Polyarylethersulfone Films Covalently Grafted with N-Containing Donor–Acceptor Molecules for Optical Power Limiting

The NLA originates from two different mechanisms: pure two‑photon absorption (TPA) and TPA‑induced singlet excited‑state absorption (ESA). The origin and full dynamics of the excited states are elucidated through femtosecond transient absorption spectroscopy and calculations of TPA cross‑sections. The HC‑based PAES film demonstrates superior OL performance, with a limiting threshold of 1.0 J cm⁻², outperforming most reported inorganic and organic materials under similar conditions.

Therefore, our proposed covalent grafting strategy for fabricating D-A nonlinear optical solid‑state films may provide new insights into the structure-property design of organic molecules in the OL field and promote their practical applications.