Singlet–triplet conversion in organic light‐emitting materials introduces non‐emissive (dark) and long‐lived triplet states, which represents a significant challenge in constraining the optical properties. There have been considerable attempts at separating singlets and triplets in long‐chain polymers, scavenging triplets, and quenching triplets with heavy metals; nonetheless, such triplet‐induced loss cannot be fully eliminated. Herein, a new strategy of crafting a periodic molecular barrier into the π‐conjugated matrices of organic aromatic fluorophores is reported. The molecular barriers effectively block the singlet‐to‐triplet pathway, resulting in near‐unity photoluminescence quantum efficiency (PLQE) of the organic fluorophores. The transient optical spectroscopy measurements confirm the absence of the triplet absorption. These studies provide a general approach to preventing the formation of dark triplet states in organic semiconductors and bring new opportunities for the development of advanced organic optics and photonics.

中文翻译：

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具有统一量子效率的共晶体中分子屏障增强的芳香荧光团。

有机发光材料中的单重态-三重态转换引入了非发光（暗态）和长寿命的三重态，这在限制光学性能方面提出了巨大的挑战。在分离长链聚合物中的单重态和三重态，清除三重态和用重金属淬灭三重态方面进行了大量的尝试。但是，这种三重态引起的损失不能完全消除。本文报道了一种新的策略，该策略将周期性分子屏障纳入有机芳香族荧光团的π共轭矩阵中。分子屏障有效地阻止了从单重态到三重态的途径，从而导致有机荧光团的近统一光致发光量子效率（PLQE）。瞬态光谱学测量证实不存在三重态吸收。