Frequency conversion through nonlinear optics (NLO) materials is a convenient and efficient method for generating laser beams. After decades of efforts, the metal chalcogenides AgGaS₂ and AgGaSe₂ are always regarded as benchmark infrared NLO materials due to their wide transmission range and large second harmonic generation (SHG) response, but they suffered from the low laser-induced damage threshold. Wide bandgap and high thermal conductivity are the keys to improving the threshold of laser damage resistance. However, as the bandgap increases, the SHG response and thermal conductivity tend to decrease, making it a huge challenge to search for nonlinear optical crystals with high thermal conductivity. With the development of computing technology, high-throughput screening based on first-principles calculation has become an important method to accelerate the discovery of new materials. However, the screening of nonlinear optical materials is usually applied to specific systems like borates or chalcogenides, exploration based on wider chemical space is in urgent need. In addition, previous screening or design conditions mainly focus on large SHG coefficients and wide band gaps, while thermal conductivity is difficult to evaluate due to the limitation of computational resources, which is often neglected in high-throughput screening process.

Recently, researchers from the Crystal Materials Research Center of Xinjiang Institute of Physics and Chemistry reported an unbiased screening method to search for nonlinear optical materials with high thermal conductivity through high-throughput design. 17 nonlinear optical candidate materials with high thermal conductivity were successfully screened from more than 140,000 materials in the Material Project through the efficient, multi-level high-throughput screening method. All of the screened compounds have good nonlinear optical properties: strong SHG response (0.5-2.9×AgGaS₂) and wide bandgaps (2.59-4.09 eV). Among which, Sr₂SnS₄ is synthesized and measured SHG response, which verifies the effectiveness of the screening. Detailed structure-property analysis reveals the differences between nitrides and chalcogenides in terms of SHG-active units and thermal conductivity. The high-throughput screening method proposed in this study provides a powerful tool to search for nonlinear optical materials with high thermal conductivity.

This work was published in Angewandte Chemie International Edition in the form of a full-text Research Article. 

Article: https://doi.org/10.1002/anie.202300581

The targeted workflow of high-throughput screening process.