Non-centrosymmetric Selenides AZnb>4b>Inb>5b>Seb>12b> (A=Rb, Cs): Synthesis, Characterization and Nonlinear Optical Properties
文摘
Two new non-centrosymmetric polar quaternary selenides, namely, RbZnb>4b>Inb>5b>Seb>12b> and CsZnb>4b>Inb>5b>Seb>12b>, have been synthesized and structurally characterized. They exhibit a 3D diamond-like framework (DLF) consisting of corner-shared MSeb>4b> (M=Zn/In) tetrahedra, in which the A+ ions are located. Both compounds are thermally stable up to 1300 K and exhibit large transmittance in the infrared region (0.65–25 μm) with measured optical band gaps of 2.06 eV for RbZnb>4b>Inb>5b>Seb>12b> and 2.11 eV for CsZnb>4b>Inb>5b>Seb>12b>. Inspiringly, they exhibit a good balance between strong second harmonic generation (SHG) efficiency (3.9 and 3.5×AgGaSb>2b>) and high laser-induced damage thresholds (13.0×AgGaSb>2b>). Theoretical calculations based on density functional theory (DFT) methods confirm that such strong SHG responses originate from the 3D DLF structure.