Fig. 2

Semi-empirical model of Wannier–Mott exciton in RPPs. a Schematics of the single quantum well system to which our model was applied to. b Computed band structure for the RPP with n equals to 4. c Corresponding electron (dashed black lines) and hole (red) probability density profiles, and high-frequency dielectric constant profile (blue) along the stacking axis ĉ. d Calculated binding energy of the exciton ground state using the exciton reduced mass in Fig. 1f and the DFT results. The values calculated using our model results (red circles) is compared to those obtained in the approximation of a pure 2D system (blue triangles) and of a pure 2D system without dielectric confinement (black squares). The binding energy of the excited exciton states (2s, 3s, 4s) were also computed and are reported in Supplementary Fig. 7. For reference, the 3D perovskite MAPbI₃ yields an exciton binding energy of about 16 meV, from Miyata et al.¹⁶ and in agreement with our results in Supplementary Fig. 3