Fine Tuning of Electrical Characteristics of Inkjet Printed Graphene for Physical and Chemical Sensing

This study highlights the versatile applications of inkjet-printed graphene/ethyl cellulose (EC) in various electronic devices. Key points include its p-type doping achieved through low-temperature annealing, its use as a temperature sensor at higher annealing temperatures, and its effectiveness in electrochemical sensing, such as phosphate detection. The precise tuning of the oxygen composition of EC in graphene via thermal annealing was crucial to these capabilities. Electrical characterization showed consistent p-type doping behavior in graphene/EC annealed at 200 °C across all inkjet-printed graphene field-effect transistors. Upon annealing at 400 °C, the conductive properties of graphene were used in a hand-held reader device, demonstrating reversible responses to temperature fluctuations from 20 to 115 °C with a linearity of 99.8%. Furthermore, integrating inkjet-printed graphene electrodes annealed at 600 °C into remote floating-gate field-effect transistors resulted in a notably low detection limit of 1 pg/mL for phosphate ions in water, maintaining a linear response from 1 pg/mL to 10 ng/mL with a linearity of 98.91%. These applications underscore the adaptability and precision of inkjet-printed graphene, solidifying its role in advancing electronic components across various technological fields.