Anomalous Pressure-Temperature Ultrahigh Sensitivities in Atomically Engineered Carbonitride MXenes for Multifunctional Wearable Human-Machine Interfaces: Joint Computational-Experimental Elucidations

Abstract

In the era of autonomous systems and multifunctional devices, sensors serve as vital sensory components in our Internet of Things and technologically advanced society. At the end of the synthetic 2D nanomaterials research, MXenes are not just chemicals but materials, depending on how they are synthesized for targeted applications, such as dual-functional temperature and pressure-sensitive wearable sensing. The current findings introduce the potential strategic role of nitrogen atoms to the Ti-Carbonitride (Ti3CNTz) structure in a controlled compositional stoichiometry of Ti3C1.8N0.2Tz, Ti3C1.5N0.5Tz, Ti3CNTz, Ti3C2Tx to deliver an ultrahigh sensitivity (300%-400% temperature & pressure sensitivity enhancement) and durability in real-time human-machine sensing interface applications. These recorded outstanding dual-sensing performance outplays many other MXene stoichiometries, graphene-related 2D nanomaterials, and their associated composites. Synchrotron radiation-based X-ray absorption fine structure and density functional theory analysis reveal that incorporating low N content (e.g., Ti3C1.8N0.2Tz) enhances temperature sensitivity by boosting electrical conductivity, and an upshift in the vibrational spectrum with increased lattice deformability significantly improves pressure sensitivity. We provide valuable insights for developing advanced sensing materials, emphasizing the need to investigate the fundamental mechanisms that control the interactions among layered 2D MXene materials and the sensing device functions that bridge human and machine interfaces.