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 CsPbX₃: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 fm. 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.