Tunable barrier-driven CuO/Cu-TCPP core–shell sensor for enzyme-free and selective glyphosate detection

CuO/Cu-TCPP was prepared by a low-energy and environmental condition process. • Interfacial barrier–driven sensing mechanism ensures high anti-interference ability. • The Cu-TCPP acts as a adsorption layer, enriching glyphosate and resisting interference. • Glyphosate adsorption dynamically tunes the heterojunction barrier for detection. • The sensor achieves 1.27 nM LOD and reliable performance in complex matrices. The widespread use of glyphosate has posed significant threats to the environment and human health, underscoring the importance of accurately detecting glyphosate in diverse environmental. However, conventional electrochemical sensors often rely on enzyme-mediated recognition to achieve selectivity, making them susceptible to environmental interference and limiting their practical applicability. Herein, we report a tunable barrier–driven sensor based on CuO/Cu-TCPP core-shell structure for highly sensitive and selective GLY detection. The Cu-TCPP shell serves dual functions: acting as a specific adsorption layer to selectively enrich glyphosate while repelling competing molecules, and serving as a physical gating switch that dynamically modulates the heterojunction barrier through adsorption of negatively charged glyphosate to trigger efficient electron transfer. Crucially, this physical-gating-based barrier modulation mechanism exponentially amplifies the current signal while physically shielding interference from analogous redox species, thereby achieving highly selective and sensitive detection. The fabricated sensor demonstrates a broad linear response (60–6000 nM) with an ultralow detection limit of 1.27 nM, supporting its potential application in environmental monitoring. More broadly, this work provides mechanistic insight into adsorption-regulated interfacial barrier modulation and offers a strategy for the rational design of enzyme-free electrochemical sensors for environmental contaminants. In this study, a CuO/Cu-TCPP core-shell heterostructure was constructed for glyphosate sensing. The Cu-TCPP shell serves both as a specific adsorption layer and a responsive switch. On the one hand, it can enrich glyphosate and suppress interfering substances. On the other hand, glyphosate adsorption can regulate the potential barrier at the heterojunction interface, promote electron transfer and trigger electrochemical signals. Under light exposure, its performance improvement is more obvious. This mechanism significantly enhances the sensing sensitivity and selectivity. The sensor maintains good linearity within the range of 60–6000 nM, with a detection limit as low as 1.27 nM. It also demonstrates stable and reliable detection performance in complex environmental samples, providing a new strategy for high-performance organophosphorus pesticide sensing. Download: Download high-res image (132KB) Download: Download full-size image