Flexible Organic Thin-Film Transistors with High Mechanical Stability on Polyimide Substrate by Chemically Plated Silver Electrodes

Conventionally, silver (Ag) electrodes for organic thin-film transistors (OTFTs) are prepared by evaporated method at high temperature. In this work, we report a new methodology to fabricate the Ag source/drain electrodes of flexible OTFTs arrays by chemically plated technique on polyimide substrate at room temperature. The indacenodithiophene-co-benzothiadiazole (IDT-BT) OTFTs with chemically plated electrodes obtain the saturation mobility of 0.25 cm2 V-1 s-1. Furthermore, compared with high-temperature thermal evaporation method, the subthreshold swing of the IDT-BT OTFTs decreases from 1.97 to 0.89 V/dec with chemically plated Ag source/drain electrodes. The smaller threshold voltage and contact resistance are also obtained, owing to the change of work function. The bending tests indicate that the electrical properties of the devices maintain unchanged during tensile bending at a radius up to 1.4 mm. Moreover, the electrical property of the devices remains stable at a tensile bending cycle of 1000 cycles at a radius of 2.5 mm. This proposed methodology has great potential for flexible and wearable electronic devices.