QCM consists mainly of quartz resonator, signal detection, oscillator and data processing.
Where, quartz resonator is the receiver and converter of sensor; it is a resonant sensor composed of AT-cut quartz crystal, which is modified by two balanced metal electrodes on the upper and lower surfaces of the crystal by vacuum deposition or evaporation. Commonly used metals are Au, Pt, Ni and Pd.
The basic principle of quartz crystal microbalance makes use of the piezoelectric effect of quartz crystal. If there is no external force, each crystal lattice in quartz crystal is in regular hexagonal shape; if mechanical pressure is applied on both sides of the crystal, the charge center of the crystal lattice will shift and polarize, generating electric field in corresponding direction. On the contrary, if an electric field is applied to the two electrodes of quartz crystal, the crystal will deform mechanically; this physical phenomenon is piezoelectric effect. If alternating voltage is applied to the two electrodes of the crystal, the crystal will vibrate mechanically; at the same time, the mechanical vibration of crystal will generate alternating voltage.