[19p-Z13-1~14] 6.1 Ferroelectric thin films

▲ [19p-Z13-13] Water Splitting by Photoelectrochemical reaction of (Pb,La)TiO₃ Ferroelectric Thin Films

〇SangHyo Kweon¹, Yoshinaka Daisuke¹, Yoshiharu Mukoyama², Kanno Isaku¹ (1.Kobe Univ., 2.Tokyo Denki Univ.)

Keywords:Photoelectrochemical

Recently, photoelectrochemical (PEC) water splitting has been spotlighted as a promising technique for a production of H₂ as a sustainable fuel source [1]. In photoelectrodes where H₂ or O₂ gases are produced at the surface, electrons and holes are generated inside photoactive materials under an illumination. In an effort to enhance the solar-to-hydrogen (STH) conversion efficiency by preventing the recombination of photogenerated charge carriers, investigations on ferroelectric materials that inherently possess internal electric field (or, depolarization field) have been initiated. (Pb,La)TiO₃ (PLT) is one of the renowned ferroelectric materials owing to its excellent ferroelectric characteristics. In this study, c-axis oriented epitaxial PLT thin films were deposited on MgO (001) substrates by a sputtering method and their PEC performances were evaluated. An illustration for the measurement setup is shown in Fig. 1. The epitaxial PLT thin films exhibited a photocathodic behavior in 0.1 M NaOH electrolyte, presenting the reductive photocurrents and the increment of open circuit potential (OCP) (Fig. 2) with the thickness of PLT thin films. Meanwhile, by shining the UV light on the PLT thin films, clear bubble generation was observed under a bias-free condition, in Fig. 3.