Fully inkjet-printed thin-film transistor array manufactured on paper substrate for cheap electronic applications
Over the past decade, inkjet technology has been well recognized for the manufacturing of products that include ""printing beyond colors."" This micrometer-scale precise technology provides a straightforward approach toward judicious deposition of electronically functional material inks on various substrates over relatively large areas, for printed/flexible electronics. The technology promotes upscalability and has become a renowned process tool for fabricating electronic devices in the field of printed/flexible electronics. Here, the fabrication of printed thin-film transistors (TFT) on cheap coated paper substrate using inkjet technology is reported. For developing the TFT layer stack conductive nanoparticle inks, a polymeric dielectric ink and a p-type organic semiconductor ink are employed. The coating on the paper provides several advantages for fabrication process of TFTs; for example, control over ink spreading. This control of ink spreading can directly influence the fabrication of interdigitated source/drain (S/D) electrodes for TFTs, when a top gate bottom contact architecture is considered. This results in better manufacturing yields and promising electrical performance, which are also the focus of this research. The all inkjet-printed TFTs on paper exhibit electrical performance with maximum S/D current ranging to 170 nA, charge carrier mobility of 0.087 cm2 V−1 s−1, and current on/off ratio of 330.