Shan Zhang,Xin Song,Xing Gao,Chunxiao Lu,Pei Han,Yunying Liu,Xiaowei Li,Junyan Zhang,Yong Li
The ferroelectric photovoltaic (PE-PV) effect has been extensively explored and plays a crucial role in constructing self-powered photodetectors. Ferroelectric materials have been attracting great interest in self-powered ultraviolet (UV) photodetectors due to their polarization-induced photovoltaic effect. In this paper, the ultraviolet self-powered photodetection properties of polycrystalline rare-earth Yb 1-x Ho x MnO 3 (0 ≤ x ≤ 0.08, Δx = 0.02) ferroelectric materials have been investigated. The substitution of Ho atoms for Mn atoms has a great influence on the ferroelectric polarization, and Ho doping increases the photocurrent density. The photodetectors show excellent reproducibility responsivity (R) and detectivity (D*) under illumination at 365 nm. In addition, at the light density of 1 mW/cm 2 , the responsivity and detectivity of the photodetectors are as high as 0.09 W/A and 3.359 × 10 11 Jones, respectively. These outstanding photodetection performances are due to the relatively high short-circuit current density ( J sc ). High J sc implies that more photogenerated carriers can be produced under illumination, which makes the device more sensitive to optical signals. This study presents a feasible method for improving the light-detection performance of the ultraviolet self-powered detector.
The use of ferroelectric materials is believed to be a viable way to construct self-powered photodetectors based on the ferroelectric photovoltaic effect. However, the low photocurrent density of ferroelectric materials is a serious drawback that restricts their photo-detection applications. Herein, ultrahigh photo-detection performances are achieved in hexagonal YbMnO3-based self-powered photodetectors by optimizing the macroscopic polarization. The responsivity (R) and detectivity (D*) can reach 0.18/0.15 A W−1 and 6.73 × 1011/5.76 × 1011 Jones under monochromatic light with a wavelength of 365/700 nm when the YbMnO3 thin film [YbMnO3(1040)] is sintered at 1040 °C. These excellent photo-detection performances are attributed to the high short-circuit current density which reaches 10.9 mA cm−2 under 1 sun illumination. A systematic structure and photo-electric characteristic analysis suggests that the formation of a strong domain and the distortion of the crystal structure lead to an enhanced macroscopic polarization in YbMnO3(1040) without changing the bandgap. The enhanced polarization causes a ripple positive effect, which increases the driving force of photo-generated carrier separation and restrains recombination, leading to a high dissociation efficiency. This work demonstrates that the ferroelectric YbMnO3 thin film has great potential in the photo-detection field.
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