Large nonlinear optical effect in tungsten bronze structures via Li/Na cross-substitutions
Shihang Chu1, Kun Lin1, Tao Yang1
1Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China. kunlin@ustb.edu.cn xing@ustb.edu.cn.
Chemical Communications (Cambridge, England)
|June 24, 2020
Summary
Researchers developed a new lead niobate compound with a superstructure by substituting A-site Li/Na in tetragonal tungsten bronze structures. This material shows a strong nonlinear optical effect, suggesting a new method for enhancing optical properties.
Area of Science:
- Materials Science
- Solid State Chemistry
- Crystallography
Background:
- Tetragonal tungsten bronze (TTB) structures are known for their potential in nonlinear optics.
- Tuning A-site cations in TTB can modify structural and optical properties.
- Developing new materials with enhanced nonlinear optical (NLO) responses is crucial for photonic applications.
Purpose of the Study:
- To synthesize a novel niobate compound with a superstructure.
- To investigate the nonlinear optical properties of the synthesized material.
- To explore the effect of A-site cation substitution on local distortion and NLO response.
Main Methods:
- Synthesis of a new niobate compound, Pb2.15(Li0.25Na0.75)0.7Nb5O15, via cross-substitution of A-site Li/Na in TTB structures.
- Characterization of the crystal structure, including the identification of a superstructure.
- Measurement of second harmonic generation (SHG) properties to quantify the NLO response.
Main Results:
- Successful synthesis of a new lead niobate compound with a superstructure.
- Observation of a strong second harmonic generation (SHG) response, approximately 47 times that of KDP (Potassium Dihydrogen Phosphate).
- Correlation between the enhanced SHG response and strengthened local structural distortion.
Conclusions:
- A-site Li/Na cross-substitution is an effective strategy for creating new TTB compounds with superstructures.
- The synthesized Pb2.15(Li0.25Na0.75)0.7Nb5O15 exhibits significant nonlinear optical properties.
- Strengthened local distortion resulting from cross-substitution is a key factor in improving the NLO effect in stiff, low-symmetry structures, indicating a generalizable approach.
