Spin‐State Reconfigurable Magnetic Perovskite‐Based Photoelectrochemical Sensing Platform for Sensitive Detection of Acetamiprid

Abstract Here, a microfluidic paper‐based analytical device (µ‐PADs) with editable electron configuration and conductivity is proposed for sensitive point‐of‐care (POC) detection of acetamiprid (ACE). The CdS‐protected CsPbX ₃ :Mn (X = Cl, Br) halide perovskite (CPCBM/CdS) quantum dots (QDs) with a core/shell structure are prepared for the first time. This advancement not only addresses the challenge of the inherent water instability of perovskites but also imparts spin‐related charge‐transfer properties to the composite material. Additionally, a simple magnetic stimulation method is employed to rearrange the spin electron occupation in perovskites, effectively enhancing the charge separation efficiency in paper‐based PEC (µ‐PEC) sensing systems. The underlying mechanism is systematically investigated using density functional theory simulations and ultrafast transient absorption spectroscopy. These studies revealed a spin‐dependent reaction pathway and the carrier lifetime extended to 4244 ps under a magnetic field (MF), which is 2.2 times longer than that of the pristine perovskite. As a proof‐of‐concept application, a µ‐PEC sensor is developed for sensitive POC monitoring of ACE in environmental samples with a low detection limit of 23 f m . This study shows that manipulating spin‐polarized electrons in photosensitive semiconductors provides an effective strategy to enhance sensing sensitivity, which holds great prospects for future environmental detection and health monitoring.