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 MAPbBr3 nuclear radiation detector. The AZO/MAPbBr3/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/MAPbBr3 contact was reduced from 2.17 × 1010 to 8.7 × 108 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·Gyair-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 MAPbBr3 detectors, which have many potential applications in medical and security detection with low radiation dose brought to the human body.
Keywords: MAPbBr3 PSC; X-ray detector; annealing; interface state density; p−n junction.