Pb2B5O9I: An Iodide Borate with Strong Second Harmonic Generation

摘要

The combination of lone-pair effects on Pb2+ cations and the smaller electronegativity of I− anions into the pentaborate framework generates a phase-matchable material, Pb₂B₅O₉I, with the largest powder SHG response among borates, about 13.5 times that of KDP (KH₂PO₄), and transparency over the near-UV to middle-IR region. DFT calculations on electronic structure and cutoff-energy-dependent SHG coefficients confirm these origins.