Polymer-modified solution-processed metal oxide dielectrics on aluminum foil substrate for flexible organic transistors

Field-effect transistors (FETs) employing the solution-processed metal oxides as dielectrics have shown excellent performance on rigid silicon substrate. However, there have been very limited reports on FETs with solution-processed, thermal-annealed metal oxide dielectrics on low-cost flexible substrates. To date, to our knowledge there is almost no report on flexible FETs having the similar or better performance than the FETs on Si substrate with solution-processed, thermal-annealed metal oxides as dielectrics. Herein, flexible pentacene-based organic FETs have been demonstrated with polystyrene (PS)-modified, solution-processed yttrium oxide (Y₂O₃), hafnium oxide (HfO₂), or aluminum oxide (Al₂O₃) as dielectrics on commercially available aluminum (Al) foil substrates. The transistors exhibit a good carrier mobility (µ), a large on/off current ratio (I_on/off), a low threshold voltage (V_T), and a small subthreshold swing (SS) at a low-operation voltage (−4 V), which is comparable with the device performance on rigid Si substrate. Therefore, the excellent electrical performance of the FETs on commercially available Al foil substrate, together with the virtue of light-weight, makes the devices possess the promising potential for various electronic system applications.