High performance Black Phosphorus/Graphitic Carbon Nitride Heterostructure-based Wearable Sensor for Real-time Sweat Glucose Monitoring

Abstract: Wearable, non-invasive glucose sensors capable of accurate and continuous monitoring are crucial for managing metabolic conditions yet achieving high sensitivity and stability in these devices remains challenging. In this work, we present a Black Phosphorus/Graphitic Carbon Nitride (BP/g-CN) heterostructure engineered to leverage phosphorus-nitrogen interactions for enhanced electrochemical glucose oxidation activity. Compared to pristine gCN, the BP-gCN heterostructure demonstrates a significantly improved electrochemical surface area (ECSA) and nearly two-fold reduction in charge transfer resistance (Rct), achieving remarkable glucose sensitivity of 1.1 uA mM(^-1) cm(^-2) at physiological pH. Density functional theory (DFT) calculations revealed stronger glucose adsorption and higher charge transfer on the BP-gCN heterostructure compared to pristine gCN surface. These theoretical insights complement the experimental findings, highlighting the superior electrocatalytic performance of the heterostructure and the role of oxidized BP surface. Furthermore, the BP-gCN sensor is integrated into a wearable device platform with microfluidic layers and a Near Field Communication (NFC) chip, forming a conformal skin patch that enables real-time sweat glucose monitoring. This demonstration of a high-performance, non-enzymatic wearable glucose sensor based on a heterostructure design underscores the potential of the device for seamless health management and paves the way for next generation biosensing platforms aimed at improving personalized and continuous health monitoring.