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

CsCuI 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 CsCuI. Using first-principles calculations and experiments, the structural phase change of 10% Ag-doped CsCuI 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 CsCuI by more than 0.2 eV, but also increases the emission intensity by multiple times. Finally, the origin of luminescence in 10% Ag-doped CsCuI is attributed to the I vacancies. This work provides insight into the structure and optoelectronic properties of 10% Ag-doped CsCuI, and offers significant guidance for the design and manufacturing of future luminescence devices.