In:
Israel Journal of Chemistry, Wiley, Vol. 54, No. 5-6 ( 2014-06), p. 650-673
Abstract:
Donoracceptor blends of conjugated polymers (CPs) are workhorse materials for the state‐of‐the‐art polymer solar cells. Although earlier it was suggested that charge transfer in these blends occurred only in the excited electronic state, a body of evidence for ground‐state charge transfer and the corresponding charge‐transfer complex (CTC) formation has been reported in the last decade. In some CP:acceptor blends, the CTC is pronounced and can be noticed visually as a colour change, while in more common CP:fullerene blends it is very weak. However, in both, the CTC governs charge separation, which is the key photophysical process for organic solar cells, through so‐called charge‐transfer states. Moreover, the pronounced CTC can substantially modify the blend properties: extend the blend absorption in the red and infrared regions, change the morphology to facilitate donoracceptor intermixing, stimulate polymer self‐organization and ordering, and increase the polymer photooxidation stability. Addition of one of the strongest organic acceptors, 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F 4 ‐TCNQ), to the CP:fullerene blend is an example of organic doping (a CTC with full charge transfer), improving the blend structural and electronic properties and finally the solar cell performance. In this review, we summarize the current knowledge on CTCs in various CP:acceptor blends and the impact of CTC on the blend properties and the device performance.
Type of Medium:
Online Resource
ISSN:
0021-2148
,
1869-5868
DOI:
10.1002/ijch.v54.5/6
DOI:
10.1002/ijch.201400063
Language:
English
Publisher:
Wiley
Publication Date:
2014
detail.hit.zdb_id:
2066481-3
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