Remarkable phase-matchable second-harmonic generation realized by strong polarities of [PbSe3] and [GaSe4] functional motifs in PbGa4Se7

Strong second-harmonic generation (SHG) and phase-matchable capability at specific transmittance windows are crucial to the real application of nonlinear optical crystals. Herein, an efficient strategy introducing Pb2+ with stereochemically active lone-pair electrons into non-phase-match-able Ga2Se3via enhancing anisotropy microstructure is first applied meet SHG intensity requirements, offering a selenide, namely, PbGa4Se7, which designed synthesized diamond-like anionic framework, where cations reside in parallel arrangement. As expected, PbGa4Se7 possesses large coefficient 3.3 times that AgGaS2 under incident laser 1910 nm. Moreover, displays high laser-induced damage threshold 7.0 2090 nm, originates from low thermal expansion (0.36) suitable band gap (2.1 eV). Theoretical calculations demonstrate considerable response can be attributed synergies tetrahedral GaSe4 pyramid PbSe3 microstructural blocks additional polarizability.