Han Zhen, Dong Xi-Yan, Luo Peng, Li Si, Wang Zhao-Yang, Zang Shuang-Quan, Mak Thomas C W
College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China.
College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454000, China.
Sci Adv. 2020 Feb 7;6(6):eaay0107. doi: 10.1126/sciadv.aay0107. eCollection 2020 Feb.
Monolayer-protected atomically precise silver clusters display low photoluminescence (PL) quantum yield (QY) and susceptibility under ambient conditions, and their chiroptical activities also remain underdeveloped. Here, we report enantiomers of an octahedral Ag cluster prepared via one-step synthesis using designed chiral ligands at ambient temperature. These clusters exhibit a highest PLQY (300 K) >95.0% and retain their structural integrity and emission up to 150°C in air. Atomically precise structural determination combined with photophysical and computational analysis revealed that thermally activated delayed fluorescence, observed in silver cluster systems, is responsible for the high PLQY, which combines chirality in excited states to generate strong circularly polarized luminescence. These unprecedented findings open up horizons of investigation of monolayer-protected silver clusters for future luminescence applications.
在环境条件下，单层保护的原子精确银簇表现出低的光致发光（PL）量子产率（QY）和磁化率，并且它们的手性光学活性也尚未得到充分发展。在此，我们报道了通过在室温下使用设计的手性配体进行一步合成制备的八面体银簇的对映体。这些簇表现出最高的PLQY（300 K）>95.0%，并且在空气中高达150°C时仍保持其结构完整性和发射。原子精确的结构测定结合光物理和计算分析表明，在银簇系统中观察到的热激活延迟荧光是高PLQY的原因，它在激发态结合手性以产生强烈的圆偏振发光。这些前所未有的发现为未来发光应用中单层保护银簇的研究开辟了新视野。
