Noncentrosymmetric Tetrel Pnictides RuSi ₄ P ₄ and IrSi ₃ P ₃ : Nonlinear Optical Materials with Outstanding Laser Damage Threshold

Noncentrosymmetric (NCS) tetrel pnictides have recently generated interest as nonlinear optical (NLO) materials due to their second harmonic generation (SHG) activity and large laser damage threshold (LDT). Herein nonmetal-rich silicon phosphides RuSi4P4 IrSi3P3 are synthesized characterized. Their crystal structures reinvestigated using single X-ray diffraction 29Si 31P magic angle spinning NMR. In agreement with previous report crystallizes in NCS space group P1, while is found crystallize Cm, contrast the previously reported C2. A combination of DFT calculations diffuse reflectance measurements reveals be wide bandgap (Eg) semiconductors, Eg = 1.9 1.8 eV, respectively. outperform current state-of-the-art infrared SHG material, AgGaS2, both inducer threshold. Due high thermal stabilities (up 1373 K), bandgaps (≈2 eV), structures, strong responses, LDT values, promising candidates for longer wavelength NLO materials.