Extending the spectral conversion of photovoltaic solar cells

The efficient harvesting of solar energy in low-cost manufactured devices is a key tool for implementing the energy transition from fossils to renewables. A major problem limiting the conversion efficiency of PV cells is their insensitivity to the full solar spectrum, with current PV cells only utilizing a relatively small fraction of the overall solar flux. Down-shifting (DS) systems represent a possible strategy to improve the features of PV cells by converting UV radiation into longer wavelength radiation, more efficiently absorbed and converted into current.1,2 Among the various DS materials, organo-lanthanide complexes stand out for their excellent optoelectronic properties, such as high photoluminescence intensity with high monochromaticity. Here, we present the synthesis and the preliminary photophysical study of a series of lanthanide (III) b–diketonate complexes where Ln= Eu and Tb, with or without polypyridine ancillary ligand.