17.13% Efficiency and Superior Thermal Stability of Organic Solar Cells Based on a Comb-Shape Active Blend

Abstract

With rapid progress, organic solar cells (OSCs) are getting closer to the target of real application. However, the stability issue is still one of the biggest challenges that have to be resolved. Especially, the thermal stability of OSCs is far from meeting the requirements of the application. Here, based on the layer-by-layer (LBL) process and by utilizing the dissolubility nature of solvent and materials, binary inverted OSCs (ITO/AZO/PM6/BTP-eC9/MoO3/Ag) with comb shape active morphology are fabricated. High efficiency of 17.13% and simultaneous superior thermal stability (with 93% of initial efficiency retained in ~9:00 h under 85 °C in N2) are demonstrated, showing superior stability to reference cells. The enhancements are attributed to the formed optimal comb shape of the active layer, which could provide a larger D/A interface, thus more charge carriers, render the active blend a more stable morphology, and protect the electrode by impeding ion's migration and corrosion. To the best of our knowledge, this is the best thermal stability of binary OSCs reported in the literature, especially when considering the high efficiency of over 17%.