Optimized ink-jet printing condition for stable and reproducible performance of organic thin film transistor

In this work we fabricated an electrically stable and reproducible organic thin film transistor (OTFT) by optimizing the electrode printing conditions to avoid the coffee ring effect and the Marangoni effect. The electrodes were printed on substrates with different temperature and line spacing to compare the uniformity of electrode morphology and their electrical performance. The Ag gate electrode was printed on poly (methyl methacrylate) (PMMA) coated glass substrate. As a top contact device source and drain electrodes were also printed on the pentacene layer. The optimized gate electrode was printed at substrate with a temperature of 30°C and 30 lm spacing size while the source drain electrodes were printed with 80 lm spacing size at 80°C. The final devices showed reproducible electrode morphology and electricalproperties with a mobility of 0.025 cm2/V-s threshold voltage Vth =-5.6 V and on/off ratio >10⁴.