Critical light instability in CB/DIO processed PBDTTT-EFT

• Verfasst von: Pearson, Andrew [VerfasserIn]
• Verfasst von: Hopkinson, Paul E. [VerfasserIn]
• Verfasst von: Couderc, Elsa [VerfasserIn]
• Verfasst von: Domanski, Konrad [VerfasserIn]
• Verfasst von: Abdi-Jalebi, Mojtaba [VerfasserIn]
• Verfasst von: Greenham, Neil C. [VerfasserIn]
• Titel: Critical light instability in CB/DIO processed PBDTTT-EFT
• Titelzusatz: PC71BM organic photovoltaic devices
• Verf.angabe: Andrew J. Pearson, Paul E. Hopkinson, Elsa Couderc, Konrad Domanski, Mojtaba Abdi-Jalebi, Neil C. Greenham
• E-Jahr: 2016
• Jahr: 8 January 2016
• Umfang: 12 S.
• Fussnoten: Gesehen am 18.06.2020 ; Im Titel ist 71 in "PC71BM" tiefgestellt ; Available online 8 January 2016
• Titel Quelle: Enthalten in: Organic electronics
• Ort Quelle: Amsterdam [u.a.] : Elsevier Science, 2000
• Jahr Quelle: 2016
• Band/Heft Quelle: 30(2016), Seite 225-236
• DOI: doi:10.1016/j.orgel.2015.12.024
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Instability
• Sach-SW: Lifetime
• Sach-SW: OPV
• Sach-SW: PBDTTT-EFT
• Sach-SW: PC71BM
• Sach-SW: Solar
• K10plus-PPN: 1701060809

Abstract

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.