α-BBO-like π-Conjugated Crystal with Large Birefringence
Yipeng Song, Weiqi Huang, Zhou Yang, Yanqiang Li, Qian-Ting Xu, Han Wang, Minjuan Li, Xiaojun Kuang, Junhua Luo, Sangen Zhao
Abstract
Birefringent crystals are in great demand for high performance polarizing devices. Designing new birefringent crystals with large birefringence remains a challenge. Herein, we successfully synthesized a new α-BBO-like π-conjugated birefringent crystal, K 2 HC 3 N 3 S 3 ·1.5H 2 O ( I ). I exhibits a relatively large birefringence of 0.31@550 nm; such a birefringence is larger than those of most present commercial birefringent crystals. This result indicates that I might be a potential candidate for polarization modulation components in optical devices. First-principles calculations reveal that the planar π-conjugated [HC 3 N 3 S 3 ] 2– anions make dominant contributions in the large birefringence of I .