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

Dual-band tungsten oxide (WO) 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 WO films with a hexagonal crystal structure, is presented. Structural characterization reveals that the GDQDs/WO 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/WO films exhabit impressive electrochromic performance, with rapid swithing (12.6/8.4 s for bleaching/coloration), high coloring efficiency (104.78 cmC at 1100 nm), and independent dual-band transmittance changes (ΔT， with ΔT  = 64.54%, ΔT  = 83.52% and ΔT  = 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 WO. This solution not only advances the development of electrochromic technology, but also opens the door for future innovative applications of smart materials.