Locally Supersaturated Inks for a Slot-Die Process to Enable Highly Efficient and Robust Perovskite Solar Cells

摘要

Perovskite solar cells (PSCs), which debuted with a lot of attention based onhigh efficiency, are establishing as one of the most promising thin-filmphotovoltaic technologies. Currently, research for upscaling andcommercialization through eco-friendly solvent and process systems is beingattempted. This study introduces for the first time a rheologicalengineering-based locally supersaturated perovskite ink (LSPI) strategy forslot-die process-based PSC fabrication suitable for roll-to-roll continuousprocesses. Here, for the greenable slot-die process, a perovskite precursor inkcomposed of a low-toxic dimethyl sulfoxide (DMSO) single solvent is usedand a small amount of 1,2-dichlorobenzene (DCB) is utilized as a modulatorto control the rheological properties of the ink. The addition of DCB lowers thehigh surface tension of the DMSO-based perovskite precursor ink to suit theslot-die process, enabling uniform wet film formation, and produces locallysupersaturated colloids, i.e., perovskite seeds, that help growth into denseand large grains by heterogeneous nucleation with low Gibbs-free energy. As aresult, the LSPI enables slot-die coating-based PSCs with an efficiency of20.61 (active areas of 0.1 cm~2), which allow high efficiencies of 18.66 and17.66 (active areas of 2.7 and 8.64 cm~2) to be achieved in scale-up tominimodules, respectively.