Near-infrared-shielding energy-saving borosilicate glass-ceramic window materials based on doping of defective tantalum tungsten oxide (Ta0.3W0.7O2.85) nanocrystals

NIR-shielding window materials were fabricated by direct embedding of Ta0.3W0.7O2.85 nanocrystals in bulk borosilicate glass-ceramics during a facile melt-quenching process. Optical and thermal performance of the prepared windows can be adjusted by varying the concentration of H2WO4 and Ta2O5 in the starting materials. The optimized window fabricated from raw materials containing 4.5 mol% H2WO4 and 0.3 mol% Ta2O5 exhibited high visible light transmittance 74.4% and strong NIR-shielding ability.T = 68.9%. Its thermal insulation performance is much better than soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The distribution of Ta0.3W0.7O2.85 functional nanocrystals in the glass matrix was confirmed by sample characterization using XRD, Raman, XPS, HRTEM and EDS. The NIR-shielding property has been attributed to local surface plasmon resonance due to oxygen vacancies in the Ta0.3W0.7O2.85 nanocrystals. This study sheds a light on fabricating energy-saving windows with a tunable NIR-shielding performance.

Automated summary

NIR-shielding window materials were made by embedding Ta0.3W0.7O2.85 nanocrystals in borosilicate glass-ceramics through a simple melt-quenching process. The concentration of H2WO4 and Ta2O5 in the starting materials can be adjusted to control the optical and thermal performance of the windows. The optimized window with 4.5 mol% H2WO4 and 0.3 mol% Ta2O5 exhibited high visible light transmittance (74.4%) and strong NIR-shielding ability (T=68.9%). Its thermal insulation performance is superior to soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The NIR-shielding property is attributed to local surface plasmon resonance caused by oxygen vacancies in the Ta0.3W0.7O2.85 nanocrystals. This study provides a method for fabricating energy-saving windows with tunable NIR-shielding performance.