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 Gyair−1 cm−2 and a low detection limit of 149 nGyair s−1, which is superior to opaque MAPbBr3 wafer detectors (5.64 × 104 µC Gyair−1 cm−2 and 316.7 nGyair 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 Gyair, 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. [ABSTRACT FROM AUTHOR]