High　power　conversion　efficiencies　(PCEs)　in　perovskite　solar　cells　(PSCs)　have　always　been　awe-inspiring,　but　perovskite　films　scalability　is　an　exacting　precondition　for　PSCs　commercial　deployment,　generally　unachievable　through　the　antisolvent　technique.　On　the　contrary,　in　the　two-step　sequential　method,　the　perovskite＇s　uncontrolled　crystallization　and　unnecessary　PbI2　residue　impede　the　device＇s　performance.　These　two　issues　motivated　to　empower　the　PbI2　substrate　with　orthorhombic　RbPbI3　crystal　seeds,　which　act　as　grown　nuclei　and　develop　orientated　perovskites　lattice　stacks,　improving　the　perovskite　films　morphologically　and　reducing　the　PbI2　content　in　eventual　perovskite　films.　Thence,　achieving　a　PCE　of　24.17%　with　suppressed　voltage　losses　and　an　impressive　life　span　of　1140　h　in　the　open　air.