Transparent Perovskite Wafers via Nanocrystals Ordered Coalescence Toward Sensitive and Stable X-Ray Detection and Imaging

Metal halide perovskite wafers have shown significant potential in large-area X-ray detection and imaging. However, a distinct difference in optical transparency between state-of-the-art perovskite wafers and single crystals indicates the inferior crystal quality of perovskite wafers, which limits the performance and stability of wafer-based X-ray detectors. Here, nano-sized MAPbBr₃ powders are utilized to fabricate dense perovskite wafers by low-temperature hot-pressing with high transparency above 60% within the 552–800 nm wavelength range. Adjacent nanocrystals assemble following the ordered coalescence mechanism, resulting in the exclusion of nanoscopic pores and crystallographic reorientation. The transparent MAPbBr₃ wafer-based detectors achieve an impressively high X-ray sensitivity of 1.14 × 10⁵ µC Gy_air⁻¹ cm⁻² and a low detection limit of 149 nGy_air s⁻¹, which is superior to opaque MAPbBr₃ wafer detectors (5.64 × 10⁴ µC Gy_air⁻¹ cm⁻² and 316.7 nGy_air s⁻¹) and comparable to MAPbBr₃ single-crystal detectors. Moreover, the detectors demonstrate high uniformity and outstanding stability under continuous X-ray irradiation of a total dose of up to 5.9 Gy_air, equaling to 29 500 times posteroanterior chest examinations. The high sensitivity and low detection limit of the detectors lead to clear X-ray imaging performance.