Abstract
There is a need to find electron acceptors for organic photovoltaics that are not based on fullerene derivatives since fullerenes have a small band gap that limits the open-circuit voltage (VOC), do not absorb strongly and are expensive. Here, a phenylimide-based acceptor molecule, 4,7-bis(4-(N-hexyl-phthalimide)vinyl)benzo[c]1,2,5-thiadiazole (HPI-BT), that can be used to make solar cells with VOC values up to 1.11 V and power conversion efficiencies up to 3.7% with two thiophene polymers is demonstrated. An internal quantum efficiency of 56%, compared to 75-90% for polymer-fullerene devices, results from less efficient separation of geminate charge pairs. While favorable energetic offsets in the polymer-fullerene devices due to the formation of a disordered mixed phase are thought to improve charge separation, the low miscibility (
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1301426 |
| Journal | Advanced Energy Materials |
| Volume | 4 |
| Issue number | 12 |
| DOIs | |
| State | Published - Apr 23 2014 |
| Externally published | Yes |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledged KAUST grant number(s): KUS-C1–015–21
Acknowledgements: The authors would like to thank S. Himmelberger from Stanford University for his efforts in preparing field effect transistor devices from spin-coated HPI-BT films. They also thank T. Burke, K. Graham, S. Sweetnam, Z. Beiley, J. Bartelt and A. Salleo for fruitful discussions regarding the morphological model presented here. This work was supported by funds provided by the Global Climate and Energy Project (GCEP) Award No. 1138721 and by the Center for Advanced Molecular Photovoltaics (CAMP), Award No. KUS-C1–015–21 made by the King Abdullah University of Science and Technology.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.