Cocrystallization Tailoring Multiple Radiative Decay Pathways for Amplified Spontaneous Emission. (31st August 2020)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: Angewandte Chemie. Volume 133:Number 1(2020)
• Page Start: 285
• Page End: 293
• Publication Date: 2020-08-31
• Subjects: amplified spontaneous emission (ASE) -- cocrystallization -- halogen bonds -- organic semiconductors -- radiative decay pathways; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202007655
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: 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 −2, 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. Abstract : A cocrystal packing arrangement has been tuned from mixed to segregated stack by subtle modulation of halogen bonds from C−Br⋅⋅⋅N to C−I⋅⋅⋅N, giving rise to significantly enhanced radiative decay rate and selectivity. Amplified spontaneous emission characteristics were improved remarkably by cocrystallization, opening up possibilities to the development of organic lasing materials by tailoring multiple radiative decay pathways.