Singlet fission has the potential to surpass current efficiency limits in next-generation photovoltaics and to find use in quantum information science. Despite the demonstration of singlet fission in various materials, there is still a great need for fundamental design principles that allow for tuning of photophysical parameters, including the rate of fission and triplet lifetimes. Here we describe the synthesis and photophysical characterization of a novel bipentacene dipyridyl pyrrole (HDPP-Pent) and its Li- and K-coordinated derivatives. HDPP-Pent undergoes singlet fission at roughly 50% efficiency (τ_SF = 730 ps), whereas coordination in the Li complex induces significant structural changes to generate a dimer, resulting in a 5-fold rate increase (τ_SF = 140 ps) and near fully efficient singlet fission with virtually no sacrifice in triplet lifetime. We thus illustrate novel design principles to produce favorable singlet fission properties, wherein through-space control can be achieved via coordination chemistry-induced multi-pentacene assembly.

中文翻译：

---

控制双峰裂变与配位化学诱导的联吡啶吡咯双戊烯的组装

单重态裂变有可能超越下一代光伏技术的电流效率极限，并有可能在量子信息科学中得到应用。尽管在各种材料中均表现出单重态裂变，但仍非常需要基本的设计原理，以允许调整光物理参数，包括裂变速率和三重态寿命。在这里，我们描述了一种新型双并五苯二吡啶基吡咯（HDPP-Pent）及其Li-和K-配位衍生物的合成和光物理特性。HDPP -戊经历单峰裂变在大约50％的效率（τ _SF = 730 ps）的，而在Li络合物诱导显著结构变化的协调，以产生二聚体，从而导致了5倍速率增加（τ _SF= 140 ps）和接近完全有效的单重态裂变，而三重态寿命几乎没有牺牲。因此，我们说明了产生有利的单线裂变性质的新颖设计原理，其中可通过配位化学诱导的多并五苯组装来实现贯穿空间的控制。