Crystalline Orientation Control Enhanced Adhesion of Perovskite to Large-Area Readout Board for High-Performance X-Ray Imaging

Abstract

Halide perovskites are reputed as highly promising photoelectronic materials for direct X-ray detectors, but realizing large-area flat-panel imaging requires to address the compatibility issue of the electronic, surficial, and mechanical properties between the perovskite and the readout circuit board. Here, a low-dimensional MA₃Bi₂I₉ perovskite is chosen to achieve a good match in a balancing act between the two by exploiting an orientation control strategy for perovskite film growth. The most striking consequence of the orientation controlled growth is the excellent adhesion of the thick perovskite film to the electronic board in large area and effectively addresses the charge sharing effect, which has been notoriously difficult to achieve. The resulting detector, exhibits an X-ray imaging area of 2.8 × 3.2 cm, with a spatial resolution of 4.0 lp mm⁻¹, the highest yet achieved for polycrystalline perovskite detectors based on TFT backplanes, and a sensitivity of 588 µCGy_air⁻¹ cm⁻² while maintaining a dark current below 10 nA cm⁻², this is also the highest value recorded to date for polycrystalline zero-dimensional perovskite detectors. This device clearly revealing the intricate internal structures of both biological specimens and industrial products. This outcome demonstrates the potential of zero-dimensional perovskites in X-ray planar imaging and highlights the critical role of orientation control strategies.