Layer Engineered MXene Empowered Wearable Pressure Sensors for Non-Invasive Vital Human-Machine Interfacing Healthcare Monitoring

Pressure sensors with high flexibility and sensitivity face significant challenges in meeting the delicate balance and synergy among suitable active sensing electrode materials, substrates, and their device geometry design. In this contribution, layer-engineered delaminated Ti-MXene (DL-Ti(3)C(2)Tx) is introduced, which has relatively wider interlayer spacing through intercalated large organic molecules and accordion-like open internal microstructure than the narrower pristine Ti(3)C(2)Tx MXene (Ti-MXene), graphene/carbon nanotube's interlayer spacing suitably fulfill the high sensitivity and flexibility requirement through accessible electronic pathways under the external pressure. Notably, a milder in-situ ambient condition etching is performed to eliminate the associated safety risks for a flexible personal healthcare monitoring pressure sensor. DL-Ti(3)C(2)Tx MXene-empowered, flexible pressure sensor demonstrates a broad range of sensitivities up to a very high-pressure of 20.8 kPa at a sensitivity of 242.3 kPa(-1) with a fast response and recovery time (<300 ms). A twofold increase in pressure sensitivity performance of DL-Ti(3)C(2)Tx MXene than that of Ti-MXene, graphene can be attributed to the engineered wider interlayer distance among the delaminated DL-Ti(3)C(2)Tx MXene layers causing a facile interlayer atomic movements, contacts, and reversible compressibility. The current economical, scalable DL-Ti(3)C(2)Tx MXene flexible pressure sensor can provide future safe personal healthcare artificial intelligence with real-time tracking ability.