Investigation of optical images in inverse opal photonic crystal films for sensing applications; a non-destructive method

Abstract

Silica inverse opal (IO) structures were fabricated by the self-assembly of silica precursors and mono-dispersed colloidal crystal template method. The morphological investigation of prepared IO films was done by SEM analyses and optical image was used for checking of all periodic microporous structure of IOs surface. For first time, in this study we introduced optical density of IO films for sensing different concentration of ethanol solutions and their optical images have been used for comparison of sensing properties. The intensity of the absorbance spectrum was decreased by increasing the ethanol concentration using silica IO structures as the sensing chip. There is a good linear relationship and very good correlation (R2 = 0.98) between the optical intensity of absorbance peak and the 2–100% ethanol concentration (v/v0) in the silica IO sensors. The results show that by the area scan of optical density in IO materials, we are able to detect of ethanol concentration. According to which, the proposed optic based imaging method can find numerous applications in non-destructive of fluid detection in IO arrays.