Efficient ultraviolet–visible-near infrared self-powered photodetector based on hexagonal YMnO₃-based ferroelectric thin film by multiscale polarity structure optimization

The utilization of ferroelectric photovoltaic effect is thought to be an effective strategy to design novel self-powered photodetectors. However, the low photocurrent output due to the incompatibility between high intrinsic ferroelectric polarization and narrow bandgap is a major disadvantage that restricts photodetection performances. Here, high-efficiency photodetection properties are achieved in a hexagonal Y_1-xBi_xMnO₃ ferroelectric self-powered photodetector using a multiscale polarity structure optimization strategy. Particularly, the photodetector based on Y_0.95Bi_0.05MnO₃ (YBMO5) can work in a wide band ranging from ultraviolet to near infrared with the maximum responsivity and detectivity up to 0.60 A/W and 2.50 × 10¹² Jones, respectively, with the fast response time of only 0.3/0.4 ms, which are superior to the traditional ferroelectric perovskite photodetectors. The excellent photodetection performances originate from the enhanced photocurrent output, owing to simultaneously achieving big light absorption and robust photogenerated carrier separation and transport. It is demonstrated that Bi doping tunes crystal lattice, domain structure and the interface state, which effectively enhance macroscopic polarity in the condition of nearly unchanged bandgap. Moreover, a denser conductance network of grain boundary is constructed by decreasing grain size, which provides more transport paths for the photogenerated carriers. This work opens up a promising route for the design of high-performance ferroelectric photodetectors.