Search

Strong ultrafast nonlinear optical (NLO) responses in near‐infrared (NIR) regions and favorable solution processability are two urgent requirements for practical NLO applications, especially for optical limiting (OL) applications. However, simultaneously optimizing these properties remains significant challenging. In this study, the successful synthesis of a phthalocyanine‐based 2D polymer (Pc‐2DP) is reported; its structure features extended π‐electrons delocalization space constructed by topologically integrating the phthalocyanine units into the 2D framework. The as‐prepared few‐layered Pc‐2DP not only exhibits power‐ and wavelength‐dependent NLO properties toward 35 fs ultrafast pulsed laser, but it also demonstrates excellent ultrafast reverse saturable absorption (RSA) responses in NIR regions. The nonlinear absorption coefficients of Pc‐2DP dispersion reach up to 0.12 and 0.19 cm GW−1 at 800 and 1550 nm, respectively, which are much higher than those of the typical MXene (Ti3C2TX) and molybdenum disulfide with hexagonal structure (2H‐MoS2). The obtained NLO devices exhibit remarkable OL performance at 800 nm and, particularly, in the telecommunication region (1300 to 1550 nm), which is highly desired but seldom reported. The study demonstrates that the as‐prepared Pc‐2DP featuring a highly conjugated aromatic framework is a very promising OL material and that this research provides a new strategy for developing high‐performance 2D organic NLO polymers. [ABSTRACT FROM AUTHOR]

Functional organic–inorganic nanocomposite materials displaying large optical nonlinearities are eagerly required for many advanced optoelectronic applications, such as data storage, optical switching, laser mode-locking, and optical limiting. Herein, a pyrazine-linked porphyrin dimer (1a)-functionalized graphene nanocomposite G-1a was successfully constructed by physical grafting of 1a onto the surface of graphene through π–π stacking. The structure of G-1a was thoroughly characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, steady-state absorption, and fluorescence analysis. Z-scan studies demonstrate that unprecedented enhancement of reverse saturable absorption (RSA) of porphyrin dimer 1a compared to that of the porphyrin monomer ZnTPP is observed under 12 ns (nanosecond) laser irradiation, which can be ascribed to its large π-conjugated system, longer excited-state lifetime in the ns scale, and reorganized excited states. G-1a exhibits the strongest nonlinear optical (NLO) absorption properties under identical laser conditions when compared to its individual precursors, stemming from a synergistic effect of the strongly enhanced RSA of 1a, the nonlinear scattering of graphene and the effective photoinduced electron/energy transfer from 1a to graphene. These results expand the applications of porphyrin dimers in developing novel NLO-active materials towards ns laser irradiation and reveal that G-1a is a very promising optical limiter candidate. This study provides a new paradigm to develop advanced optoelectronic devices with organic conjugated chromophores. [ABSTRACT FROM AUTHOR]