Improved Efficiency of Inverted Perovskite Solar Cells Via Surface Plasmon Resonance Effect of Au@PSS Core-Shell Tetrahedra Nanoparticles

Sufficient absorption to incident solar illumination, long exciton diffusion length, and efficient dissociation are extremely critical factors to guarantee an acquirement of high power conversion efficiency (PCE) in solar cells, including perovskite solar cells (PSCs). In this work, Au@poly(4-styrenesulfonate) (PSS) core–shell tetrahedra nanostructures, synthesized by seed mediated growth method, are incorporated into PSCs for the first time to improve light absorption of methylammonium lead iodide via surface plasmon resonance effect. Both the use of Au tetrahedra core and the introduction of ultrathin PSS shell are beneficial for generating a strong local field and preventing from exciton quenching at the surface of nanoparticles (NPs). With an optimal concentration of Au@PSS tetrahedra NPs, the PCE achieves 16.53%, showing a significant improvement factor of 18.83% compared to the reference device without NPs. Analyses indicate that in addition to promotion of light absorption of active layer over the broad wavelength range, the Au@PSS tetrahedra NPs also increase exciton dissociation and charge transfer efficiency by enhancing the recombination resistance inside PSCs and reducing photoluminescence intensity and exciton/carrier lifetime of perovskite films.