Na 2 Ba[Na 2 Sn 2 S 7 ]: Structural Tolerance Factor‐Guided NLO Performance Improvement

• Published in: Angewandte Chemie Vol. 135; no. 7
• Main Authors: Li, Rui‐An, Liu, Qian‐Qian, Liu, Xin, Liu, Youquan, Jiang, Xingxing, Lin, Zheshuai, Jia, Fei, Xiong, Lin, Chen, Ling, Wu, Li‐Ming
• Format: Journal Article
• Language: English
• Published: 06.02.2023
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202218048

Abstract The strong mutual coupling of and even the opposite change in the key parameters, such as the band gap ( E g ) and second‐order harmonic generation (SHG), leads to the extreme scarcity in high‐performance IR nonlinear optical (NLO) chalcogenides. Herein, we report 8 new sulfides, Na 2 Ba[(Ag x Na 1− x ) 2 Sn 2 S 7 ] ( 1 , x =0; 1   series , x =0.1–0.6; Na 2 Ba[(Li 0.58 Na 0.42 ) 2 Sn 2 S 7 ], 1‐0.6Li ); Na 2 Sr[Cu 2 Sn 2 S 7 ] ( 2 ); and Na 2 Ba[Cu 2 Sn 2 S 7 ] ( 3 ). We use the structural tolerance factor ( ) to connect the chemical composition, crystal structure, and NLO properties. Guided by these correlations, a better balance between E g and SHG is realized in 1 , which exhibits a large E g of 3.42 eV and excellent NLO properties (SHG: 1.5×AGS; laser‐induced damage threshold: 12×AGS), representing the best performance among the known Hg‐ or As‐free sulfides to date.