Dimethyl Ketone Treatment of Cross-linked Poly(4-vinylphenol) Insulators for Pentacene Thin-film Transistors

We demonstrate a dimethyl ketone treatment to produce a hydrophobic surface of cross-linked poly(4-vinylphenol) (c-PVP) insulators for pentacene thin-film transistors (TFTs). Through water contact angle measurements, the dimethyl ketone treatment is proven to significantly increase the surface hydrophobicity of c-PVP films. The results of X-ray diffraction analyses indicate that the dimethyl ketone-treated c-PVP insulator contributes to enhancing the crystallinity of pentacene films and reducing the density of lamellar grains and bulk phase crystallites in pentacene films. In addition, the growth of lamellar grains is elucidated by examining the initial growths of the pentacene films on the c-PVP films with different surface energies. Consequently, the enhancement in the performance of pentacene TFTs is achieved by incorporating the dimethyl ketone-treated c-PVP films as gate insulators.