Self-powered triboelectric/pyroelectric multimodal sensors with enhanced performances and decoupled multiple stimuli

Self-powered multifunctional sensors have been receiving great attention for their potential use in sustainable wearable electronics. In this work, we demonstrate a facile approach for the development of self-powered multimodal pressure-temperature sensors based on an identical ferroelectric copolymer, poly (vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) for the contact pair materials by switching the triboelectric polarity via ferroelectric polarization. This approach enables the identical material-based triboelectric devices with remarkably enhanced triboelectric and pyroelectric output performances. The inversely-polarized P(VDF-TrFE) device exhibits ~106 and ~12 times higher triboelectric and pyroelectric currents, respectively, compared to those of non-polarized devices. Consequently, our triboelectric device provides the highest pressure sensitivity of 40 nA kPa−1 and 1.4 V kPa−1 with a broad pressure detection range (98 Pa–98 kPa) as well as competitive temperature sensitivity of 0.38 nA °C−1 and 0.27 nA °C−1 in cooling and heating states, respectively, compared to previous PVDF-based self-powered sensors. Furthermore, our self-powered sensor can discriminate multiple stimuli including pressure as well as temperature without signal interference. Our sensor can be utilized for the monitoring of weak pulse pressure as well as multimodal finger touch. This work provides a facile fabrication approach to realize triboelectric and pyroelectric multimodal devices with outstanding output performances.