Mist-water: A key character in the perovskite film

Solution-processed CsPbBr₃ films typically exhibit significant surface defects and high roughness, leading to large open-circuit voltage (V_OC) loss and relatively poor efficiency in solar cells. Thus, an effective surface treatment method is highly anticipated to enhance both film quality and device performance.

Here, we propose and demonstrate an efficient, scalable strategy for water-mist-induced surface reconstruction of CsPbBr₃ films, utilizing a low-cost, vacuum-free mist chemical vapor deposition system. After optimization at 275 ℃ for 30 min, the mist-treated CsPbBr₃ films present the purest perovskite phase, lowest surface roughness, higher light absorption, and longer carrier lifetime. Corresponding carbonbased solar cells delivered a champion efficiency of 10.06%, with the V_OC of 1.50 V, along with improved repeatability and stability.

This work provides a new approach to direct the role of water during perovskite formation and paves the way to further break the efficiency bottleneck of CsPbBr₃ perovskite solar cells. The work titled “Mist-water-induced surface reconstruction for efficient carbon-based inorganic CsPbBr₃ perovskite solar cells”, was published on Acta Physico-Chimica Sinica (published on Dec. 16, 2025).