Thanks to its strong X-ray absorption and large carrier diffusion length, perovskites have demonstrated excellent performance for X-ray detection. Combination of perovskite with thin-film transistor (TFT) arrays to construct flat-panel X-ray imager (FPXI) is required for X-ray imaging, yet this is rarely reported. Solution processing of perovskite thick film onto TFT can enable the electronic connection, however the amounts of pinholes inevitably form during the solvent evaporation and result in a porous film with deteriorated performance and stability. Here a novel strategy is raised to achieve high-quality perovskite thick films for TFT integration via soft-pressing and in situ polymerization of multi-functional binder (TMTA). The combined process largely eliminates the pinholes, improves the surface smoothness, passivates grains boundaries, reduces ionic migration, and improves stability. Accordingly, a compact and smooth MAPbI 3 thick film integrating with TFT arrays is prepared for flat-panel X-ray imaging. The largest film (28 × 28 cm 2 ) is obtained with the state-of-theart performance (ratio of sensitivity to noise current: 1.41 × 10 11 µC Gy −1 A −1 ) among polycrystalline films. It is hoped that the work provides guidance for fabricating compact perovskite thick films and push perovskite FPXI one step further for low-dose X-ray imaging.

Organic-inorganic hybrid perovskites have demonstrated excellent performance in converting X-ray photons to electrical signals with high detectivity and sensitivity. Solution-processed large-area perovskite polycrystalline thick film is promising for scalable X-ray flat panel detection imaging. However, ionic migration is severe due to the numerous grain boundaries and pinholes in the thick films, resulting in a large dark current and serious baseline drift. Herein, a new strategy is proposed to suppress the ion migration by inserting 2D Ruddlesden-Popper layer into the 3D perovskite film. The quasi-2D perovskite thick films exhibit lower defects density, suppressed ion migration, and higher thermal stability compared to their 3D counterpart. Based on these advantages, the quasi-2D perovskite-based X-ray detector shows a sensitivity of 10 860 µC Gy air −1 cm −2 with a stable dark current and photocurrent response. Impressively, the extra-low detection limit of 69 nGy air s −1 is the lowest in all those reported polycrystalline film-based detectors. The quasi-2D film is believed to be a very promising choice for digital flat detectors for sensitive radiation detection and low-dose dosimeter.

Unevenly distributed magnesium (Mg) electrodeposits have emerged as a major obstacle for Mg‐metal batteries. A comprehensive design matrix is reported for 3D magnesiophilic hosts, which regulate the uniform Mg electrodeposition through a synergistic coupling of homogenizing current distribution, geometric confinement, and chemisorptive interaction. Vertically aligned nitrogen‐ and oxygen‐doped carbon nanofiber arrays on carbon cloth (denoted as “VNCA@C”) are developed as a proof of concept. The evenly arranged short nanoarray architecture helps to homogenize the surface current density and the microchannels built in this 3D host allow the preferential nucleation of Mg due to their geometrical confinement effect. Besides, the nitrogen‐/oxygen‐doped carbon species exhibit strong chemisorptive interaction toward Mg atoms, providing preferential nucleation sites as demonstrated by first‐principle calculation results. Electrochemical analysis reveals a peculiar yet highly reversible microchannel‐filling growth behavior of Mg metals, which empowers the delicately designed VNCA@C host with the ability to deliver a reduced nucleation overpotential of 429 mV at 10.0 mA cm−2 and an elongated Mg plating/stripping cycle life (110 cycles) under high current density of 10.0 mA cm−2. The proposed design matrix can be extended to other metal anodes (such as lithium and zinc) for high‐energy‐density batteries.