Capillary Force-Assisted CsPbBr_{3- x}I_x (x = 0, 1) Columnar Crystal Film for X-ray Detectors with Ultrahigh Electric Field and Sensitivity

Inorganic halide perovskite thin-film X-ray detectors have attracted great research interest in recent years due to their high sensitivity, low detection limit, and facile fabrication process. The poor crystal quality of the thin film with uncontrollable thickness and low background voltage during detection limits its practical application. Here, a high-quality CsPbBr_3-xI_x (x = 0, 1) columnar crystal film is prepared by an improved melt-confined method with a porous anodic aluminum oxide (AAO) template, which stabilizes the disorder perovskite systems of CsPbBr₂I by stress. The AAO-CsPbBr_3-xI_x (x = 0) detectors exhibit high detection accuracy and photoelectric conversion capability with an ultrahigh sensitivity of 32,399.5 μC·Gy_air^-1·cm^-2 at 2142.9 V mm^-1 under 20 kV_p X-rays and 19,217.4 μC·Gy_air^-1·cm^-2 with a higher background electric field of 6666.7 V mm^-1 for AAO-CsPbBr_3-xI_x (x = 1). Moreover, the AAO-CsPbBr_3-xI_x (x = 1) film detector acquires a lower detection limit of 7.65 nGy·s^-1 and a higher X-ray imaging spatial resolution of 1.6 LP/mm and 8.6 nGy·s^-1 and 1.4 LP/mm for AAO-CsPbBr_3-xI_x (x = 0). The facile, high-quality columnar crystal film devices display great potential for low-energy and low-dose X-ray imaging in flat panel detection applications.