Plasmonic Enhancement of Perovskite Absorber Layers Using Stable Metal Nanoparticles

Efficient light management remains a key challenge in perovskite solar cells, particularly for thin absorber layers. Plasmonic metal nanostructures provide an effective route to enhance light-matter interaction through localized surface plasmon resonances (LSPRs). This work presents a comparative study on plasmonic metal nanoparticles (Au, Ag, Al, and Ti) and their influence on the optical response of perovskite absorber layers.Ultrathin metal films were deposited on quartz substrates and thermally annealed at 500-700 °C to induce solid-state dewetting and nanoisland formation. The annealing process leads to metal-dependent morphological evolution, producing size-tunable nanoparticles that act as plasmonic templates prior to perovskite deposition. For annealing temperatures above 500 °C, the nanoparticles exhibit a near-Gaussian size distribution with an average diameter of ~25 nm.Optical measurements reveal distinct metal-dependent plasmonic behavior, with LSPR features near 500 nm and a broad spectral tail arising from nanoparticle size dispersion. As shown in Fig. 1, Ag and Al nanoislands show the strongest visible-range absorption, while Au exhibits moderate enhancement. Ti-based films display broadband absorption dominated by oxide-related scattering rather than classical plasmon resonance. When integrated beneath the perovskite absorber in a planar architecture, plasmonic nanoislands enhance absorption in the 350-750 nm range, yielding visible-light enhancement of ~5-10% and relative efficiency gains up to 35.51%, depending on nanoparticle size and surface coverage. These results highlight the importance of metal selection and annealing conditions for engineering plasmonic-perovskite interfaces and enhancing light management.