Fully Printed Organic Phototransistor Array with High Photoresponse and Low Power

Abstract

Organic phototransistors (OPTs) as optical chemical sensors have progressed excitingly in recent years, mainly due to the development of new materials, new device structures, and device interfacial engineering. Exploiting the maximum potential of low-cost and high-throughput fabrication of organic electronics and optoelectronics requires devices that can be manufactured in a fully printed way that also have a low operation voltage. In this work, we demonstrate a fully printed fabrication process that enables the realization of a high-yield (~90%) and low-voltage OPT array. By solution printing of a high-quality organic crystalline thin film on the pre-printed electrodes, we create a van der Waals contact between the metal and organic semiconductor, resulting in a small subthreshold swing of 445 mV dec−1 with a signal amplification efficiency over 5.58 S A−1. Our OPTs thus exhibit both a low operation voltage of −1 V and a high photosensitivity over 5.7 × 105, making these devices suitable for a range of applications requiring low power consumption. We further demonstrate the capability of the low-voltage OPT array for imaging and show high imaging contrasts. These results indicate that our fabrication process may provide an entry into integrated and low-power organic optoelectronic circuits fabricated by scalable and cost-effective methods for real-world applications.

Keywords

• full printing
• organic phototransistors
• low operation voltage
• small subthreshold swing
• image sensor