Multifunctional PVDF/CeO2@PDA nanofiber textiles with piezoelectric and piezo-phototronic properties for self-powered piezoelectric sensor and photodetector

In recent years, multifunctional sensors have attracted significant attention due to their ability to detect different types of signals. However, it still remains a challenge to develop flexible materials with multiple sensing functions. Herein, we propose a strategy to fabricate multifunctional flexible textiles (PCP) that can apply piezoelectric and piezo-phototronic effects to self-powered piezoelectric sensor and photodetector (PD) by utilizing the synergistic effect of polydopamine-coated cerium oxide (CeO2@PDA) nanoparticles and poly (vinylidene fluoride) (PVDF). The CeO2@PDA nanoparticles served as local nucleating agents and photosensitizers for the PVDF, enhancing the polar crystalline phase and inducing piezoelectric effect, semiconductor, and optical process coupling in PCP textiles. The piezoelectric sensors consisting of PCP textiles produced extremely high sensitivity (1–10 kPa: 1.27 V/kPa; 10–50 kPa: 0.085 V/kPa; 50–100 kPa: 0.02 V/kPa) and significant electrical output (25.5 V and 0.37 μA). Besides, the piezoelectric sensor had extensive applications including pulse wave measurement, limb motion detection, and active voice recognition. It's especially noteworthy that the PD based on PCP textiles is sensitive for the detecting of sunlight illumination as confirmed by response time (tOn = 2 s and tOff = 4.6 s). Meanwhile, the fabricated self-powered PD showed significant improvement in output current, confirming the realization of the piezo-phototronic effect in PCP textiles. In this work, the low-cost and high-efficiency multifunctional sensing materials were successfully prepared, providing a novel approach for the next generation of self-powered piezoelectric sensors and photodetectors.