1. High V oc in (Cu,Ag)(In,Ga)Se2 Solar Cells
- Author
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Nina Shariati Nilsson, Tobias Jarmar, Olof Stolt, William N. Shafarman, Marika Edoff, Daniel Hogstrom, Olle Lundberg, Lars Stolt, and Erik Wallin
- Subjects
010302 applied physics ,Materials science ,Band gap ,Energy conversion efficiency ,Analytical chemistry ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Alkali metal ,01 natural sciences ,Copper ,Copper indium gallium selenide solar cells ,Electronic, Optical and Magnetic Materials ,chemistry ,0103 physical sciences ,Electrical and Electronic Engineering ,0210 nano-technology - Abstract
In this contribution, we show that silver substitution for copper in Cu(In,Ga)Se2 (CIGS) to form (Ag,Cu)(In,Ga)Se2 (ACIGS) leads to a reduction of the voltage loss expressed as Eg/q – V oc. This, in turn, leads to higher device efficiencies as compared to similar CIGS devices without Ag. We report $V_{{\rm{oc}}}$ at 814 mV at a conversion efficiency of 21% for our best ACIGS device with 20% of the group I element consisting of silver. Comparing ACIGS and CIGS devices with the same Ga/(Ga + In) ratio, the ACIGS devices exhibit about 0.05 eV higher bandgap. Alkali postdeposition treatment with KF leads to improvements in efficiency both for CIGS and ACIGS, but we find that the dose of KF needed for optimum device for ACIGS is 10–20% of the dose used for CIGS.
- Published
- 2017