Structural and photoelectric properties of hybrid halide perovskites CsxMA1-xMgyPb1-yI3 from first-principles

Lead toxicity and stability are important issues to be addressed in organic/inorganic hybrid perovskite solar cell materials. In this study, the electronic, structural, and optical properties of Cs and Mg co-doped organic/inorganic hybrid perovskites were investigated through first-principles calculations. The synergistic effect of (Cs, Mg) doping improves the lattice stability, reduces the content of elemental lead, thereby reducing environmental pollution, and induces a tunable band gap of 0.96–2.58 eV. Perovskite with a bandgap of 1.5–1.6 eV is an ideal adsorbent for solar cells, while that with a bandgap greater than 1.70 eV can be used for perovskite-silicon tandem solar cells. Co-doping of Cs and Mg compresses the neighboring Pb–I and Mg–I bond and distorts the [PbI6] octahedra. The organic/inorganic hybrid perovskites co-doped with cesium and magnesium significantly increase the light absorption coefficients in the near-ultraviolet and visible regions. The predicted Cs and Mg co-doped halide perovskites with intriguing properties would become a promising candidate for applications in solar cells and optoelectronic devices.