The effect of metal-buffer bilayer drain/source electrodes on the operational stability of the organic field effect transistors

In this paper, we have investigated experimentally the effect of different drain/source (D/S) electrodes and charge injection buffer layers on the electrical properties and operational stability of a stilbene organic field effect transistor (OFET). The results show that the organic buffer layer of copper phthalocyanine (CuPc) considerably improves the electrical properties of the transistors, but has a negligible effect on their temporal behavior. On the other hand, inorganic metal-oxide buffer layer of molybdenum oxide (MoO3) drastically changes both the electrical properties and operational stability. The functionalities of this metal-oxide tightly depend on the properties of the D/S metallic electrodes. OFETs with Al/MoO3 as the bilayer D/S electrodes have the best electrical properties: field effect mobility μeff=0.32cm2V−1s−1 and threshold voltage VTH=−5V and the transistors with Ag/MoO3 have the longest operational stability. It was concluded that the chemical stability of the metal/metal-oxide or metal/organic interfaces of the bilayer D/S electrodes determine the operational stability of the OFETs. •The effect of buffer layers on the performance of the stilbene OFETs has been investigated.•Inorganic buffer layer improved the electrical and temporal behaviors simultaneously.•Organic buffer layer only changes the electrical properties.•Chemical stability of the interfaces determines the operational stability of the transistor.