Generalized Adaptive Cation-Selective Interfaces Exhibiting High Stability: Integrating Transduction Materials and Uniform Ion-Selective Membranes via One-Step Fabrication.

Abstract

Rapidly advancing all-solid-state ion-selective electrodes are promising candidates as key components in intelligent biological and chemical sensors. Ionics sensing performance, essential for sensor stability and reliability, is influenced not only by interface compositions but by often-overlooked overall interface structures. This work develops a one-step adaptive integrated interface structure (AIIS) with high interfacial stability for analyzing general cations (K⁺, Na⁺, Ca²⁺, Mg²⁺, Pb²⁺, Cd²⁺, and Cu²⁺), showcasing exceptional near-Nernst response across wide linear ranges. AIIS, based on cetyltrimethylammonium-regulated lipophilic molybdenum disulfide (2.0 CTA-MoS₂), forms single-piece ISM on top and bottom transduction layers over time due to THF volatilization in ISM solutions, ensuring performance adaptability. A kinetic model developed through electrochemical numerical simulation confirms the optimal theoretical stability of an AIIS based on maximum transduction layer charge current and minimal diffusion current. The mixed capacitive transduction mechanism driven by the adsorption of TFPB^- on the 2.0 CTA-MoS₂ surface is elucidated. Adaptive integrated cadmium ion-selective electrodes, as a case study, exhibit excellent interfacial stability (potential drift of 5.51 ± 0.32 µV h^-1 for 24 h and sensitivity loss rate of 4.77% for 30 days) and selectivity. This study proposes a promising strategy for constructing extendable interface structures, providing valuable insights for advancing sensor chip development.