Bandgap Determination of Photovoltaic Modules Through a Three-Diode Equivalent Circuit Models

This paper developed a method for bandgap determination of photovoltaic modules by equivalent circuit analysis using a three-diode model. First, the illuminated current-voltage (I-V) characteristics under different temperatures and irradiances were recorded. Then, circuit parameter identification of the three-diode model was carried out using a nonlinear least squares optimization technique from the I-V curves. Finally, the bandgap was extracted from the well-known temperature dependence of the reverse saturation current parameter of the first diode whose ideality factor is 1.0. The method is easy to apply and is promising for bandgap determination of other solid-state electronic devices.