Pb_2B_5O_9I: An Iodide Borate with Strong Second Harmonic Generation

摘要

The combination of lone-pair effects on Pb~(2+) cations and the smaller electronegativity of I" anions into the pentaborate framework generates a phase-matchable material, Pb_2B_5O_9I, with the largest powder SHG response among borates, about 13.5 times that of KDP (KH_2PO_4), and transparency over the near-UV to middle-IR region. DFT calculations on electronic structure and cutoff-energy-dependent SHG coefficients confirm these origins.