The Electrochemical Kelvin Probe allows to measure CPD (Contact Potential Difference) value and evaluate a work function of  electrochemical samples that requires an electrolyte to provide the electric contact. The measurements may be performed not only in a single point of a sample surface but the whole sample’s surface may be scanned.

Measurements of work function is particularly useful in semiconductor physics as it provides the position of Fermi level of examined material.

The Kelvin Probe equipped with the light source makes it possible to examine  surface states of electrons of the sample. Surface states of electrons play significant role in the electric charge transfer,  which is especially important for photovoltaic materials and in photoelectrochemistry.

Electrochemical Kelvin Probe is an innovative setup with dedicated electrocemichal cuvette. By providing the new type of cuvette, setup where the examined surface is both in contact with the electrolyte and is located on the top of the cuvette, the CPD measurements are conducted in conditions that fulfil the requirement that the tip interacts mainly with the sample’s surface. Still, the sample remains in contact with an electrolyte.

The Kelvin Probe  may be equipped with the light source that makes it possible to examine surface states of electrons of the sample.

Light delivery to the sample can be performed in two manners: from the top where sample’s surface is illuminated and from the bottom where the sample-electrolyte interface is exposed to the radiation.
By comparing CPDs of a dry sample and the sample in contact with electrolyte one can explore electrochemical cell voltage maintained by a possible chemical reaction between the sample and reference electrode.

Optionally, the Electrochemical Kelvin Probe may be equipped with the inert gas flow system to provide neutral environment inside the Faraday’s cage.

The instrument consists of the probe on the stand, the electronic control system and the Faraday’s cage.

• The electrochemical sample is placed on the top of the electrochemical cuvette.  Motorized table enables to move the sample in range of 5 cm in both: X and Y directions.
• Each time the probe approaches the sample being examined, an accurate distance between the sample surface and the probe is measured with 50 µm precision. In the method applied, the vertical axis precision is not important for the determination of work function.
• The probe is equipped with a laser pointer that illuminates a spot the probe will hoover above during measurement.
• The light source helps see the sample under the Faraday cage.
• Above the probe, the optical fiber adapter is mounted. The optical fiber allows to illuminate the sample with light from a Monochromator or from a LED Revolver.
• During a sample handling, the probe is hidden under a metal cover which prevents the probe from being accidentally damaged.

The probe tip

The probe tip is the component fully designed and manufactured by Instytut Fotonowy Sp. z o.o. It provides:

• Large signal even from a distance of 0.5 mm above the sample. Thus it does not matter if the sample surface is rough or polished.
• Transparency that lets the light through. This way the sample can be illuminated by a perpendicular light beam.

The tip oscillations are generated with an electromagnet.

• Light delivery from the top

Faraday’s Cage

The whole measurement instrument is covered with Faraday’s cage which shields the system from the surroundings. The grounding socket is situated on the cage.

• Hermetic Faraday’s cage with inert gas flow system, front