Zhang Jie, Sakai Hayato, Suzuki Katsuaki, Hasobe Taku, Tkachenko Nikolai V, Chang I-Ya, Hyeon-Deuk Kim, Kaji Hironori, Teranishi Toshiharu, Sakamoto Masanori
Department of Chemistry, Graduate School of Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
J Am Chem Soc. 2021 Oct 27;143(42):17388-17394. doi: 10.1021/jacs.1c04731. Epub 2021 Oct 14.
The conversion of a high-energy photon into two excitons using singlet fission (SF) has stimulated a variety of studies in fields from fundamental physics to device applications. However, efficient SF has only been achieved in limited systems, such as solid crystals and covalent dimers. Here, we established a novel system by assembling 4-(6,13-bis(2-(triisopropylsilyl)ethynyl)pentacen-2-yl)benzoic acid (Pc) chromophores on nanosized CdTe quantum dots (QDs). A near-unity SF (198 ± 5.7%) initiated by interfacial resonant energy transfer from CdTe to surface Pc was obtained. The unique arrangement of Pc determined by the surface atomic configuration of QDs is the key factor realizing unity SF. The triplet-triplet annihilation was remarkably suppressed due to the rapid dissociation of triplet pairs, leading to long-lived free triplets. In addition, the low light-harvesting ability of Pc in the visible region was promoted by the efficient energy transfer (99 ± 5.8%) from the QDs to Pc. The synergistically enhanced light-harvesting ability, high triplet yield, and long-lived triplet lifetime of the SF system on nanointerfaces could pave the way for an unmatched advantage of SF.
利用单线态裂变（SF）将高能光子转化为两个激子，这在从基础物理到器件应用等诸多领域引发了各种各样的研究。然而，高效的SF仅在有限的体系中得以实现，比如固体晶体和共价二聚体。在此，我们通过将4-(6,13-双(2-(三异丙基硅基)乙炔基)并五苯-2-基)苯甲酸（Pc）发色团组装在纳米尺寸的碲化镉量子点（QDs）上，建立了一种新型体系。通过从碲化镉到表面Pc的界面共振能量转移引发了近乎完全的SF（198 ± 5.7%）。由量子点的表面原子构型所决定的Pc的独特排列是实现完全SF的关键因素。由于三线态对的快速解离，三线态-三线态湮灭得到显著抑制，从而产生长寿命的自由三线态。此外，量子点到Pc的高效能量转移（99 ± 5.8%）提升了Pc在可见光区域的低光捕获能力。纳米界面上SF体系协同增强的光捕获能力、高三线态产率和长寿命三线态寿命可为SF带来无与伦比的优势铺平道路。
