High Efficiency InxGa1-xN-Based Multi-Junction Photo Voltaic Cells with Concentrator

In_xGa_1-xN has been found to be very potential materials for the fabrication of high efficiency multi-junction (MJ) solar cells. The cost of MJ solar cells composing of III-V materials is higher than that of Si solar cells. To resolve the problem of cost is to employ concentrator systems, which concentrate sunlight with a lens, thereby increasing the intensity of sunlight striking the solar cells. A simulation model is developed which optimizes the design of MJ solar cells with concentrator for high efficiency. An efficiency of about 72.79% is achievable for eight junctions. Also the influence of temperature on efficiency is evaluated. The photocurrent density and open circuit voltage of each junction are calculated under AM 1.5 and it is assumed that each junction absorbs the solar photons that are not absorbed by the preceding one.