Journal article 990 views
Morphology-performance relationships in polymer/fullerene blends probed by complementary characterisation techniques – effects of nanowire formation and subsequent thermal annealing
,
Craig E. Murphy,
Myungsun Sim,
Kilwon Cho,
James Durrant ,
Ji-Seon Kim
Journal of Materials Chemistry C, Volume: 3, Issue: 35, Pages: 9224 - 9232
Swansea University Authors:
Wing Chung Tsoi , James Durrant
Full text not available from this repository: check for access using links below.
DOI (Published version): 10.1039/C5TC01720C
Abstract
We report detailed analysis of the thin film morphology (molecular packing, molecular conformational order, and vertical phase separation) – performance (charge transport, photocurrent generation, and photovoltaic performance) relationships under nanowire formation and subsequent thermal annealing i...
| Published in: | Journal of Materials Chemistry C |
|---|---|
| ISSN: | 2050-7526 2050-7534 |
| Published: |
2015
|
| Online Access: |
Check full text
|
| URI: | https://cronfa.swan.ac.uk/Record/cronfa32051 |
| Abstract: |
We report detailed analysis of the thin film morphology (molecular packing, molecular conformational order, and vertical phase separation) – performance (charge transport, photocurrent generation, and photovoltaic performance) relationships under nanowire formation and subsequent thermal annealing in polymer:fullerene blends. Nanowires of poly(3-hexylthiophene) (P3HT) are formed by controlled precipitation from solution and blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) to form bulk heterojunction thin films. The formation of nanowires and further thermal annealing result in increased molecular order of the P3HT, where the short-range conformational order is maximised by annealing at 100 °C and decreases when annealed at higher temperatures, but the quality of long-range molecular packing and lamellar packing distance increase with annealing temperature up to 150 °C. The long-range order correlates strongly with an increase in hole mobility, but the reduction in short-range conformational order indicates a slight reduction in planarity of the conjugated backbone in this aggregated polymer morphology. Photoconductive atomic force microscopy reveals enhanced connectivity of the hole transporting nanowire network as a result of thermal annealing. Additionally, we find that the nanowire morphology results in a favourable vertical phase separation, with PCBM enrichment at the electron-extracting surface in the conventional architecture, which is contrary to the non-nanowire case. This effect is further encouraged by thermal annealing, resulting in an enhancement of open-circuit voltage, and represents a morphological advantage over conventional P3HT:PCBM devices. Our study identifies an important interplay between long-range and short-range molecular order in charge generation, transport, extraction, and hence solar cell device performance. |
|---|---|
| College: |
Faculty of Science and Engineering |
| Issue: |
35 |
| Start Page: |
9224 |
| End Page: |
9232 |