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Structural Symmetry and Mixed-anion Engineering in Halopnictides for Extraordinary Second-Harmonic Generation
Yi-Bing Huang1,2, Bin-Wen Liu1,3, Wen-Lin Wu1
1State Key Laboratory of Structural Chemistry, Fujian Institute of Research of the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P.R. China.
Angewandte Chemie (International Ed. in English)
|December 18, 2025
Summary
Developing new nonlinear optical (NLO) materials is challenging. This study engineered host-guest halopnictides with enhanced second-harmonic generation (SHG) by tuning symmetry and anions, showing promise for NLO applications.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Nonlinear Optics
Background:
- Achieving high nonlinear optical (NLO) coefficients in NLO materials is a significant challenge.
- Existing NLO materials often face limitations in performance and applicability.
- Developing novel NLO materials with superior properties is crucial for advanced optical technologies.
Purpose of the Study:
- To engineer novel host-guest halopnictides with enhanced nonlinear optical properties.
- To investigate the impact of structural symmetry and mixed-anion engineering on NLO coefficients.
- To explore the potential of these new materials for practical NLO applications.
Main Methods:
- Synthesis of host-guest halopnictides based on the [Cd4P2] flexible host pore framework.
- Utilizing structural symmetry and mixed-anion engineering strategies.
- Embedding different tetrahedral units as guest species to direct the structure.
- Characterization of crystal structure, second-harmonic generation (SHG) response, laser-induced damage threshold (LIDT), and infrared transmittance.
Main Results:
- Five new host-guest halopnictides were successfully synthesized: [Cd4P2][ZnCl4], [Cd4P2][MnCl4], [Cd4P2][ZnBr4], [Cd4P2][Mn0.6Cd0.4Br4], and [Cd4P2][ZnCl3I].
- Significantly enhanced SHG responses were achieved, reaching up to 6.6 times that of AgGaS2 (at 1700 nm), by tuning host framework porosity and constructing polarizable polyhedra via mixed-anion modulations.
- Millimeter-sized single crystals of [Cd4P2][ZnBr4] were obtained, exhibiting a strong SHG response (2.5 × AgGaS2), a high LIDT (3.0 × AgGaS2 at 1064 nm), and broad infrared transmittance (2.5-14.9 µm).
Conclusions:
- The combined strategy of structural symmetry and mixed-anion engineering is effective in developing high-performance NLO materials.
- [Cd4P2][ZnBr4] demonstrates significant potential as a promising NLO material due to its excellent SHG, LIDT, and IR transparency.
- This work provides valuable insights and a new avenue for the rational design of advanced NLO materials.
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