A single-structured multifunctional device capable of energy harvesting and sensing multiple physical signals has significant potential for a wide range of applications in the Internet of Things (IoT). In this study, the fabricated single-structured device based on methylammonium lead iodide-polyvinylidene fluoride (MAPbI3-PVDF) composite can harvest mechanical energy and simultaneously operate as a self-powered light and pressure sensor because of the combined photoelectric and piezoelectric/triboelectric properties of the MAPbI3-PVDF composite. Light-dependent dielectric and piezoelectric properties of composite films are thoroughly investigated. Light and contact electrification effect on device performance in both piezoelectric and triboelectric modes is also systematically investigated. When the device is operated as a harvester in both piezoelectric and triboelectric modes, remarkable light-driven outputs were observed under illumination; the outputs decreased in the piezoelectric mode, while they increased in the triboelectric mode. Such light-controlled properties enabled the device to operate as a self-powered photodetector with outstanding responsivity (∼129.2 V/mW), rapid response time (∼50 ms), and satisfactory detectivity (∼1.4 × 1010 Jones) in the piezoelectric mode. The same device could also operate as a pressure sensor that exhibited excellent pressure sensitivity values of 0.107 and 0.194 V/kPa in the piezoelectric and triboelectric modes, respectively. In addition, the device exhibits a fast response time with long-term on-off switching properties, excellent mechanical durability, and long-term stability.
Keywords: MAPbI3−PVDF composite; energy harvester; multifunctional device; photodetector; pressure sensor.