Modification of polymer gate dielectrics for organic thin-film transistor from inkjet printing

As a prominent printing technique, inkjet printing is an ideal technique for the mass production of solution-processed thin-film transistor. Therefore, in this work, the inkjet-printed organic field effect transistor (OFET) was investigated on different dielectric substrates, especially on polymer-based dielectrics, which have great potential for flexible OFET devices. Comparing with metal oxide dielectrics, polymer dielectric offered a higher surface roughness and worse surface wettability, resulting in reduced charge mobility. Meanwhile, due to the nature of polymer, it had much higher leakage current than metal oxide. Fortunately, with atomic layer deposition of a thin layer of Al2O3, the surface properties of dielectric layer and molecular packing of semiconducting layer were significantly improved, which boosted charge mobility from 0.08 to 0.65 cm(2) V-1 s(-1) along with significantly reduced leakage current. This method can be broadly applicable to the inkjet-printed OFET devices and flexible OFET devices for further improvement of device performance.