Title | Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations |
Publication Type | Journal Article |
Year of Publication | 2018 |
Authors | Varley J.B, Lordi V., Ogitsu T., Deangelis A., Horsley K., Gaillard N. |
Journal | Journal of Applied Physics |
Volume | 123 |
Issue | 16 |
Pagination | 161408 |
ISSN | 0021-8979 |
Abstract | Publshed on March 7th, 2018. Understanding the impact of impurities in solar absorbers is critical to engineering high-performance in devices, particularly over extended periods of time. Here, we use hybrid functional calculations to explore the role of hydrogen interstitial (Hi) defects in the electronic properties of a number of attractive solar absorbers within the chalcopyrite and kesterite families to identify how this common impurity may influence device performance. Our results identify that Hi can inhibit the highly p-type conditions desirable for several higher-band gap absorbers and that H incorporation could detrimentally affect the open-circuit voltage (Voc) and limit device efficiencies. Additionally, we find that Hi can drive the Fermi level away from the valence band edge enough to lead to n-type conductivity in a number of chalcopyrite and kesterite absorbers, particularly those containing Ag rather than Cu. We find that these effects can lead to interfacial Fermi-level pinning that can qualitatively explain the observed performance in high-Ga content CIGSe solar cells that exhibit saturation in the Voc with increasing band gap. Our results suggest that compositional grading rather than bulk alloying, such as by creating In-rich surfaces, may be a better strategy to favorably engineering improved thin-film photovoltaics with larger-band gap absorbers. |
Notes | 'doi: 10.1021/acsenergylett.0c01132\n - I.Am.Hydrogen' '\n - jyoungstrom' 'Jason thinks this is great.\n \n - jyoungstrom' '\n - estechel' |
URL | https://aip.scitation.org/doi/10.1063/1.5006272 |
DOI | 10.1063/1.5006272 |
Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations
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