Design of a quartz crystal with transparent electrode used for both QCM-D and LSPR technology

• We develop an optoelectronic sensor which combines QCM-D and LSPR technology to run the two technologies simultaneously.
• Dissipation D gives us the viscosity of the adsorbed layer while a single LSPR cannot obtain it.
• We employ transparent ITO as the top electrode to let the light beam go through the quartz crystal.
• The gold nanoring arrays are used in LSPR sensors due to their near-infrared resonance wavelength demonstrated with high sensitivity.

This article presents an efficient method for the design of a sensor combining localized surface plasmon resonance (LSPR) sensing with quartz crystal microbalance with dissipation monitoring (QCM-D). The sensor uses a quartz crystal coated with 7 mm radium transparent indium tin oxide (ITO) top electrode and 6 mm radium gold bottom electrode. An array of gold nanorings is fabricated on the surface of ITO electrode. The gold nanoring arrays cause 12.11 Hz frequency shift which is very small compared with 5 MHz resonance frequency. The mass sensitivity profiles of various types of “n-m” electrode sensors are compared using MATLAB and the results show that the “7-6” is more sensitive than others. Finite element modeling in ANSYS shows good sensitivity to low relative permittivity in range from 1 to 10.