Impurity photovoltaic effect with defect relaxation: Implications for low band gap semiconductors such as silicon

摘要: The impurity photovoltaic solar cell can, in principle, increase the sunlight to electricity conversion efficiency of a conventional single junction by introduction optically active impurities or defects into device. These “defects” ideally allow electrons be excited from valence band conduction via mid-gap defect level through absorption previously wasted sub-band-gap photons. In this work maximum limits for such device are calculated special case where energy partly electron relaxes lower two-stage excitation process. This relaxation when occupying state is shown give an improvement over no occurs. silicon, limit 39.7% under airmass 1.5G spectrum obtained, compared 33.0% present and 30.5% but relaxatio...