[C(NH₂)₃]₂Zn(CO₃)₂: A Guanidinium-Templated Ultraviolet Nonlinear Optical Material

Area of Science:

• Materials Science
• Crystallography
• Nonlinear Optics

Background:

• Nonlinear optical (NLO) materials are crucial for optical signal processing and photonics.
• Developing novel NLO materials with enhanced properties, particularly for UV applications, remains a significant challenge.
• Guanidinium-based hybrid materials offer a promising avenue for designing new NLO crystals.

Purpose of the Study:

• To synthesize and characterize a novel guanidinium-templated ultraviolet (UV) nonlinear optical zinc carbonate crystal, denoted as GZCO.
• To investigate the structural, thermal, optical, and NLO properties of the synthesized GZCO.
• To explore the potential applications of GZCO in UV-NLO fields.

Main Methods:

• Low-temperature synthesis in a closed system.
• X-ray crystallography for structural determination (tetragonal, noncentrosymmetric space group P41212).
• UV-visible transmittance spectroscopy to determine the cutoff edge and band gap.
• Second-harmonic generation (SHG) measurements to evaluate NLO efficiency.

Main Results:

• Successfully synthesized a novel guanidinium zinc carbonate crystal (GZCO).
• GZCO exhibits a 3D anionic framework with 12-membered ring channels.
• High thermal stability attributed to cation confinement within inorganic channels.
• Short UV cutoff edge of 210 nm and a large band gap of 5.9 eV.
• Mild second-harmonic generation efficiency of 0.5 × KDP with type-I phase-matching.

Conclusions:

• GZCO is a promising new UV nonlinear optical material with excellent thermal stability.
• Its unique crystal structure and wide band gap make it suitable for UV applications.
• Further research can explore optimizing its NLO properties and exploring device integration.