Correlation of diffusion and performance in sequentially processed P3HT/PCBM heterojunction films by time-resolved neutron reflectometry

Lee, Kwan H., Zhang, Yuliang, Burn, Paul L., Gentle, Ian R., James, Michael, Nelson, Andrew and Meredith, Paul (2013) Correlation of diffusion and performance in sequentially processed P3HT/PCBM heterojunction films by time-resolved neutron reflectometry. Journal of Materials Chemistry C, 1 14: 2593-2598. doi:10.1039/c3tc00063j

Attached Files (Some files may be inaccessible until you login with your UQ eSpace credentials)
Name Description MIMEType Size Downloads
UQ295995_peer_review.pdf HERDC evidence - not publicly available application/pdf 101.12KB 2

Author Lee, Kwan H.
Zhang, Yuliang
Burn, Paul L.
Gentle, Ian R.
James, Michael
Nelson, Andrew
Meredith, Paul
Title Correlation of diffusion and performance in sequentially processed P3HT/PCBM heterojunction films by time-resolved neutron reflectometry
Journal name Journal of Materials Chemistry C   Check publisher's open access policy
ISSN 2050-7526
2050-7534
Publication date 2013-04-14
Year available 2013
Sub-type Article (original research)
DOI 10.1039/c3tc00063j
Open Access Status Not Open Access
Volume 1
Issue 14
Start page 2593
End page 2598
Total pages 6
Place of publication Cambridge, United Kingdom
Publisher RSC Publications
Collection year 2014
Language eng
Formatted abstract
Control over the structure of donor/acceptor blends is essential for the development of solution processable organic solar cells (OSCs). We have used time-resolved neutron reflectometry (NR) and in situ annealing to investigate the nanoscale structure and interdiffusion of sequentially spin-coated thin films of poly(3-n-hexylthiophene-2,5-diyl) (P3HT)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and correlated the evolving structure with the device performance. While the as-prepared film shows a clear two-layer structure it is evident that (19 wt%) PCBM has percolated throughout the lower P3HT layer. Upon heating, analysis of time-resolved NR data shows that the diffusion process is dependent on the annealing temperature. At temperatures up to 110 °C, the two-layer structure is retained and only a small amount of PCBM diffuses from the interface into the lower layer, increasing the total PCBM content throughout the P3HT layer to 26 wt%. Significantly, this small change in acceptor content leads to a profound increase in device performance; with the power conversion efficiency (PCE) of the OSCs increasing from 0.47% (unannealed, 19 wt% PCBM) to 3.23% (annealed, 26 wt% PCBM) with the latter showing a similar efficiency to devices prepared from a blend containing 50 wt% PCBM. Further annealing at 120 and 130 °C sees rapid interdiffusion between the two layers, along with an overall expansion in the thickness of the bilayer film. Despite the complete intermixing of the PCBM and P3HT to form a structure resembling a bulk heterojunction, essentially no improvement in device performance was observed for annealing at temperatures above 110 °C.
Keyword Polymer solar-cells
Nanoscale phase-separation
Morphology evolution
Reflectivity
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
Official 2014 Collection
School of Chemistry and Molecular Biosciences
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 19 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 19 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Fri, 05 Apr 2013, 13:20:58 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences