cluster can be used as a triplet sensitizer that undergoes direct singlet–triplet transitions in the near-infrared (NIR) region (730–900 nm), inducing photon upconversion from NIR to visible light.