Zn2HgP2S8: A Wide Bandgap Hg‐Based Infrared Nonlinear Optical Material with Large Second‐Harmonic Generation Response

Abstract

AbstractHg‐based chalcogenides, as good candidates for the exploration of high‐performance infrared (IR) nonlinear optical (NLO) materials, usually exhibit strong NLO effects, but narrow bandgaps. Herein, an unprecedented wide bandgap Hg‐based IR NLO material Zn2HgP2S8 (ZHPS) with diamond‐like structure is rationally designed and fabricated by a tetrahedron re‐organization strategy with the aid of structure and property predictions. ZHPS exhibits a wide bandgap of 3.37 eV, which is the largest one among the reported Hg‐based chalcogenide IR NLO materials and first breaks the 3.0 eV bandgap “wall” in this system, resulting in a high laser‐induced damage threshold (LIDT) of ≈2.2 × AgGaS2 (AGS). Meanwhile, it shows a large NLO response (1.1 × AGS), achieving a good balance between bandgap (≥3.0 eV) and NLO effect (≥1 × AGS) for an excellent IR NLO material. DFT calculations uncover that, compared to normal [HgS4]n, highly distorted [HgS4]d tetrahedral units are conducive to generating wide bandgap, and the wide bandgap in ZHPS can be attributed to the strong s‐p hybridization between Hg─S bonding in distorted [HgS4]d, which gives some insights into the design of Hg‐based chalcogenides with excellent properties based on distorted [HgS4]d tetrahedra.