Interplay between Localized and Free Charge Carriers Can Explain Hot Fluorescence in the CHNHPbBr Perovskite: Time-Domain Ab Initio Analysis.
Delayed high-energy fluorescence observed experimentally in methylammonium lead bromine CHNHPbBr (MAPbBr) demonstrates long-lived energetic charge carriers with extremely high mobilities that can be used to enhance photon-to-electron conversion efficiency of perovskite solar cells. It has been sugge...
| Publicado en: | Journal of the American Chemical Society Vol. 139; no. 48; pp. 17327 - 17334 |
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| Autores principales: | , , , |
| Formato: | Artículo |
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American Chemical Society
12/6/2017
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=126761781&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 126761781 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 12/6/2017 vid: 139 iid: 48 pid: 997 pub: American Chemical Society artinfo: ui: 126761781 10.1021/jacs.7b06401 ppf: 17327 ppct: 7 formats: tig: atl: Interplay between Localized and Free Charge Carriers Can Explain Hot Fluorescence in the CHNHPbBr Perovskite: Time-Domain Ab Initio Analysis. aug: au: Zhaosheng Zhang Long, Run Tokina, Marina V. Prezhdo, Oleg V. affil: College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, PR China Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States su: Charge carriers Quantum theory Methylammonium Time-dependent density functional theory Perovskite sug: subj: Charge carriers Quantum theory Methylammonium Time-dependent density functional theory Perovskite ab: Delayed high-energy fluorescence observed experimentally in methylammonium lead bromine CHNHPbBr (MAPbBr) demonstrates long-lived energetic charge carriers with extremely high mobilities that can be used to enhance photon-to-electron conversion efficiency of perovskite solar cells. It has been suggested that hot fluorescence is associated with reorientational motions of the MA molecules. We support this hypothesis by time-domain ab initio quantum dynamics calculations showing that reorientation of the MA molecules can affect strongly the perovskite emission energy and lifetime. We demonstrate MAPbBr structures differing in the MA orientations and exhibiting the same emission properties as in the experiments. The higher bandgap structures responsible for hot fluorescence support delocalized wave functions that can be interpreted as free charge carriers. The lower energy structures exhibit localized polaron-like electrons and holes, and a significantly longer electron-hole recombination time, in agreement with experiment. The fluorescence lifetimes differ owing to variation in the nonadiabatic coupling between the emitting and ground states, stemming from charge carrier localization. Loss of coherence due to elastic electron-phonon scattering is similar in the two cases. The simulations provide a detailed atomistic understanding of excited-state dynamics in MAPbBr and show how structural transformations can rationalize the experimentally reported hot fluorescence in MAPbBr. Other localized structures involving inorganic lattice distortions, defects, domain boundaries, ion diffusion, electric ordering, etc., can be invoked with the proposed two-emitter interpretation of hot and regular luminescence. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2017 holdings: @attributes: islocal: N |
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