A research group led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has reported the fabrication of high efficiency large-area perovskite solar module using slot-die coating with high-pressure nitrogen-extraction (HPNE) and effective passivation strategy.

Slot-die coating is a promising deposition technique due to its advantages in low cost, high throughput, continuous roll-to-roll fabrication. However, it remains a challenge to control thin film uniformity over a large area at thickness as thin as 500 nm while maintaining crystallization quality.

The scientists reported their development of an effective high-pressure nitrogen-extraction (HPNE) strategy that drove formation of a stable intermediate phase and allowed the coating to grow into a uniform dense perovskite film. As a result, they achieved a wide processing window in the large-area printing process.

Furthermore, an effective passivation process was developed using an ionic liquid for them to achieve solar cell efficiency as high as 22.7%. More importantly, the strategies were successfully scaled-up to large-area solar cell fabrication and a 40×40 mm2 perovskite solar cell (PSC) module attained a stabilized power conversion efficiency as high as 19.4%, which was the highest-efficiency for large-area module to date.

These results suggest that this controlled printing with HPNE strategy is a highly efficient, wide-window, cost-effective, area-scalable technique for fabrication of PSCs, which could advance the development of slot-die coating as well as its application to high-throughput roll to roll deposition.