Low Noise X‐Ray Detectors From Template‐Confined 1D Metal‐Free Perovskite Nanowires

High-performance and low-cost X-ray detector is urgently needed for applications in medical imaging and wearable electronics. 1D lead-free perovskite DABCO-NH4I3 (DABCO denotes N-N'-diazabicyclo2.2.2octonium) has emerged as a promising candidate material due to its non-toxicity, aqueous solution processability, and excellent carrier transport properties. However, to produce high quality single crystals via solution methods remains challenging due to the long growth period which limits their X-ray detection performance and practical application. In this work, we innovatively employed anodic aluminum oxide (AAO) template to guide the capillary-driven infiltration and confined crystallization of a DABCO-NH4I3 precursor solution, and successfully obtained DABCO-NH4I3@AAO thick films with highly aligned 001-oriented nanowires. The appearance of interference fringes in transmittance spectra confirms the uniform and high-quality film. Thermal annealing effectively promotes grain coalescence and growth, enhances the crystal orientation and reduces Urbach energy. The vertical-structured X-ray detector based on this film achieves extremely low and stable dark current (0.8 pA at 10 V, with σstd = 0.02pA), a high ION/IOFF of 488.5 and a detection limit as low as 0.6µGy s-1 under a bias voltage of 10 V. This work provides a simple and controllable nanoconfined crystallization strategy for fabricating low dark current and high-stability lead-free perovskite film X-ray detectors.