An organic–inorganic hybrid birefringent material with diverse functional groups
Yangxin Chen, Tingting Zhu, Zheyao Xiong, Zhou Yang, Yanqiang Li, Qingran Ding, Youchao Liu, Xin Chen, Sangen Zhao, Junhua Luo
Abstract
Birefringent materials are vital materials to modulate the polarization of light, and play a key role in plorization devices such as linear optical devices, optical communication devices, and fiber optic sensors. It is still a challenge to design excellent birefringent materials. Herein, we report an organic-inorganic hybrid oxalate birefringent material, (CN4H7)SbC2O4F2(H2O)0.5, by introducing organic delocalized π-conjugated [CN4H7]+ and [C2O4]2- groups, and stereochemical active inorganic SbO4F2 polyhedra. (CN4H7)SbC2O4F2(H2O)0.5 exhibits a large birefringence (Δn = 0.126@546 nm) that is almost equal to that of the well-known birefringent material α-BaB2O4. Theoretical calculations reveal that the distinguished birefringence should stem from the synergistic arrangement of π-conjugated [CN4H7]+ and [C2O4]2- planar groups, and highly distorted SbO4F2 polyhedra with a stereochemically active lone pair. The synergistic effect of π-conjugated systems and the lone pair electrons greatly boosts the birefringence, which is helpful for the development of high-performance birefringent materials.