Interfacial Stress Decoupling enables Ultra-Stable Palladium-based Hydrogen Sensing

Interfacial adhesion between sensing layer and supporting substrate critically governs the long-term stability of electrical molecular sensors. However, achieving a robust heterointerface remains challenging due to intrinsic lattice mismatch that induces localized stress, which would be further amplified during repeated interactions between the sensing film and gas analytes. Here, we introduce a floating-structure palladium hydrogen (H ₂ ) sensor enabled by interfacial stress decoupling through a dithiol-based self-assembled monolayer (SAM). This interfacial layer acts as a molecular bridge between the palladium sensing layer and the substrate electrode, forming a dual-interface architecture that simultaneously mitigates interfacial stress and suppresses substrate clamping effects, thereby accelerating H₂ absorption kinetics. The resulting sensor demonstrates an ultra-stable and cyclable H ₂ detection, featuring a projected operational lifespan exceeding 10 years, and an ultrasensitive detection limit of 1 ppm at room temperature. Moreover, we achieve wafer-scale fabrication and integration of the device into a portable platform for real-time hydrogen leak detection. This work establishes a structurally engineered pathway toward durable and high-performance molecular sensor via interfacial stress management.