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.