Symmetric and Asymmetric Dielectric/Metal/Dielectric Electrodes for Semitransparent Perovskite Solar Cells.

The design of transparent top electrodes is essential for the implementation of advanced photovoltaic technologies, such as building-integrated photovoltaics, agrovoltaics, and tandem devices. In this context, perovskite solar cells implemented with transparent electrodes can emerge as a leading technology due to their tunable optical bandgap and high power conversion efficiency. However, achieving high transparency remains a critical bottleneck, as top electrodes are typically based on opaque noble metal films. This creates an inherent trade-off between electrical conductivity and optical transparency, which limits the overall device performance. In this work, Au-based dielectric/metal/dielectric (D/M/D) multilayers were systematically investigated as top electrodes in both chemically symmetric and asymmetric configurations, employing MoO x and WO x as dielectric layers. Through a multitechnique characterization approach, it was demonstrated that the careful design of the selected materials and thicknesses of the Au-based D/M/D constituting layers enables precise tuning of their optical properties. In particular, changing from symmetric to asymmetric configurations provides additional degrees of freedom for light management, enabling the independent modulation of transmittance in the visible and near-infrared spectral regions. The symmetric stacks tend to maximize transmittance in both regions simultaneously, and the asymmetric design allows for selective optimization of transparency in the different spectral ranges. The optimized D/M/D electrodes maintain a low sheet resistance of 4.2 Ω/sq, while reaching transmittance maxima higher than 75%, significantly surpassing standard metallic electrodes. The Au-based D/M/D multilayers herein implemented were successfully integrated as a hole-collecting top electrode into n-i-p semitransparent perovskite solar cells, achieving a power conversion efficiency (PCE) of 13%, comparable to reference devices, but providing significantly enhanced and modulable optical transparency. This strategy establishes Au-based D/M/D architectures as versatile multilayers for next-generation photovoltaics with finely tunable spectrally selective properties.