The presentation will focus first on the physical properties of multilayered perovskites, including relativistic effects, deviations from 2D Rydberg series of the exciton and hot carrier effects [1-4]. Then, their application to solar cells, either in the Ruddlesden-popper structure [5] or in the Dion-Jacobson one [6], will be described. Finally, the interplay between structural, interfacial and optoelectronic properties of 2D multilayered halide perovskites, and their interfaces with 3D perovskites in stable bilayer solar cells with thick layers will be presented [7,8]. references: [1] J Even et al Electronic model for self-assembled hybrid organic/perovskite semiconductors: Reverse band edge electronic states ordering and spin-orbit coupling, Phys. Rev. B 86 205301 (2012) [2] J.-C Blancon et al, Scaling law for excitons in 2D perovskite quantum wells, Nature Comm. 9 2254 (2018) [3] J.-C. Blancon et al, Semiconductor physics of organic-inorganic 2D halide perovskites, Nature Nano.15 969 (2020) [4] H Zhang et al, Ultrafast relaxation of lattice distortion in two-dimensional perovskites Nature Physics (DOI : 10.1038/s41567-022-01903-6) (2023) [5] H. Tsai et al, High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cells, Nature, 536, 312 (2016) [6] W. Li et al, Light-activated interlayer contraction in two-dimensional perovskites for high-efficiency solar cells, Nature Nano, 17, 45 (2022) [7] S. Sidhik et al, Deterministic fabrication of3D/2D perovskite bilayer stacks for durable and efficient solar cells, Science 377, 1425(2022) [8] B. Traore et al, A theoretical framework for microscopic surface and interface dipoles, workfunctions and valence band alignments in 2D and 3D halide perovskite heterostructures, ACSEnergy Letters, 7, 349 (2022)