2025-06-032025-06-032025-04-05García-Moreno, F., Sánchez Coronilla, A. y Martín Fernández, E.I. (2025). Lead-free hybrid perovskites: Structural and electronic analysis of MA0.5Rb0.5Bi0.5Ge0.25I3 and MA0.5Rb0.5Sb0.5Ge0.25I3. Journal of Alloys and Compounds, 1021, 179723. https://doi.org/10.1016/j.jallcom.2025.179723.1873-46690925-8388https://hdl.handle.net/11441/173896Structural and electronic stability of MA0.5Rb0.5Bi0.5Ge0.25I3 and MA0.5Rb0.5Sb0.5Ge0.25I3 lead-free hybrid perovskites is addressed. The substitution of Pb in MAPbI3 perovskite is increasing the scientific attention due to its toxicity as well as stability of interest in the design of environmentally friendly solar cells. MA cation (CH3NH3 +) is replaced by 50 % Rb+ to improve stability and retain the organic characteristics. The substitution of lead in MA0.5Rb0.5PbI3 structure has been studied up to 100 % Ge. Electron localization function (ELF) analysis for structures with 75 and 100 % of Ge, show zones with no electron localization that indicates certain degree of structural instability. ELF and density of states (DOS) analysis of the structure MA0.5Rb0.5Pb0.5Ge0.5I3 with 50 % Ge corroborate stability characteristics of this perovskite. Thus, the MA0.5Rb0.5Pb0.5Ge0.5I3 structure has been selected for the substitution of lead by Bi and Sb. ELF and non-covalent index (NCI) analysis indicate Sb structures are slightly more stable than those with Bi. The presence of Bi and Sb drastically decreases the bandgap in the MA0.5Rb0.5Bi0.5Ge0.25I3 and MA0.5Rb0.5Sb0.5Ge0.25I3 structures, respectively, which makes both structures without lead of interest for use in photovoltaic devices. These findings provide a pathway for designing stable, lead-free perovskites with improved optoelectronic properties for next-generation solar cells.application/pdf9engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/PerovskiteElectron localization functionNon covalent indexLead-freeinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess10.1016/j.jallcom.2025.179723