Quartz crystal microbalances (QCMs) with flat electrodes are typically used as mass detectors with monolayer sensitivity. However, the sensitivity of such devices can be increased by enlarging the effective surface area. Researchers in UCI’s Department of Physics have developed a highly sensitive QCM by enlarging the surface area via the application of porous materials deposited on the flat electrodes.
Researchers in UCI’s Department of Physics fabricated nanoporous alumina structures on QCM’s by electrochemically anodizing aluminum electrodes and have shown that these electrodes are very sensitive to the partial pressure of water and thus make excellent, high Q humidity sensors. By applying nanoporous structures as electrodes for QCM’s, using various techniques including evaporation, electrochemistry, spin-coating and selective etching the relative surface area is enhanced without sacrificing Q. The resulting sensors have orders of magnitude greater sensitivity than conventional QCM’s and work with two classes of materials, both condensable fluids (eg humidity sensor) and environmental toxins.
Sensors, humidity, environmental toxins, etc.
Order of magnitude sensitivity enhancement