Optically compatible infrared camouflage performance of ITO ink

With the rapid development of military reconnaissance technology, reconnaissance devices have been equipped with wideband reconnaissance ability, which imposes increased requirements on camouflage. Developing multiband camouflage materials with good compatibility has become increasingly important. Indium tin oxide (ITO), a transparent conductive oxide with good comprehensive photoelectric properties, exhibits different absorption, reflectivity, and transmission characteristics in different bands of electromagnetic waves. Therefore, ITO might be able to solve broadband and multiband camouflage problems effectively. In this paper, ITO is expressed as In_32-xSn_xO₄₈. The energy band structure, optical properties, and infrared absorption spectra at different doping ratios of Sn (x = 0, 1, 2, 3) were obtained on the basis of first principle theory, and the camouflage mechanism of ITO in different electromagnetic wavebands was explored. Results demonstrated that when x = 3, specifically, when the doping ratio of Sn atoms was 9.375%, ITO had high transmission in the visible light band and infrared band reflectivity and can realize optically compatible infrared camouflage. In accordance with calculation results, ITO nanodispersion liquid (x = 3) was mixed with green camouflage coating added with some additives to prepare green ITO camouflage ink for silkscreen printing. The ink formed a camouflage protective ink coating after it was coated onto the surface of fabric through silkscreen printing. Results showed that the emissivity of the ITO ink coating decreased by more than 0.13 when its solid content reached 20%, and its camouflage performance in the visible light band was barely affected. The results of this research can guide the application of ITO materials in the field of camouflage.