Ultrabright Au@Cu<sub>14</sub> nanoclusters: 71.3% phosphorescence quantum yield in non-degassed solution at room temperature.

Song, Yongbo; Li, Yingwei; Zhou, Meng; Liu, Xuan; Li, Hao; Wang, He; Shen, Yuhua; Zhu, Manzhou et al. · Sci Adv · 2021

basic_science · Level V

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Abstract

The photoluminescence of metal nanoclusters is typically low, and phosphorescence emission is rare due to ultrafast free-electron dynamics and quenching by phonons. Here, we report an electronic engineering approach to achieving very high phosphorescence (quantum yield 71.3%) from a [Au@Cu<sub>14</sub>(SPh <i><sup>t</sup></i> Bu)<sub>12</sub>(PPh(C<sub>2</sub>H<sub>4</sub>CN)<sub>2</sub>)<sub>6</sub>]<sup>+</sup> nanocluster (abbreviated <b>Au@Cu</b> <sub><b>14</b></sub> ) in non-degassed solution at room temperature. The structure of <b>Au@Cu</b> <sub><b>14</b></sub> has a single-Au-atom kernel, which is encapsulated by a rigid Cu(I) complex cage. This core-shell structure leads to highly efficient singlet-to-triplet intersystem crossing and suppression of nonradiative energy loss. Unlike the phosphorescent organic materials and organometallic complexes-which require de-aerated conditions due to severe quenching by air (i.e., O<sub>2</sub>)-the phosphorescence from <b>Au@Cu</b> <sub><b>14</b></sub> is much less sensitive to air, which is important for lighting and biomedical applications.