Diffusional Impedance of a Recessed Microelectrode

resistance electrolyte

R

e

(MΩ)

0.2

charge transfer resistance

R

ct

(MΩ)

0.5

double layer capacitance

C

dl

(μF)

0.0005

recess depth (μm)

1.

radius of microelectrode (μm)

10.

diffusion coefficient 

2

cm

/s

6.5×

-6

10

concentration (mM)

7.

Electrochemical impedance spectroscopy for a recessed microelectrode is evaluated as a function the recess depth. The Nyquist diagram of impedance

Z

is shown on the left. The geometry of the recessed electrode is shown on the right.