Very Thin (56 μm) Silicon Heterojunction Solar Cells with an Efficiency of 23.3% and an Open-Circuit Voltage of 754 mV

摘要

The silicon heterojunction (SHJ) is a crystalline silicon (c-Si) solar cell devicearchitecture capable of achieving high efficiencies due to excellent surfacepassivation realized by hydrogenated amorphous silicon (a-Si:H) thin layers. TheSHJ architecture also allows to process thinner Si wafers due to the structuralsymmetry and the low processing temperature. Herein, an attempt to increasethe performance of very thin c-Si solar cells is made, using an advanced SHJarchitecture. By replacing the conventional a-Si:H by hydrogenated nanocrystallinesilicon (nc-Si:H) in the hole contact layer, an increase in all solar cellparameters over a wide range of wafer thicknesses from 50 to 400 μm isobserved. This also provides an open-circuit voltage (V_(OC)) of 754 mV with thevery thin absorber, which is the highest V_(OC) independently confirmed understandard test conditions (STCs) among any c-Si solar cells ever reported. As aresult, a notable efficiency of 23.27% is realized in a SHJ cell with an averagethickness of only 56.2 μm. These results demonstrate the high potential of verythin c-Si solar cells that may open various opportunities for flexible and lightweightc-Si modules, as well as reducing the carbon footprint of solar cellmanufacture.