MAPbI3-on-CuInSe2 two-terminal monolithically integrated and four-terminal mechanically stacked tandem solar cells: A Theoretical Investigation Using SCAPS-1D

•Developed a self-consistent simulation model for MAPbI3-on-CuInSe2 2-T and 4-T tandem cells.•The best simulated PCE of MAPbI3 top sub-cell is 21.05%.•The PCE of best simulated CuInSe2 bottom sub-cell is 22.90%.•2-T monolithically integrated MAPbI3-on-CuInSe2 tandem cell produces PCE of 30.21%.•4-T mechanically stacked tandem cell generates PCE of 31.07%.