Blade-Coated All-Polymer Organic Solar Cells with 15% Efficiency Using Eco-Friendly Solvent Systems

Organic solar cells (OSCs) offer distinct advantages, such as solution processability, mechanical flexibility, and semitransparency. Recent advancements in polymerized small-molecule acceptors (PSMAs) enable high efficiencies in all-polymer solar cells (all-PSCs). As a promising candidate for next-generation organic photovoltaics, all-PSC technology holds a strong potential for large-scale commercialization, provided that device performance aligns with market demands. Critical factors influencing this transition include the development of environmentally friendly fabrication methods, as well as the optimization of active layer morphology and enhancement of charge transport layer quality. Currently, spin-coating is the predominant method for fabricating small-area OSCs, though it typically relies on toxic solvents, limiting its scalability and environmental compatibility. In this work, we report, for the first time, the scalable fabrication of PM6:PY-IT devices using the green solvent o-xylene and doctor-blade coating at ambient temperature in air. The resulting devices, fabricated in a conventional architecture incorporating PEDOT:PSS and PDINN interlayers, exhibited a short-circuit current density (J_sc) of 22.54 mA/cm², an open-circuit voltage (V_oc) of 0.91 V, and a fill factor (FF) of 67.2% yielding a power conversion efficiency (PCE) of 15%. Key ink formulation steps, including controlled heating, stirring, and vortexing, enabled the optimization of film morphology and crystallinity, as confirmed by atomic force microscopy (AFM), transmission electron microscopy (TEM), and grazing-incidence wide-angle X-ray scattering (GIWAXS). Charge transport properties were subsequently evaluated via the space-charge limited current (SCLC) method. The combination of ambient, low-energy processing, and scalable deposition techniques underscores the potential of this approach for sustainable and efficient manufacturing of all-PSC devices.