Hetero-junction kesterite Cu 2 ZnSn(S,Se) 4 solar cells with low bandgap obtained from three different methods of fabrication were exposed to red light illumination, and the changes observed in their electronic properties due to this exposure were studied via open circuit voltage transients, admittance spectroscopy, capacitance voltage profiling techniques, and SCAPS simulation fits to experimental data. The results from the aforementioned techniques, in combination with temperature-dependent current voltage analysis, can be used to reveal the dominant Shockley-Read-Hall recombination path at open circuit voltage. We also derived analytical expressions for the activation energy of the saturation current density and the diode quality factor for the specific case of a solar cell device that has no type inversion at the absorber/buffer interface and is limited by interface recombination in the open circuit condition. It is found that the dominant recombination pathway for the low bandgap Cu 2 ZnSn(S,Se) 4 solar cells under consideration is located in the space charge region and not at the absorber/buffer interface.

The use of photovoltaic cells (solar cells) for generation of electricity is no longer uncommon in Nigeria; this is because solar energy is undoubtedly part of the solution to the problem of dwindling fossil-fuel reserves. Various technologies of photovoltaic systems are imported from different countries and are being used locally with little or no information of their appraisal and field performance. In this work the performance efficiency of a silicon based solar panel operating under ambient conditions has been determined in an experiment using an off the shelf PV module. Measurements were taken while varying the direction of the panel, the tilt angle and illuminance during the day. Results show that PV installations within Benue State and most areas within the north-Central geopolitical region will perform optimally when installed at 15⁰ in the direction of the south. Apart from outlining the efficiency limiting factors, this work also provides an efficiency chart with data that can be used for solar installation.