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Multistep Photoluminescence Decay Reveals Dissociation of Geminate Charge Pairs in Organolead Trihalide Perovskites
Author(s) -
Augulis Ramūnas,
Franckevičius Marius,
Abramavičius Vytautas,
Abramavičius Darius,
Zakeeruddin Shaik Mohammed,
Grätzel Michael,
Gulbinas Vidmantas
Publication year - 2017
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201700405
Subject(s) - photoluminescence , photoexcitation , dissociation (chemistry) , materials science , charge carrier , exciton , chemical physics , recombination , molecular physics , excitation , trihalide , atomic physics , chemistry , optoelectronics , excited state , physics , condensed matter physics , inorganic chemistry , biochemistry , quantum mechanics , gene , halide
Charge carrier dynamics in organolead iodide perovskites is analyzed by employing time‐resolved photoluminescence spectroscopy with several ps time resolution. The measurements performed by varying photoexcitation intensity over five orders of magnitude enable separation of photoluminescence components related to geminate and nongeminate charge carrier recombination and to address the dynamics of an isolated geminate electron–hole pair. Geminate recombination dominates at low excitation fluence and determines the initial photoluminescence decay. This decay component is remarkably independent of the material structure and experimental conditions. It is demonstrated that dependences of the geminate and nongeminate radiative recombination components on excitation intensity, repetition rate, and temperature, are hardly compatible with carrier trapping and exciton dissociation models. On the basis of semiclassical and quantum mechanical numerical calculation results, it is argued that the fast photoluminescence decay originates from gradual spatial separation of photogenerated weakly bound geminate charge pairs.