Opportunities for breaking an energy generation limit of photovoltaic using multijunction and super-multijunction cells

This paper discusses the potential of the power conversion efficiency of solar cells from various materials considering external radiative efficiency, open-circuit voltage loss. The possibility of the power conversion efficiency is summarized in the 1st chapter. The examined cells are Silicon, III-V, CIS, CdTe, Organic, Dye-sensitized and Perovskite. The 2nd and successive chapters discuss the potential of the multijunction cells. The power conversion efficiency can be raised by using multi-junction structure. However, fluctuation of the atmospheric parameters substantially impacts the energy yield. The calculation considering the variation of atmospheric parameters showed a dramatic decline of the annual energy yield from the cells with more than five junctions. Super-multijunction solar cells were proposed, and optimization work was done. The top and the bottom junctions have lower bandgap for buffering to the mismatching and collecting a full range of the sunlight by robust energy conversion, and the annual energy substantially increases even by five or six junctions.