Fabrication and characterization of two dimensional layered materials for printed electronic devices

Abstract

newline The growth of wireless communication has greatly enhanced sensor technologies, enabling their widespread integration into daily life to improve comfort, safety, and well-being. Printed electronics have revolutionized prototyping by offering a cost-effective and efficient solution for device development. A recent key contribution to this field was the isolation of a single-atom-thick layer of graphite, Known as graphene. Two-dimensional (2D) layered materials like graphene, transition metal dichalcogenides (TMDs), and 2D metal oxides are promising candidates for next-generation sensors due to their high surface area, flexibility, and transparency, making them ideal for future electronics. However, to fully harness the potential of 2D materials in sensing applications, more experimental evidence is needed. newline A low-cost flexible humidity sensor based on 2D ZnO nanosheets is developed by printing silver interdigitated electrodes (IDE) on a polyethylene terephthalate (PET) substrate using an Epson Stylus C88+ inkjet printer, with response and recovery time of 12 seconds and 16 seconds, a sensitivity of 84.65 kand#937;/%RH and hysteresis of 8.61%, highlighting its potential for sensing devices. Additionally, an ultrafast GO nanosheets-based humidity sensor was developed to detect humidity over a wide range of humidity levels from 11% to 97% RH, with fast response time of 2 seconds and recovery time of 17 seconds, with ultra-high sensitivity (243 kand#937;/%RH), low hysteresis (2.16%) and high flexibility. The sensor exhibited excellent capabilities in monitoring human respiration, distinguishing between nose and mouth breathing, detecting finger movements without physical contact, and identifying basic spoken words. Furthermore, a high-performance MoS2 nanosheets-based humidity sensor is designed for respiratory monitoring and non-contact sensing. These advancements highlight the potential of 2D materials based printed humidity sensing devices in human healthcare applications and non-contact wearable electronics. newline