All jet-printed polymer thin-film transistor active-matrix backplanes

Thin-film transistor (TFT) backplanes fabricated by using jet printing as the only patterning method are reported. Additive and subtractive printing processes are combined to make $128\times 128$ pixel active matrix arrays with $340\mu \mathrm{m}$ pixel size. The semiconductor used, a regioregular polythiophene, $\text{poly}[5,5^{\prime }\text{-}\text{bis}(3\text{-}\text{dodecyl}\text{-}2\text{-}\text{thienyl})\text{-}2,2^{\prime }\text{-}\text{bithiophene}]$ ; (PQT-12) is deposited by inkjet printing and exhibits average TFT mobility of $0.06{\mathrm{cm}}^2∕\mathrm{Vs}$ , on/off ratios of ${10}^6$ , and minimal bias stress. The printed TFTs have high yield with a narrow performance distribution. The pixel design benefits from the registration accuracy of jet printing and it is shown that the electrical performance is suitable for addressing capacitive media displays.