American Chemical Society
jz2c01226_si_006.cif (1.86 MB)

Molecular Conformation Engineering To Achieve Longer and Brighter Deep Red/Near-Infrared Emission in Crystalline State

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posted on 2022-05-25, 15:48 authored by Jianan Dai, Lianfei Yao, Chenguang Wang, Yinghui Wang, Fangmeng Liu, Xu Yan, Peng Sun, Hongyu Zhang, Yue Wang, Ji Zhou, Geyu Lu
A series of molecules 15 containing the same fluorophore and different alkyl chains are synthesized to reveal the significant effect of molecular conformations on the emission properties. In crystalline state, molecules 13 exhibit strong orange emissions with maxima (λem) of about 600 nm and quantum yields (ΦF) of around 60%, while molecules 4 and 5 display much longer emissions to the deep red/near-infrared (NIR) region as well as even higher efficiencies (λem = 693 nm, ΦF = 73% for 4; λem = 654 nm, ΦF = 93% for 5). The largely red-shifted emissions of 4 and 5 as well as the significantly improved ΦF are very unusual. Furthermore, the ΦF of 4 and 5 represent the highest values among organic solids with similar deep red/NIR emission wavelengths. On the basis of the experimental measurements and theoretical calculations, the new molecular design of conformation engineering, the impressive emission properties, and the potential NIR fluorescence sensing and lasing applications are comprehensively investigated.