The Bruker Multimode 8 AFM features an electrochemical cell for characterizing surface structure in a liquid or electrochemical environment. EC-AFM allows real-time in situ AFM imaging with nanometer resolution of the electrode surface directly in solution under electrochemical control. EC-AFM is equipped with a fluid cell and a potentiostat.
Bruker’s bipotentiostat enables to control electrochemical processes either potentiostatically or galvanostatically. Electrochemical control and data acquisition is integrated into the NanoScope® SPM software.
|Compliance Voltage:||±12 V|
|Potential Range:||?10 to +10 V|
|Potential Rise Time:||< 100>|
|Scan Rate:||0.0003 to 10 V/s|
|Minimum Potential Increment (CV):||0.3 mV|
|Potential Update Rate:||1 kHz|
|Current Range:||0 to 100 mA|
|Current Sensitivity:||10 nA/V to 10 mA/V|
|Current Measurement Resolution:||< 50>|
|Input Impedance of Reference Electrode:||< 10>12 ?|
|Maximum Sampling Rate:||100 Hz|
|Band Width:||10 kHz at 10 mA/V, 1 kHz at 10 nA/V|
|Techniques:||cyclic voltammetry, linear sweep voltammetry|
An in situ glass fluid cell with 8 mm diameter O-ring forms on the sample surface a tiny airtight electrochemical cell. This allows only the catalyst coated plane of the sample to be in contact with the electrolyte. The cell has a pipes attached to it through which the solution goes in and out. A typical three-electrode configuration can be assembled with the sample as working electrode (WE), platinum wire as a counter electrode (CE) and miniature leak-free Ag/AgCl as a reference electrode (RE).
Contact mode is the basic mode for AFM technique in which the probe is in constant physical contact with the sample surface. While the tip scans along the surface, the sample topography induces a vertical deflection of the cantilever. A feedback loop maintains this deflection at a preset force and uses the feedback response to generate a topographic image.
In Tapping mode AFM measures topography of the sample by lightly tapping the surface with an oscillating tip. The cantilever’s oscillation amplitude changes with sample surface topography, and the topography image is obtained by monitoring these changes and closing the z-feedback loop to minimize them.
In PeakForce Tapping the probe periodically taps the sample and the pN-level interaction force is measured directly by the deflection of the cantilever which enables to precisely control probe-to-sample interaction, providing the lowest available imaging forces. The ScanAsyst, in turn, automatically optimizes imaging parameters including setpoint, feedback gains, and scan rate to get the best possible image faster, easier, and more consistently. Moreover, it simultaneously enables direct mapping of nanomechanical properties, including elastic modulus, adhesion and dissipation, at high resolution and normal scan rates. PeakForce QNM (Quantitative Nanomechanical Mapping) derives these quantities from force curves taken during imaging.
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