Aliovalent doping strategy toward band structure modulation and enhanced mechanoluminescence of CaZnOS: Mn2+

Mechanoluminescence (ML) behavior has been extensively studied in recent years in fields such as sensing and lighting. The primary obstacle hindering the large-scale commercial application of ML materials is that they only exhibit significant luminescence when subjected to relatively strong stress stimuli. We in this work employed the aliovalent doping strategy in the ML matrix CaZnOS for the first time to modify the crystal and electronic structure of the material, thereby optimizing its ML property. The impact of Ca 2+ substitution by (K + , Gd 3+ ) ionic pair on phase purity, composition and morphology was systematically analyzed by the combined techniques of XRD, ICP, TEM, and XPS. The band structure of the representative samples was further investigated using UV-Vis measurements and density functional theory (DFT) calculations. After aliovalent doping, not only the concentration of oxygen vacancy increased but also the band gap narrowed. These two changes respectively enhanced the number of hole-electron pairs and facilitated their combination during the ML process, ultimately leading to an enhancement of the ML intensity.