3D/1D Perovskite Heterojunction for High‐Performance Direct X‐ray Detector

Abstract Due to the strong X‐ray attenuation coefficient, high carrier mobility‐lifetime product, remarkable detection efficiency, and high‐resolution imaging capability, metal halide perovskites have attracted increasing attention in the field of X‐ray detection, known as promising candidates for next‐generation high‐performance radiation monitoring semiconductor materials. However, critical challenges, such as high dark current and pronounced ion migration, particularly in 3D perovskites, hinder their practical applications. Here, a unique 3D/1D perovskite heterojunction is presented as an effective strategy to address these limitations, where a distinctive, crisscross‐structured 1D perovskite crystal with a planar and smooth surface is synthesized to form a robust interface with the 3D perovskite crystal. Benefiting from the synergistic effects of the heterostructure and 1D quantum wells, the resulting 3D/1D heterojunction exhibits a high ion migration activation energy, significantly suppressing ion migration and reducing the dark current. Consequently, the fabricated direct X‐ray detector demonstrates exceptional operational and storage stability, achieving a high detection sensitivity of 1.03 × 10 5 µC Gy air −1 cm −2 and a low detection limit of 4.9 nGy air s −1 . Furthermore, X‐ray imaging experiments confirm the superior imaging quality and spatial resolution of the 3D/1D perovskite heterojunction device, highlighting its potential for high‐performance, stable, and reliable X‐ray detection applications.