Modelling, Simulation and Optimization of n-p-n-p Silicon Multilayer Solar Cells

We simulate the conception parameters of a model of a silicon multilayer solar cell. The cell is composed by four layers of opposite conductivities forming three junctions inside the cell. The electric contacts are tailored vertically to collect the minority carrier generated under illumination. We developed the equations giving the output power, the fill factor and the efficiency of the cell, taking into account the series resistances of each layer. We optimized, using MATLAB software, the thicknesses of the layers, the impurity concentration level and the distance between the electric contacts. We showed that the optimized photovoltaic structure, with the silicon properties published at the Ioffe institute website, gives an efficiency of 20.66%. The n-p-n-p silicon cell delivers a short circuit current Icc = 45.3 mA/cm2, an open circuit voltage V oc= 0.746 V and an output power of 28.5 mW/cm2. The corresponding fill factor is FF = 84.29%.