ABSTRACT
The highest theoretical efficiency of double junction solar cells is predicted for architectures with the bottom cell bandgap (E g ) of approximately 0.9-1.0 eV, which is lower than that of a typical Si cell (1.1 eV). Cu(In,Ga)(Se,S)2 (CIGS) solar cells exhibit a tunable E g depending on their elemental composition and depth profile. In this study, various CIGS solar cells with E g ranging from 1.02 to 1.14 eV are prepared and a spectrum splitting system is used to experimentally demonstrate the effect of using lower-E g cells as the bottom cell of two-junction solar cells. The four-terminal tandem cell configuration fabricated using a mixed-halide perovskite top cell (E g = 1.59 eV; stand-alone efficiency = 21.0%) and CIGS bottom cell (E g = 1.02 eV; stand-alone efficiency = 21.5%) with a 775-nm spectral splitting mirror exhibits an efficiency of 28.0% at the aperture area of 1 cm2.
ABSTRACT
Dye-sensitized photoelectrochemical cells (DSPECs) composed of a new near-infrared BODIPY dye D1 that is co-deposited with a ruthenium water oxidation catalyst C1 have been fabricated. The devices at pH 7.2 showed an excellent Faradaic efficiency of H2 production (65.8%) that was 5.4 times larger than that of a triphenylamine photosensitizer D2 and C1-coadsorbed cell.
