High sensitive self-assembled monolayer modified solid mounted resonator for organophosphate vapor detection

We fabricated a self-assembled monolayer (SAM) modified solid mounted resonator (SMR) for organophosphate vapor detection. The SMR device consisted of a piezoelectric stack and an all-metal Braggʹs reflector. The electrode surface is chemically modified with a Cu2+/11-mercaptoundecanoic acid SAM to capture organophosphate compounds. After chemical modification, both the resonance frequency and the Q-factor decrease. Fourier transform infrared external reflection spectroscopy was performed to verify the formation of SAM. Adsorption of organophosphate compounds onto the SAM increases its mass, and the resonance frequency proportionally goes down. The testing results show that the modified SMR can yield a rapid, sensitive, reversible and reproducible response to nerve-agent (dimethyl methyl phosphonate) vapor. This study proves that using the SAM modified SMR to detect trace organophosphate vapor is feasibility.