[22a-P4-1~27] 6.3 Oxide electronics

[22a-P4-18] Photorechargeable TiO₂-PANi composite film charged by visible light

〇(M1)Takeru Saisho¹, Tatsuya Yasunaga¹, Tomohiko Matsuyama¹, Daiki Maeda¹, Teruaki Nomiyama¹, Yuji Horie¹ (1.Kagoshima Univ.)

Keywords:photorechargeable battery,TiO2,polyaniline

Photorechargeable battery (PRB) is a new type solar device achieving two functions of photovoltaic and electrochemical energy storage in a single cell. One of promising electrodes for PRB is a TP film which is a composite film of mesoporous TiO₂ and conducting polymer polyaniline (PANi). The film has bilayer structure: the upper layer is a photovoltaic mesoporous TiO₂, and the lower one is a rechargeable PANi on the surface of mesoporous TiO₂. Electrons generated by an irradiation in the upper layer are injected to PANi through TiO₂ mesoporous structure, and are charged in PANi accompanying with dedoping of anions from PANi to electrolyte. The PANi in TP film has a large charge capacity of 15 mAh g^-1 at high charging/discharging rate of 20 mA cm^-2. However, the photorechargeable efficiency of TP film was low, because the photovoltaic current from bare mesoporous-TiO₂ is 0.2 mA cm^-2 which is much smaller than the charging rate of TP film. To inprove the photorechargeable efficiency, the bare mesoporous-TiO₂ must be sensitized by visible light absorbers such as dyes or semiconducting quantum dots. Furthermore, redox shuttles added to electrolyte was essential for the continuous photovoltaic conversion by reducing photoexcited sensitizer. In this report, we investigated the rechargeable properties of TP film in an electrolyte containing both of the dopants for charge/discharge and the redox shuttles for photovoltaic conversion.