Assessing the Mass Sensitivity for Different Electrode Materials Commonly Used in Quartz Crystal Microbalances (QCMs).

Xianhe Huang,Wei Pan,Qiao Chen,Jianguo Hu,Yao Yao

doi:10.3390/s19183968

Abstract

Mass sensitivity is vital for quartz crystal microbalance (QCM)-based data analysis. The mass sensitivity distribution of QCMs may differ greatly depending on the shapes, thicknesses, sizes, and materials of the metal electrodes. This is not considered by the Sauerbrey equation, and has a large potential to cause errors in QCM-based data analysis. Many previous works have studied the effects of shape, thickness, and size of metal electrodes on mass sensitivity. However, it is necessary to continue to clarify the relationship between the mass sensitivity and the electrode material of the QCM. In this paper, the results of both theoretical calculation and experimental analysis showed that the mass sensitivity of QCMs with gold electrodes is higher than that of the QCMs with silver electrodes, which in turn indicated that the mass sensitivity of QCMs varies with the electrode material. Meanwhile, the results of this study showed that the mass sensitivity of QCMs with different electrode materials is not proportional to the density of the electrode materials. This result suggests that, in order to obtain more accurate results in the practical applications of QCMs, the influence of electrode material on the mass sensitivity of the QCMs must be considered.

Highlights

The advent of quartz crystal microbalances (QCMs) has allowed intersectional research between piezoelectric devices and ultra-small mass sensing
Sensors 2019, 19, 3968 where ∆m and ∆ f are the mass change and frequency shift, respectively; CQCM is the mass sensitivity constant; f0 is the fundamental frequency of the QCM; A is the effective area of the QCM; and ρq and μq are the density and shear modulus of the piezoelectric quartz crystal, respectively
Our previous works [24,25,26,27] quantitatively analyzed the effects of the shape, thickness, and size of electrodes on the mass sensitivity of QCMs, while our latest paper [28] studied the relationship between the mass sensitivity of the n-electrode surface and the m-electrode surface in an n–m type QCM

Summary

Introduction

The advent of quartz crystal microbalances (QCMs) has allowed intersectional research between piezoelectric devices and ultra-small mass sensing. Sensors 2019, 19, 3968 where ∆m and ∆ f are the mass change and frequency shift, respectively; CQCM is the mass sensitivity constant; f0 is the fundamental frequency of the QCM; A is the effective area of the QCM; and ρq and μq are the density and shear modulus of the piezoelectric quartz crystal, respectively. Our previous works [24,25,26,27] quantitatively analyzed the effects of the shape, thickness, and size of electrodes on the mass sensitivity of QCMs, while our latest paper [28] studied the relationship between the mass sensitivity of the n-electrode surface and the m-electrode surface in an n–m type QCM. It is necessary to clarify the relationship between the mass sensitivity of QCMs and the types of electrode material in order to allow accurate QCM-based data analysis. In this paper, taking Au-QCMs and Ag-QCMs as examples, we continue to study whether the mass sensitivity of QCMs is the same for different electrode materials, and, if it is different, what is the relationship between the QCM’s mass sensitivity and the density of the electrode material

Theory

Experiment

Results and Discussion

Conclusions