Regio-asymmetric polymers based on fluorinated benzothiadiazole-benzodithiophene for polymer solar cells with a high open-circuit voltage
Two regio-asymmetric polymers PR2F and PR1F with three repeat units A-D-A, π-D-A, and π-D-π along the polymer backbone were obtained by polymerizing different fluorinated benzothiadiazole-thiophene units, FBT-T and 2FBT-T units (A-π), with a benzodithiophene unit (D), respectively. Here, the new reg...
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Published in | New journal of chemistry Vol. 43; no. 9; pp. 381 - 389 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
CAMBRIDGE
Royal Soc Chemistry
25.02.2019
Royal Society of Chemistry |
Subjects | |
Online Access | Get full text |
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Summary: | Two regio-asymmetric polymers
PR2F
and
PR1F
with three repeat units A-D-A, π-D-A, and π-D-π along the polymer backbone were obtained by polymerizing different fluorinated benzothiadiazole-thiophene units, FBT-T and 2FBT-T units (A-π), with a benzodithiophene unit (D), respectively. Here, the new regio-asymmetric polymers were different from traditional polymers featuring a D-A or D-π-A-π backbone. Both the regio-asymmetric polymers showed a low lying HOMO energy level in relation to that of the PC
61
BM acceptor and then a high open-circuit voltage of ∼1 V was observed in both
PR2F
and
PR1F
devices. Bulk-heterojunction devices based on
PR2F
with difluorinated BT exhibited an appreciable power conversion efficiency (PCE) of 4.73% due to the relatively high and balanced charge carrier mobilities, while the mono-fluorinated BT polymer
PR1F
-based devices showed a lower PCE of 2.92%. These results indicate that the regio-asymmetric conjugated polymers are a promising class of materials for polymer solar cell applications, and it is significant to further understand the influence of the polymer structure on the optoelectronic properties.
Regio-asymmetric polymer
PR2F
-based devices with SVA exhibited an appreciable PCE of 4.73% with a high
V
OC
of 0.98 V. |
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ISSN: | 1144-0546 1369-9261 |
DOI: | 10.1039/c9nj00001a |