High-Performance P-Type Copper(I) Thiocyanate Thin Film Transistors Processed from Solution at Low Temperature

Semiconducting copper(I) thiocyanate (CuSCN) is actively studied for electronic and optoelectronic applications. Although various kinds of CuSCN-based transistors are reported, these devices suffer from low charge carrier mobility of about 0.01-0.1 cm(2) V-1 s(-1). Here, ion gel electrolyte consisting of network polymer and ionic liquid is used as a high capacitance gate insulator to achieve high performance CuSCN-based electrolyte-gated transistors (CuSCN-EGTs) with low operation voltage below 1 V. 30 nm thick CuSCN semiconductor film can be formed by a simple solution process with a low processing temperature (approximate to 100 degrees C) that is directly applicable to flexible plastic substrates. By doping copper iodide to the CuSCN semiconductor, device performance including drain current and charge carrier mobility of the CuSCN EGT can be improved significantly. The measured charge carrier mobility of approximate to 0.3 cm(2) V-1 s(-1) is the highest among the reported CuSCN transistors using various gate insulators. These CuSCN-EGTs also display good operation stability under continuous quasistatic external gate voltage sweeps. Such superior electrical performance and versatile processability of ion gel-gated CuSCN transistors make them suitable for use in complimentary circuits and large-area flexible electronics.