Journal article 857 views 135 downloads
Photo-stability study of a solution-processed small molecule solar cell system: correlation between molecular conformation and degradation
Michael J. Newman,
Emily M. Speller,
Jérémy Barbé,
Joel Luke,
Meng Li,
Zhe Li,
Zhao-Kui Wang,
Sagar Jain,
Ji-Seon Kim,
Harrison Ka Hin Lee,
Wing Chung Tsoi,
Wing Chung Tsoi 
Science and Technology of Advanced Materials, Volume: 19, Issue: 1, Pages: 194 - 202
Swansea University Authors:
Sagar Jain, Wing Chung Tsoi
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DOI (Published version): 10.1080/14686996.2018.1433948
Abstract
Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-proce...
| Published in: | Science and Technology of Advanced Materials |
|---|---|
| ISSN: | 1468-6996 1878-5514 |
| Published: |
2018
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa38806 |
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| Abstract: |
Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C71 butyric acid methyl ester (BTR:PC71BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase. We find that the burn-in behaviour is strongly correlated to the crystallinity of BTR. To look at the possible degradation mechanisms, we studied the fresh and photo-aged blend films with grazing incidence X-ray diffraction, UV-Vis absorbance, Raman spectroscopy, and photoluminescence (PL) spectroscopy. Although the crystallinity of BTR affects the performance drop during the burn-in period, the degradation is found not to originate from the crystallinity changes of the BTR phase, but correlates with changes in molecular conformation – rotation of the thiophene side chains, as resolved by Raman spectroscopy which could be correlated to slight photobleaching and changes in PL spectra. |
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| Keywords: |
Small molecule solar cells, BTR, photobleaching, burn-in, Raman spectroscopy, molecular conformation |
| College: |
Faculty of Science and Engineering |
| Issue: |
1 |
| Start Page: |
194 |
| End Page: |
202 |