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Lead-based organic–inorganic hybrid perovskite single crystals (OIHP SCs) offer promising opportunity for X-ray detection and imaging owing to their high X-ray attenuation coefficient, excellent optoelectronic properties, and simple fabrication processes. Nevertheless, it remains a key challenge to reduce its dark current and meanwhile maintain a high sensitivity. Herein, we developed an on-substrate method for growing methylamine lead bromide (MAPbBr3) SCs on aluminum oxide (Al2O3) layer coated indium tin oxide (ITO) glass. The photodiode based on this approach exhibits an ultralow-dark-current density of 1 nA cm−2 at an operative voltage of −5 V, a signal-to-noise ratio (SNR) more than 80 dB, and meanwhile retaining a high X-ray sensitivity of 2.02 $\times 10^{{3}}\,\, \mu \text{C}\cdot $ ${\mathrm {Gy}}_{\text {air}}^{-1} \cdot $ cm−2. Our further investigation reveals that the dark current was reduced due to two beneficial effects of the Al2O3 layer in tandem, including the interfacial defect passivation and blocking of hole injection by increased interfacial energy barrier. Our approach sheds light on advancing the fabrication of high-performance OIHP SCs-based X-ray sensors that can be potentially integrated with large-area readout panel at low temperature. [ABSTRACT FROM AUTHOR]

Organolead halide perovskites provide tremendous opportunities for ideal radiation detection due to their high atomic numbers, large carrier mobilities, and long lifetimes. Here, we synthesized high-quality single crystal CH3NH3PbBr3 with a high mobility-lifetime product of $\text {4.1} \times \text {10}^{\text {-2}}$ cm2/V by the developed inverse low temperature crystallization method. The sensitive X-ray detector was fabricated by depositing 50 nm of gold on both sides of the perovskite crystal. This device exhibited a high sensitivity up to $259.9~\mu \text{C}$ /Gy $_{\text {air}}$ /cm2 under the 39 keV X-ray exposure at a small electric field of ~0.83 V/mm and yielded a low noise of $\text {3.1} \times \text {10}^{-\text {23}}\,\,\text{A}^{\text {2}}$ /Hz. Additionally, the sensitivity can be further improved by increasing operating voltage. Our results provided a solution for constructing high-performance X-ray detectors. [ABSTRACT FROM AUTHOR]