Efficiency Enhancement of Solar Cells by Application of a Polymer Coating Containing a Luminescent Dye

One of the major loss mechanisms in state of the art photovoltaic cells is spectral loss resulting from inefficient use of ultraviolet photons and the lack of absorption of infrared photons by the solar cell. For a Si solar cell, e.g., spectral losses alone result in over 55% loss of the energy of the solar spectrum. Converting the spectrum of the incoming light such that it has a better match with the absorption spectrum of the solar cell can reduce spectral losses, especially in the case of a small absorption band, such as for dye sensitized solar cells and polymer solar cells. In this paper it is shown that the ultraviolet response of a multicrystalline silicon solar cell and polymer solar cell can be enhanced by application of a polymer coating doped with a luminescent dye. An increase in the power conversion efficiency is obtained for coatings with luminescent dyes with an absorption onset <450 nm. Coatings with luminescent dyes that absorb at higher wavelengths give rise to lower power conversion efficiencies. When applied to a dye sensitized solar cell, a decrease in the cell performance is observed.