Medical Design Briefs - August 2021 - 14

Electrodes and Microelectrode Arrays
8×10-4
8×10-4
6×10-4
6×10-4
-2×10-5
Laser
Pt10lr
4×10-4
4×10-4
-2×10-5
-0.8 -0.4 0 0.4 0.8
Potential (V)
2×10-4
Laser
Energy
-2×10-4
-4×10-4
CSCtotal
TiN
-2×10-4
100 µm
2×10-4
Pt10lr
103
Restructured
Pt10lr
Laser
Energy
104
-4×10-4
-6×10-4
10 µm
-8×10-4
-0.8
-0.4
0.4
Potential versus Ag AgCI (V)
0.8
-8×10-4
-0.8
-0.4
0.4
Potential versus Ag AgCI (V)
104
5×102
Fig. 7 - Cyclic voltammagrams of a series of electrodes restructured under varying pulsing conditions
(a), and a pristine Pt10Ir electrode and a 4 μm thick TiN coating for comparison with a laser
restructured electrode (b).
Pt10lr
4×102
104
3×102
2 µm
0.8
-6×10-4
2 µm
102
10-1
100
101
102
103
Frequency (Hz)
104
105
TiN
2×102
Laser
Energy
10-1
103
100
101
102
103
Frequency (Hz)
104
105
102
10-1
100
101
102
103
Frequency (Hz)
104
105
104
10 µm
200
180
160
140
120
100
80
60
40
20
500
TiN
Laser
Restructured
Pt10lr
300
Laser
Restructured
Pt10lr
200
102
10-1
100
101
102
103
Frequency (Hz)
104
105
TiN
400
TiN
2 µm
Fig. 9 - Focused ion beam (FIB) cross sections of a hierarchically restructured electrode (left) and
TiN coating (right).
103
Laser
Energy
100
104
Pt10lr
Laser Energy
Laser Energy
Fig. 10 - Total charge storage capacity (CSCtotal) (a) and specific capacitance of various hierarchically
laser restructured electrodes as a function of laser pulse energy (b). Included, for the sake of comparison,
is also CSCtotal and specific capacitance of a 4 μm TiN coated electrode and a pristine
Pt10Ir electrode. The CSCtotal is calculated by integrating the area under the cyclic voltammagrams
in Figure 7. Specific capacitance was calculated by the use of EIS data and common Randles model.
Each data point is an average of three measurements on three electrodes, i.e., a total of nine measurements.
tured
under various pulsing conditions by
adjusting laser pulse energies to tune surface
morphology and hierarchy (see
Figure 7a). The CV behavior of the
highest- performing hierarchically restructured
electrode exhibiting the largest
voltammagram is compared against a
14
Intro
Cov
smooth Pt10Ir electrode and a 4-µm-thick
TiN coating (see Figure 7b).
The Pt10Ir electrode exhibits distinct
oxidation and reduction peaks similar to
Pt electrodes. TiN voltammogram has the
approximately rectangular shape expected
for an electrode exhibiting only
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ToC
+
-
A
Laser
Energy
Pt10lr
103
TiN
102
10-1
100
101
102
Frequency (Hz)
Fig. 8 - Impedance magnitude as a function of
frequency for various hierarchically laser
restructured electrodes as a function of laser
pulse energy, a 4 μm TiN coated electrode and
a pristine Pt10Ir electrode for comparison.
Medical Design Briefs, August 2021
µ
103
104
105
Current (A)
CSC (mC/cm2)
Capacitance (µF/mm2)
Current (A)
Current (A)
Impedance (Ω)
Impedance (Ω)
Impedance (Ω)
Impedance (Ω)
Impedance (Ω)
È
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Medical Design Briefs - August 2021

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