Illuminated Open-Circuit Potential OCP

The three different techniques that can estimate the Ea, are illuminated OCP (Section Illuminated Open-Circuit Potential (OCP) ), Mott-Schottky (Section Mott-Schottky ) and photocurrent onset (Section Three-Electrode J-V and Photocurrent Onset ). The Eft, should be independent of the technique used to determine it. Due to the inherent shortcomings of each technique, there is often a lack of agreement of the values determined by the various analyses. Researchers should be aware of these limitations in interpreting results. 

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As discussed in section Potential Range of Photocurrent Generation , the conductivity type of the semiconductor determines the direction of the potential scan (anodic of Eonset for n-type and cathodic of Eonset for p-type). The initial potential should be close to Eonset- In theory, Eonset should be close to which can be determined using an illuminated OCP measurement (see section Illuminated Open-Circuit Potential (OCP) ). In practice these values can differ by a few hundred mV. Consequently, the user may need to adjust the window of the sweep to collect the full j-V curve. 

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