Coalescent 2D heterostructure for high-efficient surface-enhanced Raman scattering and electrochemical sensing

Surface-enhanced Raman scattering (SERS) and electrochemical sensing (ECS) are integrated components of modern and smart multifunctional electronic systems, but there are still plenty of rooms in mechanisms and fabrication strategies that need to be optimized. Herein, we report a coalescent 2D heterostructures to enhance electrocatalytic activity, sensitivity, and selectivity, made up of coalescent CuO@rGO on indium tin oxide, which serves as a dual-mode sensing platform delivering sheet resistance of 10.3 Ω/sq., transparency of 85.4 %, carrier mobility of 2.7 × 10⁴ cm²/V·s, and work function of 2.2 eV. This interface enables a SERS enhancement factor of 9.62 × 10⁶ by facilitating methylene blue detection efficacy of 1 × 10⁻⁹ M as a Raman reporter. For ECS, redox-active hydroquinone (HQ) and acetaminophen (ACP) perceive higher linearity compared with single 2D materials or metal oxide and exhibit exceptional limit of detection and sensitivity of 4.7 nM (1.7740 μA μM⁻¹ cm⁻²) for HQ and 6.3 nM (0.9037 μA μM⁻¹ cm⁻²) for ACP and applied in real tap water sample detection. This work highlights the capacity of rationally engineered 2D heterostructures for futuristic, high-performance, miniaturized, and multifunctional sensing technologies.