Ultra-low Temperature Solution Processed Steep Subthreshold Organic Thin-film Transistor for On-Display Integrated Sensing

Organic thin-film transistors (OTFTs) of steep subthreshold swing (SS) and excellent operational stability are fabricated with the maximum processing temperature not exceeding 80 °C. A low temperature processed bi-layer structure organic gate insulator (OGI) is designed to achieve good electrical insulation and provide a smooth low-polar surface. A blended solution of small molecule organic semiconductor and polymer binder in solvent of suitable boil point is deposited on top to form uniform crystalline channels of low trap channel interface without thermal annealing. The device exhibits steep SS and excellent operational stability for sensing applications. The OTFTs are fabricated onto an organic light emitting diode (OLED) display for integrated touch sensing without affecting the display performance.