Cationic Substitution Strategy Produces Nonlinear Optical Crystals

The study was published in Small on September 11, 2023.

M[M₄Cl] [Ga₁₁S₂₀] (M=A/Ba, A=K, Rb) are the first salt-inclusion chalcogenides with diamond-like anionic frameworks produced via a cationic substitution method.

Researchers formerly considered typical diamond-like chalcogenides viable candidates for IR NLO materials. However, due to their small band gaps, they frequently display restricted LIDTs.

To produce two novel salt-inclusion sulfides, the researchers used an unorthodox cationic substitution technique, [[SZn₄] S₁₂ + [S₄Zn₁₃] S₂₄ + 11ZnS₄ => MS₁₂+ [M₄Cl] S₂₄ + 11GaS₄], M[M₄Cl] [Ga₁₁S₂₀] (M=A/Ba, A=K, Rb). As predicted, adding mixed cations to the GaS4 anionic frameworks resulted in broadband gaps (3.04 and 3.01 eV) and enhanced high LIDTs (9.4 and 10.3×[email protected] μm).

Furthermore, the researchers discovered that the ordered arrangement of tetrahedral GaS4 units favored significant second-harmonic generation intensities (0.84 and 0.78×AgGaS₂@2.9 μm).

The study shows how a cationic substitution technique based on diamond-like structures can manufacture high-performance NLO materials.

Journal Reference:

Lou, X.-Y., et al. (2023) Excellent Nonlinear Optical M[M₄Cl] [Ga₁₁S₂₀] (M=A/Ba, A=K, Rb) Achieved by Unusual Cationic Substitution Strategy. Small. doi:10.1038/s41565-023-01436-w