Use of the longitudinal mode of screen-printed piezoelectric cantilevers coated with PEUT for toluene detection: Comparison with silicon cantilevers

Self-actuated and self-read-out piezoelectric cantilevers made of Au/PZT/Au (8mm×2mm×0.095mm) beam layers on an alumina substrate are fabricated thanks to the association of screen-printing and sacrificial layer techniques. Then, PZT cantilevers used as piezoelectric resonant type sensors are functionalized with an organic PEUT layer (≈30μm) for toluene detection at room temperature. The first and second unusual in-plane 31-longitudinal modes presenting high resonant frequencies (respectively 70kHz and 214kHz) and good quality factors (≈200) are used for toluene detection. Sensitivities and LOD are compared for both modes. Due to their higher resonant frequency, PZT cantilevers using these longitudinal vibration modes have higher sensitivities (15.0mHzppm−1 at 70kHz) than those actuated with the classical flexural mode of silicon cantilever (0.9mHzppm−1 at 3kHz). These interesting results demonstrate the potentialities of printed piezoelectric cantilevers for gas detection. Their performances are compared with those of silicon cantilevers actuated with transverse classical flexural modes.