Preparation of smooth potassium hexatitanate nanofilms by sol–gel method

New nanosmooth potassium hexatitanate films have been prepared on crystalline Si (111) and ITO glass substrates by sol–gel method using Ti(n-OC₄H₉)₄ and CH₃COOK as precursors. Atomic force microscopy (AFM) topographic images were analyzed to select the optimal preparation conditions for the films. It is shown that the films consist of flat particles with the ratio of diameter to height around 11. The root mean square (RMS) roughness of the films based on the measurement of an area of 2,000 nm × 2,000 nm in AFM images is 6.4 nm. The crystal growth process of potassium hexatitanate film was characterized by XRD, Raman spectra, and TEM. The results showed that the crystal growth of potassium hexatitanate nanofilm is a confined growth mechanism. Electrochemical measurements demonstrated that the photocurrent of potassium hexatitanate film electrode is more stable than that of TiO₂ film electrode.