Lin Chenjian, Qi Yue, Brown Paige J, Williams Malik L, Palmer Jonathan R, Myong Michele, Zhao Xingang, Young Ryan M, Wasielewski Michael R
Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113 United States.
Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States.
J Phys Chem Lett. 2023 Mar 16;14(10):2573-2579. doi: 10.1021/acs.jpclett.2c03621. Epub 2023 Mar 7.
Singlet fission (SF) is a spin-allowed process in which a photogenerated singlet exciton down-converts into two triplet excitons. Perylene-3,4-dicarboximide (PMI) has singlet and triplet state energies of 2.4 and 1.1 eV, respectively; thus making SF slightly exoergic and providing triplet excitons that have sufficient energy to raise the efficiency of single-junction solar cells by reducing thermalization losses from hot excitons formed when absorbed photons have energies higher than the semiconductor bandgap. However, PMI SF in the solid state has not been studied previously. Here, we show that 2,5-diphenyl--(2-ethylhexyl)perylene-3,4-dicarboximide () crystallizes into a slip-stacked intermolecular morphology favorable for SF. Transient absorption microscopy and spectroscopy show that SF occurs in ≤50 ps in both single crystals and polycrystalline thin films with a triplet yield of 150 ± 20%. Ultrafast SF in the solid state, the high triplet yield, and its photostability make an attractive candidate for SF-enhanced solar cells.
单线态裂变（SF）是一种自旋允许的过程，其中光生单线态激子向下转换为两个三线态激子。苝-3,4-二甲酰亚胺（PMI）的单线态和三线态能量分别为2.4和1.1电子伏特；因此，SF略有放能，并提供三线态激子，这些激子具有足够的能量，通过减少吸收光子能量高于半导体带隙时形成的热激子的热化损失，来提高单结太阳能电池的效率。然而，固态PMI的SF此前尚未得到研究。在这里，我们表明2,5-二苯基-（2-乙基己基）苝-3,4-二甲酰亚胺（）结晶成有利于SF的滑移堆积分子间形态。瞬态吸收显微镜和光谱表明，在单晶和多晶薄膜中，SF在≤50皮秒内发生，三线态产率为150±20%。固态中的超快SF、高三线态产率及其光稳定性使成为SF增强型太阳能电池的有吸引力的候选材料。
