Hydrothermal fabrication of graphdiyne-doped tungsten trioxide nanocomposite films

Electrochromic tungsten trioxide (WO₃) films are promising candidates for smart windows, while their practical applications are restricted by unsatisfactory cyclic stability and sluggish ion transport kinetics. Herein, graphdiyne (GDY)-doped WO₃ composite films were synthesized via a seed-layer-assisted hydrothermal strategy. GDY doping endows WO₃ with a hexagonal crystal structure and flower-like nanosheet morphology, which cannot be observed in pure WO₃. The conjugated π-electron system of GDY accelerates interfacial charge transfer, and the unique structure provides abundant active sites and rapid Li⁺ diffusion pathways. The optimized GDY/WO₃ film achieves a transmittance modulation of 84.91% at 1100 nm, bleaching/coloring times of 10.9/6.2 s, a coloration efficiency of 78.22 cm²/C, and retains 99.5% of the initial modulation after 1000 cycles. This work verifies that GDY doping optimizes the microstructure and electrochromic performance of WO₃ films, offering a novel strategy for the development of high-performance smart windows.