Modulation of naphthanthryl chalcone derivatives by push-pull electronic substituents: Ultrafast nonlinear absorption and transient dynamics

The ultrafast optical nonlinearities of two novel naphthanthryl chalcone derivatives (NAn-1 and NAn-2) with different push-pull effects were investigated and compared. Combined with femtosecond Z-scan and quantum chemical calculations, the results indicate that both compounds exhibited broadband (532-800 nm) two-photon induced excited-state absorption, and NAn-2 exhibited wider spatial electron delocalization. The push electronic effects of the peripheral substituent increased the transition dipole moment, originating from the main nonlinear group retained stronger local excitation and ultimately enhanced the nonlinear absorption of NAn-2. Transient absorption spectroscopy revealed a transition from the locally excited to charge transfer state and showed that the dynamic processes of excited states were readily tunable via peripheral push-pull substituents. The results suggest that NAn-2 possess the potential in optical limiting applications and provide guidance for designing polycyclic aromatic hydrocarbon (PAH)-based nonlinear optical materials.

Automated summary

The ultrafast optical nonlinearities of two novel naphthanthryl chalcone derivatives (NAn-1 and NAn-2) with different push-pull effects were investigated and compared. The results showed that both compounds exhibited broadband two-photon induced excited-state absorption, and NAn-2 had wider spatial electron delocalization. The push electronic effects of the peripheral substituent increased the nonlinear absorption of NAn-2. Transient absorption spectroscopy revealed that the dynamic processes of excited states were tunable via peripheral push-pull substituents. The study suggests the potential of NAn-2 in optical limiting applications and provides guidance for designing PAH-based nonlinear optical materials.