EFFICIENCY SIMULATION OF AN n-p-n-p SILICON MULTILAYER SOLAR CELL

摘要

Our investigation is centred on a model of silicon multilayer solar cell, composed by four layers of opposite conductivities n-p-n-p connected together forming three junctions inside the cell. The electric contacts are tailored vertically in such way that they collect the generated minority carriers separately. The thicknesses of each layer of the simulated model used in this numerical study were optimized in a previous work, giving the maximum photocurrent generated under AM0 solar spectrum. In this work, we simulate the I-V characteristic of the model for a different level of the impurity concentration varying between 10~(15) and 10~(19) cm~(-3).We used MatLab software to simulate, under AMO solar spectrum, the output power, the fill factor and the efficiency of the model taking into account the series resistance of the layers and assuming 100 cm/s surface recombination velocity. We showed that the maximum efficiency were obtained for an impurity concentration of 10~(18) cm~(-3) giving an efficiency of 20.64% and an output power of 28.1 mW/cm~2, which represent the maximum theoretical value of the power generated by an n-p-n-p silicon multilayer solar cell. The efficiency of the cell using an impurity concentration of 10~(19) cm~(-3) is only about 13%.