Highly efficient charge transfer in nanocrystalline Si:H solar cells

We demonstrate that in nanostructured films of nanocrystalline silicon imbedded in a hydrogenated amorphous silicon matrix, carriers generated in the amorphous region are transported out of this region and therefore do not recombine in the amorphous phase. Electron paramagnetic resonance (EPR) and photoluminescence (PL) measurements show that the EPR and PL from the amorphous phase are rapidly quenched as the volume fraction of Si nanocrystals exceeds about 30 vol. %. We propose the use of similar structures to dramatically increase the open circuit voltages in solar cell devices.