Weak X‐Ray to Visible Lights Detection Enabled by a 2D Multilayered Lead Iodide Perovskite with Iodine‐Substituted Spacer

Broadband photodetectors (PDs) with low detection limits hold significant importance to next-generation optoelectronic devices. However, simultaneously detecting broadband (i.e., X-ray to visible regimes) and weak lights in a single semiconducting material remains highly challenging. Here, by alloying iodine-substituted short-chain cations into the 3D FAPbI