DEVELOPMENT OF HIGH EFFICIENCY NANOCRYSTALLINE DYE-SENSITISED/ Cu(In,Ga)Se_2 TANDEM SOLAR CELLS

摘要

The opto-electronic properties of Cu(In,Ga)Se_2 (CIGS) absorbers, especially the high photon absorption even at longer wavelengths ( > 900 nm) and the possibility to adapt the band gap of the semiconductor from 1.04 eV to 1.67 eV, makes them highly attractive candidates for the bottom cell in a tandem configuration. Different combinations like CuGaSe_2/CuInSe_2 or CdTe/CIGS have already been tried by different groups. In a novel approach we used nanocrystalline dye sensitized solar cells (DSC) as a top cell for the conversion of the high energy photons in wavelengths of 350 - 700 nm and applied a CIGS solar cell as the bottom cell for the remaining unabsorbed photons of wavelengths > 700 nm. The resulting tandem solar cell shows a conversion of 15.1 % under AM1.5 illumination and further potential for efficiency improvement.