Multi-component oxide lens glass with ultra-high mechanical properties inspired by the high-entropy concept

Lenses with high transmittance, high refractive index and excellent scratch resistance are in urgent need for cameras in high-end smartphones, and existing resin lenses exhibits intrinsic upper limits in those properties. Glass, with its naturally high refractive index and mechanical properties, is considered an ideal candidate for high-end lenses, however, due to the lack of targeted design, the intrinsic hardness, modulus and fracture toughness of conventional glass are low and its scratch resistance is inadequate. Here, we combined multi-compositional design and structural modulation of high mechanical lens glass with high-entropy concept, and successfully prepared multi-component 31.6RO-4.1Y2O3-23.7TiO2-7.4ZrO2-33.2Al2O3 (R = Ba, Sr, Ca) glasses with ultra-high hardness (11.06 GPa), modulus (147.6 GPa) and indentation fracture toughness (1.334 MPa m0.5). The excellently comprehensive properties of the glass are attributed to the synergistic effect of multiple high dissociation energy and high field strength oxides, which leads to the movement of low-coordinated Al[4] to the higher-coordinated Al[5]/Al[6].