Developing thermally activated delayed fluorescence (TADF)‐active silver clusters with near‐unity quantum efficiency is of practical importance in cutting‐edge optoelectronic devices, but remains a tremendous challenge due to the difficulty of de novo synthesis and uncertainty of properties. Herein, we demonstrate a lattice modulation on parent TADF‐activate silver cluster, acheving TADF‐driven photoluminescence quantum yield (PLQY) from 12% to near‐unity. Systematic experimental and calculated results reveal that the lattice modulation effectively lower the singlet‐triplet splitting (ΔEST) from 718 to 549 cm‐1, thereby facilitating thermally activated reverse intersystem crossing: T5→S5, leading to extremely efficient TADF by surpassing both phosphorescence and non‐radiative decay, thus boosting the near‐unity PLQY. Such high PLQY are extremely rare in the TADF‐active silver clusters and even in the whole noble‐metal clusters. This research showcases an unparalleled example of lattice modulation to realize near unity PLQY of TADF‐active silver clusters.

中文翻译：

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银簇单重态-三重态分裂的晶格调制提高了近乎一致的光致发光量子产率


开发具有近乎统一的量子效率的热激活延迟荧光 （TADF） 活性银簇在尖端光电器件中具有实际重要性，但由于从头合成的困难和性质的不确定性，仍然是一项巨大的挑战。在此，我们展示了母体 TADF 激活银簇上的晶格调制，使 TADF 驱动的光致发光量子产率 （PLQY） 从 12% 降低到接近一。系统的实验和计算结果表明，晶格调制有效地将单重态-三重态分裂 （ΔEST） 从 718 cm-1 降低到 549 cm-1，从而促进热激活反向系统间交叉：T5→S5，通过超越磷光和非辐射衰减实现极其高效的 TADF，从而增强近一 PLQY。如此高的 PLQY 在 TADF 活性银簇中甚至在整个贵金属簇中都极为罕见。这项研究展示了一个无与伦比的晶格调制示例，以实现 TADF 活性银簇的近乎统一的 PLQY。