Luminescent Ethylene Vinyl Acetate Encapsulation Layers for Enhancing the Short Wavelength Spectral Response and Efficiency of Silicon Photovoltaic Modules

The inclusion of luminescent material in the ethylene vinyl acetate (EVA) encapsulation layer of multicrystalline silicon (mc-Si) photovoltaic modules offers a production-ready method for the improvement of their short-wavelength (lambda) spectral response and overall conversion efficiency. Several luminescent materials and mixtures thereof were evaluated for this purpose in an EVA matrix, including perylene and violanthrone dyes and a novel ligand-sensitised europium complex. The external quantum efficiency of mc-Si modules can be greatly improved in the region of 300 nm < lambda < 400 nm via luminescent down-shifting (LDS) of the incident light. In the best-case scenario, an increase in efficiency of 0.3% absolute is reported for a 59-cm(2) minimodule. The LDS technology cannot only be simply transferred to a standard production line with no added layers and/or manufacturing processes but can be used to color photovoltaic (PV) modules for architectural purposes as well.