Abstract: Tandem photovoltaic device combining a silicon-based sub-cell and a perovskite-based sub-cell including an N-layer with a controlled carbon content. A tandem photovoltaic device, comprising, in this superimposition order: A/ a silicon-based sub-cell A, in particular a silicon heterojunction sub-cell or a TOPCon architecture sub-cell; and B/ a perovskite-based sub-cell B, comprising at least: —an N-type conductive or semiconductor layer (ETL); —a P-type conductive or semiconductor layer (HTL); and —a perovskite-type active layer, interposed between said N-type and P-type conductive or semiconductor layers, wherein the N-type conductive or semiconductor layer is based on individualised nanoparticles of N-type metal oxide(s), and has an atomic carbon content lower than or equal to 20%.