SnI₄ ⋅(S₈ )₂ : A Novel Adduct-Type Infrared Second-Order Nonlinear Optical Crystal

Area of Science:

• Inorganic Chemistry
• Materials Science
• Crystallography

Background:

• Tin tetraiodide (SnI₄) and octasulfur (S₈) are known chemical compounds.
• Nonlinear optical (NLO) crystals are crucial for technologies like frequency conversion.
• Developing new NLO materials with high laser-induced damage thresholds (LIDT) is an active research area.

Purpose of the Study:

• To synthesize a novel adduct of tin tetraiodide and octasulfur.
• To investigate the NLO properties of the synthesized adduct.
• To evaluate the potential of this new material for infrared NLO applications.

Main Methods:

• Facile chemical reaction to synthesize the adduct SnI₄ ⋅(S₈ )₂.
• Experimental characterization of the adduct's structure and properties.
• Density Functional Theory (DFT) calculations to confirm NLO characteristics.

Main Results:

• A new adduct, SnI₄ ⋅(S₈ )₂ (1), was successfully synthesized.
• The material exhibits phase-matchable infrared NLO properties.
• A moderate second-harmonic generation (SHG) response and a very high laser-induced damage threshold (LIDT) were observed.
• DFT calculations supported the experimental findings regarding NLO performance.

Conclusions:

• The synthesized tin-sulfur adduct is a promising candidate for infrared NLO applications.
• The unique combination of Sn⁴⁺ ions, acentric SnI₄ tetrahedra, and S₈ lone-pair effects contributes to its NLO properties.
• The high LIDT suggests potential for use in high-power laser systems.