Critical light instability in CB/DIO processed PBDTTT-EFT: PC71BM organic photovoltaic devices
Organic photovoltaic (OPV) devices often undergo ‘burn-in’ during the early stages of operation, this period describing the relatively rapid drop in power output before stabilising. For normal and inverted PBDTTT-EFT:PC71BM OPVs prepared according to current protocols, we identify a critical and sev...
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| Hauptverfasser: | , , , , , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
8 January 2016
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| In: |
Organic electronics
Year: 2016, Jahrgang: 30, Pages: 225-236 |
| DOI: | 10.1016/j.orgel.2015.12.024 |
| Online-Zugang: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.orgel.2015.12.024 Verlag, lizenzpflichtig, Volltext: http://www.sciencedirect.com/science/article/pii/S1566119915302445 
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| Verfasserangaben: | Andrew J. Pearson, Paul E. Hopkinson, Elsa Couderc, Konrad Domanski, Mojtaba Abdi-Jalebi, Neil C. Greenham |
| Zusammenfassung: | Organic photovoltaic (OPV) devices often undergo ‘burn-in’ during the early stages of operation, this period describing the relatively rapid drop in power output before stabilising. For normal and inverted PBDTTT-EFT:PC71BM OPVs prepared according to current protocols, we identify a critical and severe light-induced burn-in phase that reduces power conversion efficiency by at least 60% after 24 hours simulated AM1.5 illumination. Such losses result primarily from a reduction in photocurrent, and for inverted devices we correlate this process in-situ with the simultaneous emergence of space-chare effects on the μs timescale. The effects of burn in are also found to reduce the lifetime of photogenerated charge carriers, as determine by in-situ transient photovoltage measurements. To identify the underlying mechanisms of this instability, a range of techniques are employed ex-situ to separate bulk- and electrode-specific degradation processes. We find that whilst the active layer nanostructure and kinetics of free charge generation remain unchanged, partial photobleaching (6% of film O.D.) of PBDTTT-EFT:PC71BM occurs alongside an increase in the ground state bleach decay time of PBDTTT-EFT. We hypothesise that this latter observation may reflect relaxation from excited states on PBDTTT-EFT that do not undergo dissociation into free charges. Owing to the poor lifetime of the reference PBDTTT-EFT:PC71BM OPVs, the fabrication protocol is modified to identify routes for stability enhancement in this initially promising solar cell blend. |
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| Beschreibung: | Gesehen am 18.06.2020 Im Titel ist 71 in "PC71BM" tiefgestellt Available online 8 January 2016 |
| Beschreibung: | Online Resource |
| DOI: | 10.1016/j.orgel.2015.12.024 |