Are hot charge transfer states the primary cause of efficient free-charge generation in polymer:fullerene organic photovoltaic devices? A kinetic Monte Carlo study

Jones, M.L.; Dyer, R.; Clarke, N.; Groves, C.

Abstract

Kinetic Monte Carlo simulations are used to examine the effect of high-energy, ‘hot’ delocalised charge transfer (HCT) states for donor:acceptor and mixed:aggregate blends, the latter relating to polymer:fullerene photovoltaic devices. Increased fullerene aggregation is shown to enhance charge generation and short-circuit device current – largely due to the increased production of HCT states at the aggregate interface. However, the instances where HCT states are predicted to give internal quantum efficiencies in the region of 50% do not correspond to HCT delocalisation or electron mobility measured in experiments. These data therefore suggest that HCT states are not the primary cause of high quantum efficiencies in some polymer:fullerene OPVs. Instead it is argued that HCT states are responsible for the fast charge generation seen in spectroscopy, but that regional variation in energy levels are the cause of long-term, efficient free-charge generation.

Citation

Jones, M., Dyer, R., Clarke, N., & Groves, C. (2014). Are hot charge transfer states the primary cause of efficient free-charge generation in polymer:fullerene organic photovoltaic devices? A kinetic Monte Carlo study. Physical Chemistry Chemical Physics, 16(38), 20310-20320. https://doi.org/10.1039/c4cp01626b

• Journal Article Type: Article
• Acceptance Date: May 29, 2014
• Online Publication Date: Jun 19, 2014
• Publication Date: Oct 14, 2014
• Deposit Date: Apr 17, 2014
• Publicly Available Date: Jul 23, 2014
• Journal: Physical Chemistry Chemical Physics
• Print ISSN: 1463-9076
• Electronic ISSN: 1463-9084
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 16
• Issue: 38
• Pages: 20310-20320
• DOI: https://doi.org/10.1039/c4cp01626b
• Public URL: https://durham-repository.worktribe.com/output/1434097