英国谢菲尔德大学的Jenny Clark课题组取得一项新突破。他们的研究认为发射自旋为0的三重态对是并五苯单晶和蒽并噻吩衍生物薄膜中三线态-三线态湮灭的直接产物。该项研究成果发表在2020年出版的《自然—化学》上。

这里该团队使用强度依赖的低温光致发光测量，结合动力学模拟，展示了在高质量的并五苯单晶和蒽并噻吩衍生物(diF-TES-ADT)薄膜中，独特的1(TT)发射直接来源于三线态-三线态湮灭。这项工作表明，真实的、可发射的三重态对在单线态分裂和三线态-三线态湮灭中均起着中间体作用，这对于吸热和放热的单线态分裂材料都是如此。

研究人员表示，单线态分裂和三线态-三线态湮灭代表了提高光电元件效率的两种高度有希望的方式。这两种过程都被认为是由双激子三重态对1(TT)所介导的。然而，最近对于1(TT)在三线态-三线态湮灭中的角色一直有争论。

附：英文原文

Title: Emissive spin-0 triplet-pairs are a direct product of triplet–triplet annihilation in pentacene single crystals and anthradithiophene films

Author: David G. Bossanyi, Maik Matthiesen, Shuangqing Wang, Joel A. Smith, Rachel C. Kilbride, James D. Shipp, Dimitri Chekulaev, Emma Holland, John E. Anthony, Jana Zaumseil, Andrew J. Musser, Jenny Clark

Issue&Volume: 2020-12-07

Abstract: Singlet fission and triplet–triplet annihilation represent two highly promising ways of increasing the efficiency of photovoltaic devices. Both processes are believed to be mediated by a biexcitonic triplet-pair state, 1(TT). Recently however, there has been debate over the role of 1(TT) in triplet–triplet annihilation. Here we use intensity-dependent, low-temperature photoluminescence measurements, combined with kinetic modelling, to show that distinct 1(TT) emission arises directly from triplet–triplet annihilation in high-quality pentacene single crystals and anthradithiophene (diF-TES-ADT) thin films. This work demonstrates that a real, emissive triplet-pair state acts as an intermediate in both singlet fission and triplet–triplet annihilation and that this is true for both endo- and exothermic singlet fission materials.

DOI: 10.1038/s41557-020-00593-y

Source: https://www.nature.com/articles/s41557-020-00593-y