Selection Strategies for Flexible Pressure Sensor Electrode Materials Toward Ultrafast Response

Abstract Achieving ultrafast response time is critical for pressure sensors in real‐time healthcare monitoring and hazard detection, yet enabling design strategies remain unestablished compared to other key metrics, such as sensitivity or pressure range. Here, we introduce, for the first time, an interface‐engineering approach to accelerate sensor response by tuning the electrostatic energy level alignment between the electrode and the sensing layer. Using vapor‐deposited PEDOT as the sensing element and systematically selected metal electrodes (Pt, Au, Cu, Ti), we reveal that response time is governed by the Schottky barrier height (SBH) formed at the metal–PEDOT interface. Ohmic contacts (Pt, Au) yield response times of ≈36–42 µs by enabling efficient charge transfer at the interface, whereas Schottky contacts (Cu, Ti) significantly delay the response time (τ) by over 100%. In a mechanistic model, the SBH‐τ relationship exhibits two distinct regimes in which response time is limited by thermionic emission at high SBH, whereas by carrier transport at low SBH. Real‐time LED switching visualizes how the contact properties and SBH influence response time, while acoustic excitation up to 10 kHz demonstrates the frequency‐resolved tracking capabilities of our sensors. These results establish a unified design principle: engineering the work functions of the electrode and sensing element is crucial for achieving ultrafast piezoresistive sensors without compromising sensitivity or detection limit. This study reframes response time as an interfacial transport problem and offers practical guidelines for engineering high‐speed flexible sensors for biomedical and dynamic‐environment applications.