Non-contact intelligent sensor for recognizing transparent and naked-eye indistinguishable materials based on ferroelectric BiFeO₃ thin films

At present, the research on ferroelectric photovoltaic materials mainly focuses on photoelectric detection. In the context of the rapid development of the Internet of Things (IoT), it is particularly important to use smaller thin-film devices as sensors. In this work, an indium tin oxide/bismuth ferrite (BFO)/lanthanum nickelate device has been fabricated on an F-doped tin oxide glass substrate using the sol–gel method. The sensor can continuously output photoelectric signals with little environmental impact. Compared to other types of sensors, this photoelectric sensor has an ultra-low response time of 1.25 ms and ultra-high sensitivity. Furthermore, a material recognition system based on a BFO sensor is developed. It can effectively identify eight kinds of materials that are difficult for human eyes to distinguish. This provides new ideas and methods for developing the IoT in material identification.