A universal hole transport layer for efficient organic solar cells processed by blade coating.

Doctor-blade coating technology is a roll-to-roll compatible high-throughput thin film fabrication route. In this work, doctor-blading was applied for fabricating organic solar cells (OSCs) using a polyoxometalates material phosphomolybdic acid (PMA) as a hole transport layer (HTL). Compared to PEDOT:PSS, PMA-based devices demonstrate lower trap-assisted recombination, higher hole mobility, prolonged charge carrier lifetime and faster charge collection. With PM6:Y6 as active layer, PMA-based device delivered a high power conversion efficiency (PCE) of 17.79 % with a boosted short-circuit current density (J SC) value of 28.08 mA/cm2, which is one of the best performances for PM6:Y6-based solar cells through doctor-blading process. In addition, the performance improvement was observed in both conventional and inverted structured devices with various donor: acceptor combinations. These results indicate the high universality of PMA for printable processing and its prospect in preparation of the industrial production of OSCs. [Display omitted] • Phosphomolybdic acid (PMA) was introduced as a hole transport layer (HTL) in organic solar cells (OSCs). • PMA is compatible for both conventional and inverted structured devices. • The blade-coating processed OSCs based on PM6:Y6 achieved a high efficiency of 17.8 %. • One of the highest performance for PM6:Y6-based OSCs through blade-coating. [ABSTRACT FROM AUTHOR]