Effect of organic buffer layers on the performance of n-type organic field-effect transistor based on C60 active layer

The performance of n-type organic field-effect transistors (OFETs) based on C60 active layer was investigated by focusing on the role of 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene (TPBi), bathocuproine (BCP) and bathophenanthroline (Bphen) as buffer layers. It was found that the OFETs with the organic buffer layers exhibited significant improved electrical characteristics, such as saturation current, threshold voltage, field-effect mobility and current on/off ratio. Moreover, by optimizing the film thicknesses of these buffer layers, we also found that the buffer layers with appropriate film thickness can effectively improve charge carrier injection from Ag source/drain electrodes to C60 films. Also, the interface properties and the contact resistance between Ag source/drain electrodes and C60 films have been analyzed.