Pb₃Ba₇B₇O₂₀F: A new nonlinear optical material exhibiting large second harmonic generation response induced by its unprecedented Pb-B-O framework

A new non-centrosymmetric borate fluoride, Pb3Ba7B7O20F exhibiting a large powder second harmonic generation (SHG) response (5 x KH2PO4) at 1064 nm was obtained in the open system. To the best of our acknowledge, it displays the strongest SHG response among the reported lead-barium borates. More interestingly, its three-dimensional (3D) framework contains the 1D Pb-B-O chain and isolated PbB3O8 groups, which is the first compound with two different dimensional Pb-B-O frameworks in the inorganic lead-containing borate system. The first-principles theoretical calculations are carried out to understand the origin of its linear and nonlinear optical properties. (c) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.