Plasmon-Driven Light Absorption and Hole Extraction in Efficient Tin-Based Perovskite Solar Cells

Tin halide perovskites are among the most promising candidate materials for high-performance, lead-free perovskite solar cells. However, insufficient light utilization, particularly at longer wavelength ranges, and inefficient interfacial hole extraction continue to limit the performance of tin (Sn)-based perovskite solar cells (TPSCs). Herein, we introduce a plasmonic Ag nanostructured interlayer at the Sn-based perovskite/PEDOT:PSS interface to synergistically regulate optical absorption and carrier transport through localized surface plasmon resonance (LSPR) and near-electric field enhancement. The plasmonic interlayer reduces interfacial carrier accumulation, accelerates hole extraction, and suppresses non-radiative recombination, while simultaneously improving long-wavelength light harvesting through enhanced optical field confinement. As a result, the efficiency of TPSCs increases from 13.03% to 16.48%, accompanied by a pronounced enhancement in incident photon-to-current conversion efficiency in the long-wavelength region. In addition, the TPSCs incorporating Ag nanoparticles exhibit improved operational stability, retaining over 86% of their initial efficiency after 800 h. This work demonstrates an effective strategy for integrating plasmonic metallic nanostructures into TPSCs to overcome key optical and electronic limitations and advance high-efficiency lead-free photovoltaics.