π–π Stacking Distance and Phase Separation Controlled Efficiency in Stable All-Polymer Solar Cells
[3];
[4];
- Linköping University, Linköping (Sweden). IFM. Biomolecular and Organic Electronics; Xi'an Jiaotong Univ., Shaanxi (China). State Key Lab. for Mechanical Behavior of Materials
- Xi'an Jiaotong Univ., Shaanxi (China). State Key Lab. for Mechanical Behavior of Materials
- Linköping University, Linköping (Sweden). IFM. Biomolecular and Organic Electronics
- Linköping University, Linköping (Sweden). IFM. Division of Surface Physics and Chemistry
- Linköping University, Linköping (Sweden). IFM. Biomolecular and Organic Electronics; Nanjing Univ. (China). Key Lab. of Flexible Electronics (KLOFE) & Inst. of Advanced materials (IAM)
The morphology of the active layer plays a crucial role in determining device performance and stability for organic solar cells. All-polymer solar cells (All-PSCs), showing robust and stable morphologies, have been proven to give better thermal stability than their fullerene counterparts. However, outstanding thermal stability is not always the case for polymer blends, and the limiting factors responsible for the poor thermal stability in some All-PSCs, and how to obtain higher efficiency without losing stability, still remain unclear. By studying the morphology of poly [2,3-bis (3-octyloxyphenyl) quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl](TQ1)/poly[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl]] (PCE10)/PNDI-T10 blend systems, we found that the rearranged molecular packing structure and phase separation were mainly responsible for the poor thermal stability in devices containing PCE10. The TQ1/PNDI-T10 devices exhibited an improved PCE with a decreased π–π stacking distance after thermal annealing; PCE10/PNDI-T10 devices showed a better pristine PCE, however, thermal annealing induced the increased π–π stacking distance and thus inferior hole conductivity, leading to a decreased PCE. Thus, a maximum PCE could be achieved in a TQ1/PCE10/PNDI-T10 (1/1/1) ternary system after thermal annealing resulting from their favorable molecular interaction and the trade-off of molecular packing structure variations between TQ1 and PCE10. This indicates that a route to efficient and thermal stable All-PSCs can be achieved in a ternary blend by using material with excellent pristine efficiency, combined with another material showing improved efficiency under thermal annealing.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1628524
- Journal Information:
- Polymers, Vol. 11, Issue 10; ISSN 2073-4360
- Publisher:
- MDPICopyright Statement
- Country of Publication:
- United States
- Language:
- English
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