Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit
Abstract Carrier multiplication (CM), multiexciton generation by absorbing a single photon, enables disruptive improvements in photovoltaic conversion efficiency. However, energy conservation constrains the threshold energy to at least twice bandgap (2Eg$ E_ ext{g}$). Here, a below threshold limit C...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Wiley
2022-11-01
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| Series: | Advanced Science |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/advs.202203400 |
| _version_ | 1811192799255592960 |
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| author | Yuxiang Liu Thomas Frauenheim ChiYung Yam |
| author_facet | Yuxiang Liu Thomas Frauenheim ChiYung Yam |
| author_sort | Yuxiang Liu |
| collection | DOAJ |
| description | Abstract Carrier multiplication (CM), multiexciton generation by absorbing a single photon, enables disruptive improvements in photovoltaic conversion efficiency. However, energy conservation constrains the threshold energy to at least twice bandgap (2Eg$ E_ ext{g}$). Here, a below threshold limit CM in monolayer transition metal dichalcogenides (TMDCs) is reported. Surprisingly, CM is observed with excitation energy of only 1.75 Eg$E_ ext{g}$ due to lattice vibrations. Electron–phonon coupling (EPC) results in significant changes in electronic structures, which favors CM. Indeed, the strongest EPC in monolayer MoS2 leads to the most efficient CM among the studied TMDCs. For practical applications, chalcogen vacancies can further lower the threshold by introducing defect states within bandgap. In particular, for monolayer WS2, CM occurs with excitation energy as low as 1.51 Eg$E_ ext{g}$. The results identify TMDCs as attractive candidate materials for efficient optoelectronic devices with the advantages of high photoconductivity and efficient CM. |
| first_indexed | 2024-04-11T23:57:33Z |
| format | Article |
| id | doaj.art-7a92b0f35d1a4f51b64e508419213363 |
| institution | Directory Open Access Journal |
| issn | 2198-3844 |
| language | English |
| last_indexed | 2024-04-11T23:57:33Z |
| publishDate | 2022-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advanced Science |
| spelling | doaj.art-7a92b0f35d1a4f51b64e5084192133632022-12-22T03:56:19ZengWileyAdvanced Science2198-38442022-11-01931n/an/a10.1002/advs.202203400Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold LimitYuxiang Liu0Thomas Frauenheim1ChiYung Yam2Bremen Center for Computational Materials Science University of Bremen Am Fallturm 1 28359 Bremen GermanyBremen Center for Computational Materials Science University of Bremen Am Fallturm 1 28359 Bremen GermanyShenzhen Institute for Advanced Study University of Electronic Science and Technology of China Shenzhen 518000 ChinaAbstract Carrier multiplication (CM), multiexciton generation by absorbing a single photon, enables disruptive improvements in photovoltaic conversion efficiency. However, energy conservation constrains the threshold energy to at least twice bandgap (2Eg$ E_ ext{g}$). Here, a below threshold limit CM in monolayer transition metal dichalcogenides (TMDCs) is reported. Surprisingly, CM is observed with excitation energy of only 1.75 Eg$E_ ext{g}$ due to lattice vibrations. Electron–phonon coupling (EPC) results in significant changes in electronic structures, which favors CM. Indeed, the strongest EPC in monolayer MoS2 leads to the most efficient CM among the studied TMDCs. For practical applications, chalcogen vacancies can further lower the threshold by introducing defect states within bandgap. In particular, for monolayer WS2, CM occurs with excitation energy as low as 1.51 Eg$E_ ext{g}$. The results identify TMDCs as attractive candidate materials for efficient optoelectronic devices with the advantages of high photoconductivity and efficient CM.https://doi.org/10.1002/advs.2022034002D materialscarrier multiplicationchalcogen vacancynon‐adiabatic molecular dynamicstime‐dependent density‐functional theory |
| spellingShingle | Yuxiang Liu Thomas Frauenheim ChiYung Yam Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit Advanced Science 2D materials carrier multiplication chalcogen vacancy non‐adiabatic molecular dynamics time‐dependent density‐functional theory |
| title | Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit |
| title_full | Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit |
| title_fullStr | Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit |
| title_full_unstemmed | Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit |
| title_short | Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit |
| title_sort | carrier multiplication in transition metal dichalcogenides beyond threshold limit |
| topic | 2D materials carrier multiplication chalcogen vacancy non‐adiabatic molecular dynamics time‐dependent density‐functional theory |
| url | https://doi.org/10.1002/advs.202203400 |
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