密度泛函和π共轭限域理论研究KBe_(2)BO_(3)F_(2)深紫外非线性光学性能的构效关系  

The dependence of crystal structure and ultraviolet nonlinear optical property of KBe_(2)BO_(3)F_(2) by density functional theory andπ-conjugate confinement

作　　者：刘欣 陈玲 吴立明 Xin Liu;Ling Chen;Li-Ming Wu(Key Laboratory of Theoretical and Computational Photochemistry,Ministry of Education,College of Chemistry,Beijing Normal University,Beijing 100875,China;Beijing Key Laboratory of Energy Conversion and Storage Materials,College of Chemistry,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学化学学院,理论及计算光化学教育部重点实验室,北京100875 [2]北京师范大学化学学院,能量转换与存储材料北京市重点实验室,北京100875

出　　处：《中国科学：化学》2022年第6期947-955,共9页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(编号:22193043,21971019);北京市自然科学基金(编号:2202022);广东省普通高校重点领域项目(编号:2021ZDZX1026)资助项目。

摘　　要：KBe_(2)BO_(3)F_(2)(KBBF)不仅是目前唯一能够商用的深紫外倍频晶体,还为该类材料设计提供了优秀的模板,因此其构效关系的研究具有重要意义.本文运用密度泛函理论(DFT)深入探讨了KBBF的成键模式和电子结构,首次依据“π共轭限域”理论,从全新的角度诠释了KBBF晶体结构的两种构筑基元(π共轭BO_(3)基团和非π共轭BeO_(3)F基团)对该化合物表现出的优异深紫外非线性光学性能所起的重要作用,并指出“π共轭限域”结构特征确保了KBBF能实现带隙和双折射率的平衡,从而使得KBBF能够在深紫外波段直接实现倍频转换.对构效关系的理解和阐释为设计合成高效深紫外非线性光学材料提供了重要参考.KBe_(2)BO_(3)F_(2)(KBBF)is currently the only commercialized deep-ultraviolet(DUV)nonlinear optical(NLO)crystal,and its crystal structure is one of the most-utilized templates for the rational design;therefore,the understanding and elaboration of its structure–property relationship has an important significance.Herein,on the basis of density-functional theory(DFT),the bonding mode and the electronic structure of the KBBF are deeply investigated,and the contributions of the component groups,i.e.,the BO_(3)π-conjugated group and the BeO_(3)F non-π-conjugated group,to the DUV–NLO properties are explored and explained.The“π-conjugated confinement”feature of the KBBF structure allows it to achieve the highly desired balance between the wide band-gap and the large birefringence,and eventually enables KBBF to achieve the second harmonic generation in the high-energy DUV-spectral region.These understanding and elaboration of the“π-conjugated confinement”may provide useful insights for the future design of the DUV–NLO materials.

关 键 词：非线性光学材料 深紫外倍频晶体 KBBF DFT π共轭限域 

分 类 号：TB34[一般工业技术—材料科学与工程]