Three-dimensional lead iodide perovskites based on complex ions

Lead-halide perovskites have demonstrated outstanding optical, electrical, and spintronic properties and have made significant breakthroughs in many fields, especially in solar cells. Although substantial efforts have been devoted to developing novel 3D perovskites with a lower band gap towards the application in perovskite solar cells, none of them succeeded. Here we propose three novel 3D lead iodide perovskites with complex ions, Cu(NH3)2PbI3, Ag(NH3)2PbI3 and Au(NH3)2PbI3. Based on the optimized structures, formation and dissociation energies, phonon spectra, and ab initio molecular dynamics simulations, it is found that Ag(NH3)2PbI3 and Au(NH3)2PbI3 are kinetically and thermodynamically stable. Furthermore, Ag(NH3)2PbI3 and Au(NH3)2PbI3 exhibit large absorption coefficients, suitable optical band gaps and small electron effective masses, which are very promising towards application in perovskite solar cells. 3D perovskites based on complex ions, Cu(NH3)2PbI3, Ag(NH3)2PbI3 and Au(NH3)2PbI3 are proposed. Ag(NH3)2PbI3 and Au(NH3)2PbI3 are found not only structural 3D but also electronic 3D, which are good candidates towards high-performance solar cells.