In this paper, we analyzed the effects of the number of TIPS-pentacene droplets and also the substrate temperature on the performance of OTFTs As the number of the droplets increased, the mobility increased and reached the perk value and then reduced at all temperatures. The peak mobility was 0.14 ± 0.03 cm²/V sec at 3 droplets and 41℃, 0.19 ± 0.02 cm²/V.sec at 4 droplets and 46℃,and 0.35 ± 0.10 cm²/V sec at 7 droplets and 51℃. The reason of existence of peak mobility can be found in matching the evaporation of solvent with the velocity of crystal formation. When two parameters were properly matched, the mobility produced the highest.

In this paper the author proposes a method of implementing a numerical model for threshold voltage (V_th) shift in organic thin-film transistors (QTFTs) into SPICE tools. V_th shift is first numerically modeled by dividing the shift into sequentially ordered groups. The model is then used to derive a simulations model which takes into simulation parameters and calculation complexity. Finally, the numerical and simulation models are implemented in AIM-SPICE. The SPICE simulation results agree well with the V_th shift obtained from an OTFT fabricated without any optimization. The proposed method is also used to implement the stretched-exponential time dependent V_th shift in AIM-SPICE and the results show the proposed method is applicable to various types of V_th shifts.

In this study, the influence of the intermolecular distance on the charge mobility in a pentacene thin-film was investigated. In order to increase the mobility which depends on the π-overlap between molecules, the intermolecular distance was shortened by compressive force along the conduction channel. Pentacene thin-film was fabricated on flexible substrates bent outward at different radii to stretch the gate dielectric surface and then the substrates were unbent, producing the compressive force to the film. The result showed that the mobility increased proportionally to the strain applied during the pentacen deposition and the molecular packing inside a grain was not optimal for the charge transport.

In this paper a printing process for patterning electrodes on large area substrate was developed by combining screen printing with reverse off-set printing. Ag ink was uniformly coated by screen printing. And then etching resist (ER) was patterned in the Ag film by reverse off-set printing, and then the non-desired Ag film was etched off by etchant. Finally, the ER was stripped-off to obtain the final Ag patterns. We extracted the suitable conditions of reverse Using the process we successfully fabricated gate electrodes and scan bus lines of OTFT-backplane used for e-paper, in which the diagonal size was 6 inch, the resolution 320x240, the minimum line width 30 um, and sheet resistance 1 Ω/□.

In this study, we fabricated the flexible pentacene TFTs with the polymer gate dielectric and contact printing method by using the silver nano particle ink as a source/drain material on plastic substrate. In this experiment, to lower the cross-linking temperature of the PVP gate dielectric, UV-Ozone treatment has been used and the process temperature is lowered to 90℃ and the surface is optimized by various treatment to improve device characteristics. We tried various surface treatments; O2 Plasma, hexamethyl-disilazane (HMDS) and octadecyltrichlorosilane (OTS) treatment methods of gate dielectric/semiconductor interface, which reduces trap states such as -OH group and grain boundary in order to improve the OTFTs properties. The optimized OTFT shows the device performance with field effect mobility, on/off current ratio, and the sub-threshold slope were extracted as 0.63 cm2 V-1s-1, 1.7 x 10(-6), and of 0.75 V/decade, respectively.