In situ one-step hydrothermal preparation of nano-structured spinel film with ultra-broadband low-reflectance through high absorption

Abstract

Material with low reflectance in the ultra-broadband range of UV-Vis-IR is strongly desired for advanced optical instruments. Herein, in situ one-step hydrothermal methods were first introduced to prepare nanostructured spinel films on a low-priced Fe-Cr alloy substrate. The films show a superior low-reflectance feature of 4.71% in 300–2500 nm and 6.16% in 2500–13000nm, which attribute to its uniform nano-micron pores distributed on the surface. Besides, they can tolerate 180 °C due to strong film adhesion stemming from in situ growth. The preparation process is convenient, low-cost, non-poisonous, pollution-free, and suitable for quantity production. Moreover, it unnecessarily requires any template, catalyst, or expensive apparatuses. The resultant spinel films are a promising candidate for developing optical instruments with higher accuracy in the ultra-broadband range.