Decoupling the SHG‐Birefringence Trade‐off in UV NLO Materials via Triple‐Control Coordination Engineering: Achieving Synergistic Performance Optimization

Abstract Decoupling the trade‐off between second‐harmonic generation (SHG) and birefringence ( Δn ) while maintaining a wide bandgap ( E g ) is a critical challenge in the field of ultraviolet (UV) nonlinear optical (NLO) materials. In this work, we introduce a novel “triple‐control coordination engineering” strategy that successfully addresses this challenge. By integrating dihedral angle modulation, coordination mode switching, and polarizability engineering, we have synthesized three zinc halides—[(C 5 H 6 N 2 O 2 )(C 5 H 5 N 2 O 2 )ZnCl ( I ), (C 5 H 6 N 2 O 2 )ZnCl 2 ( II ), and (C 5 H 6 N 2 O 2 )ZnBr 2 ( III )]—that exhibit exceptional UV NLO performance. Through dynamic C─C─N bond rotation, we achieved…

• NN
  National Natural Science Foundation of China

  Award: 22275052
• SA
  Science and Technology Department of Hubei Province

  Awards: 2025AFA111, 2024CSA076