Direct-Written AgNP Electrodes in All-Solution-Processed Low-Voltage Organic Thin Film Transistors Employing High-k PVP Dielectric

Researchers have explored various fabrication methods for organic devices to meet the growing demand for printed electronics and wearables. Inkjet printing has been widely used for deposition of solution-processable materials at low temperatures, making it ideal for flexible electronics. However, nozzle clogging and strict ink and substrate requirements limit its commercialization for OTFTs. Besides, the practical applications of OTFT devices are limited by their high operating voltages. To address these limitations, this study proposes a simple, solution-based fabrication method for developing low-voltage OTFTs on Silicon substrates. A novel direct-write printing technique was utilized to deposit the source/drain electrodes at temperatures below 150 °C in ambient conditions without experiencing nozzle clogging issues, while a spin-coating method was employed for the deposition of TIPS-pentacene semiconducting and high-k PVP dielectric layers. Remarkably, the fabricated OTFT achieved a channel length of 120 µm with saturation mobility of 4.49 × 10-1 cm2/Vs, a threshold voltage of –1.5 V, an On/Off current ratio of 108, and a subthreshold swing of 66.8 mV/decade, operating below –5 V. The integration of direct-write printing with a high-k dielectric layer offers a new approach for fabricating OTFTs and other organic devices at lower temperatures, making it suitable for flexible electronics.