Pb2TiFO(SeO3)2Br: a new polar compound with the strongest second harmonic generation in the selenite bromide family

Abstract

Combining different acentric functional units is an effective strategy to design and synthesize new nonlinear optical (NLO) crystals. Guided by this idea, two new polar selenite bromide compounds, Pb₂TiFO(SeO₃)₂Br and Pb₂VO₂(SeO₃)₂Br, have been synthesized via hydrothermal method. Attributable to the synergistic effect of multiple NLO-active units, Pb₂TiFO(SeO₃)₂Br exhibits the largest second harmonic generation (SHG) response among all reported NLO selenite bromides under 1064 nm laser radiation, about 10.0 × KH₂PO₄ (KDP). Pb₂TiFO(SeO₃)₂Br has no obvious absorption from the near-ultraviolet (UV) to the middle-infrared (IR) region. Meanwhile, the structure–property relationship in Pb₂TiFO(SeO₃)₂Br was also elucidated by first-principles studies.