Electronic structure optimization of titanium-based layered oxide to boost flexible sensing performance

Abstract

Flexible chemical sensors have attracted significant interest in real-time health monitoring, the internet of things, and robots. Titanium-based layered oxide (TLO) is a potential material for high-performance sensors, but the drawbacks of poor conductivity and low adsorption capacity limit its practical applications. Herein, we effectively optimize the electron structure of Na2Ti3O7 (NTO) through S and N dual anions doping technology, which can reduce the electron density of interlayer sodium ions, enhance the hybridization of Ti 3d-O 2p bonds, and optimize the p-blocking center near the Fermi level. These changes decrease the band gap and favor the electron transfer and adsorption capacity for S, N-Na2Ti3O7 (S, N-NTO). As a result, the S, N-NTO displays favorable neurotransmitter dopamine (DA) selectivity, wide detection range, low limit of detection, and ultrafast response for electrochemical sensing. Furthermore, the prepared flexible paper-based portable microsensors enable rapid and in-situ identification of DA in artificial sweat and human serum and show excellent mechanical stability and durability. This study provides an important perspective to develop practical wearable medical test devices as well as highlights the key role of anion doping in modulating the electronic structure of TLO.