Polymer binder effects on the electrical characteristics of 6, 13-bis(triisopropylsilylethynyl)-pentacene thin-film transistors in different solvents

This paper presents the effects of the polymer binder on the electrical properties of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) organic thin-film transistors (OTFTs) which have been fabricated using a variety of 2wt.% TIPS-pentacene solutions that have been prepared in different solutions, including anisole, toluene, and chlorobenzene. Poly(triarylamine) (PTAA) is added as a polymer binder to help the TIPS-pentacene form a stronger binding, thus improving device performances. By using these materials as the active channel, a molecular guest-host system is formed, with TIPS-pentacene as the host and the PTAA as the guest. Introducing the TIPS-pentacene solutions means that the polymer binder and the solvent dependent electrical characteristics can be investigated to determine if the device exhibits the best performance when the solution is prepared with anisole as the solvent and PTAA as the polymer binder. Consequently, a device made from anisole with PTAA exhibits superior electrical properties in comparison to the devices made with the other solutions including the saturation field-effect mobility (μsat) of 0.21cm2/V∙s, current on/off ratios of 5×106, and a sub-threshold slope (SS) of 0.46V/dec at a gate bias VGS=–40V.