Synergistic Design of UV Nonlinear Optical Crystals: Harnessing Flexible π-Conjugated Anions and Guanidinium Cations for Enhanced Performance
Nonlinear optical (NLO) materials are vital for advanced optical applications, particularly in the laser industry. While borate-based NLO crystals have been extensively studied, recent research has expanded to novel materials featuring flexible organic π-conjugated systems. In this work, we report the synthesis of a new ultraviolet NLO crystal [C(NH<sub>2</sub>)<sub>3</sub>][NH<sub>2</sub>(CH<sub>2</sub>COO)<sub>2</sub>], which crystallizes in the noncentrosymmetric monoclinic space group <i>Pc</i> (No. 7). The structure is composed of a three-dimensional network formed by the [C(NH<sub>2</sub>)<sub>3</sub>]<sup>+</sup> cation and the flexible π-conjugated [NH<sub>2</sub>(CH<sub>2</sub>COO)<sub>2</sub>]<sup>-</sup> anion, linked through hydrogen bonding and Coulombic interactions. Optical measurements reveal a short ultraviolet cutoff edge at 216 nm, a significant birefringence (0.194 at 546.1 nm), and a notable second-harmonic generation response (1.5 × KDP). Theoretical calculations suggest that synergistic interactions between the cation and anion group enhance the material's anisotropic polarizability and hyperpolarizability, positioning it as an excellent candidate for high-performance ultraviolet NLO applications. This study demonstrates the potential of combining flexible organic anions with strategically selected cations to design advanced NLO materials for next-generation optical devices.
Authors
- Chensheng Lin (ORCID: https://orcid.org/0000-0003-1895-4980)
- Min Luo (ORCID: https://orcid.org/0000-0001-9062-8931)
- Tao Yan (ORCID: https://orcid.org/0000-0003-4246-0964)
- Chao Wang (ORCID: https://orcid.org/0000-0003-4981-9335)
- Yunxia Song
- Yujie Fan (ORCID: https://orcid.org/0000-0002-2635-9420)
- Cheng Hu
Institutions
- Fujian Normal University (CN)
- Chinese Academy of Sciences (CN)
- Fujian Institute of Research on the Structure of Matter (CN)
- Southerners on New Ground (US)
- Fujian University of Technology (CN)
Publication Details
- Journal
- Inorganic Chemistry
- Published
- 2025-08-22
- DOI
- https://doi.org/10.1021/acs.inorgchem.5c03490
- Citations
- 1
- Primary Topic
- Crystal Structures and Properties
- Type
- article
- Field-Weighted Citation Impact
- 0.43
Funders
- National Natural Science Foundation of China
- Haixi Institute, Chinese Academy of Sciences
- Natural Science Foundation of Fujian Province
- Youth Innovation Promotion Association of the Chinese Academy of Sciences