Enhanced X-ray Sensitivity of MAPbBr ₃ Detector by Tailoring the Interface-States Density

An important factor for the high performance of light-harvesting devices is the presence of surface trappings. Therefore, understanding and controlling the carrier recombination of the organic-inorganic hybrid perovskite surface is critical for the device design and optimization. Here, we report the use of aluminum zinc oxide (AZO) as the anode to construct a p-n junction structure MAPbBr ₃ nuclear radiation detector. The AZO/MAPbBr ₃ /Au detector can tolerate an electrical field of 500 V·cm ^-1 and exhibit a very low leakage current of ∼9 nA, which is 1 order of magnitude lower than that of the standard ohmic contact device. The interface state density of AZO/MAPbBr ₃ contact was reduced from 2.17 × 10 ¹⁰ to 8.7 × 10 ⁸ cm ^-2 by annealing at 100 °C under an Ar atmosphere. Consequently, a photocurrent to dark current ratio of 190 was realized when exposed to a green light-emitting diode with a wavelength of 520 nm (∼200 mW·cm ^-2 ). Simultaneously, a high X-ray sensitivity of ∼529 μC·Gy _air ^-1 cm ^-2 was achieved under 80 kVp X-ray at an electric field of 50 V·cm ^-1 . These results demonstrate the use of surface engineering to further optimize the performance of MAPbBr ₃ detectors, which have many potential applications in medical and security detection with low radiation dose brought to the human body.