Device fabrication of plasma polymerized aniline/TiO₂ heterojunction

Sadia Ameen, S. G. Ansari, Young Soon Kim, Hyung- Shik Shin^*

Thin Film Technology Laboratory, School of Chemical Engineering, Chonbuk National University, Chonju-561756, Republic of Korea

E-mail: hsshin@chonbuk.ac.kr

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An assembly of FTO/nano-crystalline TiO₂/polyaniline was prepared in a simple way. A diode was fabricated using p-type plasma polymerized polyaniline (PANI) and n-type TiO₂ on fluorine doped tin oxide (FTO) coated glass. The carrier transportation between the TiO₂ layer and the polyaniline layer was one of the most important factors that determined the overall efficiency of the solar cells. The deposition of TiO₂ on FTO substrate was achieved through doctor blade technique and was kept in an electric oven for 60min before subjected to plasma polymerization. The influences of the density of plasma were examined in the case of polyaniline polymerization. Plasma polymerization was carried out through RF plasma using 13.5MHz. Aniline (monomer) flowed into the reactor and pumped by the vacuum system, by using the pressure gradient between the reactor and the container. The plasma deposition was carried out for 15min without using any carrier gas for preventing the contamination. The fabricated p-n heterojunction was characterized by FESEM, FTIR, UV-VISIBLE, and XRD. The IR analysis indicated the characteristic polyaniline peaks. The junction thus obtained showed rectifying behavior. The I–V characteristics indicated that a p–n junction at nano-crystalline TiO₂/polyaniline interface was created.

Keywords: TiO₂, Polyaniline, Plasma polymnerization, IV properties

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* Corresponding author. Fax: +82 63 270 2306.

E-mail address: hsshin@chonbuk.ac.kr (Hyung-Shik Shin)