Preparation and characterization of Ge/TiO2 one-dimensional photonic crystal with low infrared-emissivity in the 8–14 μm band

Ge/TiO2 one-dimensional photonic crystals (1DPC), with low infrared-emissivity in the 8−14 μm band, were successfully designed and prepared by alternating the Ge and TiO2 layers on the quartz substrate using optical coating technology. The microstructure and spectral emissivity of the as-prepared 1DPC were characterized using scanning electron microscopy (SEM) and Fourier-transform infrared spectrometry (FTIR), respectively. The microstructural analysis indicates that the as-prepared 1DPC has clear structural multilayer characteristics, and the thicknesses of Ge layer and TiO2 layer are very close or identical with the target values. The spectral emissivity shows the as-prepared 1DPC has low infrared emissivity in the 8−14 μm band. In fact, the average emissivity can be as low as 0.202, and meets the requirement of our design. The results of this paper show that low infrared emissivity materials can be prepared successfully using materials, which are not transparent for infrared light, via a suitable one-dimensional photonic structural design. This result increases the selection range of raw materials needed to prepare low infrared-emissivity materials.