Infrared nonlinear optical (IR–NLO) materials are crucial for a broad range of applications, such as signal communication, microscopy, and data processing. Yet, the big issue is how to obtain a strictly structural non-centrosymmetric (NCS) compound, which is the primary requirement for the IR–NLO materials.
In a study published in Chem. Mater., the research team led by Prof. ZHU Qilong and Prof. LIN Hua from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences proposed a partial isovalent anion substitution (PIAS) strategy to design and synthesize a novel IR–NLO material SrGeOSe2.
The researchers, for the first time, reported the structural transformation from centrosymmetric (CS) compound SrGeO3 to the NCS SrGeOSe2 through a generic and effective PIAS strategy.
They found that SrGeOSe2 exhibits a desired balance between the strong powder second harmonic generation efficiency (SHG = 1.3 × benchmark AgGaS2) and the large laser induced damage threshold (LIDT = 36 × benchmark AgGaS2).
Theoretical calculations indicated that the large second-harmonic generation (SHG) efficiency mainly originates from the cooperative effects of 1D hetero-ligand [GeO2Se2] asymmetric building units.
This study provides a powerful way to rationally induce the symmetry breaking and enhance the local dipole moments of the active units.
Structural transformation from CS compound SrGeO3 to the NCS SrGeOSe2. (Image by Prof. ZHU’s Group)
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