Hyun Suk Jung of Sungkyunkwan University, Dong Hoe Kim of Korea University and others recently published a study in ACS Energy Letters (IF23.101). Flexible perovskite solar cells (f-PSC) have attracted increasing attention in various applications (e.g., wearable electronics, aerospace, etc.) due to their desirable form factor, higher durability, bendability, and low installation cost. However, the manufacturing process of f-PSC has not been optimized, resulting in uneven efficiency.

　　Here, the researchers report a van der Waals stacking (vdWS) process that produces uniform and highly crystalline perovskite films on flexible substrates through uniform heat transfer during the perovskite annealing process. The results of the study found:

1. The surface and grain boundary defects of the perovskite films were effectively reduced after vacuum-assisted passivation post-treatment; therefore, the environmental and mechanical stabilities of the f-PSCs were improved.
2. The power conversion efficiencies (PCEs) of the best f-PSC with an active area of 0.14 cm² reached 41.23% and 22.54% under 1000 lx and 1 sun illuminations, respectively.
3. The vdWS process showed scalable uniformity through flexible perovskite solar micro-modules, with a certified PCE of 18.35% over an active area of 48.90 cm².