A Flexible, 2.4‐GHz Wireless Ion Sensor System Using Printed Organic Amplifiers with 3‐V Single Supply

Abstract

AbstractIntegration of organic thin‐film transistor (OTFT) devices with a wireless data transmission system such as 2.4‐GHz Bluetooth low energy (BLE) is a significant requirement for activating the Internet of Thing (IoT) ecosystem based on a vast number of sensors, while conventional OTFT circuits have problems with their high output impedance and the need for multiple power supplies. Here, a wireless, real‐time, and flexible sodium ion sensing system composed of a printed Na+ sensor, printed OTFT‐based amplifiers, inorganic passive elements, a BLE module, and a 3‐V sheet‐type battery is demonstrated. The printed organic amplifier circuits based on dual threshold technology and dual‐gate structure are combinable with a BLE module because of their low output impedance of 50 kΩ and operate with 3‐V single supply as well as improving operational stability under illumination. The sensitivity to Na+ concentration is improved from 53.7 to 242.5 mV dec−1 (4.5 times higher) by the OTFT‐based amplifier, and the data is transmitted in real‐time to a tablet via the BLE wireless communication.