A Comparison of the Optoelectronic Properties of High-Efficiency Polycrystalline and Epitaxial Cu(In,Ga)Se2 Photovoltaic Films

Conference · Tue Mar 03 04:00:00 EST 2020

DOI:https://doi.org/10.1117/12.2544950· OSTI ID:1669408

Guthrey, Harvey; Norman, Andrew; Nishinaga, Jiro; Shibata, Hajime; Al-Jassim, Mowafak; Ishizuka, Shogo

Over the last several decades, champion photovoltaic (PV) devices using CuInGaSe2 (CIGS) as the absorber material have been achieved using polycrystalline films exclusively. This has led to the assumption that polycrystalline CIGS generally outperform single-crystal CIGS in PV devices. However, recently, very high-quality epitaxial CIGS has been grown on GaAs substrates producing PV device efficiencies of 20.0%. These results have revived the debate on what effects grain boundaries have on PV device efficiencies. In this contribution, we compare the optoelectronic properties of polycrystalline CIGS films with those of high-efficiency epitaxial CIGS films. This comparison reveals that grain boundaries are associated with properties that negatively impact PV device efficiency. Additionally, we find that the grain interiors in polycrystalline films exhibit properties that are similar to the high-performance epitaxial films. Our results suggest that it may be possible to achieve higher device efficiencies with epitaxial CIGS than with polycrystalline films.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1669408
• Report Number(s): NREL/CP-5K00-75781; MainId:6776; UUID:b1e2391f-3a32-ea11-9c2f-ac162d87dfe5; MainAdminID:13502
• Country of Publication: United States
• Language: English

Related Subjects

41 EE - Solar Energy Technologies Office (EE-4S)
cathodoluminescence
epitaxial CIGS
recombination