Ultrafast band-gap oscillations in iron pyrite
With its combination of favorable band gap, high absorption coefficient, material abundance, and low cost, iron pyrite, FeS[subscript 2], has received a great deal of attention over the past decades as a promising material for photovoltaic applications such as solar cells and photoelectrochemical ce...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2014
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| Online Access: | http://hdl.handle.net/1721.1/88761 https://orcid.org/0000-0002-9789-0403 https://orcid.org/0000-0002-4347-0139 |
| _version_ | 1811093397284323328 |
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| author | Kolb, Brian Kolpak, Alexie M. |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Kolb, Brian Kolpak, Alexie M. |
| author_sort | Kolb, Brian |
| collection | MIT |
| description | With its combination of favorable band gap, high absorption coefficient, material abundance, and low cost, iron pyrite, FeS[subscript 2], has received a great deal of attention over the past decades as a promising material for photovoltaic applications such as solar cells and photoelectrochemical cells. Devices made from pyrite, however, exhibit open circuit voltages significantly lower than predicted, and despite a recent resurgence of interest in the material, there currently exists no widely accepted explanation for this disappointing behavior. In this paper, we show that phonons, which have been largely overlooked in previous efforts, may play a significant role. Using fully self-consistent GW calculations, we demonstrate that a phonon mode related to the oscillation of the sulfur-sulfur bond distance in the pyrite structure is strongly coupled to the energy of the conduction-band minimum, leading to an ultrafast (≈100 fs) oscillation in the band gap. Depending on the coherency of the phonons, we predict that this effect can cause changes of up to ±0.3 eV relative to the accepted FeS[subscript 2] band gap at room temperature. Harnessing this effect via temperature or irradiation with infrared light could open up numerous possibilities for novel devices such as ultrafast switches and adaptive solar absorbers. |
| first_indexed | 2024-09-23T15:44:36Z |
| format | Article |
| id | mit-1721.1/88761 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:44:36Z |
| publishDate | 2014 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/887612022-10-02T03:48:05Z Ultrafast band-gap oscillations in iron pyrite Kolb, Brian Kolpak, Alexie M. Massachusetts Institute of Technology. Department of Mechanical Engineering Kolb, Brian Kolpak, Alexie M. With its combination of favorable band gap, high absorption coefficient, material abundance, and low cost, iron pyrite, FeS[subscript 2], has received a great deal of attention over the past decades as a promising material for photovoltaic applications such as solar cells and photoelectrochemical cells. Devices made from pyrite, however, exhibit open circuit voltages significantly lower than predicted, and despite a recent resurgence of interest in the material, there currently exists no widely accepted explanation for this disappointing behavior. In this paper, we show that phonons, which have been largely overlooked in previous efforts, may play a significant role. Using fully self-consistent GW calculations, we demonstrate that a phonon mode related to the oscillation of the sulfur-sulfur bond distance in the pyrite structure is strongly coupled to the energy of the conduction-band minimum, leading to an ultrafast (≈100 fs) oscillation in the band gap. Depending on the coherency of the phonons, we predict that this effect can cause changes of up to ±0.3 eV relative to the accepted FeS[subscript 2] band gap at room temperature. Harnessing this effect via temperature or irradiation with infrared light could open up numerous possibilities for novel devices such as ultrafast switches and adaptive solar absorbers. National Science Foundation (U.S.) (Grant OCI-1053575) United States. Advanced Research Projects Agency-Energy (Award DE-AR0000180) 2014-08-18T16:10:02Z 2014-08-18T16:10:02Z 2013-12 2013-10 Article http://purl.org/eprint/type/JournalArticle 1098-0121 1550-235X http://hdl.handle.net/1721.1/88761 Kolb, Brian, and Alexie Kolpak. “Ultrafast Band-Gap Oscillations in Iron Pyrite.” Phys. Rev. B 88, no. 23 (December 2013). © 2013 American Physical Society https://orcid.org/0000-0002-9789-0403 https://orcid.org/0000-0002-4347-0139 en_US http://dx.doi.org/10.1103/PhysRevB.88.235208 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society American Physical Society |
| spellingShingle | Kolb, Brian Kolpak, Alexie M. Ultrafast band-gap oscillations in iron pyrite |
| title | Ultrafast band-gap oscillations in iron pyrite |
| title_full | Ultrafast band-gap oscillations in iron pyrite |
| title_fullStr | Ultrafast band-gap oscillations in iron pyrite |
| title_full_unstemmed | Ultrafast band-gap oscillations in iron pyrite |
| title_short | Ultrafast band-gap oscillations in iron pyrite |
| title_sort | ultrafast band gap oscillations in iron pyrite |
| url | http://hdl.handle.net/1721.1/88761 https://orcid.org/0000-0002-9789-0403 https://orcid.org/0000-0002-4347-0139 |
| work_keys_str_mv | AT kolbbrian ultrafastbandgaposcillationsinironpyrite AT kolpakalexiem ultrafastbandgaposcillationsinironpyrite |