Revolutionizing Dual-Band Modulation and Superior Cycling Stability in GDQDs-Doped WO₃ Electrochromic Films for Advanced Smart Window Applications

Dual-band tungsten oxide (WO₃) electrochromic films are extensively investigated, yet challenges persist regarding complex fabrication processes and limited cyclic stability. In this paper, a novel approach to prepare graphdiyne quantum dots (GDQDs) doped WO₃ films with a hexagonal crystal structure, is presented. Structural characterization reveals that the GDQDs/WO₃ possesses a coral-like, loose structure with high crystallinity due to the synergistic modulation of morphology and crystallinity. Electrochemical tests confirm that this unique structure provides abundant multi-active sites and efficient electrolyte ion channels, which facilitate the ion insertion/extraction to promote the electrochromic process. The GDQDs/WO₃ films exhabit impressive electrochromic performance, with rapid swithing (12.6/8.4 s for bleaching/coloration), high coloring efficiency (104.78 cm²C^-1 at 1100 nm), and independent dual-band transmittance changes (ΔT， with ΔT_{633 nm} = 64.54%, ΔT_{1100 nm} = 83.52% and ΔT_{1600 nm} = 79.80%), and exceptional stability (remained 95.1% modulation range after 20 000 cycles). The unique characteristics of GDQDs lead to the formation of a built-in electric field via charge transfer, which optimizes and enriches the energy level structure of WO₃. This solution not only advances the development of electrochromic technology, but also opens the door for future innovative applications of smart materials.