Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite
Cs2AgBiBr6 is a promising metal halide double perovskite offering the possibility of efficient photovoltaic devices based on lead-free materials. Here, we report on the evolution of photoexcited charge carriers in Cs2AgBiBr6 using a combination of temperature-dependent photoluminescence, absorption...
| Autori principali: | , , , , , , |
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| Natura: | Journal article |
| Lingua: | English |
| Pubblicazione: |
American Chemical Society
2021
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| _version_ | 1826266027456987136 |
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| author | Wright, AD Buizza, LRV Savill, KJ Longo, G Snaith, HJ Johnston, MB Herz, LM |
| author_facet | Wright, AD Buizza, LRV Savill, KJ Longo, G Snaith, HJ Johnston, MB Herz, LM |
| author_sort | Wright, AD |
| collection | OXFORD |
| description | Cs2AgBiBr6 is a promising metal halide double perovskite offering the possibility of efficient photovoltaic devices based on lead-free materials. Here, we report on the evolution of photoexcited charge carriers in Cs2AgBiBr6 using a combination of temperature-dependent photoluminescence, absorption and optical pump–terahertz probe spectroscopy. We observe rapid decays in terahertz photoconductivity transients that reveal an ultrafast, barrier-free localization of free carriers on the time scale of 1.0 ps to an intrinsic small polaronic state. While the initially photogenerated delocalized charge carriers show bandlike transport, the self-trapped, small polaronic state exhibits temperature-activated mobilities, allowing the mobilities of both to still exceed 1 cm2 V–1 s–1 at room temperature. Self-trapped charge carriers subsequently diffuse to color centers, causing broad emission that is strongly red-shifted from a direct band edge whose band gap and associated exciton binding energy shrink with increasing temperature in a correlated manner. Overall, our observations suggest that strong electron–phonon coupling in this material induces rapid charge-carrier localization. |
| first_indexed | 2024-03-06T20:32:41Z |
| format | Journal article |
| id | oxford-uuid:3195869b-2a4d-482f-98b1-1369b0c51ef8 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T20:32:41Z |
| publishDate | 2021 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:3195869b-2a4d-482f-98b1-1369b0c51ef82022-03-26T13:08:54ZUltrafast excited-state localization in Cs2AgBiBr6 double perovskiteJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:3195869b-2a4d-482f-98b1-1369b0c51ef8EnglishSymplectic ElementsAmerican Chemical Society2021Wright, ADBuizza, LRVSavill, KJLongo, GSnaith, HJJohnston, MBHerz, LMCs2AgBiBr6 is a promising metal halide double perovskite offering the possibility of efficient photovoltaic devices based on lead-free materials. Here, we report on the evolution of photoexcited charge carriers in Cs2AgBiBr6 using a combination of temperature-dependent photoluminescence, absorption and optical pump–terahertz probe spectroscopy. We observe rapid decays in terahertz photoconductivity transients that reveal an ultrafast, barrier-free localization of free carriers on the time scale of 1.0 ps to an intrinsic small polaronic state. While the initially photogenerated delocalized charge carriers show bandlike transport, the self-trapped, small polaronic state exhibits temperature-activated mobilities, allowing the mobilities of both to still exceed 1 cm2 V–1 s–1 at room temperature. Self-trapped charge carriers subsequently diffuse to color centers, causing broad emission that is strongly red-shifted from a direct band edge whose band gap and associated exciton binding energy shrink with increasing temperature in a correlated manner. Overall, our observations suggest that strong electron–phonon coupling in this material induces rapid charge-carrier localization. |
| spellingShingle | Wright, AD Buizza, LRV Savill, KJ Longo, G Snaith, HJ Johnston, MB Herz, LM Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite |
| title | Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite |
| title_full | Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite |
| title_fullStr | Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite |
| title_full_unstemmed | Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite |
| title_short | Ultrafast excited-state localization in Cs2AgBiBr6 double perovskite |
| title_sort | ultrafast excited state localization in cs2agbibr6 double perovskite |
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