Department of Chemistry, Columbia University, New York, NY, 10027, USA.
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA.
Adv Mater. 2017 Nov;29(41). doi: 10.1002/adma.201701416. Epub 2017 Sep 14.
Singlet fission (SF), a promising mechanism of multiple exciton generation, has only recently been engineered as a fast, efficient, intramolecular process (iSF). The challenge now lies in designing and optimizing iSF materials that can be practically applied in high-performance optoelectronic devices. However, most of the reported iSF systems, such as those based on donor-acceptor polymers or pentacene, have low triplet energies, which limits their applications. Tetracene-based materials can overcome significant challenges, as the tetracene triplet state is practically useful, ≈1.2 eV. Here, the synthesis and excited state dynamics of a conjugated tetracene homopolymer are studied. This polymer undergoes ultrafast iSF in solution, generating high-energy triplets on a sub-picosecond time scale. Magnetic-field-dependent photocurrent measurements of polytetracene-based devices demonstrate the first example of iSF-generated triplet extraction in devices, exhibiting the potential of iSF materials for use in next-generation devices.
单线态裂变 (SF)，一种有前途的多激子产生机制，最近才被设计为一种快速、高效的分子内过程 (iSF)。现在的挑战在于设计和优化可实际应用于高性能光电设备的 iSF 材料。然而，大多数报道的 iSF 系统，如基于给体-受体聚合物或并五苯的系统，具有较低的三重态能量，这限制了它们的应用。基于苝的材料可以克服重大挑战，因为苝的三重态状态在实际上是有用的，约为 1.2eV。在这里，研究了一种共轭苝均聚物的合成和激发态动力学。该聚合物在溶液中经历超快 iSF，在亚皮秒时间尺度上产生高能三重态。基于聚苝器件的磁场依赖光电流测量证明了器件中 iSF 产生的三重态提取的第一个例子，显示了 iSF 材料在下一代器件中的应用潜力。
