Black phosphorus assisted in-situ growth method towards large-scale Prussian blue smart windows

The production electrochromic smart windows (ESWs) still faces significant challenges due to large-scale preparation methods, high cost, and poor cycling stability. To address the limitations of current inorganic electrochromic film fabrication processes, this paper proposes a novel, simple, efficient, cost-effective, and environmentally friendly method for producing Prussian blue (PB) films assisted by black phosphorus. The PB films exhibited excellent electrochromic performance, with an optical modulation rate of 79.78 % at 745 nm, fast switching time and high coloring efficiency of 367.37 cm²C^-1. Importantly, the optical modulation ability remained at 98.4 % of its original value even after 10,000 cycles, surpassing the best reported record for PB films. Furthermore, TGA and GIWAXS confirmed that the PB films had lower structural water content and a polycrystalline structure, leading to a significant improvement in their electrochemical stability. DFT calculations further confirmed that the PB films exhibited a lower bandgap and larger electron transitions. Additionally, the large-area ESWs (100 × 70 cm²) were fabricated via a simple immersion process, demonstrating the economic, environmental, efficient, practical, and reliable nature of this approach in industrial-scale production. This research represents a milestone in improving the performance and industrial-scale production of ESWs, with significant implications for the development of electrochromic technologies.