Improving the photo-stability of triple cation perovskite solar cells using chromophore-infused optically transparent Pectin/polymethyl methacrylate composite

Perovskite solar cells (PSCs) show great promise due to their high efficiency and low manufacturing costs, yet they encounter notable challenges such as optical losses and stability issues, mainly due to high surface reflection and degradation from UV irradiation, and heat[1-3]. In this study, we present a novel, bio-based composite material comprising pectin, polymethyl methacrylate (PMMA), and a spirobifluorene compound designed to mitigate these issues. This innovative composite exhibits high optical transparency, up to 85%, and significant haze (48% at 550 nm), which helps in minimizing reflection-induced losses. The composite incorporates spirobifluorene, which facilitates down-conversion of UV radiation around 350 nm to higher wavelengths above 400 nm, thereby enhancing both photostability and overall device performance. This material, with its lower thermal conductivity compared to glass, also cools the solar cell surface by serving as a thermal barrier. This composite was subsequently attached to the front side of PSCs, which were structured in an inverse architecture (ITO/Me4pacz/SiOx/PSK/C60/SnOx/Cu) for performance measurements and in a different configuration (FTO/c-TiO/m-TiO/PSK/spiro-meotad/gold) for stability tests ( see Figure 1). The composite's implementation leads to up to a 5 ±0.1% increase in the current density and power conversion efficiency of perovskite solar cells. Additionally, it significantly delays initial photodegradation, enhancing T80 life by 1.1-fold for PP-0.25TSBF and 1.9-fold for PP-0.75TSBF. These advancements highlight the potential of this innovative composite to significantly improve the efficiency, stability, and durability of perovskite solar cells, offering a promising route for future photovoltaic technologies.