Dark Current Suppression in Two-dimensional Histamine Lead Iodine Perovskite Single Crystal for X-ray Detection and Imaging

Lead halide perovskites have emerged as attractive X-ray detector materials, owing to properties such as strong X-ray stopping power, excellent carrier transport, and high sensitivity. Additionally, they can be easily prepared by using solution-based synthesis approaches. However, traditional 3D (three-dimensional) perovskites X-ray detectors have shown limited application due to high dark currents generated under bias voltage as a result of strong ion migration. In this work, an X-ray detector with a vertical structure device is demonstrated using 2D (two-dimensional) histamine lead halide perovskite single crystal HAPbI₄ (HPI, HA = histamine). Due to the dielectric screening effect of diamine and the vertical structure of the HPI device, the fabricated detector shows a sensitivity of 7737 µC Gy_air⁻¹ cm⁻² under a bias voltage of 30 V. Furthermore, the detector shows a sensitivity of 293 µC Gy_air⁻¹ cm⁻² and detection limit of 51.38 nGy_air s⁻¹ without bias voltage, wherein the dark current is almost completely suppressed. All of these properties indicate the X-ray detection device is a promising candidate for next-generation optoelectronic applications.