Birefringence determined by optical anisotropy is one of the most pivotal and fundamental performance of optical materials.However,optimizing the birefringence remains a significant challenge.Herein,a simple and effec...Birefringence determined by optical anisotropy is one of the most pivotal and fundamental performance of optical materials.However,optimizing the birefringence remains a significant challenge.Herein,a simple and effective method of cation chemical substitution for improving the birefringence has been accomplished and three Y-based borates,namely,LiNa_(2)Y(BO_(3))_(2),RbNa_(2)Y(BO_(3))_(2)and RbSrY(BO_(3))_(2),were successfully synthesized.They all have deep-ultraviolet(DUV)cutoff edges below 190 nm.Single-crystal analysis reveals that LiNa_(2)Y(BO_(3))_(2)and RbNa_(2)Y(BO_(3))_(2)possess three-dimensional(3D)frameworks with small channels filled by alkali metal cations,whereas RbSrY(BO_(3))_(2)features a two-dimensional(2D)layered structure separated by alkali metal and alkali-earth metal cations.The birefringence exhibits a progressive doubling increase from LiNa_(2)Y(BO_(3))_(2)(0.017@532 nm)to RbNa_(2)Y(BO_(3))_(2)(0.033@532 nm)and then to RbSrY(BO_(3))_(2)(0.070@532 nm).Using cation size arguments,coordination environment,and the arrangement of groups demonstrate that cation substitution have a decisive effect on the birefringence enhancement.In addition,other optical and thermal properties of the three title compounds were characterized.The structure–property relationships were analyzed by the first-principles calculations.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52322202 and 22071179)Natural Science Foundation of Tianjin(Grant No.20JCJQJC00060 and 21JCJQJC00090).
文摘Birefringence determined by optical anisotropy is one of the most pivotal and fundamental performance of optical materials.However,optimizing the birefringence remains a significant challenge.Herein,a simple and effective method of cation chemical substitution for improving the birefringence has been accomplished and three Y-based borates,namely,LiNa_(2)Y(BO_(3))_(2),RbNa_(2)Y(BO_(3))_(2)and RbSrY(BO_(3))_(2),were successfully synthesized.They all have deep-ultraviolet(DUV)cutoff edges below 190 nm.Single-crystal analysis reveals that LiNa_(2)Y(BO_(3))_(2)and RbNa_(2)Y(BO_(3))_(2)possess three-dimensional(3D)frameworks with small channels filled by alkali metal cations,whereas RbSrY(BO_(3))_(2)features a two-dimensional(2D)layered structure separated by alkali metal and alkali-earth metal cations.The birefringence exhibits a progressive doubling increase from LiNa_(2)Y(BO_(3))_(2)(0.017@532 nm)to RbNa_(2)Y(BO_(3))_(2)(0.033@532 nm)and then to RbSrY(BO_(3))_(2)(0.070@532 nm).Using cation size arguments,coordination environment,and the arrangement of groups demonstrate that cation substitution have a decisive effect on the birefringence enhancement.In addition,other optical and thermal properties of the three title compounds were characterized.The structure–property relationships were analyzed by the first-principles calculations.
