Thermal characteristics of temperature-controlled electrochemical microdevices
Nicholas M. Contento, Stephen Semancik
The development of novel, miniaturized sensing systems is driven by the demand for better and faster chemical measurements with lower power consumption and smaller sample sizes. Emerging miniature sensors, or microsensors, also offer rapid thermal and diffusive transport characteristics. For instance, temperature changes, during both heating and cooling, can be achieved on micrometer-scale surfaces much more rapidly than on bulk, macro-scale surfaces. While these rapid thermal characteristics have been most successfully exploited to date in gas-phase sensing devices, the prospect of developing analogous microfabricated, temperature-controlled microsensors for use in aqueous, or solution-phase, environments has been relatively unexplored. In this work, electrochemical sensors with microheaters were designed and fabricated, and thermal characterization was performed using temperature imaging, transient temperature measurements, and theoretical modeling to determine temperature distributions and thermal response times. These results will guide the development of a solution-phase electrochemical sensor. Temperature-controlled electrochemical characterization was performed using cyclic voltammetry of a model analyte, ruthenium hexamine chloride (III), to demonstrate the use of the multilayer, microfabricated devices, which consisted of a gold disk electrode and an underlying microheater. Electrochemical signals were enhanced at elevated temperatures such that a signal enhancement of 3x was achieved at 81.5 °C. This improved signal at elevated temperatures was explained by finite element method calculations that accounted for both temperature-dependent diffusion and thermal convection near the heated electrode surface.
and Semancik, S.
Thermal characteristics of temperature-controlled electrochemical microdevices, Sensors and Actuators B-Chemical, [online], https://doi.org/10.1016/j.snb.2015.11.019
(Accessed November 29, 2023)