**1.3 Photovoltaic parameters**

In addition to series and shunt resistance, the photovoltaic solar cells' performance is mainly characterized by six important parameters, (1) short-circuit current density, (2) open-circuit voltage, (3) maximum power output, (4) fill factor, (5) incident photon-to-current conversion efficiency, and (6) solar energy to power conversion efficiency, which are thoroughly discussed as follows [4].
