Ultra-low infrared emissivity at the wavelength of 3–5 μm from Ge/ZnS one-dimensional photonic crystal

• Ge/ZnS 1DPC was successfully prepared by optical coating technology.
• Infrared emissivity at the wavelength of 3–5 μm of the 1DPC can be as low as 0.052.
• The infrared emissivity reached the level of high conductive precious metal films.

Ge/ZnS one-dimensional photonic crystal (1DPC) was successfully prepared by alternating thin films of Ge and ZnS on the quartz substrate by using the optical coating technology. The microstructure and spectral emissivity of as-prepared 1DPC were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR), respectively. The test result of spectral emissivity shows that the as-prepared 1DPC has ultra-low infrared emissivity at the wavelength of 3–5 μm, the average emissivity can be as low as 0.052, fully reached the level of high conductive precious metal films. The results indicate that not only the high conductive precious metal films have ultra-low infrared emissivity, the semiconductor materials such as Ge and ZnS through rational design of 1DPC can also get ultra-low infrared emissivity. The as-prepared 1DPC with ultra-low infrared emissivity is promising for use as materials for efficient solar thermal collectors and infrared stealth.