Reversible electron–hole separation in a hot carrier solar cell
Hot-carrier solar cells are envisioned to utilize energy filtering to extract power from photogenerated electron–hole pairs before they thermalize with the lattice, and thus potentially offer higher power conversion efficiency compared to conventional, single absorber solar cells. The efficiency of...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2015-01-01
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| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/17/9/095004 |
| _version_ | 1797751071304581120 |
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| author | S Limpert S Bremner H Linke |
| author_facet | S Limpert S Bremner H Linke |
| author_sort | S Limpert |
| collection | DOAJ |
| description | Hot-carrier solar cells are envisioned to utilize energy filtering to extract power from photogenerated electron–hole pairs before they thermalize with the lattice, and thus potentially offer higher power conversion efficiency compared to conventional, single absorber solar cells. The efficiency of hot-carrier solar cells can be expected to strongly depend on the details of the energy filtering process, a relationship which to date has not been satisfactorily explored. Here, we establish the conditions under which electron–hole separation in hot-carrier solar cells can occur reversibly, that is, at maximum energy conversion efficiency. We thus focus our analysis on the internal operation of the hot-carrier solar cell itself, and in this work do not consider the photon-mediated coupling to the Sun. After deriving an expression for the voltage of a hot-carrier solar cell valid under conditions of both reversible and irreversible electrical operation, we identify separate contributions to the voltage from the thermoelectric effect and the photovoltaic effect. We find that, under specific conditions, the energy conversion efficiency of a hot-carrier solar cell can exceed the Carnot limit set by the intra-device temperature gradient alone, due to the additional contribution of the quasi-Fermi level splitting in the absorber. We also establish that the open-circuit voltage of a hot-carrier solar cell is not limited by the band gap of the absorber, due to the additional thermoelectric contribution to the voltage. Additionally, we find that a hot-carrier solar cell can be operated in reverse as a thermally driven solid-state light emitter. Our results help explore the fundamental limitations of hot-carrier solar cells, and provide a first step towards providing experimentalists with a guide to the optimal configuration of devices. |
| first_indexed | 2024-03-12T16:42:55Z |
| format | Article |
| id | doaj.art-d12b213286254b67a079f868f84f638b |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:42:55Z |
| publishDate | 2015-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-d12b213286254b67a079f868f84f638b2023-08-08T14:23:38ZengIOP PublishingNew Journal of Physics1367-26302015-01-0117909500410.1088/1367-2630/17/9/095004Reversible electron–hole separation in a hot carrier solar cellS Limpert0S Bremner1H Linke2School of Photovoltaic and Renewable Energy Engineering, University of New South Wales , 2052 Sydney, AustraliaSchool of Photovoltaic and Renewable Energy Engineering, University of New South Wales , 2052 Sydney, AustraliaNanoLund and Solid State Physics, Lund University , Box 118, SE-22100 Lund, SwedenHot-carrier solar cells are envisioned to utilize energy filtering to extract power from photogenerated electron–hole pairs before they thermalize with the lattice, and thus potentially offer higher power conversion efficiency compared to conventional, single absorber solar cells. The efficiency of hot-carrier solar cells can be expected to strongly depend on the details of the energy filtering process, a relationship which to date has not been satisfactorily explored. Here, we establish the conditions under which electron–hole separation in hot-carrier solar cells can occur reversibly, that is, at maximum energy conversion efficiency. We thus focus our analysis on the internal operation of the hot-carrier solar cell itself, and in this work do not consider the photon-mediated coupling to the Sun. After deriving an expression for the voltage of a hot-carrier solar cell valid under conditions of both reversible and irreversible electrical operation, we identify separate contributions to the voltage from the thermoelectric effect and the photovoltaic effect. We find that, under specific conditions, the energy conversion efficiency of a hot-carrier solar cell can exceed the Carnot limit set by the intra-device temperature gradient alone, due to the additional contribution of the quasi-Fermi level splitting in the absorber. We also establish that the open-circuit voltage of a hot-carrier solar cell is not limited by the band gap of the absorber, due to the additional thermoelectric contribution to the voltage. Additionally, we find that a hot-carrier solar cell can be operated in reverse as a thermally driven solid-state light emitter. Our results help explore the fundamental limitations of hot-carrier solar cells, and provide a first step towards providing experimentalists with a guide to the optimal configuration of devices.https://doi.org/10.1088/1367-2630/17/9/095004quantum thermodynamicshot carrier solar cellsefficiencyentropy productionphotovoltaicsthermoelectrics |
| spellingShingle | S Limpert S Bremner H Linke Reversible electron–hole separation in a hot carrier solar cell New Journal of Physics quantum thermodynamics hot carrier solar cells efficiency entropy production photovoltaics thermoelectrics |
| title | Reversible electron–hole separation in a hot carrier solar cell |
| title_full | Reversible electron–hole separation in a hot carrier solar cell |
| title_fullStr | Reversible electron–hole separation in a hot carrier solar cell |
| title_full_unstemmed | Reversible electron–hole separation in a hot carrier solar cell |
| title_short | Reversible electron–hole separation in a hot carrier solar cell |
| title_sort | reversible electron hole separation in a hot carrier solar cell |
| topic | quantum thermodynamics hot carrier solar cells efficiency entropy production photovoltaics thermoelectrics |
| url | https://doi.org/10.1088/1367-2630/17/9/095004 |
| work_keys_str_mv | AT slimpert reversibleelectronholeseparationinahotcarriersolarcell AT sbremner reversibleelectronholeseparationinahotcarriersolarcell AT hlinke reversibleelectronholeseparationinahotcarriersolarcell |