Realizing Excellent Nonlinear Optical Performance in Near‐Infrared Region of Helicene‐Functionalized Arenes

Abstract Construction of novel arenes bearing promising optical limiting characteristics in the near‐infrared region is in high demand but is limited. Herein, two novel helicene‐embedded arenes 4 and 6 have been strategically synthesized and characterized. Under 190 fs pulse width, both of them exhibit broadband reverse saturable absorption over a range from 750 to 800 nm, 900 nm, 1030 nm, 1200 nm, then to 1250 nm. The optical limiting thresholds are determined to be 8.1 mJ cm⁻² for 4, 6.2 mJ cm⁻² for 6 at 800 nm, and 26.4 mJ cm⁻² for 4, 20.8 mJ cm⁻² for 6 at 1030 nm, respectively. In addition, compounds 4 and 6 display obviously reverse saturable absorption at pulse widths of 22 ps and 5 ns at a wavelength of 532 nm. The findings clearly suggest that the cyclopenta‐ring‐fused pyrene core governs their electronic nature and the construction of such twistacene‐functionalized arenes may be a promising design strategy to realize the relationship between molecular structure and nonlinear optical property.