Bolla Geetha, Liao Qing, Amirjalayer Saeed, Tu Zeyi, Lv Shaokai, Liu Jie, Zhang Shuai, Zhen Yonggang, Yi Yuanping, Liu Xinfeng, Fu Hongbing, Fuchs Harald, Dong Huanli, Wang Zhaohui, Hu Wenping
Key Laboratory of Organic Solids, Bejing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing, 100190, China.
Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, China.
Angew Chem Int Ed Engl. 2021 Jan 4;60(1):281-289. doi: 10.1002/anie.202007655. Epub 2020 Aug 31.
Amplified spontaneous emission (ASE) is intrinsically associated with lasing applications. Inefficient photon energy transfer to ASE is a long-standing issue for organic semiconductors that consist of multiple competing radiative decay pathways, far from being rationally regulated from the perspective of molecular arrangements. Herein, we achieve controllable molecular packing motifs by halogen-bonded cocrystallization, leading to ten times increased radiative decay rate, four times larger ASE radiative decay selectivity and thus remarkable ASE threshold decrease from 223 to 22 μJ cm , albeit with a low photoluminescence quantum yield. We have made an in-depth investigation on the relationship among molecular arrangements, vibration modes, radiative decay profiles and ASE properties. The results suggest that cocrystallization presents a powerful approach to tailor the radiative decay pathways, which is fundamentally important to the development of organic ASE and lasing materials.
放大自发辐射（ASE）与激光应用有着内在联系。对于由多种相互竞争的辐射衰变途径组成的有机半导体而言，向ASE的光子能量转移效率低下是一个长期存在的问题，从分子排列的角度来看，这远非能够合理调控。在此，我们通过卤键共结晶实现了可控的分子堆积模式，使得辐射衰变率提高了十倍，ASE辐射衰变选择性增大了四倍，ASE阈值也从223显著降低至22 μJ cm ，尽管光致发光量子产率较低。我们对分子排列、振动模式、辐射衰变谱和ASE性质之间的关系进行了深入研究。结果表明，共结晶是一种定制辐射衰变途径的有效方法，这对于有机ASE和激光材料的发展具有至关重要的意义。
