Please you have to tell us hoe the current is detected and how large is its value?
Is this due to imperfections in the voltmeter which measures the open circuit voltage? Theoretically speaking the terminals of the solar cells must be open circuit with strictly current is zero. In order to access the open circuit voltage and measure it one realizes a practical open circuit by a very large resistance which may be the resistance of the voltage measuring instrument as hinted by the colleagues.
Yes. The internal resistance of a common voltmeter is at least 10 Mohm. A common value for OCP in most electrochemical experiments is below 1V . "No current" means in fact a very low current, in nA range (use the Ohm's law to verify).
The theory of the voltage measurement requests an internal resistance for voltmeter to be 1000 times higher than the resistance of the measured circuit (the aim is to minimise the measurement error below 0.1%).
The "open circuit potential" (OCP) measures using a high impedance voltmeter so that no current flows between the working electrode and reference electrode.
Please you have to tell us hoe the current is detected and how large is its value?
Is this due to imperfections in the voltmeter which measures the open circuit voltage? Theoretically speaking the terminals of the solar cells must be open circuit with strictly current is zero. In order to access the open circuit voltage and measure it one realizes a practical open circuit by a very large resistance which may be the resistance of the voltage measuring instrument as hinted by the colleagues.