Hierarchical molecular design of high-performance infrared nonlinear Ag2HgI4 material by defect engineering strategy

• DOI: 10.1016/j.mtphys.2021.100432
• Publication Date: 2021-05-20T02:06:44Z
• Authors: C. Yang; X. Liu; C. Teng; X. Cheng; F. Liang; Q. Wu
• Keywords: Optical materials; Crystal (programming language); Valence electron

Abstract Mid-far infrared nonlinear optical (NLO) materials are gaining both scientific and technological interest in wide applications. The practical properties of one crystal are determined by its constituent atoms, electrons, lattices and their coupled interaction. Herein, by applying a hierarchical molecular design strategy, we synthesized a promising NLO material Ag2HgI4 by a simple solution method, which shows the strongest second harmonic generation (SHG) response in inorganic halides (4 × AgGaS2 (AGS)) and wide transparency range. The deep insights on nonlinearity enhancement and broadening transmittance were elaborated by theoretical calculations, which are attributed to reduced phonon frequency and increased nonbonding electronic states on top valence band. This physical mechanism is applicable in all NLO optical materials generally, opening a novel and exciting avenue for explorations of new NLO candidates with high performance.