Silver‐Alloyed Wide‐Bandgap (Ag,Cu)(In,Ga)S <sub>2</sub> Thin‐Film Solar Cells With 15.5% Efficiency
ABSTRACT Sulfide chalcopyrite Cu(In,Ga)S 2 (CIGS) is a wide‐bandgap semiconductor suitable for the top cell of a tandem solar device. Here, we demonstrate significant improvements in absorber quality by alloying with Ag to form (Ag,Cu)(In,Ga)S 2 (ACIGS) absorbers. We report the Ag alloying effect on compositional, structural, and optoelectronic properties of absorbers. We demonstrate suppressed bulk recombination and improved carrier lifetime in ACIGS, as a result of improved grain size, porosity reduction, and defect passivation. We also show that Ag alloying flattens the Ga gradient. Consideration of this impact of Ag will be necessary in future engineering of the Ga profile to maximize charge carrier collection and avoid interface recombination. Exploiting the beneficial effects of Ag alloying, we report a wide‐bandgap (1.58 eV) ACIGS solar cell with a high power conversion efficiency of 15.5% and a large open‐circuit voltage ( V OC ) of 948 mV, improving on the reference pure CIGS solar cell, with an 11.2% efficiency and an 821 mV V OC . Ag alloying is a useful route to further increase the efficiency of CIGS solar cells and future tandem devices.
Authors
- R. A. Oliver
- Andrea Griesi (ORCID: https://orcid.org/0000-0003-2173-5164)
- Kulwinder Kaur (ORCID: https://orcid.org/0000-0002-6509-2001)
- Gunnar Kusch (ORCID: https://orcid.org/0000-0003-2743-1022)
- Tobias Törndahl (ORCID: https://orcid.org/0000-0001-7757-5847)
- Wolfram Witte (ORCID: https://orcid.org/0000-0002-9429-506X)
- Adam Hultqvist (ORCID: https://orcid.org/0000-0002-2402-5427)
- Simon M. Fairclough (ORCID: https://orcid.org/0000-0003-3781-8212)
- Wolfram Hempel (ORCID: https://orcid.org/0000-0002-6589-0767)
- Yucheng Hu (ORCID: https://orcid.org/0009-0008-0888-0299)
- Michele Melchiorre (ORCID: https://orcid.org/0000-0003-0536-907X)
- Arivazhagan Valluvar Oli (ORCID: https://orcid.org/0000-0003-2821-6076)
- M. R. Pelling
- Giorgio Divitini
- Yurii P. Ivanov
- Ece Washbrook
- Susanne Siebentritt
Institutions
- Uppsala University (SE)
- University of Luxembourg (LU)
- University of Cambridge (GB)
- Italian Institute of Technology (IT)
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (DE)
- Luxembourg Institute of Science and Technology (LU)
Publication Details
- Journal
- Progress in Photovoltaics Research and Applications
- Published
- 2026-03-22
- DOI
- https://doi.org/10.1002/pip.70097
- Primary Topic
- Chalcogenide Semiconductor Thin Films
- Type
- article
- Field-Weighted Citation Impact
- 0.00