Sustainable transparent bamboo/W-VO2 composites for solar modulation and energy-efficient buildings

Energy-efficient buildings require sustainable materials that combine structural performance with advanced optical and thermal functionalities to minimize energy consumption and greenhouse gas emissions. Here, we reported a new strategy to develop biodegradable transparent bamboo with a dense and ordered structure, achieved through selective delignification followed by directional pressing to align cellulose nanofibrils. This process yielded large-scale transparent bamboo with remarkable mechanical strength, 78% optical transparency in the visible spectrum, and a high haze (> 90%) that ensured uniform daylight distribution and reduced reliance on artificial lighting. To further impart dynamic solar modulation, a thin polylactic acid film containing tungsten-doped vanadium dioxide (W-VO 2 ) nanoparticles was integrated onto the transparent bamboo substrate. The resulting thermochromic bamboo exhibited a solar modulation ability of 9.7% along with effective thermal regulation that lowered indoor heating loads in hot regions. By synergizing biodegradability, mechanical robustness, and active photothermal control, this transparent bamboo/W-VO 2 composite offered a sustainable and high-performance alternative to conventional glass, holding great promise for energy-efficient building applications.