The first alkali–metal selenate nonlinear optical (NLO) crystal,Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2),has been obtained by in situ hydrothermal synthesis.It crystallizes in the polar and noncentrosymmetric (NCS) ...The first alkali–metal selenate nonlinear optical (NLO) crystal,Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2),has been obtained by in situ hydrothermal synthesis.It crystallizes in the polar and noncentrosymmetric (NCS) space group Cc (no.9).The structure of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) can be described as isolated [SeO_(4)]/[HSeO_(4)] tetrahedra connected by H-bonding interactions and Na–O bonds,forming a three-dimensional framework.Powder second-harmonic generation (SHG) measurements show that Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) is phase-matching with a moderate SHG response of ca.1.6 times that of benchmark KH_(2)PO_(4).The UV-Vis-NIR spectrum shows that the title compound is a wide-band semiconductor with an optical band gap of 3.57 eV.The birefringence of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) was calculated to be 0.037 at 1064 nm.First-principles studies show that the [SeO_(4)]/[HSeO_(4)] tetrahedra are the main contributors to its NLO properties.This study indicates that pure selenate is a promising material system to afford NCS structures with SHG responses.展开更多
基金supported by the National Natural Science Foundation of China(nos.51432006 and 52002276)the Ministry of Education of China for the Changjiang Innovation Research Team(no.IRT14R23)+2 种基金the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project(no.B13025)the Innovation Program of Shanghai Municipal Education Commission.C.W.thanks the National and Shanghai Postdoctoral Program for Innovative Talents(no.BX201800216 and 2018192)the Australian Research Council for support(DP170100411).
文摘The first alkali–metal selenate nonlinear optical (NLO) crystal,Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2),has been obtained by in situ hydrothermal synthesis.It crystallizes in the polar and noncentrosymmetric (NCS) space group Cc (no.9).The structure of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) can be described as isolated [SeO_(4)]/[HSeO_(4)] tetrahedra connected by H-bonding interactions and Na–O bonds,forming a three-dimensional framework.Powder second-harmonic generation (SHG) measurements show that Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) is phase-matching with a moderate SHG response of ca.1.6 times that of benchmark KH_(2)PO_(4).The UV-Vis-NIR spectrum shows that the title compound is a wide-band semiconductor with an optical band gap of 3.57 eV.The birefringence of Na_(5)(SeO_(4))(HSeO_(4))_(3)(H_(2)O)_(2) was calculated to be 0.037 at 1064 nm.First-principles studies show that the [SeO_(4)]/[HSeO_(4)] tetrahedra are the main contributors to its NLO properties.This study indicates that pure selenate is a promising material system to afford NCS structures with SHG responses.
