In the current investigation, it is demonstrated that the absorption of an organic–inorganic hybrid crystalline-based CH₃NH₃PbX₃ perovskite solar cell can be amply enhanced using noble metal nanoparticles that are coupled in double and triple formation. Due to boosted localized surface plasmon resonance (LSPR), the photocurrent is anticipated to improve. At first, by the incorporation of Ag-Au core–shell nanoparticles, the absorption spectrum of an ultrathin perovskite solar cell is calculated. The results show that the photocurrent is increased to 16.45 mA/cm³ for a cell with a thickness of 100 nm, with an enhancement factor of 22.67% in comparison to the reference cell. Using the proposed arrangement of nanoparticles inside the designated perovskite material, its photocurrent density rises from 13.41 mA/cm² to 19.81 mA/cm² and 20.2 mA/cm² for the double and triple arrangement of nanoparticles, respectively. This improves the photocurrent ratio from 22.67% up to 47% and 50.63%, respectively. Moreover, the boosted photon absorption is confirmed through the electrical field distribution illustration.