Dual-Band Modulation of Emissivity and Solar Transmittance Through Chemical Composition-Tuned Asymmetric...

Buildings contribute approximately 40% of global energy consumption, with windows being among the least energy-efficient and most complex components of building envelopes. Recent advancements in vanadium dioxide (VO₂)-based Fabry-Pérot (F-P) resonators, which integrate both solar modulation and radiative cooling (RC) regulation into a single, energy-efficient window, present a significant opportunity for year-round global energy conservation. However, the effectiveness of this innovation is often limited by inadequate modulation capabilities and low luminous transmittance (T_lum) resulting from spatial disorder at the nanoscale. In this study, we introduce an unconventional asymmetric Layer-by-Layer (LbL) assembly technique that spatially leverages wavelength-specific functional components to enhance spectral selectivity. This approach achieves a 52.1% improvement in T_lum and an 8.6% increase in solar modulation (ΔT_sol) compared to current state-of-the-art technologies, while maintaining a comparable mid-infrared (MIR) emissivity modulation (Δε_MIR) of 0.4. These findings validate the efficacy of the LbL process in fabricating spectrally selective smart devices and underscore its significant potential beyond just energy-efficient smart windows.