The environmental and economical merits of converting solar energy into electricity via photovoltaic cells have caused an ever increasing interest among developed and developing countries to allocate more budget on photovoltaic systems in order to boost up their efficiency in recent years. Besides the material and design parameters, there are several external factors such as magnetic field, air mass, intense light, external electric field, solar spectrum…. that can influence the PV cell's performance. There have been a handful of studies conducted on the effect of various influential parameters on the efficiency and performance of photovoltaic cells; however none has taken these two parameters (magnetic field and air mass) into account simultaneously. In this 3D study the effects of magnetic field and the air mass illumination on space charge region width extension of a bifacial polycristalline solar cell front side illumination will be elaborated. Based on the columnar model of the grain and the quasi-neutral base, the continuity equation is established and the boundaries conditions are defined in order to use Green's functions to solve this equation. New analytical expression of charge carriers' density is found and the diffusion capacitance to the junction is calculated. The normalized carriers' density plot versus base depth and magnetic field with various air mass illumination are presented and analyzed. The effects of magnetic field and air mass illumination on space charge region width extension are then deducted. The influences of magnetic field and air mass illumination on the junction capacitance and on the reverse of junction capacitance are also shown and analyzed.

In this work, we present an experimental transient 3-Dimensionnal study for the minority charge carriers' effective lifetime measurement under magnetic field in transient dynamic state. The magnitude of the magnetic field B is varied from 0 mT to 0.03 mT. The method used is mainly based on the open circuit voltage decay method. The solar cell is injected by a low electrical excitation which protects against capacitance effects. Our approach is based on the open circuit voltage decay response analysis. From an experimental set-up, we get the transient voltage data on a digital scope. The data are used for plotting transient voltage decay curves. The curves obtained and analyzed are fitted in their linear zone. This zone presents an ideal decay which permits to get good values of lifetime. The slope of the linear decay is inversely proportional to effective lifetime. The results of fitting permit determinate the effective charge carriers' lifetime directly. The results obtained are then presented and analyzed. The observations indicate that the charge carriers effective lifetime decrease when the magnetic field increases.