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Hyperspectral Imaging as a Tool to Study Optical Anisotropy in Lanthanide-Based Molecular Single Crystals
Published on: April 14, 2020
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Two rare-earth-based quaternary chalcogenides EuCdGeQ4 (Q = S, Se) with strong second-harmonic generation
Wenhao Xing1, Naizheng Wang, Yangwu Guo
1Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China. wlyin@caep.cn.
Dalton Transactions (Cambridge, England : 2003)
|November 23, 2019
Summary
Two novel rare-earth chalcogenides, EuCdGeS4 and EuCdGSe4, exhibit significant nonlinear optical properties and large band gaps. Their suitable melting points facilitate crystal growth for advanced optical applications.
Area of Science:
- Materials Science
- Solid State Chemistry
- Crystallography
Background:
- Nonlinear optical (NLO) materials are crucial for technologies like frequency conversion.
- Rare-earth chalcogenides offer unique electronic and optical properties.
- Developing new NLO materials with enhanced performance and processability is an ongoing challenge.
Purpose of the Study:
- To design and synthesize novel rare-earth-based chalcogenides.
- To investigate the nonlinear optical properties and electronic structures of the new compounds.
- To evaluate their potential for bulk crystal growth.
Main Methods:
- Crystal structure determination (Ama2 space group).
- Powder second harmonic generation (SHG) measurements.
- Optical band gap determination.
- First-principles electronic structure calculations.
- Congruent melting point analysis.
Main Results:
- Successful synthesis of EuCdGeS4 and EuCdGSe4.
- Observation of type-I phase-matching behavior and large SHG effects (2.6-3.8 × AgGaS2).
- Large direct band gaps of 2.5 eV (sulfide) and 2.25 eV (selenide).
- Low congruent melting points (997 °C and 882 °C) suitable for Bridgman crystal growth.
- Calculated electronic structures and optical coefficients.
Conclusions:
- EuCdGeQ4 (Q = S, Se) are promising new NLO materials.
- Synergistic effects of [GeQ4] and distorted [CdQ4] tetrahedra contribute to their optical properties.
- The compounds are suitable for bulk crystal growth, enabling practical applications.
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