Excellent ultrafast broadband optical limiting of functionalized twistacenes based on two-photon absorption-induced excited state absorption

• Published in: Dyes and pigments 2023-01, Vol.208, p.110842, Article 110842
• Main Authors: Han, Yanbing, Xiao, Jinchong, Wu, Xingzhi, Wang, Yuxiao, Zhang, Xueru, Song, Yinglin
• Format: Article
• Language: English
• Subjects: Molecular design; Optical limiting; Twistacenes; Two photon absorption; Ultrafast dynamics
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2022.110842

Twistacene is an outstanding building block due to the large conjugated system. Herein, a series of twistacenes have been designed and synthesized with the assistant from a theoretical analysis based on the morphology of the natural transition orbitals of first excited state. These twistacenes exhibit two photon absorption and unique broadband excited singlet state absorption features, which is systematically confirmed by transient absorption spectra, two-photon excited fluorescence and z-scan experiments. The overlap of two-photon absorption band with excited state absorption band can improve the OL performance. The experimental results are consistent with theoretical prediction, which confirm the rationalization of molecular design strategy. The screened twistacene 5 exhibits excellent optical limiting behavior with extremely high transmittance and low threshold, where the threshold is 1.3–3.1 mJ/cm2 in a wide optical window from 532 nm to 900 nm in femtosecond regime and 69 mJ/cm2 in picosecond regime. The experimental results suggest twistacene is a promising candidate for nonlinear optical applications, especially for protection against ultrashort laser pulses. Twistacenes are fascinating ultrafast broadband optical limiters due to the overlap the two-photon absorption band and excited singlet state absorption band, which can be screened out by a theory-assisted method based on the analysis of the morphology of the natural transition orbitals. The optimal twistacene screened exhibits excellent ultrafast OL behavior with low thresholds in femtosecond and picosecond regimes. [Display omitted] •A series of newly constructed twistacenes exhibit broadband two-photon absorption-induced excited singlet state absorption.•Twistacenes can be screened as optical limiters based on analysis of the morphology of the natural transition orbitals.•The screened twistacene exhibits excellent OL performance with low thresholds in femtosecond and picosecond regimes.•The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.