All-Inkjet-Printed Organic Thin-Film Transistor Inverter on Flexible Plastic Substrate

We report an all-inkjet-printed inverter using two p-type organic thin-film transistors (OTFTs) on a flexible plastic substrate. Metal-organic precursor-type silver ink, poly-4-vinylphenol solution, and 6,13-bis (triisopropylsilylethynyl)-pentacene solution were used to print gate and source/drain electrodes, gate-dielectric layer, and active semiconductor layer, respectively. By optimizing fabrication conditions, we obtained OTFTs with a mobility of 0.02 cm
²
/V·s, an on/off ratio of 10
⁴
, and a threshold voltage of -1.2 V, and inverters with good switching performance showing a gain of 7.8 at a supply voltage of
V
_DD
= -40 V .