Suppressing dark current for high-detectivity perovskite photodetectors via defect passivation

Understanding the mechanisms that determine the reverse bias dark current of perovskite photodetectors is significantly crucial for minimizing the noise current and achieving high detectivity. Here, a defect passivation strategy utilizing the Lewis base additive urea is adopted to effectively decrease the reverse bias dark current density (∼3.48 × 10−8 A/cm2 at −0.1 V) of perovskite photodetectors with an active area of 50 μm × 50 μm, accompanying with the improved photoresponsivity at a peak value of 1.06 A/W. As a result, the device exhibits a peak specific detectivity of 7.28 × 1012 Jones, giving a 468% improvement compared to the control device. Such improvement could be attributed to the Lewis base urea assisted grain growth and boundary passivation effects on MAPbI3 perovskites. Moreover, it further confirms the role of boundary defects on reverse bias dark currents of perovskite photodetectors. The results herein provide new insights into the reverse dark current mechanism and device design of high-detectivity perovskite photodetectors for weak light detection.