Formation of PPy/Ta₂O₅/Ta structure by electropolymerization

Abstract

Electropolymerization of pyrrole on tantalum (Ta) electrodes was carried out in buffer solutions (0.04 M phosphoric acid, 0.04 M acetic acid, 0.04 M boric acid and 0.2 M sodium hydroxide) containing 0.1 M sodium ptoluenesulfonate (TsONa) under galvanostatic conditions and it was found that a polypyrrole (PPy) and a tantalum oxide (Ta2O5) layer are formed on a Ta electrode by an electrochemical oxidation process. The conditions of this simultaneous formation were studied in respect to current density (id), pyrrole concentration ([Py]), pH and the amount of electricity. Under certain conditions ([Py] = 0.25 M, pH = 1.8, id = 10–20 mA cm−2, the amount of electricity = 1 C), 6–8 μm thick PPy films were efficiently formed on homogeneous 30–50 nm thick Ta2O5 layers. The PPy film showed a high electrical conductivity (110 s cm−1), adhered well and covered the Ta2O5 layer. The resulting PPy/Ta2O5/Ta system is therefore proved to have excellent properties as a capacitor.

Simple and rapid synthesis of NiO/PPy thin films with improved electrochromic performance

“…Some organic/inorganic composites have already been reported in the literatures, such as PPy/TiO 2 [20], PPy/Ti [21], PPy/Au [22], PPy/Ag [23], PPy/Pt [24], PPy/Pd [25], Fe 3 O 4 /PPy [26], PPy/Ta 2 O 5 [27], PPy/Cu 1.4 Mn 1.6 O 4 [28], RuO 2 -PPy [29], FeO-PPy [30], and PPy/ZnO [31] for various applications. Interestingly, PPy has been effectively used to enhance/improve several properties of the inorganic oxides, hence it offers promising organic counterpart in the electronic devices.…”

Oxidation of a PPy‐modified tantalum electrode

“…Such a low electrical conductivity of the PPy ClO;) film is due to the smaller size of easily from the PPy film during potential sweeping to cathodic direction. Furthermore, compared with PPy(C10;) films, PPy(Ts0-) films were more dense, strong and flexible [13].…”

“…This can be explained in terms of the difference in the morphology of PPy films. The molecular packing of the PPy(Ts0-) film is better than that of the PPy(C10;) film [13]. Therefore, the oxidation of PPy accompanied by the replacement of OHwith TsO-and the oxidation of Ta by OH-coming through the PPy film would be slow.…”