Enhanced thin-film transistor performance by combining 13,6-N- sulfinylacetamidopentacene with printed PEDOT:PSS electrodes

Bottom-contact/bottom-gate organic thin-film transistors (OTFTs) are fabricated using a soluble pentacene precursor (13,6-N- sulfinylacetamidopentacene; SAP) and inkjet printed PEDOT:PSS electrodes on bare SiO₂ dielectrics. Saturation mobility, I_on/I _off ratio, and threshold voltage parameters, respectively, of 0.27 cm² V^-1 s^-1, 10⁵, and -4.25 V were measured under ambient conditions after the thermal conversion of SAP to pentacene in 100 ?m long channel OTFT devices. The results obtained by the above solution approach are comparable to that of vapor-phase grown pentacene-based OTFTs with photolithographic gold contacts and organic buffer layers and/or inorganic injection layers. The present high performance level is ascribed to the morphological continuity and uniformity of the first few layers of the polycrystalline semiconductor phase at the interface with the organic electrodes, which in effect constitute an ideal chemical interface for the converted SAP. In contrast, gold electrodes thermally evaporated by employing shadow masks result in blurred-edge regions, drastically affecting the semiconductor morphology along with the transport properties.