Thin heterojunction a-Si:H photovoltaic cell design with no doped a-Si:H layers

Thin heterojunction a-Si:H photovoltaic cell structures that eliminate the use of the p- and n-doped a-Si:H layers of the conventional single junction p-i-n a-Si:H photovoltaic cell design are investigated. In each of these cell structures, a 100 nm thick intrinsic a-Si:H layer is used as the absorption layer. The cell with the structure of glass / ITO / MoO₃ / intrinsic a-Si:H / LiF / Al has the best efficiency at 6.30% and the cell with the structure of glass / ITO / PEDOT:PSS / Cu₂O / intrinsic a-Si:H / LiF / Al has the highest short circuit density at 16.01 mA/cm²; all measured under AM1.5 test conditions. These thin a-Si:H cell designs have the potential to significantly reduce or eliminate the effects of light degradation of the cells while retaining similar level of efficiency of a conventional single junction p-i-n a-Si:H photovoltaic cell with 200 - 400 nm thick intrinsic layer. They also reduce the use of silane and the bulk gasses used during cell processing. Furthermore, these thin heterojunction cell designs eliminate the need to use the costly, complex multi-chamber amorphous silicon deposition systems and the toxic dopant gases for a-Si:H; therefore making the cell manufacturing process safer and potentially cheaper.