Singlet fission in pentacene dimers
Singlet fission in pentacene dimers
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DOI：
10.1073/pnas.1422436112
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
Johannes Zirzlmeier;Dan Lehnherr;P. B. Coto;Erin T. Chernick;Rubén Casillas;Bettina S. Basel;M. Thoss
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文献类型：
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作者：
Johannes Zirzlmeier;Dan Lehnherr;P. B. Coto;Erin T. Chernick;Rubén Casillas;Bettina S. Basel;M. Thoss
意义在目前的工作中，我们展示了令人信服的证据，证明在室温和稀溶液中，一组三种不同的区域异构并五苯二聚体中发生了前所未有的分子内单线裂变。泵浦-探针实验，辅以使用高级从头算多参考微扰理论方法的理论计算，证实了高达 156 ± 5% 的三重态量子产率。为此，二聚体中两个并五苯之间通过键合或空间相互作用的电子耦合对于调节单线态裂变速率至关重要。单线态裂变 (SF) 有潜力通过将光子到电流的转换效率提高到超过 30% 的 Shockley-Queisser 极限来取代传统的太阳能转换方案。在这里，我们展示了室温溶液中区域异构并五苯二聚体中前所未有的分子内 SF 的明确且令人信服的证据，观察到的三重态量子产率高达 156 ± 5%。虽然之前的研究表明光激发发色团与基态发色团的碰撞可以产生SF，但在这里我们证明并五苯二聚体中通过键或空间的接近和充分耦合足以诱导分子内SF，其中一个分子上生成两个三联体。
Significance In the present work, we show compelling evidence for the unprecedented intramolecular singlet fission at room temperature and in dilute solutions within a set of three different regioisomeric pentacene dimers. Pump–probe experiments, which were complemented by theoretical calculations using high-level ab initio multireference perturbation theory methods, corroborate triplet quantum yields as high as 156 ± 5%. To this end, electronic couplings between the two pentacenes in the dimers, by virtue of through-bond or through-space interactions, are decisive in tuning the rates of singlet fission. Singlet fission (SF) has the potential to supersede the traditional solar energy conversion scheme by means of boosting the photon-to-current conversion efficiencies beyond the 30% Shockley–Queisser limit. Here, we show unambiguous and compelling evidence for unprecedented intramolecular SF within regioisomeric pentacene dimers in room-temperature solutions, with observed triplet quantum yields reaching as high as 156 ± 5%. Whereas previous studies have shown that the collision of a photoexcited chromophore with a ground-state chromophore can give rise to SF, here we demonstrate that the proximity and sufficient coupling through bond or space in pentacene dimers is enough to induce intramolecular SF where two triplets are generated on one molecule.