Surface mode induced extinction of potassium titanate nanoplatelets

Abstract Extinction spectra of aqueous dispersions of potassium titanate nanoplatelets obtained with and without different surfactants were analyzed in the near UV region. The existence of two closely spaced extinction peaks was interpreted in terms of excitation of low order surface modes in small disk-like particles near the zeros of the real part of the dielectric function of the particle material. One oscillator model for the dielectric function in combination with the theory of extinction of randomly oriented small disks provided evaluation of the peak height ratio, which reasonably agrees with the experimental data.