Indium tin oxide nanoparticle: TiO2: Air layers for one-dimensional multilayer photonic structures

In this work we study the optical properties of one-dimensional photonic crystals in which layers of silica nanoparticles are alternated with layers of indium tin oxide nanoparticle (ITO)/titania nanoparticle mixture, using the transfer matrix method. The dielectric function of the mixed ITO/TiO2 nanoparticle layer is carefully accounted for with a generalized Rayleigh equation for the ternary mixture ITO:TiO2:air. We studied the light transmission of the multilayer photonic crystal as a function of the ITO/TiO2 ratio. We observe that, by increasing the ITO content and its carrier density in the three-phase mixture, the intensity of the plasmon resonance in the near infrared (NIR) increases and the intensity of the photonic band gap (visible) decreases. Thus, our study is of major importance for the realization of electrochromic smart windows, in which separate and independent NIR and visible light control is required.