Polycrystalline silicon heterojunction thin-film solar cells on glass exhibiting 582 mV open-circuit voltage

Abstract

In this paper we present silicon heterojunction solar cells based on polycrystalline silicon (poly-Si) prepared by electron-beam induced liquid phase crystallisation. A single sided contact system has been developed to tap the full potential of the heterojunction concept. Open-circuit voltages as high as 582mV demonstrate the high potential of poly-Si absorber material. This is supported by a high pseudo fill factor of 80.5% as determined by Suns-VOCmeasurements. The still moderate best efficiency of 5.7% can be attributed to ohmic losses due to a broken front contact grid and to short circuit current densities not exceeding 16mAcm−2. The latter are largely explained by the missing light-trapping scheme and by recombination losses in the absorber or at the burried SiC/Si interface. The results demonstrate that open-circuit voltages above 600mV are in reach for poly-Si thin-film solar cells on glass, opening up exciting perspectives towards high efficiencies for a new type of potentially low cost silicon based thin-film solar cells.