Impact of inkjet printing parameters on the morphology and device performance of organic photovoltaics

The morphology of the active layer is vital for the device performance of organic electronics. However, most research is primarily focused on the active layer prepared from the spin coating method, which is not suitable for large area manufacturing. The inkjet printing technique has been widely studied in the field of organic electronics due to its advantages of scalability, patternability, and affordability. Nevertheless, morphological changes in the active layer during inkjet printing have received little attention. Herein, for the first time, the influence of inkjet printing parameters on the bulk heterojunction morphology and device performance of organic photovoltaics (OPVs) was systematically studied. The crystal sizes decreased as the inkjet printing speed or substrate temperature increased, which was vital for bimolecular recombination and carrier transport. Moreover, the π–π stacking distance decreased as the inkjet printing speed increased, which is beneficial to charge transport, resulting in improved device performance. However, an uneven film was formed when the substrate temperature increased, degrading the device performance. It is demonstrated that the control of inkjet printing parameters can effectively improve the morphology of active layer, paving guides for high-efficiency large-area production of OPVs and other organic electronics.