Plasmonic-enhanced electrochemical detection of volatile biomarkers with gold functionalized TiO2 nanotube arrays

Titania nanotubular arrays (TNA) synthesized via electrochemical anodization is a stable and versatile material, widely studied for photocatalytic and sensing applications, whereas nano-sized gold particles are a known plasmonic material. Semiconductor￢ﾀﾓmetal nanocomposites in isolated, embedded, or encapsulated form, when irradiated with proper light frequency can exhibit localized surface plasmon resonance (LSPR) effect. This effect can result in improved light adsorption and electrical properties of a material. In this study, we report the enhanced visible light photo-response of LSPR induced volatile organic biomarker vapor sensing at room temperature using a Au-embedded TNA electrochemical sensor. Two mechanisms are proposed. One based on classical physics (band theory), which explains operation under non-irradiated conditions. The second mechanism is based on the coupling of classical and quantum physics (molecular orbitals), and explains sensor operation under irradiated conditions.