Application of rare-earth complexes for photovoltaic precursors

By applying rare-earth complexes as photovoltaic precursors, the conversion efficiency of solar cells were improved. Rare-earth complexes absorb light al shorter wavelengths and subsequently emit light at longer wavelengths. The high-energy region of the solar spectrum is shifted to longer wavelengths, hence the cell-output power is higher because the emitted light matches with a higher sensitivity region of the basic Si solar cell. For a CaF2:Eu single crystal placed on top of an a-Si solar cell experiments showed a maximum relative conversion efficiency of 1.5. Eu ions in CaF2-SrF2 mixed crystals, whose emission is even more red-shifted compared with CaF2 crystals, showed slight improvements. The ion implantation of rare-earth ions into CaF2 evaluated potential application for antireflection (AR) coatings, Furthermore, porous glass doped with Eu-chelete complexes have been investigated.