Measuring Photocurrent

The current produced by a solar cell when illuminated by light is known as the photocurrent of a solar cell. It is measured when the solar cell is short-circuited and not connected to a load, as shown below.

Quantum Efficiency

Since the photocurrent depends on the incident light, to establish a relation between the two quantities we can consider the quantum efficiency of the solar cell.

Photons that hit the solar cell have an energy E. The photons have a probability of being absorbed an releasing one electron from the solar cell into the external circuit. This probability is the quantum efficiency QE(E)