High-pressure effects on the electronic properties and photoluminescence of Ag-doped CsCu₂I₃

CsCu₂I₃ is a popular lead-free metal halide perovskite with good thermal and air stability. To facilitate its applications in optoelectronics, Ag doping and high pressure are employed in this work to improve the optoelectronic properties of CsCu₂I₃. Using first-principles calculations and experiments, the structural phase change of 10% Ag-doped CsCu₂I₃ is found to occur at about 4.0 GPa. This reveals the regulation of band structures by hydrostatic pressure. In addition, the high pressure not only increases the emission energy of photoluminescence of 10% Ag-doped CsCu₂I₃ by more than 0.2 eV, but also increases the emission intensity by multiple times. Finally, the origin of luminescence in 10% Ag-doped CsCu₂I₃ is attributed to the I vacancies. This work provides insight into the structure and optoelectronic properties of 10% Ag-doped CsCu₂I₃, and offers significant guidance for the design and manufacturing of future luminescence devices.