Weather-Resistant Janus-Nozzle Electrospinning Nanofibers with Heterogeneous Interfaces Enable Complementary Infrared Emission for Multifunctional Radiative Cooling Windows

Abstract Radiative cooling windows represent a promising strategy for enhancing indoor thermal comfort without external energy input. However, their practical implementation necessitates multifunctional integration, including weather-resistance, ventilation, mosquito-proofing, and privacy-protection, concurrently maintaining high-performance radiative cooling capabilities. To address these requirements, a calcium carbonate (CaCO3)/silica (SiO2) nanofiber laminate (NL) was fabricated via Janus-nozzle electrospinning to circumvent rapid gelation in the precursor solutions. Notably, the CaCO3/SiO2 NL exhibits high solar reflectivity (0.3–2.5 μm; ∼98.2%), which is attributed to heterogeneous interfaces and nanofiber network structure. Simultaneously, complementary infrared emission of CaCO3 and SiO2 enables high emissivity within the atmospheric transparent window (8–13 μm; ∼96.2%). Thus, under outdoor hot conditions, a temperature reduction of ∼13.8 °C was achieved. Furthermore, building energy simulations conducted using a CaCO3/SiO2 NL-integrated model demonstrated an annual average cooling energy saving of ∼8.8 MJ m–2 relative to the commercial curtain fabric, corresponding to an energy saving ratio of ∼50.2% across China. Additionally, intrinsic characteristics of the CaCO3/SiO2 nanofibers endow the laminate with weather-resistance, air permeability, nonperforation, and opacity. This multifunctional material offers a viable approach to fabricating weather-resistant, breathable, mosquito-proof, and privacy-protective windows for building energy conservation.