Pulse-width-dependent optical limiting properties of a novel twist-acene compound

Organic materials with large nonlinear optical coefficient and ultrafast response speed have attracted considerable attention due to their potential applications in optical limiting (OL). However, it is a challenging obstacle to develop a candidate material with optimal nonlinear absorption response while avoiding undesirable low transmittance. Here, a novel symmetrical heteroacenes compound 4,4'-(buta-1,3-diyne-1,4-diylbis(2,7-di-tert-butyl-9,14-diphenyldibenzo[de,qr]tetracene-12,11-diyl))bis(N,N-diphenylaniline)(abbreviated as JPC-42) was synthesized and its nonlinear optical properties were investigated under different pulse-width excitation conditions at 532 nm. Results show that the compound with twisted structure displays superior optical limiting response in which extremely high transmittance (91% in 532 nm) and low OL threshold (3 × 10⁻³ J/cm² in femtosecond regime, 130 × 10⁻³ J/cm² in picosecond regime) are obtained. Our results demonstrate that this twist-acene compound is a promising candidate in laser protection fields.