Printed Large-Area Photovoltaic Modules Based on Small Molecules with Different Alkyl Terminal Chains

Despite significant progress in organic photovoltaics (OPVs), efforts to fabricate the small-molecule OPVs by scalable printing methods have hardly been devoted. Herein, we demonstrate large-area photovoltaic modules using two carbazole-based small molecules, named LGC-D023 and LGC-D073, with different alkyl terminal chain lengths. To investigate the influence of alkyl terminal chain length on slot-die coated devices, careful analysis of morphology and crystalline properties was also conducted as well as optimization of the slot-die coating process. Furthermore, under optimized conditions, large-area photovoltaic modules with an active area of 24 cm² were fabricated by a slot-die coating method, exhibiting the champion power conversion efficiency (PCE) of 5.5% for LGC-D073 and 4.53% for LGC-D023, respectively. To the best our knowledge, this is the not only the largest area but also the highest efficiency for small-molecule OPV modules fabricated by roll-to-roll compatible printing techniques. As a result, our work proves that small molecules have great potential in terms of printed large-area photovoltaics and further applications for practical use in industry.