Simultaneous observation of free and defect-bound excitons in CH3NH3PbI3 using four-wave mixing spectroscopy
| العنوان: | Simultaneous observation of free and defect-bound excitons in CH3NH3PbI3 using four-wave mixing spectroscopy |
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| المؤلفون: | Drew B. Riley, Daniel Webber, Kimberley C. Hall, Charlotte Clegg, Samuel A. March, Ian G. Hill |
| بيانات النشر: | arXiv, 2016. |
| سنة النشر: | 2016 |
| مصطلحات موضوعية: | Multidisciplinary, Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Exciton, Binding energy, FOS: Physical sciences, 02 engineering and technology, Electron, 010402 general chemistry, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Molecular physics, Crystallographic defect, Spectral line, 0104 chemical sciences, Four-wave mixing, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0210 nano-technology, Spectroscopy, Coherence (physics) |
| الوصف: | Solar cells incorporating organic-inorganic perovskite, which may be fabricated using low-cost solution-based processing, have witnessed a dramatic rise in efficiencies yet their fundamental photophysical properties are not well understood. The exciton binding energy, central to the charge collection process, has been the subject of considerable controversy due to subtleties in extracting it from conventional linear spectroscopy techniques due to strong broadening tied to disorder. Here we report the simultaneous observation of free and defect-bound excitons in CH3NH3PbI3 films using four-wave mixing (FWM) spectroscopy. Due to the high sensitivity of FWM to excitons, tied to their longer coherence decay times than unbound electron- hole pairs, we show that the exciton resonance energies can be directly observed from the nonlinear optical spectra. Our results indicate low-temperature binding energies of 13 meV (29 meV) for the free (defect-bound) exciton, with the 16 meV localization energy for excitons attributed to binding to point defects. Our findings shed light on the wide range of binding energies (2–55 meV) reported in recent years. |
| DOI: | 10.48550/arxiv.1608.02019 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ff4e0e79f0da0df0cc1b3f46f09b8a2b |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....ff4e0e79f0da0df0cc1b3f46f09b8a2b |
| قاعدة البيانات: | OpenAIRE |
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