Thinning CIGSe absorber layer to less than 500 nm is desirable for reducing the cost per unit watt of photovoltaic-generated electricity, and also, the semitransparent solar cell based on such… Click to show full abstract
Thinning CIGSe absorber layer to less than 500 nm is desirable for reducing the cost per unit watt of photovoltaic-generated electricity, and also, the semitransparent solar cell based on such a thin absorber can be used in bifacial and superstrate configurations if the back electrode is transparent. In this study, a WO x layer is inserted between Cu(In,Ga)Se2 (CIGSe) absorber and tin-doped indium oxide back-contact to enhance the hole collection at the back electrode. A WO x interlayer with a thickness of 6 nm is found to be optimum because it causes a ∼38% relative increase in the fill factor of a ∼450 nm thick CIGSe-based device compared to the reference device without a WO x interlayer. While fixing the thickness of CIGSe, increasing the WO x interlayer thickness to ≥6 nm results in decreases of solar cell parameters primarily because of the emergence of a GaO x interfacial layer at the CIGSe/WO x junction.
               
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