Birefringence and second harmonic generation(SHG)are important optical properties of functional crystals.However,it is relatively rare for a compound to exhibit both enhanced properties simultaneously.In this study,we...Birefringence and second harmonic generation(SHG)are important optical properties of functional crystals.However,it is relatively rare for a compound to exhibit both enhanced properties simultaneously.In this study,we used DFT calculations to discover an ideal functional gene:protonated 3,5-dipicolinic acid(C_(7)H_(4)NO_(4),HDPA).By combining HPDA with the traditional IO_(3)-anion,we obtained a non-centrosymmetric and polar semiorganic iodate,namely HDPA(IO_(3)).The organic cations and iodate anions in HDPA(IO_(3))are bridged via the N-H···O and O-H···O hydrogen bonds,forming the wave-shaped layers.The synergistic effect between the expandedπ-conjugation of the organic cation and the stereochemically active lone pair electrons in the inorganic iodate anion results that HDPA(IO_(3))exhibiting a strong SHG effect,3.6 times that of KH_(2)PO_(4),and an unusually large birefringence of 0.35 at 546 nm,larger than most of SHG-active iodates.Additionally,HDPA(IO_(3))has a wide bandgap of 4.12 e V with a corresponding cutoff edge at 269 nm,indicating its potential as a promising short-wave ultraviolet(UV)optical crystal.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22205037 and 22373014)the Natural Science Foundation of Fujian Province(No.2023J01498)。
文摘Birefringence and second harmonic generation(SHG)are important optical properties of functional crystals.However,it is relatively rare for a compound to exhibit both enhanced properties simultaneously.In this study,we used DFT calculations to discover an ideal functional gene:protonated 3,5-dipicolinic acid(C_(7)H_(4)NO_(4),HDPA).By combining HPDA with the traditional IO_(3)-anion,we obtained a non-centrosymmetric and polar semiorganic iodate,namely HDPA(IO_(3)).The organic cations and iodate anions in HDPA(IO_(3))are bridged via the N-H···O and O-H···O hydrogen bonds,forming the wave-shaped layers.The synergistic effect between the expandedπ-conjugation of the organic cation and the stereochemically active lone pair electrons in the inorganic iodate anion results that HDPA(IO_(3))exhibiting a strong SHG effect,3.6 times that of KH_(2)PO_(4),and an unusually large birefringence of 0.35 at 546 nm,larger than most of SHG-active iodates.Additionally,HDPA(IO_(3))has a wide bandgap of 4.12 e V with a corresponding cutoff edge at 269 nm,indicating its potential as a promising short-wave ultraviolet(UV)optical crystal.
